i

OGWUEGBU, MERCY CHISARA

PG/M.Sc./14/76559

GROWTH PERFORMANCE, CARCASS TRAIT, ORGAN CHARACTERISTICS

AND LIPID PROFILE OF BROILERS FED DIETS CONTAINING

DIFFERENT FAT SOURCES

DEPARTMENT OF ANIMAL SCIENCE

FACULTY OF AGRICULTURE

Godwin Valentine

Digitally Signed by: Content manager’s Name

DN : CN = Webmaster’s name

O= University of Nigeria, Nsukka

OU = Innovation Centre

ii

GROWTH PERFORMANCE, CARCASS TRAIT, ORGAN CHARACTERISTICS

AND LIPID PROFILE OF BROILERS FED DIETS CONTAINING

DIFFERENT FAT SOURCES

BY

OGWUEGBU, MERCY CHISARA

PG/M.Sc./14/76559

DEPARTMENT OF ANIMAL SCIENCE,

FACULTY OF AGRICULTURE,

UNIVERSITY OF NIGERIA, NSUKKA

MARCH, 2016

i

GROWTH PERFORMANCE, CARCASS TRAIT, ORGAN CHARACTERISTICS

AND LIPID PROFILE OF BROILERS FED DIETS CONTAINING

DIFFERENT FAT SOURCES

A PROJECT SUBMITTED TO THE DEPARTMENT OF ANIMAL SCIENCE,

UNIVERSITY OF NIGERIA, NSUKKA, IN PARTIAL FULFILLMENT OF THE

REQUIREMENTS FOR AWARD OF DEGREE OF MASTER OF SCIENCE (M.Sc.) IN

ANIMAL SCIENCE, (ANIMAL NUTRITION AND BIOCHEMISTRY) OF THE

UNIVERSITY OF NIGERIA, NSUKKA.

BY

OGWUEGBU, MERCY CHISARA

PG/M.Sc./14/76559

SUPERVISORS: DR. A.O. ANI

MARCH, 2016.

ii

CERTIFICATION

I, OGWUEGBU, MERCY CHISARA, a postgraduate student in the Department of Animal

Science, with registration number, PG/M.Sc/14/76559, have satisfactorily completed the

requirements for research work for the award of the degree of Masters of Science in the

Department of Animal Science (Nutrition and Biochemistry). This work is original and has

not been submitted in part or full for any other diploma or degree of this or any other

University.

_________________ ______________

Ogwuegbu, Mercy C.

Student Date

__________________ ________________

Dr. A.O. Ani Date

Supervisor

________________ ________________

Prof. A.G. Ezekwe Date

H.O.D

__________________ ________________

External examiner Date

iii

DEDICATION

This work is dedicated to God the Father, God the Son and God the Holy Spirit.

iv

ACKNOWLEDGEMENT

My profound gratitude and indebtedness are first and foremost to His Majesty, God Almighty

for His sufficient grace and incomparable mercy towards me even before the world began. I

am also indebted to a number of distinguished personalities who helped me in measures to

make this research work a success. I owe a lot of gratitude to my supervisor, Dr. A.O. Ani for

his kindness, support, assistance, encouragement, patience and unique approach to

instructions and teachings. My sincere prayer is that your aim of bringing out the best in me

will not be thwarted. God bless you daddy.

I wish to appreciate my Head of Department, Prof. A.G Ezekwe for providing a sound

atmosphere for learning. Remain blessed Sir. I wish also to appreciate these dynamic and

erudite Professors- D.N. Onah of Veterinary Medicine, C.C Nwosu, G.C. Okeke and S.O.C.

Ugwu of the Department of Animal Science, University of Nigeria, Nsukka for their humane

approach to teaching and fatherly advice. Also recognized are: Dr. A.E. Onyimonyi, Dr.

(Mrs.) H.N. Folhngu, Mr. O.C. Osita and all members and staff of the Department of Animal

Science, UNN for their concern and input in one way or the other which have enabled me

achieve this feat, May God bless them.

To my parents, Mr. and Mrs. I.O Ogwuegbu, and my lovely siblings: Onyekachukwu and

Makuochukwu who always believed in me and my ability to attain greater height in life, I

want to say a big thank you for your support and encouragement, I love you all.

I will not forget my friends and colleagues: Micheal, Akumjika, Ogumba, Prisca,

Omumabuike, Jecinta, Egom, Marvin, Odo, Kenneth, Ilekuba, Chineye, etc. for all your

constructive criticisms, suggestions and ideas. Space will fail me to mention all. Thank you

enough.

My special thanks go also to all the members of Graduate Students’ Fellowship (GSF) UNN

for your prayers and encouragement. You are indeed a wonderful family. Remain blessed.

Meet you all at the top.

v

TABLE OF CONTENTS

Title page i

Certification ii

Dedication iii

Acknowledgement iv

Table of Contents v

List of Tables vii

Abstract viii

CHAPTER ONE: INTRODUCTION

1.1 Background of the study 1

1.2 Objectives of the study 2

1.3 Justification 2

CHAPTER TWO: LITERATURE REVIEW

2.1 Poultry Nutrition 3

2.2 Broilers 3

2.3 Nutrient Requirements for broilers 5

2.3.1 Energy 5

2.3.2 Protein and amino acids 7

2.3.3 Water 10

2.3.4 Minerals 10

2.3.5 Vitamins 11

2.4 Lipids in poultry nutrition 11

2.4.1 Lipid digestion 13

2.42 Lipid absorption 13

2.5 Dietary fats in poultry nutrition 15

2.5.1 Importance of dietary fats to poultry 16

2.5.2 Advantages of dietary fat supplementation 16

2.5.3 Fats Digestibility in young chicks 19

2.5.4 Efficient utilization of dietary fats 20

2.6 Sources of dietary fats in poultry nutrition 21

2.7 Effects of dietary fats on poultry performance 30

vi

2.8 Lipid profile 32

CHAPTER THREE: MATERIALS AND METHODS

3.1 Location and duration of study 37

3.2 Experimental materials 37

3.3 Experimental diets 37

3.4 Experimental animals and managements 37

3.5 Data collection and measurements 40

3.6 Carcass and Organ evaluation 40

3.7 Blood collection and analysis 40

3.8 Experimental Design 41

3.9 Proximate Analysis 42

3.10 Statistical analysis 42

CHAPTER FOUR: RESULTS AND DISCUSSION

4.1 Results 43

4.1.1 Proximate composition of experimental diets 43

4.1.2 Growth performance of broiler birds fed diets containing different fat sources 44

4.1.3 Carcass and organ characteristics of broiler birds fed diets containing different fat sources 47

4.1.4 Relative organ weight of broiler birds fed diets containing different fat sources 49

4.1.5 Lipid profile of broiler birds fed diets containing different fat sources 50

4.2 Discussion 52

4.2.1 Growth performance of broiler birds fed diets containing different fat sources 52

4.2.2 Carcass and organ characteristics of broiler birds fed diets containing different fat sources 53

4.2.3 Relative organ weights of broiler birds fed diets containing different fat sources 55

4.2.4 Lipid profile of broiler birds fed diets containing different fat sources 55

CHAPTER FIVE: SUMMARY AND DISCUSSION

5.1 Summary 57

5.2 Conclusion 58

5.3 Recommendation 58

References 59

Appendices 73

vii

LIST OF TABLES

Table page

1: Amino acid requirement at different ages of broiler birds 9

2: Percentage composition of broiler starter diets 38

3: Percentage composition of broiler birds finisher diets 39

4: Proximate composition of experimental diets 43

5: Growth performance of broiler birds fed diets containing different fat sources 44

6: Carcass and organ characteristics of broiler birds fed diets containing different fat

sources 47

7: Relative organ weights of broiler birds fed diet containing different fat sources 49

8: Lipid profile of broiler birds fed diets containing different fat sources 50

viii

ABSTRACT

This study was conducted to determine the effect of four different fat sources on growth performance, carcass trait, and organ characteristics and lipid profile of broiler birds reared to 8weeks of age. One hundred and twenty day-old broiler chicks were randomly assigned to five treatments, each with three replicates of 8 chicks in a completely randomized design experiment. The dietary treatments consisted of 1% added fat from four different sources as follows: T1, diet containing no oil; T2 diet containing 1% palm oil; T3, diet containing 1% soybean oil; T4, diet containing 1% palm kernel oil and T5, diet containing 1% groundnut oil. Dietary fat type affected significantly (p<0.05) body weight gain as well as feed efficiency in birds fed the palm kernel oil diet compared with those fed the other diets. The live weight, carcass weight and dressing % of birds on T4 was significantly different (p<0.05) from all other treatments. Most of the internal organ weights of birds on T4 and T1 were significantly (p<0.05) higher than in other treatments. The abdominal fat weight of birds on T4 was significantly (p<0.05) higher than those in the other treatment. Dietary treatment had significant effect on all the parameters evaluated in the lipid profile. Birds on T4 had significantly (p<0.05) higher level of total cholesterol while birds on T3 had lower level of triglyceride. Birds on T2 and T3 had similar (p>0.05) values of Low Density Lipoprotein cholesterol while the least value was observed in the control group. Birds on T2 had the highest High Density Lipoprotein Cholesterol though this was similar to the values observed in T1 and T4. Based on the results obtained in the present study it was concluded that addition of vegetable fat from palm kernel oil and groundnut oil in broiler diets enhanced the growth performance, carcass and organ weights of birds. Birds that consumed the diets containing soybean oil had the least very low density lipoprotein, while those that consumed diet containing palm kernel oil had similar High Density Lipoprotein Cholesterol value with birds on control.

1

CHAPTER ONE

INTRODUCTION

1.1 Background of the Study

The broiler industry has been developed worldwide to the most intensive and efficient model

in comparison to other animal production sectors. The rapid growth, efficient utilization of

feed, tender meat production, ability to thrives and produce under varied environmental

conditions have been achieved through advanced genetic improvement of the modern broiler

chicken. The energy intake of the fast growing broiler chickens fed ad libitum is estimated to

reach two or three times greater than their maintenance needs; and so carcass fat deposition

increases, causing broiler metabolic and skeletal disorders, beside its undesirable effect on

human health. Current commercial hybrids of broiler with high performance require high

energy diets, which would enable the maximum exploitation of their genetic potential.

Increasing demands for energy in growing chickens can be satisfied by the addition of fat to

the feeding mixtures. An increasing supplementation of diets with animal or plant fats or oils

for intensive poultry production has been observed (Sadeghi and Tabeidian, 2005).

The inclusion of fats and oil in animal feed is a common practice in modern poultry

production to increase the energy content of diet. Besides supplying energy, it improves the

absorption of fat-soluble vitamins (Baiao and Lara, 2005), provides essential fatty acids in

large quantity, diminishes the dustiness, increases the palatability of the rations and improves

the energy efficiency (Moav, 1995; Palmquist, 2002). Furthermore, dietary fat reduces

passage rate of the digesta through the gastrointestinal trait, allowing for better nutrient

absorption and utilization (Peebles et al., 2000; Baião and Lara, 2005; Latshaw, 2008).

Digestibility of dietary fats is affected by the fatty acid profiles and several studies have

shown better utilization of unsaturated fats leading to a higher metabolizing energy than

saturated fats (Celebi and Utlu, 2004). Jeffri et al. (2010) reported that increasing fat in

broiler diet will increase the amount of feed intake and feed efficiency.

2

To date, a number of different fat sources are available for poultry from both animal and

vegetable sources and from the rendering industry (Sanz et al., 2000). According to Rose

(2001), animal fat or vegetable oils may be used as a source of energy up to a maximum of

6% in the diet. Above this level it becomes difficult to maintain pellet quality, or to move

mechanically the sticky feed when it is not pelleted.

1.2 Objectives of the Study

The broad objective of the study is to evaluate the effect of dietary fat sources on growth

performance, carcass trait, organ characteristics and lipid profile of broilers.

Specific Objectives:

1. To determine the growth performance of broiler birds fed diets containing different

fat sources.

2. To determine the carcass and organ characteristics of broiler birds fed diets

containing different fat sources.

3. To evaluate the lipid profile of broiler birds fed diets containing different fat sources.

1.3 Justification of the Study

Broilers have unique potential as possible solution to Nigeria meat supply situation because

of some attributes like high growth rate, high efficient carcass yield, short production cycle

and good quality meat. Despite all these attributes, the productivity of poultry in Nigeria has

been low due to the problem of poor utilization of feed and high cost of feed. Current

commercial hybrids with high performance require high energy diets, which enable the

maximum exploitation of their genetic potential. Because of the increasing demand of energy

in growing chicks and the high cost of energy feed ingredient, the addition of fat or oil in low

energy feed can help increase the energy content of the feed and as well reduce the cost.

Besides fat metabolism and deposition in poultry can be affected by different dietary fat

intake and this can lead to poor nutrient absorption and utilization (Sanz et al., 1999; Peebles

et al., 2000; Balao and Lara, 2005).

3

CHAPTER TWO

LITERATURE REVIEW

2.1 Poultry Nutrition

The nutrition of animal involves various activities that result in the conversion of feed into

animal tissues or animal products, for example egg, milk, meat etc (Richard and Church,

1998). Pond et al. (1995) defined nutrition as a series of processes by which an organism

takes and assimilates food for promoting growth and replacing worn-out tissue. Also Obioha

(1992) defined nutrition as a process which a living organism takes in is used primarily for

two major purposes; maintenance and productive function.

Olomu (1995) emphasized that poultry nutrition is more critical than other farm animal

(except pig) because poultry birds are usually reared in confinement. Poultry are more active

and more sensitive to environmental influences than other farm animals. According to

Obioha (1992), Poultry have high growth rate, intensive metabolic rates and rapid developed

reproductive organ. He further reported that during the first ten weeks of post embryonic

growth, the weight of broilers increases for about thirty to forty times and that such rate of

growth has not been encountered in other farm animals.

The ultimate aim of poultry nutrition is to increase the productive efficiency of the poultry.

The economic importance of poultry feeding has become apparent, when it was realized that

feed is the highest single cost factor, about two third of the total production cost. Many cases

of poultry business failures can be traced to poor or improper feeding of the birds. Therefore,

it is pertinent that the right nutrients in adequate quantities and proportions must be supplied

to the birds. According to Richard and Church (1998), quality of ingredients as well as

quality of nutrients present must be evaluated.

2.2. Broilers

Broilers, also known as Cornish Cross, are a type of chicken raised specifically for meat

production. Produced by fast-growing breeds with low mortality, broilers can be reared

successfully in standard housing conditions on readily available, custom-formulated broiler

feed rations. Consumers expect the meat from broilers to be tender and of high quality. The

whole broiler production process is designed for this requirement but the same inputs are at

4

odds with those required for egg production by broiler breeders. The three main steps and

stages in the whole broiler production process are

• Rearing and managing broiler breeders (i.e. the birds that produce eggs for hatching

into broiler chicks)

• Fattening of broiler chicks

• Marketing and processing of finished broiler birds.

The broiler producer clearly requires birds that will achieve a high body weight, with good

carcass quality, over the shortest possible period of time using the minimum amount of

regular feed. In addition the producer also wants birds that posses the correct body

conformation, which will feather rapidly and have a minimal mortality rate.

Selection and breeding for fast growth rates in broilers form the most important processes in

the world poultry industry. Male broilers achieve rapid gain from the start, and at 6 weeks of

age can weigh at 2kg (live weight). Female birds will tend to grow at a slower rate but this

has definite marketing advantages because overall consumer demand is for broiler carcasses

of various weights. It is not the amount of feed consumed but the efficiency of feed

utilization and feed conversion into body tissue which underpins the growth rate.

