CHAPTER-1

1.0. GENERAL INTRODUCTION

1.1. Importance and status of Aquaculture

Aquacuiture is one of the fastest growing food production sectors in the world.

Aquaculture plays a vital role in many countries by offering better nutrition, higher

income, foreign exchange and employment opportunities. As aquaculture technology

has evolved, traditional extensive culture, which has been practised by farmers for

generations, is being replaced by semi- intensive and intensive culture to generate

higher yields and faster growth. This has led to enhance the natural availability of food

by fertilization (extensive systems), supplementation of natural food with moist or dry

feed materials (semi- intensive systems), or supplying all the nutrients to the fish as

prepared pelleted diets (intensive systems). As the fish become more dependent on

prepared feeds, the need for nutritionally complete feeds becomes inevitable. Thus low-

cost, well balanced feeds have been designed for farming systems and good husbandry

practices become fundamental in achieving the expected production goals (Lim, 1994;

Lovell, 1998).

Aquaculture has been recognized as a growth area of economic importance in

many countries especially developing ones and has attracted the attention of both

private as well as and public sectors. The potential of aquaculture to meet the

challenges of food security and to generate employment and foreign exchange has

clearly demonstrated the rapid expansion of this sector (Rana, 1997). Fish has been

long valued as a source of high quality animal protein, relatively cheaper for human

nutrition. Fish proteins are essential components of the human diet in densely populated

countries where the total protein intake level may be meager. Presently fish accounts

for more than, or close to 50% of the total animal protein consumed in most countries

I

of the world. According to FAO statistics per capita fish supply and production has

been increased dramatically over the last 20 years indicating the growing importance of

fish as one of the major animal protein sources for human diet (FAQ, 2000). On the

other hand, the world's population has been increasing more quickly than total fish

production. Present world per capita food fish supply stands as 15.8 kg / year, which

still leads to a negative balance between consumption (demand) and supply (FAQ,

2000). The growth of the human population has led to an intensified search for methods

of producing animal protein, other than conventional animal livestock and capture

fisheries, as both face limitations in production. Therefore, aquaculture will presumably

expand geographically, in terms of species cultured and technologies used, as time

passes. The nutritional quality of diets and their adequate presentation are the

foundation of fish farming and can largely determine the success of fish husbandry.

Nutrition influences behaviour, structural integrity, general health, reproduction,

environmental impact and growth in fish (Weatherley and Gill, 1987). Therefore it is

necessary to establish more precisely the nutritional requirements of fish, establish

knowledge on nutrient bioavaiiability of various feedstuffs, and cost, and feed

technology under cultured conditions. This is in order that nutritionally adequate cost-

effective diets can be formulated to maximize growth and also maintain fish in good

health.

In most aquaculture operations today, the cost of food accounts for one half of

the production of fish. This means that small savings in the cost of food can make

aquaculture enterprise more profitable. However the cost of food cannot be

compromised with decreased amounts of essential nutrients, nutrient's availability or

unbalanced composition of nutrients. The requirements for optimum growth, survival

and health of fish set the limits of economic diet formulation.

2

-I9'i '-I092 '-I4 -I)5 '-Io Y'-I997 W1998 '_I9)

40L0Ii'I I

00

so

-cI

40

2(l

E 1ciI iq1Iacu kiii EJ Total capture 0 fatal vvorld h.shiie:

Year

Figure 1.1 \\crld FisIis [rc'diicicii FA(I)_ 2I100:

IiIiininar eStiI11]tc.E:

Ri-ackish walercAmm (I u. g rnIIin

on . . j... Fre-Iawi Fcrculturel IS. I million

Foone-s. ji

Figure I 2 \k ild Aquacu Itur' Piducti:ii in 199A b y conti n.nt FAO,

a riu I UI: 0.9I11IIIifl t:Iafles.

Figure 1.3 WcilcI Aquaculture Prcdu:tioii in )S: l3iakcic''ii by Eiiininiii?iij)

Note: Data cia not i ic lude aquatic plants

The development plans of most producing countries are aimed at increasing fish

supplies from aquaculture for local and export markets, and at increasing the sector's

contribution to food security in rural areas. It has grown rapidly during the last decade

(Figure ii) between 1990 and 1999 aquaculture production expanded by about 150%.