Broilers producers tend to plump for white feathered strains because they result in a ‘cleaner-

looking ’carcass after processing. But there are instances where production management

considerations outweigh this and coloured-feathered strains are preferred. Examples include

broiler production in countries with high rainfall and the indigenous soil is red. In these

situations, red/brown Rohde Island Reds may be the most sensible choice. Feather cover

must be good to maintain insulation and restrict heat loss from the body, as well as

minimizing incidence of skin blistering which ruins marketability of processed birds. Many

modern strains of broilers will produce yellow fat because they have been custom-bred for

the American market. In markets where yellow fat is undesirable, producers should remove

carotene and carotenoid pigments (coloured chemical) from the ration. Similarly, factors that

determine carcass quality in one country may not suit another. For instance, consumers in

some countries may consider the body conformation, texture and taste of carcasses high

quality by ‘Western’ standards to offer an unattractive and insufficiently chewy eating

experience. For supermarket sales in general, breast meat should be broad and deep. Many

5

such problems are overcome by incorporating local strains into cross breeding programmes

to produce appropriate broiler parents stock.

2.3. Nutrients Requirement for Broilers

Poultry diets must be formulated to provided all the bird’s nutrient requirements if optimum

growth and production is to be achieved. On the basis of physiology structures of the poultry,

a good knowledge of the digestive system of birds could put the producer in a serious

problem. Nutrient can be defined as chemical substances found in feed ingredients which

when made available to the animal are used for maintenance, production and health of the

animals (Atteh, 2002). It can also be described as a specific chemical element or compound

supplied by or derived from the diet and absorbed into the body tissues to support

physiological processes. These nutrients are essential to be in appropriate amounts and

proportions in the diets of intensively housed birds, because they have no access to other

sources of nutrients. The essential nutrients required by the poultry birds are carbohydrates,

fat and oil (mostly served as energy givers); protein (amino acid), minerals (micro and

macro), vitamins and water (Pond et al., 1995; Olomu, 1995 and Smith, 2001).

The dietary requirement of nutrients varies with age, bodyweight and rate of growth of the

birds. Thus the requirement for any nutrient may be defined as the amount of that nutrient

which must be supplied in the diet to meet the needs of the normal healthy animal given on

otherwise completely adequate diet in an environment compatible with good health (Olomu,

1995). Such level of nutrient must meet the requirement for maintenance, growth, productive

and reproductive potential of the animal (NRC, 1994).

2.3.1. Energy

Energy is not a nutrient but a property of energy- yielding nutrients when they are oxidized

during metabolism. The dietary energy levels have been shown to affect broiler chickens’

feed intake. Nahashan et al. (2001) reported that as dietary energy level increases, birds

satisfy their energy needs by decreasing feed intake. Decreased in feed intake with high

energy levels in the diets of broiler chickens have also been reported by Leeson and

Summers (2001) and Veldkamp et al.,(2005). Thus, in formulating poultry diets, the nutrient

requirements of broiler chickens have frequently been expressed per unit of dietary

metabolisable energy (Gonzalez and Pesti, 1993). This practice is based on the theory that

6

birds will adjust their feed intake according to their metabolisable energy requirements and

was summarized by the NRC (1994) as an absolute requirement for energy in terms of

kilocalories per kilogram of diet cannot be stated because poultry adjust their feed intake to

obtain their necessary daily requirement.

Also, based on a re-evaluation of numerous research data, the NRC (1994) has revised their

previous conclusions by stating that the practice of relating nutrient concentrations as a

function of dietary metabolisable energy concentration while, as a result of the over-

consumption of energy on diets with a high metabolisable energy concentration, the

application of specific nutrient-to-metabolisable energy rations in broiler chickens and

turkeys should be re-evaluated. Leeson et al. (1996) showed that broiler chickens fed up to

25 and 49 days of age were able to adjust their feed intake to a constant energy intake over a

range of dietary metabolisable energy levels from 11.29 to 13.80 MJ ME/kg DM, which

indicated that broiler chickens retain an innate ability to eat to a fixed energy requirement

rather than to physical capacity as was suggested by Newcombe and Summers (1984).

However, on closer observation of the data of Leeson et al (1996), it can be seen that early

feed intake to 25 days of age was not greatly affected by dietary metabolisable energy

concentrations over the range of 12.13 to 13.80 MJ ME/kg DM that a significant increase in

feed intake occurred. Also, the effects of metabolisable energy concentration on feed intake

were very different between the early (0-25 days) and later (26-49 days) growth periods, with

the metabolisable energy concentration having a far greater effect on increasing feed intake

during the grower-finisher phase. This led to the overall conclusion by these authors that

broiler chickens do indeed eat to a constant metabolisable energy intake when viewed over

the entire 49-day growing period.

Contrary to the observation above, Richard (2003) observed that modern broiler chickens

selected for rapid growth do not regulate voluntary feed intake to achieve energy balance.

This altered ability of broiler chickens to adjust feed intake due to differences in

metabolisable energy density of the diet was postulated to result from continued selection for

rapid juvenile growth rates, which may have altered hypothalamic mechanisms that regulate

feed intake in broiler chickens (Bokkers and Koene, 2003). Other reports have also shown no

effect of dietary metaboisable energy concentration on feed intake between two groups of

7

broiler chickens fed ad-libitum diets containing two energy levels of 13.38 and 15 MJ ME/

kg DM.

2.3.2. Protein and Amino Acid

Dietary requirements for protein are actually requirements for the amino acids contained in

the dietary protein. Amino acids obtained from dietary protein are used by poultry to fulfill a

diversity of functions. For example, amino acids, as protein, are primary constituents of

structural and protective tissues, such as feather, bone matrix and ligaments, as well as of the

soft tissues, including organs and muscles. Also, amino acids and small peptides resulting

from digestion-absorption may serve a variety of metabolic functions and as precursors of

many important nonprotein body constituents. Because body proteins are in a dynamic state,

with synthesis and degradation occurring continuously, an adequate intake of dietary amino

acids is required. If dietary protein (amino acids) is inadequate, there is a reduction or

cessation of growth or productivity and a withdrawal of protein from less vital body tissues

to maintain the functions of more vital tissues.

There are 22 amino acids in body proteins and all are physiologically essential (NRC, 1994).

Nutritionally, ten of these are indispensable because chickens are unable to synthesize them

or cannot synthesize them at a rate sufficient to meet their needs. These are methionine,

lysine, threonine, leucine, valine, isoleucine, arginine, phenylalanine, histidine and

tryptophan (Austic, 1995; NRC, 1994).

The amino acid requirements of poultry represent the requirements for the indispensable

amino acids plus sufficient nitrogen in an appropriate chemical form for synthesis of the

dispensable amino acids. Chickens are sensitive to the dietary balance of these amino acids

(Austic, 1995). For the diet to be used with maximum efficiency the chicken must receive the

indispensable amino acids in the correct quantities and sufficient amino acids for metabolic

demands must be available. The presence of adequate amounts of nonessential amino acids in

the diets reduces the necessity of synthesizing them from essential amino acids. Amino acid

requirements may be classified as those for maintenance, carcass growth, egg production and

feather growth on the basis of their respective amino acid profiles (Hurwitz et al., 1978). In

8

order for the bird to realize its genetic potential and achieve the best levels of performance

through maximum rates of protein synthesis, amino acids must be provided in the necessary

quantities, avoiding both excesses and deficiencies (Sainbury, 1984). Thus, stating dietary

requirements for both protein and essential amino acids is an appropriate ways to ensure that

all amino acids needed physiologically are provided. Protein and amino acid requirements

vary considerably according to the physiological state of the bird, that is, the rate of growth

or egg production. Other factors contributing to variations in amino acid requirements of the

chickens include age, body size, sex and breed. Amino acid requirements decrease with age

and at the same time, the ideal balance of amino acids changes gradually to reflect those of

maintenance (Zubair and Leeson, 1996). For instance, the percentage of amino acid required

in the diet is the highest for young growing animals and gradually to maturity, when only

enough amino acid to maintain body tissue is required (Pond et al., 1995). The balance of

amino acids needed for maintenance is not proportional to the balance of amino acids in a

bird’s tissue, but rather reflects the relative rate of obligatory loss of each individual amino

acid (Gous et al., 1987).

Because of this reason, the balance needed for maintenance is considerably different from

that needed for growth or egg production (Nemavhola, 2001). Dietary amino acid levels

slightly below maintenance can sustain life, but muscle mass and functions are impaired

(Leeson et al., 1996). Matching the amino acid profile of the diet with animal requirements is

crucial for maximizing animal performance. For instance, turkey poults and broiler chickens

have high amino acid requirements to meet the needs for rapid growth while indigenous

chickens such as the Venda breed will require less amino acid to meet their needs because of

their slow growth rate and small body size. Because the contributions of maintenance and

growth to total amino acid requirement change with body size and the ideal amino acid

profiles for maintenance and growth are different, the composition of the ideal amino acid

pattern will change continuously during the growth period (Mack et al., 1999).

9

Table 1: Amino acid requirement (g kg-1 feed) at different ages of broiler chickens

Amino acid Starter Finisher

Arginine 14.4 12.0

Glycine+ Serine 15.0 10.0

Histidine 3.5 3.0

Isoleucine 8.0 7.0

Leucine 13.5 11.8

Lysine 12.0 10.0

Methionine+Cystine 9.3 7.2

Methionine 5.0 3.8

Phenylalanine+Tyrosine 13.4 17.7

Phenylalanine 7.2 6.3

Threonine 8.0 7.4

Tryptophan 2.3 1.8

Valine 8.2 7.2

Source: NRC (1994)

Amino acid requirements at different ages of broiler chickens are shown in Table 1, it is now

well documented that male broiler chickens have higher dietary amino acid requirements

than females (Thomas et al., 1986; Han and Baker, 1993), because male chickens contain

more protein and less fat in their weight (Edwards et al., 1973; Han and Baker, 1993).

Unlike the effect of diet energy concentration, the effect of protein density on feed intake

responses in broiler chickens has not been consistent. Buyse et al. (1992) reported that broiler

chickens reared on lower protein density of 15% crude protein in the increased their feed

intake in an attempt to meet their protein requirement. Contrary to these findings, a decrease

in feed intake with reduced protein density has been reported in broiler chickens by Kemp et

al. (2005) and Berhe and Gous (2005). These authors observed that Ross 308 broiler

chickens decreased their feed intake as dietary protein content was reduced, resulting in a

lower growth rate.

10

2.3.3 Water

Water is one of the most important nutrients needed by broilers. Water constitutes more than

half of the weight of poultry meat and about two-third of the weight of egg (Ranjhan, 1981).

The newborn animal contains 750 to 800g of water per kg weight, though this falls to about

500g/kg in the matured fat animal (McDonald et al., 1995). Oluyemi and Roberts (2007)

reported that drinking water for poultry should be free from salt and toxic substances. He also

reported that the ratio of dry matter intake by poultry in a temperate environment is normally

1:2, but does depend to some extent on the diet. Thus, increase in protein level also increases

the water consumption of the birds.

Water is available in the feed (metabolisable water) but the bulk of water must be provided

separately in drinking cans or troughs. The water must be provided ad-libitum, clean and free

from excessive salts, which might have a laxative effect and must be cool. Olomu (1995)

suggested that 2 to 2.5 liters of water in the first two weeks is adequate for 100 chicks, this

doubled after another 2 weeks. In practice, the daily water consumption per 1000 broilers

ranges from 20 liters at one week of age to 380 liters at 8weeks of age. On very hot days, the

water consumption may be increased as much as three times of the water intake on cooler

days.

2.3.4 Minerals

Minerals are mainly inorganic components of feed. The body of animals contains large

number of mineral elements, which occur in combination with the organic constituents.

Chickens body contains about 4% mineral matter (Ranjhan, 1981). Phosphorus and calcium

are the two most abundant mineral elements in the bone and other skeletal components of the

birds.

Olomu (1995) classified mineral elements as macro and micro depending on the quantitative

requirement for each. Macro elements include; calcium, phosphorus, sodium, chlorine,

sulphur, magnesium and potassium while some of the micro-elements are iodine, zinc,

cobalt, iron, copper and molybdenum. Excess or deficiency of these mineral elements is

detrimental to the health and development of the birds. Minerals function in many ways such

11

as in body structural components and acid-base balance. Calcium and phosphorus have been

found to have closely related metabolic functions. The requirement of these minerals appears

to be higher for warm climates than for cold climates (Olomu, 1995). It is therefore

recommended that the level of calcium be increased from 1-1.2% to 4-4.5% and the level of

total phosphorus from 0.7-0.8% to 1-1.1% during periods of hot weather. Ranjhan (1981)

stated that mineral deficiency and over supply have serious adverse effects and could lead to

death of chicks. Thus, in practice 0.30-0.35% common salt or sodium chloride would take

care of the requirements for sodium and chlorine which must be supplied from sources other

than the normal ingredients used in formulating poultry diets.

2.3.5 Vitamins

Vitamins are organic compounds that cannot be synthesized in the poultry body and they are

required in extremely small quantities but absolutely essential for normal growth and health.

Oluyemi and Robert (2007) listed the vitamins required in poultry diets as follows: the fat

soluble- vitamins A, D, E and K and the water soluble vitamins- thiamine (B1), niacin,

riboflavin (B2), pyridoxine (B6), biotin, pantothenic acid, folic acid, choline, and vitamin B12.

Vitamin C can be synthesized in the body of birds but they are required as antistress in hot

environment.

The deficiency of these vitamins in the feed consumed by birds or non-availability of these

vitamins to the birds usually result in disease symptoms, such as rickets which is caused by

vitamin D deficiency associated with low or imbalance of calcium and or phosphrous level in

the diet; curled toe paralysis (Vitamin B12) and perosis associated with deficiency of choline

and biotin (Olomu, 1995). Deficiency of folic acid cause poor feathering, poor feather

pigmentation and anemia (Obioha, 1992).

2.4 Lipids in poultry Nutrition

Lipids are substances soluble in non-polar organic solvents (chloroform and ether) and

insoluble in water, which can be divided into four categories: simple, compound, derived and

terpenoids.

Simple lipids are esters of fatty acids and certain alcohols, particularly glycerol and

cholesterol. These can be divided into three classes: triglycerides, steroids, and waxes.

12

Triglycerides are constituted by glycerol esterified with three fatty acids and represent more

than 90% of the foods used in animal feeding. Steroids are lipids that cannot be saponified,

which means that heating in the presence of alkalis does not hydrolyze them; therefore soap

is not produced from their fatty acids. Sterols are the most abundant steroids, and cholesterol

is the main sterol of animal tissues (Ferreira, 1999). Waxes are esters of fatty acids with long-

chain alcohols and constitute the natural protecting coverage of leaves, stems, insects, skin,

feathers, hairs and also the structural material of beehives. They have no nutritional value,

since they are hydrophobic and cannot be degraded by the digestive enzymes of superior

animals (Ferreira, 1999). Compound lipids are esters of glycerol that contain two fatty acids

plus another chemical group such as choline or serine. The most important groups are the

phospholipids, which contain phosphate in their structures, whereas glycolipids have one

carbohydrate replacing a fatty acid, and lipoproteins, which constitute the principal means by

which lipids are transported in the blood (Leeson and Summers, 2001). Derived lipids

include substances with fatty acid, glycerol and with other alcohols that derive from simple

and compound lipids after hydrolysis (Ferreira, 1999). Terpenoids are characterized by a

repeating unity, which is the isopropene. This group includes the carotenoids, xantophylls,

tocopherols and vitamins A and K (Ferreira, 1999).

According to Fats in animal feed (1985), the so-called free fatty acids are not linked to

another organic component as the glycerol. The free fatty acids comprise a small fraction of

total lipids in natural foods. The physical and chemical properties of lipids are determined by

the composition of their fatty acids, and the length and saturation degree of the carbonic

chain.

The term saturated means the absence of double bonds, whereas unsaturated indicates the

presence of one or more double bonds. The identification and nomenclature of the main fatty

acids are represented on.

Birds are not able to synthesize all fatty acids and thus, some are considered essential fatty

acids. Linoleic (18:2, n-6) and linolenic (18:3, n-3) fatty acids are recognized as

metabolically essential. However, the linoleic acid is the only essential fatty acid whose diet

requirement has been demonstrated (National Research Council, 1994).

13

The increase in the length of the carbonic chain of saturated fatty acids increases the melting

point of the fat and the presence of the double bond decreases the melting point. The longer

is the chain, the smaller is the number of double bonds, and less soluble it will be in water.

The geometry of the double bond also influences the melting point. Trans fatty acids have

higher melting point than their cis isomers. The importance of knowing the fatty acid

composition of each lipidic source is as fundamental as knowing the carbonic chain length,

its saturation degree, and the position of the double bond. All of these factors influence the

digestion process (Fats in animal feeds, 1985).

2.4.1. Lipid Digestion

The digestion and absorption of fat in the chicken occurs mainly in the small intestine (Scott,

et al., 1982). The presence of digesta, with intact dietary fat in the duodenum, stimulates

cholecystokinin secretion, which in turn induces the secretion of pancreatic enzymes and bile

(Friedman and Nylund, 1980). While bile salts emulsify fat along with co-lipase providing

more surface area for the enzymes to act upon, lipase hydrolyses the emulsified triglycerides

on sn-1 and sn-3 positions to release monoglycerides and free fatty acids (Mu and Høy,

2004). Cholesterol esterase hydrolyses cholesterol-fatty acid esters into cholesterol and free

fatty acids (Mu and Høy, 2004). Also large amounts of endogenous phospholipids enter

through bile, predominantly phosphatidylcholine in addition to dietary phospholipids.

Phospholipase A2 cleaves phospholipids at the sn-2 position to release lysolecithins and free

fatty acids (Scott, et al., 1982).

2.4.2. Lipid Absorption

The main factor that affects the metabolizable energy value of oils and fats is their

digestibility, which is dependent on the following factors: the length of the carbonic chain,

the number of double bonds, the presence or absence of ester bonds (triglyceride or free fatty

acid), the specific arrangement of the saturated and unsaturated fatty acids on the glycerol

backbone, the composition of the free fatty acid, the composition of the diet, the type and

quantity of triglycerides supplemented in the diet, the intestinal flora, the sex and age of the

birds (Renner & Hill, 1961a; Leeson and Summers, 2001, Nascif et al., 2004).

14

The lipids arrive intact in the duodenum. The presence of food in the duodenum stimulates

the secretion of cholecystokinin, which induces the contraction of the gall bladder and the

secretion of the pancreatic juice, making the chyme. Colipase binds to the oil-water interface

and produces the emulsion. Afterwards, triglycerides undergo hydrolysis under the action of

the pancreatic lipase, and micelles are formed by monoglycerides, diglycerides and free fatty

acids. Micelles are able to solubilize high amounts of fatty acids of low polarity and fat-

soluble vitamins.

Monoglycerides and long-chain unsaturated fatty acids when linked to the conjugated bile

salts promptly form the micelles, whereas saturated fatty acids have less ability to form

micelles due to their characteristic low polarity. Since long-chain unsaturated fatty acids have

greater ability to form micelles, they may act synergistically in the absorption of saturated

fatty acids when mixed with them (Ferreira, 1999). Once inside the enterocytes,

monoglycerides and free fatty acids are re-esterified and combined with free and esterified

cholesterol, lipoprotein and phospholipids to form the so-called lipoproteins or chylomicrons

or still portomicrons. Thus, re-esterified triglycerides are taken from the digestive system to

the circulatory system of the bird in this form (Leeson & Summers, 2001).

As the lymphatic system of the birds is not well developed, the absorption route of the lipids

is through the portal venous system. Very Low density lipoproteins (VLDL) are

quantitatively more important in birds, particularly during the laying period, because they are

the proteins that carry fat from the liver to the extra hepatic tissues, as for example, to the

ovary, where they will be used for egg yolk synthesis. Triglycerides that are not utilized in

the liver or not incorporated into the egg yolk are utilized in other tissues (heart, muscle) or

are stored in the adipose tissue (Escribano, 1991). During absorption and transportation

processes, no alterations occur in the composition of fatty acids. Therefore, there is a great

similarity between the dietary fat fed to birds and the body fat that is deposited. Triglycerides

can be synthesized from the glucose resulting from the digestion of the carbohydrates. The

composition of the fat synthesized through this route is characterized by an elevated content

of palmitic acid, estearic acid, and oleic acid, which constitute 90% of the total fatty acids.

The presence of fat in the diet inhibits the synthesis of fat from carbohydrates. The final

composition of body fat is a pondered average among the fat produced endogenously from

15

glucose, the quantity and composition of the fatty acids in the diet and the fat resulting from

catabolism through b-oxidation (Ferreira, 1999, Sanz et al., 2000). Carew et al. (1972)

evaluated the absorption of corn oil and tallow in light male birds and observed that

absorption of both fats was lower in younger birds. The capability to absorb corn oil

increased from 84 to 95% from the first to the second week of age and absorption of tallow

has increased from 40 to 79%. These results indicated that newly hatched chicks do not have

complete physiological ability to absorb fat. Nevertheless, this ability develops quickly after

the first days of life. Broiler breeder males showed lower apparent digestibility of fat in the

first week of life than in the second and third weeks of age (Mahagna et al., 1988).

Despite the existing contradictions in the literature and the common sense between the

nutritionists that the chicks on the first days of age are not able to digest oils, Zelenka et al.

(1997) has used 2.9% and 3.3% of ether extract in the diet in two experiments and

demonstrated that the apparent digestibility of the fat is high during the first week of age, low

on the second and high after the third week of life. Noy and Sklan (1995) studied the

digestion and absorption of fats in young birds (from 1 to 21 days) and have reported that the

true digestibility of the unsaturated fat in four-day-old birds was higher than 85%, increasing

a little on the subsequent days. This demonstrates that the activity of lipases and bile salts on

the fourth day of age were enough for the complete fat digestion. It was concluded that fat

digestibility is not a limiting factor for the growth of young birds. According to Freitas

(1999), broilers show high digestibility of fat on the first week of life and the inclusion of oil

in the initial diet promotes a better performance of the chickens until 21 days of age. During

the first three weeks of age, chicks fed diets with oil have shown higher apparent digestibility

values of ether extract than the ones that received rations without oil (Cançado, 1999).

2.5 Dietary Fats in Nutrition

Fats are usually added to the feed for meat-type poultry to increase overall energy

concentration and, in turn, improve productivity and feed efficiency. Oxidation of fat is an

efficient means to obtain energy for the cell in large quantity, whereas anabolic use involves

direct incorporation into the body as a part of growth. Lipid accrual is most obvious in

adipose tissue; however, cell multiplication also requires an array of lipids to form associated

16

membrane. These two uses can occur simultaneously; however. the extent of each may vary

considerably.

2.5.1 Importance of Dietary Fat to Poultry

Scott et al.,(1982) have concluded that the net amount of energy obtained by chicks is 60% of

the metabolizable energy of proteins, 75% of the metabolizable energy of carbohydrates,, and

90% of the metabolizable energy of fats (Scott, et al., 1982), underscoring the high efficiency

of metabolizable energy contributed by fat. Baião and Lara observed that the inclusion of oil

in the starter diet increased the fat digestibility in broiler chicks during the first week of life

and resulted in better performance through 21 days of age, compared to the chicks received

rations without oil (Baião and Lara, 2005). Furthermore, chicks utilized metabolizable energy

more efficiently for growth if part of the carbohydrate portion of the diet was replaced

isocalorically with corn oil (Carew and Hill, 1964) or acidulated soybean soap stock

(Lipstein et al., 1965). For growing chicks, the net availability of metabolizable energy from

corn oil was about 10% higher than that of carbohydrate-rich feed ingredients; yellow corn

and milo (De Groóte, 1968). Also, chicks fed diets devoid of supplemental fat had higher

levels of lipogenesis and increased adipose fat deposition (Dvorin et al., 1998).

2.5.2 Advantages of Dietary Fat Supplementation

1. Essential Fatty Acids

Birds are not able to synthesize all fatty acids and thus, some are considered metabolically

essential viz. linoleic (18:2, n-6) and linolenic (18:3, n-3) fatty acids. However, to date the

NRC has only defined the dietary requirements for linoleic acid (NRC, 1994). These

essential fatty acids are absorbed from the feed, in which dietary fat is the major source

(Dvorin, et al., 1998). Fatty acids obtained from crude soybean oil and corn oil are very high

in unsaturated fatty acids, with high levels of linoleic acid (Scragg et al., 1987). Any

deficiency of linoleic acid adversely affects egg production, and it has been proven that

supplementation of linoleic acid, present in vegetable oils, increases egg weight (Shutze and

Jensen, 1963; Balnave, 1971). Depressed growth (especially in male chickens) may be the

first sign of an inadequate supply of essential fatty acids (Wiseman and Salvador 1991). Zero

hatchability represents the most acute deficiency of linoleic acid that has been reported to

17

date. It was manifested by increased susceptibility to respiratory infections, poor egg

production, small egg size, and low fertility (Miller, et al., 1963; Menge, et al., 1965).

Furthermore, the conjugated isomers of linoleic acid have been reported to be effective in

minimizing reduced growth rates by preventing the catabolic effects of immune stimulation

(Cook et al., 1993).

2. Micronutrients

Dietary fats play a significant role in the absorption of fat-soluble vitamins (A, D, E and K)

by acting as their "carriers" - apart from serving as major sources of these vitamins (Iqbal and

Hussain, 2009). The fat-soluble vitamins are incorporated into portomicrons for

transportation after absorption, and are also deposited in body lipid stores (Drevon, 1991).

Hence impairment of the absorption of fat-soluble vitamins is the most serious consequence

of a dietary deficiency of fat (Jacob et al., 2011).

Vitamin A: Acid oil and corn oil are rich vegetable sources of carotenoids which are

precursors for the synthesis of vitamin A. Vitamin A plays a significant role in regulating cell

growth, specifically epithelial cells. It is also necessary for bone metabolism through

involvement with osteoblasts (bone forming cells) and osteoclasts (cells involved in bone

resorption) (Surai et al., 2001). Vitamin A influences both antibody production and T-

lymphocyte proliferation responses, thus a deficiency can result in decreased immune

responses (Friedman and Sklan, 1989a, b). Moreover it has been observed that for maximal

immune response in growing chickens, it may be beneficial to include dietary vitamin A at

higher levels than NRC (NRC, 1994) recommendations (Sklan et al., 1994) and dietary fats

would be an ideal option in doing so.

Vitamin D: Vitamin D is required for normal calcium absorption and utilization, hence

inadequate levels of vitamin D induces calcium deficiency resulting in decreased egg

production (Fritts and Waldroup, 2003; Jacob et al., 2011). Vitamin D also plays a vital role

in the immune responses of chickens, particularly cellular immune responses (Aslam et al.,

1998). Moreover vitamin D prevents tibial dyschondroplasia by increasing bone health

substantially (Edwards Jr, 1990). Recently, it has also been reported that vitamins A and D

18

regulate bile acid synthesis, thus controlling fat absorption as well as their own absorption

(Schmid, et al., 2010).

Vitamin E: Lipid and myoglobin oxidation are major causes of meat quality deterioration

during storage (Jensen et al., 1998) and poultry meat has higher sensitivity to oxidation

damages among all meats, which may be ranked according to oxidation susceptibility in the

following order: turkey > chicken > pork > beef > lamb (Tichivangana and Morrissey, 1985).

It has also been successfully demonstrated that dietary vitamin E supplementation

significantly increased the α-tocopherol content of muscle membranes in many animals

(Lauridsen et al., 1997). α-tocopherol functions as a lipid antioxidant and free radical

scavenger (Hsu and Guo, 2002). Moreover vitamin A and E also have a profound effect on

alleviating heat stress in chickens (Sahin et al., 2001). The cost factor of dietary vitamin E

supplementation demands efficient utilization of dietary vitamin E as well as lipid

metabolism (Zouari et al., 2010).

3. Lecithin

Lecithin (phosphatidylcholine) is a phospholipid that is extracted commercially from

soybeans. It promotes the incorporation of fatty acids into micelles by acting as an emulsifier,

facilitating fat absorption (Cho et al., 2008). Dietary lecithin plays an important role in the

transport of triglycerides out of intestinal mucosa by providing surfactant lecithin for the PM

envelope and supporting mucosal protein biosynthesis (O'Doherty et al., 1973). Lecithin also

alters the serum hormone levels, affects hepatic gene expression, and thereby regulates fat

metabolism of broilers (Huang et al., 2008). Dietary supplementation of lecithin increased

the metabolizable energy of added fat, but parallel to lipid availability (Sibbald et al., 2000).

Lecithin has also been observed to improve the tenderness of meat (Collins et al., 2011).

When supplemented at 6%, lecithin significantly increased yolk percentage, improved haugh

unit score (albumen density) and yolk color, while increasing fat digestibility and plasma

total lipids (Attia et al., 2009).

19

4. Milling Benefits

Added fat in the diet acts as a binder, improving pellet quality and providing optimal

durability (Wilson and Bayer, 2000). It has also been observed for many years that dietary fat

reduces dusting and wastage of feed during the milling process (Wilson and Bayer, 2000).

5. Diet-Induced Thermogenesis

The reduced heat increment of fat-containing diets, which appears to be one of the primary

causes of the extra-caloric effect, has been explained (Edwards, 1969) as follows: the

conversion of carbohydrates and protein to fatty acids is a heat-producing process, while the

presence of an adequate level of dietary fat prevents this process. A high proportion of the

dietary fatty acids can be used directly in the synthesis of tissue triglycerides, while fatty

acids formed from carbohydrates must pass through a series of heat-producing metabolic

transformations. The heat increment lost to the environment constitutes a loss of expensive

energy utilized to produce fatty acids. Moreover, this additional heat produced during the

fatty acid synthesis from dietary carbohydrate may also accentuate the effects of heat stress,

under hot weather conditions. In high-temperature environments adequate amounts of dietary

fat should be present in order to inhibit the conversion of dietary carbohydrates to fatty acids,

a heat-producing process (Edwards, 1969). The beneficial effects of vegetable oil on the

efficiency of energy utilization was due to a reduced heat increment rather than to a reduction

in the basal component of the heat production (Shannon and Brown, 1969).

2.5.3 Fat Digestibility in Young Chicks

It has been proven that fat digestibility is not a limiting factor in the growth of young broilers

(Noy and Sklan, 1996). These authors reported that the true digestibility of the unsaturated

fatty acids in four-day old birds was over 85%, which demonstrates that the activity of

lipases and bile salts by the fourth day of age were sufficient for near complete fat digestion.