In recent years the world fish production from capture fisheries has continued to

increase (Figure 1.1) with estimated total landings of 125 million metric tonnes in 1999

(FAQ, 2000). Total recorded fish production in 2005-2006 was about 2.6 million

tonnes, of which inland fisheries provided almost 50%. While per capita consumption

is officially estimated at 36 kg of fish per year, it may be much higher considering the

countries enormous wetland potential. (Wolf Hartmann and Suchart Ingthamjitr, 2007).

Reported global aquaculture production in 1999 was estimated as 32.9 million

metric tones or 26% of the total fisheries production. Aquaculture is supplementing or

replacing capture fishery production of over-exploited fish and shellfish stocks. Reports

of global capture fisheries and aquaculture production indicate a figure of 122 million

tonnes in 1997 to 117 million tonnes in 1998 (Figure 1.1). This was mainly due to

decline in some major marine capture fisheries. However, production recovered in 1999

for which the preliminary estimate is about 125 million tonnes. The production increase

of 20 million tonnes over the last decade was mainly due to aquaculture, as capture

fisheries production remained relatively stable (FAQ, 2000) (Fig 1.3).

According to FAQ (1998) global aquaculture production continues to be

dominated by Asia (Figure 1.2) whose role in aquaculture has been perpetuated through

the centuries. Asia's contribution towards total world production increased from 82% to

89% from 1989 to 1998, while Europe's share is 6.33% of global aquaculture

production; Africa, South America and North America contributed only 4.38% in 1998.

The low contribution from such continents is attributed to the fact that unlike Asia

3

Europe, Africa, South America and North America do not have long histories of

aquaculture. China has reported an increase in production of 0.7 million tonnes per year

until 1992 and 26 millions tonnes per year thereafter. For the rest of the world,

combined growth in production has averaged to 0.4 million tonnes per year (FAQ,

2000). However, statistical data reported by FAQ (1998) show that aquaculture

production expanded rapidly from 1989 to 1998 in Asia (169%), Africa (90%), Europe

(32%), South America (400%) and North America (27%). The growth of the human

population has caused an increasing search for alternative means of producing animal

protein in addition to those of animal live stock and capture fisheries: both face limits

in production as well as performance. The need for mobilizing and increasing all

possible protein food sources is considerably great for a country like India where

human population is increasing at the alarming annual rate of 15.2 millions (Anon,

1985. The present per capita consumption of fish is only 3.5 kg year in India as against

the desired consumption level of 31 kg as recorded by the National Advisory

Committee on Human Nutrition. Along with increased production, the per capita

consumption of fish is expected to go up from the present level to over 8.6 kg by turn

of the century (Anon, 1985). Hence there is an urgent need to make the best use of

every possible protein source. India has a large number of freshwater bodies both lotic

and lentic, some of these are perennial and others are seasonal. Most of them are

suitable for fish production.

The development of inland aquaculture is seen as an important source of food

security in Asia particularly in land- locked countries. Fresh water aquaculture

productions dominated by fin fishes has contributed to high total aquatic production in

many Asian countries (FAQ, 2000). In Southeast Asia (Brunei Darussalam, Cambodia,

Indonesia, Laos, Malaysia, Philippines, Singapore, Thailand, Vietnam) freshwater fish

4

dominate aquaculture production and account for 29% (by weight) of the total

production (Subasinghe et al., 1997). In South Asia (Bangladesh, Bhutan, India,

Maldives, Nepal, Pakistan, Sri Lanka) freshwater fish accounted for 94.2% of the total

aquaculture production in 1995 (Subasinghe, 1997). In 1995, world production of

Clariidae catfish was more than 0.2 million metric tonne which was the second most

important group of farmed catfish in the world (FAO, 1997).

1.2. Aquaculture Nutrition

Aquaculture has made its greatest advance during the later part of the 20th

century. Aquaculture is now recognized as a viable and profitable enterprise

worldwide. It will presumably continue to grow and supply an increasingly larger

percentage of fishery products as time passes (Lovell, 1998). Most of the early fish

nutrition research was conducted with salmonid fishes and more recently attention has

also been paid to other important species of fish cultured in different parts of the world,

as well as new fish species with aquaculture potential (NRC, 1983, 1993; Steffens,

1989). The purpose of fish culture is to increase the weight of fish in the shortest

possible time under economically acceptable conditions.