It has also been shown that fats of vegetable origin are more digestible in young birds. For

example, the capability of broiler chicks to absorb vegetable oil increased from 84% during

the first week of age to 95% during the second, while the absorption of tallow increased from

40 to 79% over the same time period (Carew Jr et al., 1972). The metabolizable energy of a

corn-soy diet supplemented with soybean oil was maximized as early as two weeks of age in

20

broilers (Batal and Parsons, 2002). Day-old broiler chicks had increased apparent fat

digestibility when fed with soy oil at a dietary inclusion level of 3.5% (Zollitsch et al., 1997).

2.5.4 Efficient Utilization of Dietary Fat

The main factor affecting the metabolizable energy value of fats is their digestibility, which

is dependent on the length of carbon chain and the degree of saturation of the constituent

fatty acids (Renner and Hill, 1961a; Leeson and Summers, 1976; Waldroup et al., 1995;

Leeson and Summers, 1997). Interactions between the degrees of saturation, relative to fat

absorption have been suggested by several authors (Young and Garrett, 1963; Leeson and

Summers, 1976). The poultry grease and palm oil samples consistently had the lowest

metabolizable energy values, while blends apparently based on soybean oil consistently had

the highest metabolizable energy values (Pesti et al., 2002). Renner and Hill (1961b) asserted

that fats which had previously been used for deep frying such as restaurant grease have

substantially lower and more variable metabolizable energy values. This decrease depends to

a great extent on the duration of heating, temperature used, and fatty acid profile. Heating

increases the loss of poly-unsaturated fatty acids, as they are much more sensitive to

oxidative degradation than saturated fatty acids, and it changes the fatty acid profile (Renner

and Hill, 1961a). Metabolizable energy values may also be reduced by the presence of

damaged fats including, for example, dimeric or polymerized fatty acids. This same pattern is

applicable to animal fats such as tallow, choice white grease and poultry fat, which typically

have very low poly-unsaturated fatty acid levels with high saturated fatty acid content. These

"animal" renderers' fats have wide variation not only in metabolizable energy value, but also

in chemical characteristics. Consequently, the metabolizable energy of these saturated fats

may be increased if the basal diet contains fats high in poly-unsaturated fatty acids (Lewis

and Payne, 1966; Ketels et al., 1987; Wiseman and Salvador, 1991). It has been proven that

the best way to use fats with more saturated fatty acids, viz. stearic and palmitic acids, such

as animal and palm fats, is by blending them with unsaturated fatty acids (Renner and Hill,

1961a, b). Oleic acid (C18:1) plays a more direct role in the absorption process, either in the

lumen or in the mucosa cells, to facilitate the increased absorption of saturated fatty acids

(Young and Garrett, 1963). These researchers have usually found a synergism between fatty

21

acids that improve fat digestibility, and the resulting impact on its metabolizable energy

content, particularly at high levels of dietary inclusion.

2.6 Sources of Dietary Fat in poultry Nutrition

Cotton oil

The utilization of cotton oil is limited by the presence of the natural yellow pigment

denominated gossypol, which is a toxic or anti-nutritional element. It causes iron deficiency

and lysine unavailability due to Maillard reactions, thus reducing the nutritional value of

proteins (when utilized in the meal form). Ferrous sulphate must be added to broiler diets in

which cotton oil is included, because it chelates gossypol, preventing its absorption in the

digestive tract and thus neutralizes its deleterious effects. Broilers tolerate levels higher than

100 ppm of free gossypol without performance impairment. It is not recommended to use

gossypol in laying hen diets. The presence of cyclopropenoic fatty acids (malvalic and

sterculic) intensifies the effects of gossypol, resulting in green yolk and pink coloration of the

albumen. When high amounts of these fatty acids are ingested, the yolk develops redness and

viscous appearance after short time of refrigeration. This alteration is caused by the increase

in the concentration of saturated fatty acids in the yolk as a function of the inhibition of the

enzymes 6 e 5 desaturase, which hinders the denaturation of stearic and palmitic acids

and their corresponding monounsaturated fatty acids. Besides the ability of changing the

composition of yolk fatty acids, the cyclopropenoic fatty acids alter the permeability of the

vitelline membrane and cause iron diffusion from the yolk to the albumen, where

ovotransferrin acts as iron chelator. This reaction between ovotransferrin and iron is

responsible for the pink coloration of the albumen. On the other hand, some ovotransferrin

may diffuse to the yolk, combine with iron and also cause red yolk coloration. The pink

albumen coloration is seen more often in eggs stored for long periods of time. In breeder

flocks, besides yolk discoloration, high levels of gossypol and the diffusion of ovotransferrin

can reduce egg hatchability (Leeson & Summers, 2001).

22

Canola oil or Rapeseed oil

Canola is the name given to rapeseed that contains less than 2% of erucic acid (docosenoic

acid, C22:1, -9) in relation to the total fatty acid and less than 30 umoles of glucosinolates

per gram of free oil on seed dry matter basis (Leeson & Summers, 2001).

In birds, the adverse effects of adding erucic acid to the diets are reflected on intake, growth

and the apparent digestibilities of total lipid and individual fatty acids ( Leeson & Summers,

2001). Furthermore, chicks fed with diets containing erucic acid deposit less fat and utilize

energy from this lipid less frequently ( Leeson & Summers, 2001).

Female broilers fed diets containing two different forms of canola oil showed better growth

rate when compared to females fed diets containing tallow and acidulated soybean oil

soapstock. This observation confirms the advantage of using vegetal oils instead of tallow

and acidulated soybean oil soapstock as energy sources for birds. The better growth rates are

a result from the higher percentage of long chain fatty acids and higher contents of

triglycerides (Thacker et al., 1994). Andreotti et al. (2001) observed similar performance,

carcass yield and cut yields of broilers with 49 days old fed poultry fat, canola, sunflower,

corn, soybean or lard. To evaluate the effects of different lipidic sources on the physical and

chemical characteristics of thigh meat, broilers were fed diets containing soybean oil,

sunflower oil, canola oil, corn oil, poultry fat or lard. Lard and corn oil resulted in more red-

colored meat when compared to the meat of birds fed with oil of canola, sunflower or

soybean, but did not differ from the poultry fat (Souza et al., 2001).

Sunflower oil

Alao and Balnave (1984) reported better development and feed conversion of birds fed with

diets containing sunflower oil when compared to birds fed olive oil. It was suggested that the

difference was a function of the fatty acid composition of the different vegetable oils. Sanz et

al. (1999) fed broilers with sunflower oil or a mixture of beef tallow/lard and the utilization

of saturated fats resulted in greater abdominal fat deposits than unsaturated fats. According to

Sanz et al. (2000a), the utilization of a source of unsaturated lipids reduces fat and increases

protein on the broiler carcasses. The difference in protein accretion was attributed to the level

23

of saturation of the fat, since the energy derived from unsaturated fat may be used for other

metabolic purposes, whereas the energy derived from saturated sources is less promptly

utilized and accumulates as body fat. In general, corporal fat accumulation may be

considered the result of the balance between the fat absorbed from the diet, the endogenous

synthesis of fat (lipogenesis) and the catabolism of fat by -oxidation (lipolysis).Therefore,

in cases in which the quantity of absorbed fat is the same, lower fat depositions may be

attributed to an increase in catabolism or endogenous decrease in the synthesis of fatty acids,

or both.

Sanz et al. (2000b) evaluated inclusion levels of 8% of two lipid sources, one saturated (beef

tallow) and one unsaturated (sunflower oil). There was a significant reduction in the

abdominal fat of birds fed diets with sunflower oil (Sanz et al.,2000b). Provided that the

quantity of absorbed fat was higher in birds fed diets containing sunflower oil, the reduction

in the fat deposit of these birds seemed to be a function of higher fat oxidation rates

(catabolism) and lower synthesis of fatty acids. Using 8% of inclusion of three lipidic sources

(sunflower oil, fish oil and beef tallow) in broiler feeding, Newman et al. (2002) observed a

higher proportion of linoleic acid and higher polyunsaturated/saturated ratio in the

composition of the fat of birds fed with sunflower oil.

Linseed oil

The effects of soybean, canola, sunflower and linseed oils on the nutritive and organoleptic

traits of the meat and the profile of fatty acids were evaluated in 5-week-old broilers (López

Ferrer et al., 1999). The parameters of meat quality were not different between treatments,

even though meat juiciness of the samples from birds fed with canola oil has been inferior to

the other treatments. The values of TBARS were higher in fresh abdominal fat of birds fed

linseed oil and soybean oil and in the breast muscle stored for 12 months when compared to

the samples of fresh breast. Higher levels of omega-3 in both tissues were observed in birds

fed linseed oil.

24

Rosa (1999) used three types of oils (linseed, soybean and a mixture of linseed and fish) at

inclusion levels of 1, 2 and 3% in broiler diets and observed that the composition of fatty

acids of the rations influenced the fatty acid profile of the breast and thigh.

It has been suggested that the size of fat deposits may be changed according to the fatty acid

profile of the diet. The use of beef tallow, olive oil, sunflower oil and linseed oil in broiler

diets evidenced that fat sources rich in polyunsaturated fatty acids produce less fat deposits

than the ones rich in saturated or monounsaturated fatty acids (Crespo and Esteve-Garcia

(2002).

Palm oil

According to Rodriguez et al. (2002), palm oil or mixtures of palm oil, fatty acids distilled

from the palm and calcic soap are sources of vegetal oils with a fatty acid profile that might

replace animal fats without any kind of negative impact on carcass quality.

Soybean oil

The raw soybean oil has on its composition several substances considered as impurities that

must be removed using several processes (filtration, hydration and degum). These substances

are solid residues from the extraction process, and they are phospholipids, gums, metallic

complexes, free fatty acids, peroxides, polymers, secondary products from oxidation and

pigments (Beauregard et al., 1996).

Degummed Soybean oil

The degummed soybean oil is a product obtained from the raw oil after degumming, which

consists of centrifugation the soybean oil to separate it into the two following parts:

degummed oil and unsaponifiable matters (Baiao and Lara 2005).

Scaife et al. (1994) fed female broilers with rations containing different sources of lipids

(beef tallow, soybean oil, canola oil, marine fish oil or a mixture of these oils) and observed

that live weight was significantly higher when soybean oil was used. Birds fed with canola

oil also showed higher intake and higher weight. Birds fed beef tallow had the poorest

conversion rate.

25

Vieira et al. (2002) evaluated broiler rations containing 0, 4 and 8% of soybean oil and

acidulated soybean oil soapstock, and observed similar weight gain between the different

lipidic sources and improved feed conversion in birds fed with soybean oil in comparison to

the birds fed with acidulated soybean oil soapstock. They also observed a reduction in feed

intake of birds fed with acidulated soybean oil soapstock when the inclusion level was

increased from 4 to 8%, whereas no reduction in feed intake was observed in birds fed with

soybean oil.

Lara et al. (2004) fed male broilers with different lipidic sources (degummed soybean oil,

poultry fat, acidulated soybean oil soapstock, a mixture of poultry fat/soybean oil and other

mixture of soybean oil/ acidulated soybean oil soapstock). It was observed better weight gain

and intake in birds fed with soybean oil in relation to the birds fed with acidulated soybean

oil soapstock. The different lipidic sources had no influence on the levels of moisture, ether

extract, and protein of the breast, thigh and whole carcasses. According to Moura (2003), the

inclusion of soybean oil in broiler diets does not affect the moisture and ether extract in the

breast and thigh muscles. Furthermore, the deposition of fat on the breast muscle and viscera

is not affected by the inclusion of the oil in the diet.

Acidulated soybean oil soapstock

The acidulated soybean oil soapstock, also denominated as soybean fatty acid, is a sub-

product of the industry of soybean oil. This sub-product is obtained through the alkaline

neutralization of the raw oil, which produces a raw soap (a mixture of soaps, neutral oil,

water, sterols, pigments, and other constituents). This unstable product is converted in

acidulated soybean oil soapstock after a treatment of sulfuric acid in hot aqueous solution.

Compared to soybean oil, acidulated soybean oil soapstock contains high levels of free fatty

acids (50%), unsaponifiable matter, and oxidized fatty acids, besides being also rich in

carotenoids (Bornstein and Lipstein, 1963; Lipstein et al., 1965; Pardio et al.,2001). Free

fatty acids affect absorption negatively and, consequently, also the nutritive value of the fats.

The ratio between free fatty acids and intact triglycerides is important, since supplements

with free fatty acids are absorbed less efficiently than the free fatty acids in form of

triglycerides. The reason for this is that monoglycerides are essential to incorporate insoluble

26

fatty acids in the micellar complex. There are not enough monoglycerides to combine with

all free fatty acids when they are offered as the only fat source and absorption is then

impaired (Fats in animal feeds, 1985; Blanch et al., 1995).

Wiseman and Salvador (1991) worked with diets for broilers supplemented with 3 different

sources of lipids (tallow, soybean oil and palm oil) and their respective acid oils, with

different levels of free fatty acids. The reduction in metabolizable energy values of the fats

with higher contents of free fatty acids tend to be more pronounced with greater inclusion

levels of lipids.

Besides, reduction is also greater with greater saturation levels. The increase in free fatty acid

levels reduces progressively the ME values of the energy source, and such effect is more

pronounced in young birds.

The use of refined soybean oil, raw soybean oil or acidulated soybean oil soapstock showed

an increase on the levels of linoleic fatty acid on the carcass of birds fed with refined soybean

oil and raw soybean oil in relation to the acidulated soybean oil (Cascabulho, 2000).

The value of nitrogen-corrected metabolizable energy of acidulated soybean oil soapstock

(8.144 kcal/kg DM) determined for 28-day-old broilers was 5% inferior than the value of raw

soybean oil. The inclusion of acidulated soybean oil soapstock in rations for animals depends

on the maintenance of a minimum of quality control, so that the product has surely not been

adulterated by the inclusion of other low-quality oils (Vieira et al., 2002).

The values of nitrogen-corrected metabolizable energy of the acidulated soybean oil

soapstock suggested for young and adult birds were 7.788 and 8.610 cal/kg DM, respectively

(Freitas et al., 2002).

Palm kernel oil

Palm kernel oil, similarly to coconut oil, is high in saturated fats and is more saturated than

palm oil. Palm kernel oil is high in lauric acid which has been shown to raise blood

cholesterol levels, both as LDL-C (cholesterol contained in low-density lipoprotein) and

HDL-C (cholesterol contained in high-density lipoprotein) Cascabulho (2000). Palm kernel

oil does not contain cholesterol or trans fatty acids (Rodriguez et al., 2002).

27

Animal fats

Deaton et al. (1981) used diets with similar nutritive values added with 4, 7 and 10% of

animal fat, and observed that the increasing fat level of the diet increased the quantity of

abdominal fat, corroborating results reported by Yalçin et al. (1998).

Poultry fat

Poultry fat is also known as viscera oil and is obtained after the extraction of fat by

autoclaving or in a percolator tank and expeller. After extraction, the fat is placed into a

decantation tank to extract the acidulated soapstock and moisture excess. At this point, it is

ready to be used in ration or to be refined. Product yield varies from 1.3 to 1.6% of the live

weight of the bird (Mano et al., 1999). This range depends on the level and source of energy

used in the ration, besides bird sex, age and weight at slaughter. Higher percentages of fat are

obtained when higher levels of energy are used, older birds are slaughtered and consequently

with higher live weight; moreover, females produce more fat than males, independent of

dietary energy level and age at slaughter. Assessing the effects of the mixtures of vegetal and

animal fats, corn oil and poultry fat on the proportions of 0, 3, 6 and 9% in the alimentation

of broilers,

Griffiths et al. (1977) observed that the birds fed with corn oil and poultry fat were

significantly heavier than birds non-supplemented with fat. Weight gain, feed intake and feed

conversion of broilers fed with diets containing 4% of poultry fat, 4% of soybean oil or a

mixture of 2% of soybean oil and 2% of poultry fat were not affected by oil sources (Dutra Jr

et al., 1991). However, there was a decrease in feed intake and weight when the mixture was

used.

The effects of increasing inclusion levels (0, 2, 4, 6, 8 and 10%) of refined palm oil (8,000

kcal/kg ME), palm oil (8,500 kcal/kg ME), corn oil (9,000 kcal/kg ME) and poultry fat

(9,000 kcal/kg ME) in diets for broiler were studied by Valencia et al. (1993). There were no

effects of the sources of oil on weight gain and feed conversion. On the other hand,

performance was proportionally better with increasing inclusion levels of the oil sources.

28

Performance parameters were evaluated in broilers fed different lipidic sources (raw soybean

oil, poultry fat and acidulated soybean soapctock and its mixtures). There were no significant

differences in weight gain, feed intake, feed conversion and viability when soybean oil and

poultry fat were used (Lara et al., 2003).

The effects of the oxidized poultry fat on the values of metabolizable energy for broilers

from 31 to 34 days old was evaluated by Racanicci et al. (2000). Oxidized poultry fat is

produced by heating from 80 to 90oC, with constant aeration for 40 days. The birds fed with

rations containing 10% of fresh poultry fat or oxidized poultry fat showed apparent

metabolizable energy and apparent adjusted energy for nitrogen values of 9,240, 9,150, 7,700

and 7,595kcal/kg, respectively. According to Edwards et al. (1973), the inclusion of poultry

fat in broiler diets resulted in an increase in the deposition of oleic acid and a reduction in the

levels of the linoleic acid in the adipose tissue of the birds. The use of cotton oil or acid

cotton oil increased the deposition of linoleic acid. Similar results were obtained by Lara et

al. (2003), who observed a higher deposition of monounsaturated fatty acids on the carcass of

broilers fed with poultry fat when compared to birds fed with raw soybean oil and acidulated

soybean oil soapstock.

Beef tallow

Newman et al. (2002) fed broilers with 8% of sunflower oil, fish oil or beef tallow in the diet

and observed poorer feed conversion in the birds fed with beef tallow. There was a positive

relationship between the composition of the fatty acid present in diet and the composition of

the fatty acid of the breast, thigh and skin of broilers fed corn oil, beef tallow or a mixture of

both (Marion and Woodroof, 1963). The type of fat added to the diet has a significant

influence on the profile of fatty acids of the abdominal fat, and birds fed tallow have shown

higher concentrations of saturated fatty acids and lower concentrations of unsaturated fatty

acids comparing to the birds fed with acidulated soybean oil soapstock (Thacker et al., 1994).

Sanz et al. (1999) formulated broiler diets containing sunflower oil and bovine/swine fat and

reported that the inclusion of saturated fats produced higher accumulation of intramuscular

fat and abdominal fat. In a study using one saturated (beef tallow) and one unsaturated

(sunflower oil) lipid source at 8% of inclusion, Sanz et al. (2000b) observed a significant

reduction in the deposit of abdominal fat in the birds that received diets with sunflower oil.

29

According to Crespo & Esteve-Garcia (2002b), the location of fat deposition depends on the

kind of fatty acid added to the diet (saturated and polyunsaturated). Birds fed with diets rich

on animal saturated fatty acids tend to have proportionally larger abdominal and mesenteric

fat than other fat deposits.

Lard

Working with broilers fed diets containing sunflower oil and mixture of bovine tallow/swine

fat, Sanz et al. (2000a) did not observed effects of the lipidic sources on feed intake, weight

gain and feed conversion of the birds. No effects on performance was observed when broilers

were fed from 21 to 49 days with diets containing one of the following lipid sources: poultry

fat, refined soybean oil, refined canola oil, refined sunflower oil, lard and refined corn oil

(Andreotti et al., 2001). Souza et al. (2001) evaluated six different lipid sources in rations for

broilers and observed that the meat of birds fed with lard presented a more pronounced red

coloration in relation to the meat from birds fed with soybean oil, sunflower oil and canola

oil, but it was not different from birds fed poultry fat.

Fish oil

Fish oil is produced by the compression of whole fishes and sub-products for industries of

fishery. This kind of oil contains high percentages of long-chain polyunsaturated fatty acids,

which accounts for the oxidative instability and the transference of characteristic fish flavor

to the meat of animals fed fish oil. In general, fish oils are rich sources of omega- 3 fatty

acids and poor sources of omega-6, and the contents of linoleic acid are also low (<2%).The

fatty acid profile of the different oils varies with the period of the year, processing method

and predominant fish species that was captured (Fedna, 1999). Some authors reported the

unpleasant flavor of fish in the meat of broilers fed with 1.5% to 2.5% of fish oil (Miller &

Robisch, 1969). Phetteplace and Watkins (1990) evaluated different relations of poultry fat

and fish oil (Menhaden) in broiler feeding. Birds fed with diets containing more fish oil have

deposited more quantities of unsaturated fatty acids in the abdominal fat, as well as more n-3

fatty acids. On the other hand, both total n-6 fatty acids and the relation of n-6:n-3 were

higher in the abdominal fat of birds fed with rations containing higher quantities of poultry

fat.

30

Chanmugam et al. (1992) also demonstrated that the content of -3 fatty acids in the thigh of

broilers might be increased by the addition of linseed oil or fish oil in the diet (Menhaden).

Therefore, it has been suggested the inclusion of low dietary levels of fish oil together with

another source of linoleic fatty acid to obtain an acceptable product with increased ratio

between -3:-6 fatty acids. Scaife et al. (1994) have utilized beef tallow, soybean oil, colza

oil, oil of marine fish or mixtures of these oils in female broiler diets. The relation -6:-3

was significantly increased with the inclusion of soybean oil and decreased with the inclusion

of marine fish oil. Rosa (1999) observed that the composition of fatty acids of the rations has

influenced the profile of fatty acids of the breast and thigh using linseed oil, soybean oil and

a mixture of linseed plus fish oil at inclusions levels of 1, 2 an 3% in diets for broilers.

Diet inclusion of 8% of sunflower oil, fish oil or beef tallow resulted in lower deposition of

corporal fat on birds fed with fish oil and sunflower oil. It was concluded that feeding

broilers with sources of n-3 and n-6 produced less carcass fat, and also improved feed

conversion. The results are interesting both from an economical point of view and from the

point of view of the health of consumers (Newman et al., 2002).

2.7 Effects of Dietary Fats on Poultry Performance

A number of different fat sources are available for poultry from both vegetable and animal

sources and from the rendering industry. (Sanz et al., 2000). It was observed that the

replacement of tallow by vegetable fats rich in polyunsaturated fatty acids like sunflower oil,

soybean oil, or linseed oil resulted in a decrease of abdominal fat deposition in broilers

(Newman et al., 2002; Ferrini et al., 2008). In a study, Sanz et al., (1999) fed broilers with

tallow in diet and found that the utilization of saturated fats resulted in greater abdominal fat

deposits compared to birds fed unsupplemented diet. Newman et al. (2002) reported a

significant depression of feed efficiency in broilers fed 8% beef tallow compared to birds fed

sunflower or fish oil. Furthermore, addition of 3% canola oil in broiler diet resulted in a

significant improvement in body weight and feed conversion ratio when compared to birds

fed animal fat (Newman et al., 2002). On the other hand, Shahryar et al. (2011) found that

the addition of 6% fat in broiler lad to an increase of abdominal fat and gizzard weight in

comparison with those of birds fed unsupplemented diets.

31

The improvement in body weight for age of the modern broiler chicken, due to increased

growth rate and associated higher nutrient supply, have lead to frequent occurrence of

metabolic and skeletal disorders (Robinson et al.,1992) or increased carcass fat deposition

(Yu and Robinson, 1992). The two main metabolic disorders affecting broiler chickens are

ascitis disease and sudden death syndrome, which is closely related to the rapid rate and

increased feed intake, particularly overconsumption of dietary energy. These pathological

conditions commonly occur in fast growing broilers chickens, fed ad-libitum.

The findings of Hrdinka et al. (2002) showed that feeding with feed-grade PG resulted in

significantly smaller abdominal fat pads compared to the other fat sources as SO, palm oil

and restaurant grease. Previous reports indicate that broiler chickens fed with diets enriched

with PUFA have less abdominal fat deposition than broiler chickens fed with diets containing

SFA. This is of particular interest in the rearing of female broilers, because the amount of

abdominal fat at slaughter age may represent >3% of the live weight.

Azman et al (2005) noted that final body weight was significantly affected by dietary fat

sources. Daily weight gain and daily feed intake was significantly higher in the beef tallow

group compared to the other groups. The feed conversion ratio of the poultry grease group

was better compared to the other groups. In the soybean oil supplemented group, the amount

of long-chain polyunsaturated fatty acids was significantly higher in thigh skins, breast

muscle and abdominal fat pad. In the thigh and breast muscle of the poultry grease fed group

oleic acid content was significantly higher, and beef tallow caused increased accumulation

of saturated fatty acid in thigh skins and abdominal fat pad.

Crespo and Esteve Garcia (2002) found that chickens fed dietary fat showed higher live

weight when compared to birds fed diet with no supplemental fat.

Oils of plant origin such as soybean oil contain high level of unsaturated fatty acids and are

more completely digested by fowls than animal fats such as tallow. (Leeson and Atteh 2003).

Sanz et al (2000) have reported that broiler chickens fed with diets enriched of

polyunsaturated fatty acids have less abdominal fat or total body fat deposition than do

broilers chickens fed with diets containing saturated fatty acids.

32

2.8 Lipid Profile

A lipid profile is a measurement of various lipids that are found in the blood. This kind of

blood test is often used to assess risk of heart disease (www.wikipedia.com). There are two

common concerns people have about lipids in diet: One is their high caloric value, which

may lead to undesired weight gain. The other is their association with high total cholesterol

levels, which are a risk factor for cardiovascular disease. Limiting the intake of fat and oil in

the diet, especially saturated fats, may help keep cholesterol levels low and thus lower one’s

risk of heart disease (Alfred, 2002).

One reason the USDA recommends that 10% or fewer of one’s calories come from saturated

fats is because the amount of saturated fat in one’s diet correlates strongly with cholesterol

levels. Saturated fats are generally solid at room temperature. Fat from animals (e.g. butter

and lard) is almost always saturated, but some oils from plants are saturated, too (e.g. palm

oil or coconut oil.)

A lipid profile contains information about several different kinds of lipid that normally

circulate in the blood. Values are numerical, but in order to simplify explanation, ranges of

numerical values are often placed into categories such as ‘low risk,’ or ‘high risk.’ For

example, a total cholesterol level over 240 mg/dl is said to be ‘high risk’, but that doesn’t

mean a reading of 238 is fine. With total cholesterol and LDL cholesterol the higher the

number, the higher the risk. Conversely, the lower the LDL cholesterol, the lower the risk.

However, a low number is not a guarantee against heart disease. The population with low

cholesterol is at lower risk of heart disease, but heart disease is not absent in this population.

Triglycerides:

According to (Nomenclature of Lipids), triglyceride (TG, triacylglycerol, TAG, or

triacylglyceride) is an ester derived from glycerol and three fatty acids (tri- + glyceride).

Triglycerides are the main constituent of body fat in humans and animals, as well as

vegetable fat (Nelson and Cox, 2000). They are also present in the blood to enable the

bidirectional transference of adipose fat and blood glucose from the liver, and are a major

component of human skin oils (Alfred, 2002).

33

There are many different types of triglyceride, with the main division being between

saturated and unsaturated types. Saturated fats are "saturated" with hydrogen – all available

places where hydrogen atoms could be bonded to carbon atoms are occupied. These have a

higher melting point and are more likely to be solid at room temperature (Davidson, 2008).

Unsaturated fats have double bonds between some of the carbon atoms, reducing the number

of places where hydrogen atoms can bond to carbon atoms. These have a lower melting point

and are more likely to be liquid at room temperature

This is the most common type of lipid formed in animals. Fat tissue is primarily for the

storage of this form of lipid. Triglyceride levels vary quite a bit over short time periods. A

meal high in sugar, fat, or alcohol can raise the triglyceride level drastically, so the most

repeatable measures of this lipid are taken after 12 hours of fasting. Even though sugar and

alcohol are not lipids, your body will convert any form of excess calories into triglycerides

for long-term storage. A value below 150 mg/dl indicates no increased risk, 150 -200

indicates a slight risk, and over 200 mg/dl is a high risk.

Cholesterol: It is a sterol (or modified steroid), a lipid molecule and is biosynthesized by all

animal cells because it is an essential structural component of all animal (not plant or

bacterial) cell membranes that is required to maintain both membrane structural integrity and

fluidity. Cholesterol enables animal cells to not need a cell wall (like plants and bacteria) to

protect membrane integrity and cell viability, thus are able to change shape and move about

(unlike bacteria and plant cells which are restricted by their cell walls). In addition to its

importance within cells, cholesterol also serves as a precursor for the biosynthesis of steroid

hormones, bile acids, and vitamin D (Westover et al., 2003). Cholesterol is the principal

sterol synthesized by animals. All kinds of cells in animals can produce it. In vertebrates the

hepatic cells typically produce greater amounts than other cells. It is almost completely

absent among prokaryotes (bacteria and archaea), although there are some exceptions such as

Mycoplasma, which require cholesterol for growth (Rizos, 2011). Cholesterol is present in

the blood in three forms. The three defined below are all combinations of protein,

cholesterol, and triglyceride. Cholesterol is a lipid and is insoluble in water. It is transported

through the blood encased in a soluble protein.

34

Cholesterol is a necessary molecule in human metabolism (Gérard et al., 2007). It is a

component of cell membranes, and is a building block of bile, estrogen and testosterone. The

cholesterol necessary for normal metabolism is manufactured by the liver. Generally, a level

less than 200 mg/dl is considered desirable. Between 200 mg/dl and 240 mg/dl is considered

borderline high, and over 240 mg/dl is considered high.

Low-density lipoprotein (LDL)

LDL is one of the five major groups of lipoproteins. These groups, from least dense to most

dense, are chylomicrons, very low-density lipoprotein (VLDL), intermediate-density

lipoprotein (IDL), low-density lipoprotein and high-density lipoprotein (HDL), all of which

are far smaller than human cells. In nutrition, LDL is sometimes referred to as the "bad

cholesterol"; however, this is a misleading misnomer. LDL and cholesterol are completely

different molecules – LDL is about 10 times larger in diameter than cholesterol (~200

angstroms compared with ~20 angstroms).

Lipoproteins transfer fats around the body in the extracellular fluid, can be sampled from

blood and allow fats to be taken up by the cells of the body by receptor-mediated endocytosis

(Dashty et al., 2014). Lipoproteins are complex particles composed of multiple proteins

which transport all fat molecules (lipids) around the body within the water outside cells.

They are typically composed of 80-100 proteins/particle (organized by a single

apolipoprotein B for LDL and the larger particles). A single LDL particle is about 220-275

angstroms in diameter (Segrest et al., 2001), typically transporting 3,000 to 6,000 fat

molecules/particle, varying in size according to the number and mix of fat molecules

contained within. The fats carried include cholesterol, phospholipids, and triglycerides;

amounts of each vary considerably.LDL particles pose a risk for cardiovascular disease when

they invade the endothelium and become oxidized, since the oxidized forms are more easily

retained by the proteoglycans. A complex set of biochemical reactions regulates the

oxidation of LDL particles, chiefly stimulated by presence of necrotic cell debris and free

radicals in the endothelium (http://www.rpi.edu/dept/bcbp/molbiochem.htm). Increasing

concentrations of LDL particles are strongly associated with increasing rates of accumulation

of atherosclerosis within the walls of arteries over time, eventually resulting in sudden plaque

35

ruptures and triggering clots within the artery opening, or a narrowing or closing of the

opening, i.e. cardiovascular disease, stroke, and other vascular disease complications

(http://www.nejm.org).

LDL particles (though far different from cholesterol per se) are sometimes referred to as bad

cholesterol because they can transport their content of fat molecules into artery walls, attract

macrophages, and thus drive atherosclerosis. In contrast, HDL particles (though far different

from cholesterol per se) are often called good cholesterol or healthy cholesterol because they

can remove fat molecules from macrophages in the wall of arteries (Kumar et al., 2011).

This is sometimes referred to as the “bad cholesterol.” This form contains the highest amount

of cholesterol. A value between 130 – 159 mg/dl is borderline high, and over 160 mg/dl is

considered ‘high” (Zhang et al., 2008).

High-density lipoprotein (HDL)

HDL is one of the five major groups of lipoproteins. Lipoproteins are complex particles

composed of multiple proteins which transport all fat molecules (lipids) around the body

within the water outside cells. They are typically composed of 80-100 proteins/particle

(organized by one, two or three ApoA; more as the particles enlarge picking up and carrying

more fat molecules) and transporting up to hundreds of fat molecules/particle. Unlike the

larger lipoprotein particles which deliver fat molecules to cells, HDL particles remove fat

molecules from cells which want to export fat molecules (Sorrentino, 2011). The fats carried

include cholesterol, phospholipids, and triglycerides; amounts of each quite variable.

Increasing concentrations of HDL particles are strongly associated with decreasing

accumulation of atherosclerosis within the walls of arteries (Stephens et al., 2012). This is

important because atherosclerosis eventually results in sudden plaque ruptures,

cardiovascular disease, stroke and other vascular diseases. HDL particles are sometimes

referred to as "good cholesterol" because they can transport fat molecules out of artery walls,

reduce macrophage accumulation, and thus help prevent or even regress atherosclerosis.

However, studies have shown that HDL-lacking mice still have the ability to transport

cholesterol to bile, suggesting that there are alternative mechanisms for cholesterol removal

(Toth, 2005)

36

This is sometimes called “good cholesterol” the higher the number, the better. A value below

40 mg/dl is considered a risk factor. A value above 60 mg/dl is considered protective against

heart disease. HDL cholesterol is cholesterol that is packaged for delivery to the liver, where

the cholesterol is removed from the body.

Very-low-density lipoprotein (VLDL)

This is a type of lipoprotein made by the liver (Gibbons et al., 2004). VLDL is one of the five

major groups of lipoproteins (chylomicrons, VLDL, low-density lipoprotein, intermediate-

density lipoprotein, high-density lipoprotein) that enable fats and cholesterol to move within

the water-based solution of the bloodstream. VLDL is assembled in the liver from

triglycerides, cholesterol, and apolipoproteins. VLDL is converted in the bloodstream to low-

density lipoprotein (LDL). VLDL particles have a diameter of 30-80 nm. VLDL transports

endogenous products, whereas chylomicrons transport exogenous (dietary) products.

Recently both the lipid composition (Dashti et al., 2011) and protein composition (Dashty et

al., 2014) of this lipoprotein were characterised in great detail.

This form contains the highest amount of triglyceride. Like LDL, this is considered “bad

cholesterol.” A value less than 32 mg/dl is desirable. VLDL is usually not measured directly,

but is estimated from the triglyceride count by dividing the triglyceride count by 5. This

mathematical way to estimate VLDL is not valid when the triglyceride is above 400 mg/dl.

37

CHAPTER THREE

MATERIALS AND METHODS

3.1 Location and duration of the Study

The study was carried out at the Poultry Unit of the Department of Animal Science Teaching

and Research Farm, University of Nigeria, Nsukka. Nsukka lies in the Derived Savanna

region, and is located on longitude 60 25□ N and latitude 70 24□ E (Offomata, 1975) and at

an altitude of 430m above the sea level (Breinholt etal., 1981). The climate of the study area

is a typical humid tropical type, with a relative humidity range of 56.01-103.83%. Average

diurnal minimum temperature ranges from 220C-24.70C while the average maximum

temperature ranges from 330C- 370C (0konkwo and Akubuo, 2007, Energy Center, UNN,

2008). Annual rainfall ranges from 1567.05mm to 1846.98mm (Meteorological Center, Crop

Science Department, University of Nigeria Nsukka, 2009 unpublished). The study lasted

(8wks).

3.2. Experimental materials

Palm oil, soybean oil, palm kernel oil and groundnut oil and other feed ingredients were used

for the study.

3.3. Experimental Diets

In the starter and finisher phases of the experiment five diets were formulated. The

percentage compositions of the diets are shown in Tables 1 and 2, respectively.

3.4 Experimental Animals and Management

In the starter phase, one hundred and twenty day-old broiler chicks were used for the study.

The birds were randomly allotted to five treatment groups of 24 birds each, and assigned to

five diets (Table 1). Each treatment group was replicated three times with 8 birds per

replicate. The birds in each replicate were brooded in a deep litter pen measuring 1.50m x

1.50m in the experimental poultry house. The poultry house is an open-sided one; the sides

and demarcations between individual pens are covered with wire gauze. The litter material

was fresh wood shavings. Heat was provided with charcoal pots placed under metal hovers.

Feed and water were provided to the birds ad libitum while additional light was provided at

38

night using kerosene powered lamps to enable the birds eat at night. The chicks were

vaccinated against Newcastle and Gumboro diseases as at and when due.

In the finisher phase, birds from the starter phase were randomly assigned to 5 treatment

groups with 24 birds per group. Each group were replicated three times with eight birds per

replicate placed on deep litter of fresh wood shavings in open sided house partitioned into

pens measuring 1.50m x 1.50m. The birds were randomly assigned to 5 diets (table 2).

Table 2: Percentage composition of broiler starter diets

Ingredients (%)Diets 1 2 3 4 5

Maize 22.5 22.5 22.00 22.5 22.00 Cassava root meal 21.5 20.00 20.00 20.5 19.5 Wheat offal 5.0 5.5 6.3 5.0 6.8 Soybean meal 14.00 14.00 14.00 14.00 14.00 Groundnut cake 24.00 24.00 23.07 24.00 23.07 Palm kernel cake 5.00 5.00 5.00 5.00 5.00 Fish meal 3.00 3.00 3.00 3.00 3.00 Bone meal 4.00 4.00 4.00 4.00 4.00 Salt 0.25 0.25 0.25 0.25 0.25 Vit-min premix* 0.25 0.25 0.25 0.25 0.25 Methionine 0.25 0.25 0.25 0.25 0.25 Lysine 0.25 0.25 0.25 0.25 0.25 Palm oil - 1.00 - - - Soybean oil - - 1.00 - - Palm kernel oil - - - 1.00 - Groundnut oil - - - - 1.00 Total 100 100 100 100 100 Calculated Composition: Crude protein (%) 24.01 24.08 24.02 24.03 24.07 Energy(Mcal/kg ME) 2.89 2.89 2.89 2.89 2.89 Crude fibre(%) 4.84 4.85 4.90 4.81 4.94

* Vit A – 10,000.00 iu., D3-2,000 iu., B1-0.75g., B2-5g., Nicotinic acid – 25g., K3-2.5g., E-25g., Biotin – 0.05g., Folic acid – 1g., Choline Cholride 250g., Cobalt –0.400g., Copper 8g., Managnese 64g., Iron –32g., Zn – 40g., Iodine – 0.8g., Flavomycin – 100g., Spiramycin 5g 3-Nitro-50g., DL-Methionie –50g., Selenium 0.6g., Lysine 120g., BAT-5g.

39

Table 3: Percentage composition of broiler finisher diets

Ingredients(%)/Diets 1 2 3 4 5

Maize 34.00 35.00 35.00 36.00 35.00

CRM 20.04 17.00 16.00 17.4 16.00

Wheat offal 5.00 6.00 7.0 5.0 7.0

SBM 12.42 11.80 11.50 12.20 11.50

GNC 16.00 16.00 16.00 16.00 16.00

PKC 5.4 6.2 6.50 5.4 6.5

Fish meal 2.00 2.00 2.00 2.00 2.00

Bone meal 4.00 4.00 4.00 4.00 4.00

Salt 0.25 0.25 0.25 0.25 0.25

Vit-min premix* 0.25 0.25 0.25 0.25 0.25

Methionine 0.25 0.25 0.25 0.25 0.25

Lysine 0.25 0.25 0.25 0.25 0.25

Palm oil - 1.00 - - -

Soybean oil - - 1.00 - -

Palm kernel oil - - - 1.00 -

Groundnut oil - - - - 1.00

Total 100 100 100 100 100

Calculated Composition:

Crude protein (%) 20.13 20.12 20.14 20.11 20.14

Energy(Mcal/kg ME) 2.93 2.93 2.93 2.92 2.93

Crude fibre(%) 4.51 4.54 4.63 4.39 4.63

* Vit A – 10,000.00 iu., D3-2,000 iu., B1-0.75g., B2-5g., Nicotinic acid – 25g., Calcium pantothenate 12.5g., B12-0.015g., K3-2.5g., E-25g., Biotin – 0.050g., Folic acid –1g., Manganese 64g., Choline chloride 250g. Cobalt-0.8g., Copper 8g., Manganese 64g., Iron –32G., Zn-40g., Iodine-0.8g., Flavomycin-100g., Spiramycin 5g., Dl-methionie-50g, Selenium 0.6g., Lysine 120g., BAT-5g.

40

3.5 Data Collection and measurements

Body weight, feed intake were measured. Feed intake was done daily by a weigh back

technique, in which feed remaining at the end of the day was subtracted from the initial feed

offered to the birds. Body weight of all the birds was recorded on a weekly basis. Data

obtained were used to calculate feed conversion ratio (FCR), average daily weight gain and

protein efficiency ratio.

3.6 Carcass and organ evaluation

At the end of the experimental period, two birds per treatment were randomly selected from

each treatment, starved overnight and weighed for carcass and organ evaluation. The birds

were slaughtered by severing the jugular vein, scalded in warm water for a minute and de-

feathered by manual plucking. The birds were eviscerated and weighed to obtain their

dressed carcass weight. The kidney, abdominal fat, liver, gizzard, heart, spleen and

proventiculus were removed and weighed using a sensitive scale and their weigts were also

recorded. The dressed carcass and organ weight were expressed as percentages of live

weight.

3.7 Blood collection and Analysis

Blood sample for serum triglyceride and cholesterol were collected into anticoagulant free

test tubes and later centrifuged at 3000 revolutions per minute(rpm) for 10 minutes at room

temperature. The serum was separated into different test tubes leaving the thick blood

residue. Total cholesterol, triglycerides, HDL-C, LDL-C and VLDL were determined

thereafter.

Parameters determined

The parameters determined include as follows

i. Final body weight (g)

ii. Daily feed intake (g)

iii. Average daily weight gain (g)

iv. Feed conversion ratio (g)

v. Protein efficiency ratio (g)

vi. Cost of feed / kg weight gain

41

Carcass Traits

i. Live weight

ii. Dressed carcass

iii. Organ weight

iv. Carcass dressing %

v. Relatives organ weight %

Lipid profile

i. Triglyceride , mg/dl

ii. Total cholesterol

iii. HDL- cholesterol mg/dl

iv. LDL- cholesterol mg/dl

v. VLDL- cholesterol mg/dl

3.8 Experimental Design

The study was conducted in a Completely Randomized Design experiment with five

treatment groups (T1, T2, T3, T4, and T5). Each diet (treatment) was repeated three times,

with each replicate comprising 8 birds. The dietary treatments consist of 1% added fat from

four different sources and were arranged according to the following treatments: T1- birds in

this treatment served as the control group and received diet with no added fat. T2- birds in

this treatment 2 received diet containing 1% palm oil, T3 – birds in this treatment 3 received

diet containing 1% soybean oil, T4- birds in this treatment received diet containing 1% palm

kernel oil and T5- birds in this treatment received diet containing 1% groundnut oil.

The experimental model is as shown.

Xi j= μ + τi + εij

Where: Xi j= individual observation

μ = population mean

τi= effect of dietary fat sources

εij= experiment or random error

42

3.9 Proximate analysis

Feed samples were assayed for their proximate composition at the laboratory of the

Department of Animal Science, University of Nigeria Nsukka. Feed and excreta samples

were assayed for proximate composition by the method of AOAC (1990).

3.10 Statistical analysis

Data generated were subjected to analysis of variance (ANOVA) in CRD using the SPSS

computer package (Snedecor and Cochram, 1980). Significantly different means were

separated using Duncan’s New Multiple Range test. (Duncan, 1955).

43

CHAPTER FOUR

RESULTS AND DISCUSSION

4.1 Results

4.1.1 Proximate composition of experimental Diets

Result of the proximate composition of the experimental diets is presented in Table 4

Table 4: Proximate composition of experimental diet

Treatments*

T1 T2 T3 T4 T5

Dry matter(g) 88.5 91.0 89.0 90.5 89.5

Ash (%) 7.91 6.59 9.55 8.84 9.50

Crude Fibre (%) 5.08 6.04 6.33 4.42 5.03

Crude protein (%) 22.47 21.85 21.78 22.39 23.12

Ether Extract (%) 4.52 3.85 2.25 2.76 5.59

Nitrogen Free Extract

(%)

60.02 61.67 60.09 61.59 56.76

T1 = No oil; T2 = Palm oil; T3 = Soybean oil; T4 = Palm kernel oil; T5 = Groundnut oil.

The crude protein contents of the diets are 23.12%, 22.47%, 22.39 % 21.85% and 21.78 for

diets 5,1,4,2 and 3, respectively. Dietary treatment 5 had the highest crude protein value.

Diets 1,2,3,4 and 5 contained 5.08%, 6.04%, 6.33%, 4.42 % and 5.03% crude fibre,

respectively. The crude fibre content of treatment 3 was the highest while diet 4 had the least

fibre content. The nitrogen- free extract contents of diets 1,2,3,4 and 5 were 60.02%, 61.67%.

60.09%, 61.59%, and 56.76 %, respectively. Treatment had the highest NFE value while

treatment 5 had the least value of NFE. Treatment 5 had the highest content of ether extract

while treatment 3 had the least ether extract content. Treatment 2 had the least ash content of

6.59%, while treatment 3 had the highest ash content of 9.55%.

44

4.1.2 Growth performance of broiler birds fed diets containing different fat sources

Data on growth performance of broiler birds fed diets containing different fat sources are

presented in table 5.

Table 5: Growth performance of broiler birds fed diets containing different fat sources

Treatments*

Parameters T1 T2 T3 T4 T5 SEM

Initial body weight (g) 366.74 358.76 363.19 361.67 370.84 5.1

Final body weight (g) 3065.80b 3057.00b 3171.80b 3507.70a 3006.20b 62.4

Daily feed intake (g) 145.01ab 138.25b 138.32b 152.29a 147.00ab 1.85

Average daily weight gain (g) 55.08b 55.07b 57.19ab 64.21a 53.73b 1.33

Feed conversion ratio 2.63ab 2.53ab 2.42b 2.37b 2.74a 0.05

Protein efficiency ratio 1.89ab 1.98ab 2.05ab 2.10a 1.82b 0.04

Cost of 1kg of feed (N) 101.94 102.09 104.86 103.76 108.00 0.00

Cost of feed per kg wt gain (N) 268.10ab 258.30b 253.75b 245.90b 295.93a 5.62

45

Mortality (%) 4.17c 8.33b 16.67a 8.33b 0.00d 2.38

a,b,c,d Means on the same row with different superscript are significantly (P < 0.05) different

SEM= Standard error of mean.

T1 = No oil; T2 = Palm oil; T3 = Soybean oil; T4 = Palm kernel oil; T5 = Groundnut oil.

Final body weight (FBW) varied significantly (p < 0.05) among the treatments. Birds fed diet

containing palm oil (T4) had high FBW than the birds on the other treatments whose values

were statistically the same. Daily feed intake (DFI), average daily weight gain (ADWG),

feed conversion ratio (FCR), protein efficiency ratio (PER), cost feed per kg weight gain

(CFG) and mortality were all significantly (p<0.05)affected by dietary treatments. Birds on

treatment 4 had similar DFI as birds on treatment 5 and 1 but higher than those of on

treatments 2 and 3.

Birds fed diet containing with palm kernel oil (treatment 4) had similar (p>0.05) average

daily weight gain value as birds on treatment 4 (soybean oil) and this was significantly

(p<0.05) higher than the average weight gain value of birds on treatments 1, 2 and 5. The

average daily weight gain value of birds on treatments 1, 2, 3 and 5 were similar (p>0.05).

The feed conversion ratio values of birds on treatment 5 were similar (p>0.05) to those of

birds on treatments 1 and 2 and this was significantly (p<0.05) higher than the feed

conversion ratio value of birds on treatments 3 and 4. Birds on treatments 1, 2, 3 and 4 had

similar values in fed conversion ratio.

Birds on treatment 4 had similar (p>0.05) protein efficiency ratio value as those of birds on

treatments 1, 2 and 3, and this was significantly (p<0.05) higher than the protein efficiency

ratio value of birds on treatment 5. The PER values of birds on treatments 1, 2, 3, and 5 were

similar (p>0.05).

Birds fed diet containing groundnut oil had similar (p>0.05) cost of feed per kg weight gain

with those on treatment 1, and this was significantly higher than the cost of feed per kg

46

weight gain of birds on treatments 2, 3 and 4. The cost of feed per kg gain values of birds on

treatment 1, 2, 3 and 4 were similar (p>0.05).

Birds on treatment 3 had the highest (p<0.05) % mortality, followed by birds on treatment 2

and 4 whose values were however similar (p>0.05), followed by birds on treatment 1, while

birds on treatment 5 had the lowest (p<0.05) % mortality.

4.1.3 Carcass and organ characteristics of broiler birds fed diets containing different fat

sources

Data on carcass and organ characteristics of broiler birds fed diets containing different fat

sources are presented in table 6.

Table 6: Carcass and Organ Characteristics of broiler birds fed diets containing different fat

sources.

Treatments*

Parameters T1 T2 T3 T4 T5 SEM

Live weight (kg) 3.43a 3.05ab 3.13ab 3.58a 2.55b 0.14

Carcass weight (kg) 2.35ab 2.05b 2.35ab 2.90a 1.75b 0.14

Dressing % 70.68bc 67.26c 74.94ab 81.10a 68.52bc 1.77

Kidney (g) 1.70b 1.20b 3.70ab 5.60a 2.25b 0.58

Abdominal fat (g) 37.35b 37.35b 16.05c 46.10a 11.05c 5.58

Spleen (g) 4.80a 3.45b 3.60b 4.21a 2.30c 0.38

Proventiculus (g) 13.70a 11.55ab 12.60ab 13.85a 9.45b 0.65

Heart (g) 13.75a 11.15ab 13.05a 14.15a 8.55b 0.78

47

Liver (g) 69.45a 59.35ab 58.65ab 59.75ab 48.00b 2.86

Gizzard (g) 56.35a 51.20ab 50.15ab 46.45b 40.85b 2.65 a,b,c,d Means on the same row with different superscript are significantly (P < 0.05) different

SEM= Standard error of mean.

T1 = Control; T2 = Palm oil; T3 = Soybean oil; T4 = Palm kernel oil; T5 = Groundnut oil

The result showed that there were significant differences (p<0.05) in all the carcass and

organ parameters measured.

Birds on treatments 1 and 4 had similar (p>0.05) live weight values with those on treatments

2 and 3 and these were significantly (p<0.05) higher than the mean live weight value of birds

on treatment 5. Treatments 2, 3 and 5 birds had similar (p>0.05) mean live weight values.

Birds on treatments 1, 3 and 4 had similar (p>0.05) mean values of carcass weight, while

birds on treatments 1, 2, 3 and 5 had similar (p>0.05) mean values. Treatment 4 birds had

significantly (p<0.05) mean higher from dressed carcass weight value than birds on

treatments 2 and 5.

Birds on treatments 3and 4 had significantly (p<0.05) higher mean dressing % value than

those on treatments 1, 2 and 5 which had similar mean dressing values.

Birds on treatment 4 had similar (p>0.05) mean kidney value with those on treatment 3 , and

this was significantly (p<0.05) higher than the mean kidney values of birds on treatment 1,2

and 5. The mean kidney values of birds on treatments 1, 2, 3 and 5 were similar (p>0.05).

Birds on treatment 4 had the highest (p<0.05) mean abdominal fat value. Birds on treatment

1 had similar (p>0.05) abdominal fat value with those on treatment 2, and these were

significantly (p<0.05) higher than the abdominal fat values of birds on treatment 3 and 5.

The mean spleen values of birds on treatments 1 and 2 are similar (p>0.05), and are

significantly (p<0.05) higher than those of the birds on treatments 2 and 4 which were also

similar (p>0.05), but were significantly (p<0.05) higher than the abdominal fat value of birds

on treatment 5 which had the least mean value of (2.30g).

48

Birds on (p<0.05) higher than the mean proventiclous value of birds on treatment 5. The

mean proventiculous values of birds on treatments 2 , 3, and 5were similar.

Birds on treatment 1 had similar (p>0.05) mean proventiculous weight value with those on

treatments 4,3 and 2and this was significantly weight value of birds on treatment 1 was

similar (p<0.05) to the mean heart weight values of birds on treatments 2,3 and 4,and this

was significantly (p<0.05) higher than the mean heart weight value of those on treatment

5.Birds on treatments 2 and 3 had similar (p<0.05) values.

Birds on treatment 1 had similar (p>0.05) mean liver weight value with those on treatments

2, 3 and 4, and this was significantly (p<0.05) higher than the liver weight value of birds on

treatment 5. Birds on treatments 2, 3,4 and 5 had similar values. The liver value of birds on

treatment 1 were significant different those on treatment 5. Treatment 1 birds had the highest

mean value of (69.45g) and treatment 5 had the least mean value of (48.00g).

The gizzard weight value of birds on treatment 1 was similar (p<0.05) to the mean gizzard

weight values of those on treatments 2 and 3, and this was significantly (p<0.05) higher than

the gizzard value of birds on treatments 4 and 5. Treatments 2, 3, 4 and 5 birds had similar

(p<0.05) gizzard weight values.

4.1.4 Relative Organ Weight of broiler birds fed diets containing different fat sources

Data on relative organ weights of broiler birds fed diets containing different fat sources are

presented in Table 7.

Table 7: Relative Organ Weight of broiler birds fed diet containing different fat

sources.

Treatments*

Parameters T1 T2 T3 T4 T5 SEM

Gizzard (%) 1.70 1.68 1.64 1.30 1.59 1.85

Heart (%) 0.42a 0.37ab 0.42a 0.40ab 0.33b 0.01

Kidney (%) 0.05c 0.04c 0.12ab 0.16a 0.09bc 0.02

Abdominal fat (%) 1.12 1.23 0.56 1.29 0.44 0.16

Spleen (%) 0.15 0.12 0.12 0.12 0.09 0.01

49

Proventiculus(%) 0.42 0.38 0.41 0.39 0.37 0.01

Liver (%) 2.09 1.95 1.89 1.68 1.88 0.06

a,b,c,d Means on the same row with different superscript are significantly (P < 0.05) different

SEM = Standard Error of Mean.

T1 = Control; T2 = Palm oil; T3 = Soybean oil; T4 = Palm kernel oil; T5 = Groundnut oil

While no significant (p>0.05) differences existed among treatments in relative gizzard

weight, relative abdominal fat weight, relative spleen weight, relative proventicles weight

and relative liver weight, there were significant (p<0.05) differences among treatments in

relative heart weight and relative kidney weight.

The relative heart weight values of birds on treatments 1 and 3 were significantly (p<0.05)

higher than the RHW values of birds on treatment 5. However birds on the treatments 1 and

3 had similar (p>0.05) RHW values with those on treatments 2 and 4. The RHW value of

birds on treatments 2, 4 and 5 were also similar (p>0.05).

Birds on treatment 4 had similar (p>0.05) relative kidney weight value as those on treatment

3 but significantly (p<0.05) higher than the RKW of birds on treatments 1,2 and 5 which had

similar RKW values. The RKW of birds on treatments 3 and 5 were also similar (p>0.05).

4.1.5 Lipid profile of broiler birds fed diets containing different fat sources

Data on Lipid Profile of broiler birds fed diets containing different fat sources are presented

in Table 8.

Table 8: Lipid profile of broiler birds fed diet containing different fat sources.

Treatments*

Parameters T1 T2 T3 T4 T5 SEM

Total

cholesterol(mmol/l)

3.34b 3.09b 3.84ab 4.58a 3.22b 0.21

HDL-C (mmol/l) 0.74ab 0.93a 0.55b 0.68ab 0.61b 0.05

LDL-C(mmol/l) 1.37c 1.88bc 2.19b 3.88a 1.83bc 0.29

Trigys(mmol/l) 1.48a 1.39a 0.53b 1.36a 1.39a 0.14

VLDL(mmol/l) 0.75a 0.70a 0.27b 0.69a 0.70a 0.07

50

a,b,c,d Means on the same row with different superscript are significantly (P < 0.05) different

SEM= standard error of mean

T1 = Control; T2 = Palm oil; T3 = Soybean oil; T4 = Palm kernel oil; T5 = Groundnut oil.

HDL-C= High density lipoprotein cholesterol, LDL-C= Low density lipoprotein cholesterol,

Trigs= Triglycerides, VLDL= Very low density lipoprotein.

The result showed that significant differences (p<0.05) existed among treatments in all the

lipid profile parameters measured.

Birds on treatment 4 had similar (p>0.05) total cholesterol value as those on treatment 3, but

was significantly (p<0.05) higher than the mean total cholesterol values of birds on

treatments 1, 2, and 5.The total cholesterol value of birds on treatments 1, 2,3 and 5 were also

similar(p>0.05).

The mean HDL values of birds on treatment 2 was similar (p>0.05) to those on treatments 1

and 4, but was significantly (p<0.05) higher than the mean HDL values of birds on

treatments 3 and 5. The mean HDL values of birds on treatments 1, 3, 4 and 5 were similar

(p<0.05).

The mean LDL value of birds on treatment 4 was significantly (p<0.05) higher than the mean

LDL values of birds on treatments 1, 2, 3 and 5 followed, birds on treatment 3 whose LDL

values was similar (p>0.05) to those of birds on treatment 2 and 5,but significantly (p>0.05)

higher than the mean LDL value of birds treatment 1.

Birds on treatments 1, 2, 4 and 5 had similar (p> 0.05) triglycerides values which were

however, significantly (p<0.05) higher than the triglycerides value of birds on treatment 3.

Also, the mean VLDL value of birds on treatments 1, 2, 4 and 5 were similar (p>0.05) but

significantly (p<0.05) higher than the VLDL value of birds on treatment 3.

51

4.2 Discussion

4.2.1 Growth performance of broiler birds fed diets containing different fat sources.

As shown in Table 2, there were significant differences (p<0.05) among dietary treatments

on growth performance of broilers. In the present study, it was observed that birds fed diets

with supplemented fat sources improved in body weight and feed efficiency than the control

group.

The significant improvement in growth performance of birds fed diets containing dietary fat

from palm kernel oil and soybean oil could be attributed to the ability of these fat sources to

reduce the passage rate of the digesta through the gastrointestinal tract, thereby allowing for

better nutrient absorption and utilization (Latshaw, 2008). It has been previously reported

that dietary supplementation with vegetable or animal fats did not affect feed passage rate

through the digestive tract in Leghorn chicken (Golian and Polin, 1984). However, the

dissimilarity between the report of Golian and Polin (1984) and the present results could be

attributed to the differences in dietary fat sources and also to the type of birds used in the two

studies. Although the inclusion of fat in broiler feed is beneficial to the growth of birds, one

of the major concerns with regards to dietary fat supplementation is the actual metabolizable

energy (ME) value that can be assigned to each fat source. However, the improvement in

utilization of dietary fat components in bird is enhanced by different sources regardless of

ME content (Jeffri et al., 2010). Early research on the inclusion of fats in poultry diets

indicated that plant-derived oils had higher ME value when compared to animal sources with

high free fatty acid content (Waldroup et al., 1995). Contrally to the results obtained in the

present study, Pesti et al. (2002), Ghazalah et al., (2008) and Mohammadu et al. (2011)

indicated that there were no significant differences among treatments in all the growth

parameters evaluated when broilers were fed diets containing fat from different sources.

The result showed that there were marked differences in daily. Birds on diets supplemented

with palm oil and soybean oil (treatments 2 and 3) had lower values than the rest of the

treatments, which might be as a result of the energy content of these dietary fat sources

(Jeffri et al., 2002). The observed result on feed intake thus could indicate that the

improvement in body weight may have partially been due to improved nutrient digestibility

52

and better nutrient absorption as reflected by improved feed efficiency. It was also found that

broilers fed diets containing palm kernel oil had better growth rate than those in the other

treatments, especially the control group. This observation confirms the advantage of adding

vegetable oil in birds’ diet (Gallardo et al.2012). The improved growth rate may be due to

the higher percentage of long chain fatty acids and higher contents of triglycerides in

vegetable oil (Thacker et al., 1994). The observed similarities in protein efficiency ratio

(PER) of birds in the various treatments may be attributed to the fact that vitamins present in

most dietary fat sources are involved in amino acid metabolism. Vitamin B12 for instance is

required for the production and development of blood cells (sources: Rita T. dela Cruz of

www.bar.gov.ph).

As shown in Table 2, the percentage mortality of birds in treatment 5 was significantly lower

than the values observed in the rest of the treatments. It does seem that groundnut oil had

high level of monounsaturated fatty acid and reduced level of saturated fatty acid which

might have helped to decrease the level of cholesterol. Groundnut oil also has antioxidants

such as vitamin E which might also play an important role in reducing stress in the birds fed

dietary groundnut oil (Anyasor et al. 2009).

4.2.2 Carcass and Organ characteristics of broiler birds fed diets containing different

fat sources.

As shown in table 3, birds fed diet containing palm kernel oil (treatment 4) had significantly

(p<0.05) higher dressing % than those on treatments 1(control), 2 (palm oil) and 5

(groundnut oil). The results are similar to the findings of Felton and Kerley (2004), but

differed from the results reported by Alaedein (2013) which showed that there were no

significant difference in dressing percentage of birds fed soybean oil. The results are also in

consonance with that reported by Andretti et al .(2001) which showed that broilers fed diets

containing poultry fat, canola, sunflower oil, corn, soybean and lad, respectively had similar

carcass yield values. However, the authors observed significant differences (p>0.05) among

treatments in the organ weights measured.

Table 3 also shows that broilers fed diet containing palm kernel oil had the highest

abdominal fat value, while the least values were observed in treatments 3 and 5(diet

53

containing soybean oil and groundnut oil, respectively). Among available fat sources in

poultry nutrition, it has been recognized that soybean oil has adequate essential fatty acids,

unsaturated fatty acid (such as linolenic acid) that can improve broiler performance, and also

linolenic acid can be converted to longer chain omega -3 fatty acids that is an important

factor in animal feeding as health promoter (Bezard et al., 1994). The increase in abdominal

fat observed in birds that consumed the diet containing palm kernel oil is in line with the

results reported by Shahyar et al .(2011) which showed that the addition of 6% fat caused a

significant increase in abdominal fat weight of broilers as compared to those fed control diet.

The results reported by Sanz et al. (2000b) in a study in which the effect of two lipid sources

(beef tallow, sunflower and soybean oil) were evaluated, showed that there was a significant

reduction in the abdominal fat of birds fed diet containing sunflower oil. This shows that the

treated broilers were able to utilize the unsaturated lipids in the vegetable oils very

efficiently. This may have resulted in the reduction of the abdominal fat with the resultant

increase in the lean carcass weight of broilers. This is in agreement with the result of the

present study were birds fed diets with soybean oil and groundnut oil has the least abdominal

fat deposition. Crespo and Esteve- Grarcia (2002) suggested that reduction in the abdominal

fat of broilers fed diets containing soybean oil and groundnut oil seems to be a consequence

of higher lipid oxidation despite the higher synthesis of endogenous fatty acids. Soybean oil

contains high levels of unsaturated acids and are more completely digested of by fowls.

The dressed carcass weight and most of the organ weights (kidney, spleen, heart,

proventriculus, liver and gizzard weights) were significantly (p<0.05) affected by the

inclusion of fat from different sources when compared to the control group. The spleen,

heart, proventriculus, liver and gizzard weights were significantly (p<0.05) higher in the

control as compared to the group fed diet containing groundnut oil. Similar observation had

been reported by Tabiedian et al. (2005) in a study that investigated the effect dietary fats on

organ characteristics of birds. The difference observed in the gizzard weight for instance

might be due to decrease in the passage rate of food which might have gradually increased

gizzard function with the resultant increase in gizzard muscular mass, a condition known as

muscular hypertrophy. This suggestion is in agreement with the observations of Lopez-Ferrer

et al. (2001) and Habib et al. (2011). The liver and to some extent the heart play a major role

54

in detoxification, their similarity in weight tends to suggest that the different dietary

treatments did not have any toxicity effect on these organs. This is in line with the findings of

Diara et al. (2014).

4.2.3 Relative organ weights of broiler birds fed diets containing different sources

Table 4 shows that there were significant differences (p<0.05) among treatments in the

relative weights of heart and kidney of broiler birds fed dietary fat sources. This result

contradicts the result reported by Aydin (2007) which showed that there were no significant

differences among treatments in relative organ weights of birds fed diets containing oil and

linoleic acid.

4.2.4 Lipid profile of broiler birds fed diets containing different fat sources

As shown in Table 5, dietary treatments had significant (p<0.05) effects on all the

parameters (total cholesterol, HDL-C, LDL-C, triglycerides and VLDL) evaluated. The

present results are in agreement with the findings reported by Ozdogan and Aksit (2003).

Birds on treatment 4(diet containing palm kernel oil) had significantly (p<0.05) higher level

of total cholesterol, while birds on treatment 3(diet containing soybean oil) had significantly

(p<0.05) lower level of triglycerides when compared to the control group. Palm kernel oil is

high in lauric acid which has been shown to raise blood cholesterol (Cascaboulho, 2000).

Cholesterol serves as a precursor for biosynthesis of steroid hormones, bile acid and vitamin

D (Weslover et al., 2003). According to (Blanch et al., 1995), blood cholesterol values are

influenced by dietary ingredients. This could be the reason for the various changes seen in

the blood cholesterol parameters of birds fed different dietary fat sources in this study. The

results (Table 5) reveal that a negative relationship existed between cholesterol and

triglyceride values as seen in some of the treatment groups. For instance the total cholesterol

levels of birds fed diet containing 0% oil, palm oil and groundnut oil were low while the

triglyceride levels were higher. In previous studies, animals fed diets rich in cholesterol or

saturated fat had elevated carcass and blood cholesterol levels. However, dietary ingredients

can be manipulated to change the blood values (Blanch et al., 1995; Verma et al; 1995). Low

density lipoprotein (LDL) cholesterol and high density lipoprotein (HDL) cholesterol were

significantly affected by dietary fat sources. This result is in agreement with that of Nobar et

al. (2010) in a study which investigated the effect of canola oil as dietary fat source on lipids

55

profiles of turkey. The lowest value of LDL was observed in the control group, although

birds fed diets containing palm oil and groundnut oil had similar values. It does seem that the

inclusion of dietary fat from soybean and palm kernel oil increased significantly the serum

LDL. The LDL particles pose a risk for cardiovascular diseases, and increase in the

concentration of LDL particles is strongly associated with increasing rates of accumulation of

atherosclerosis within the walls and may eventually lead to sudden plaque rupture and trigger

clot within arterial opening (www.nejm.org). The HDL was higher in the treatment group

that was fed dietary palm oil, although the HDL value was similar to the values observed in

the control group and the group on palm kernel oil. It has been demonstrated that increases in

dietary fat correlate closely with the secretion of lipases and levels of high density lipoprotein

(Coring et al., 1989). However, there is relatively little information regarding the effects of

the quality of the dietary fat on the secretory activity of the pancreas, liver and other vital

organs in monogastrics. Ozdogan and Aksit (2003) also reported significant differences in

LDL and HDL of broilers fed different fat sources which had different energy levels.

According to Sorrentino (2011), unlike other larger lipoprotein particles which deliver fat

molecules to cells, HDL particles remove fat molecule from cells which are involved in the

export of fat molecules. Stephen et al. (2012) reported that increasing concentrations of HDL

particles are strongly associated with decreasing accumulation of atherosclerosis which

eventually results in sudden plaque ruptures, cardiovascular disease and other vascular

diseases. The inclusion of fat from palm oil and palm kernel oil in broiler diets seem to be

beneficial since this leads to increase in HDL. It is therefore safe to consume meat from

broilers fed diets containing vegetable oil, especially palm oil. The VLDL values of birds on

all the treatments were significantly (p<0.05) different, with birds on treatment 3 (soybean

oil) having the least value of 0.27mg/dl. A value of less than 32mg/dl is desirable (Gibbons

et al., 2004). The value obtained in the present study is therefore below normal range and this

does not pose any danger to the animals or those who consume the meat. It is known that

VLDL transport endogenous products and is converted in the blood stream to LDL (Dashti et

al., 2011). The result observed is in agreement with that reported by Ozdogan and Aksit

(2003).

56

CHAPTER FIVE

SUMMARY AND CONCLUSION

5.1 Summary

In an eight-week study conducted at the Poultry Unit of the Department of Animal

Science Teaching and Research Farm, University of Nigeria, Nsukka with one hundred and

twenty day-old broiler chicks, the effect of dietary fat sources on growth performance,

carcass trait, organ characteristics and lipid profile of broilers was evaluated. Results showed

that there were significant differences (p<0.05) among dietary treatments on growth

performance of broilers. Birds supplemented with fat sources improved in body weight and

feed efficiency than the control group, especially treatment 4 (palm kernel oil), and treatment

3 (soybean oil). The observed significant improvement in growth performance of birds was

attributed to the ability of these fat sources to reduce the passage rate of the digesta through

the gastrointestinal tract, thereby allowing for better nutrient absorption and utilization. The

results also showed that there were marked differences in daily and total feed intake. Birds on

diets supplemented with palm oil and soybean oil (treatments 2 and 3) had lower values than

the rest of the treatments.

Birds fed diet containing palm kernel oil (treatment 2) had significantly (p<0.05) higher

dressing % than those on treatments 1(control), 2 (palm oil) and 5 (groundnut oil). The

results also showed that broilers fed diet containing palm kernel oil had the highest

abdominal fat value, while the least values were observed in treatments 3 and 5(diet

containing soybean oil and groundnut oil, respectively. The dressed carcass weight and most

of the organ weights (kidney, spleen, heart, proventriculus, liver and gizzard weights) were

significantly (p<0.05) affected by the inclusion of fat from different sources when compared

to the control group. The spleen, heart, proventriculus, liver and gizzard weights were

significantly (p<0.05) higher in the control as compared to the group fed diet containing

groundnut oil. There were significant differences (p<0.05) among treatments in the relative

weights of heart and kidney of broiler birds fed dietary fat sources.

57

Dietary treatments had significant (p < 0.05) effects on all the parameters (total cholesterol,

HDL-C, LDL-C, triglycerides and VLDL) evaluated. Birds on treatment 4(diet containing

palm kernel oil) had significantly (p<0.05) higher level of total cholesterol, while birds on

treatment 3(diet containing soybean oil) had significantly (p<0.05) lower level of

triglycerides when compared to the control group. Low density lipoprotein (LDL) cholesterol

and high density lipoprotein (HDL) cholesterol were significantly affected by dietary fat

sources. The HDL was higher in the treatment group that was fed dietary palm oil, although

the HDL value was similar to the values observed in the control group and the group on palm

kernel oil. The VLDL values of birds on all the treatments were significantly (p<0.05)

different, with birds on treatment 3 (soybean oil) having the least value of 0.27mg/dl.

5.2 Conclusion

It is evident from the results obtained in the present study that addition of vegetable fat from

palm kernel oil and groundnut oil in broiler diets enhanced the growth performance, carcass

and organ weights of birds. Birds that consumed the diets containing soybean oil had the

least very low density lipoprotein, while those that consumed diet containing palm kernel oil

had similar High Density Lipoprotein Cholesterol value with birds on control.

5.3 Recommendation

Based on the findings of the present study it is recommended that farmers should add any of

vegetable oils investigated, especially soybean oil in the diets of broiler starters and finishers

because such addition will enhance growth performance and carcass yield of birds, result

in less abdominal fat, induce the production of high levels of unsaturated fatty acids and

high density lipoprotein cholesterol and reduce the level of very low lipoprotein

cholesterol.

58

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APPENDIX 1

ANOVA Table on Growth performance of broilers fed diets containing different fat sources

Sum of Squares Df Mean Square F Sig.

TFI Between Groups 1037759.064 4 259439.766 3.758 .041

Within Groups 690351.921 10 69035.192

Total 1728110.986 14

DFI Between Groups 431.976 4 107.994 3.756 .041

Within Groups 287.556 10 28.756

Total 719.532 14

FBW Between Groups 492562.480 4 123140.620 3.786 .040

Within Groups 325216.294 10 32521.629

Total 817778.774 14

IBW Between Groups 262.571 4 65.643 .126 .970

Within Groups 5195.444 10 519.544

Total 5458.015 14

TWG Between Groups 502451.019 4 125612.755 3.280 .058

Within Groups 383018.797 10 38301.880

Total 885469.816 14

ADWG Between Groups 209.129 4 52.282 3.228 .060

Within Groups 161.968 10 16.197

Total 371.097 14

FCR Between Groups .283 4 .071 2.559 .104

Within Groups .276 10 .028

Total .559 14

PER Between Groups .153 4 .038 2.457 .114

Within Groups .156 10 .016

Total .309 14

FCKG Between Groups 3436.162 4 859.041 3.335 .062

Within Groups 2317.910 9 257.546

Total 5754.073 13

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APPENDIX 2:

ANOVA Table on Carcass and Organ characteristics of broilers fed diets containing different fat sources

Sum of Squares Df Mean Square F Sig.

KIDN Between Groups 25.364 4 6.341 6.162 .036

Within Groups 5.145 5 1.029 Total 30.509 9

ABFAT Between Groups 1838.606 4 459.652 2.394 .182

Within Groups 960.175 5 192.035 Total 2798.781 9

SPLN Between Groups 6.997 4 1.749 1.424 .348

Within Groups 6.141 5 1.228 Total 13.139 9

PRVT Between Groups 26.226 4 6.557 2.902 .137

Within Groups 11.295 5 2.259 Total 37.521 9

LIVER Between Groups 462.004 4 115.501 2.108 .217

Within Groups 273.980 5 54.796 Total 735.984 9

DCWT Between Groups 1.456 4 .364 5.200 .050

Within Groups .350 5 .070 Total 1.806 9

DPCT Between Groups 252.907 4 63.227 10.457 .012

Within Groups 30.230 5 6.046 Total 283.137 9

HTW Between Groups 42.656 4 10.664 4.434 .067

Within Groups 12.025 5 2.405 Total 54.681 9

LW Between Groups 1.254 4 .313 3.453 .103

Within Groups .454 5 .091 Total 1.707 9

GIZ Between Groups 266.220 4 66.555 .915 .521

Within Groups 363.580 5 72.716 Total 629.800 9

75

APPENDIX 3:

ANOVA Table on Relative Organ weight of broilers fed diets containing different fat sources

Sum of Squares df Mean Square F Sig.

GIZ Between Groups 133.557 4 33.389 .950 .506

Within Groups 175.647 5 35.129 Total 309.203 9

HRT Between Groups .011 4 .003 2.891 .137

Within Groups .005 5 .001 Total .015 9

KID Between Groups .018 4 .004 7.716 .023

Within Groups .003 5 .001 Total .021 9

ABFAT Between Groups 1.283 4 .321 1.781 .270

Within Groups .900 5 .180 Total 2.183 9

SPLN Between Groups .003 4 .001 .535 .718

Within Groups .007 5 .001 Total .010 9

PVRT Between Groups .003 4 .001 .660 .646

Within Groups .006 5 .001 Total .009 9

LIVR Between Groups .183 4 .046 1.460 .339

Within Groups .157 5 .031

Total .340

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APPENDIX 4:

ANOVA Table on Lipid profile of broilers fed diets containing different fat sources

Sum of Squares Df Mean Square F Sig.

TCHOL Between Groups 2.972 4 .743 4.469 .066

Within Groups .831 5 .166

Total 3.804 9

HDL Between Groups .166 4 .042 3.752 .090

Within Groups .055 5 .011

Total .221 9

LDL Between Groups 7.467 4 1.867 40.994 .001

Within Groups .228 5 .046

Total 7.695 9

TRGL Between Groups 1.239 4 .310 3.244 .114

Within Groups .477 5 .095

Total 1.716 9

VLDL Between Groups .317 4 .079 3.165 .119

Within Groups .125 5 .025

Total .443 9