A major determinant of successful intensification of aquaculture is feed. It

accounts for a major part of the total operational cost of an average fish farm. The

performance of a feed is not only dependent on its quality but also on feeding

management. Good quality and nutritionally adequate feed can give poor performance

unless proper feeding practice (feed allowance, feeding frequency and method, and

daily feeding schedules) is employed (Lim and Poernomo, 1985). Thus, particular

attention must be directed towards the development of feeding strategies necessary to

obtain economical production and maintain a clean environment.

The continued expansion and improvement in the efficiency of aquaculture

production requires more improvements in nutritional formulation and feed technology.

Till recent time more than 300 different species of finfish have been cultivated, all with

different feed and nutritional requirements and it is clear that much research has to be

carried out in order to achieve a basic knowledge of their nutrition (Watanabe, 1982).

However, nutritional studies have demonstrated that any diet must, in order to promote

growth, include an energy source, essential amino acids, essential fatty acids, certain

vitamins and minerals. The science of aquaculture nutrition is concerned with the

supply of these dietary nutrients to cultured animals (Lovell, 1998).

1.3. Fish Feed and Dietary Requirements

Fish require dietary sources of energy and other nutrients for growth,

reproduction and health. Growth is characterized primarily by an increase in protein,

minerals and water. Energy-yielding nutrients such as lipid and carbohydrate are

important to support the growth, and an adequate supply of vitamins is also required.

These nutrients may come from natural aquatic organisms or prepared feed; however,

in contemporary aquaculture prepared feeds from commercial foodstuffs are the

primary sources. Thus a familiarization with the nutrients and their sources,

requirements and their roles in metabolism are necessary for successful aquaculture

(Lovell, 1998).

Growth of fish and feed conversion together with carcass composition are

generally influenced / affected by species, genetic strain, sex, stage of reproductive

cycle, etc., leading to different nutritional requirements. Growth is also greatly affected

by quality of diets in terms of nutrient balance, energy content, and bioavailability of

each nutrient and environmental conditions. The total requirement for a given nutrient

on

during growth must include the amount needed for maintenance as well as the amount

required for the new tissue formed (Jauncey, 1998).

Dietary requirements for energy, protein and amino acids, vitamins, essential

lipids and minerals have been analyzed for several fish species of commercial

importance. With a few exceptions, the nutrient requirements of fish (per unit weight

gain or per unit protein gain) are similar to those of terrestrial animals although energy

requirements for fish are lower. Fish are poikilothermic animals and consequently do

not have to spend a large proportion of ingested energy in maintaining body

temperature in contrast to warm-blooded vertebrates (De Silva and Anderson, 1995). In

addition, the primary end-product of nitrogen metabolism i.e., ammonia, is rapidly

excreted by passive diffusion through the gills, and consequently fish employ less

energy in protein catabolism than do terrestrial animals, which must convert ammonia

to non-toxic substances such as urea or uric acid (Brett and Groves, 1979). These two

important metabolic differences between these vertebrate groups, according to Tacon

and Cowey (1985), contribute to the high energetic efficiency of fish and thus, the

absolute difference in requirements of fish and homeothermic vertebrates would reside

in their requirements for energy, not protein (Cho and Kaushik, 1985).

The nutritional quality of diets depends upon the levels of available nutrients

that have been shown to be needed by fish. This is also greatly affected by the energy

value of the diets because fish generally appear to adjust their food intake to satisfy

their need for energy. The available energy level of the diets and the energy

requirements of the fish regulate the actual nutrient intake (Grove et al., 1978; Smith,

1989). Not all fish exhibit such effects experimentally, for example Koskela et al.,

(1998) did not find reduced absolute feed consumption in whitefish, Coregonus

lavaretus fed high energy diets.

7

Dietary protein quality and quantity influence growth provided that other

physiological requirements needed for growth are fulfilled. Further, in fish, proteins are

used as a major energy source and the optimal dietary protein level required for

maximum growth is considerably higher than that of terrestrial farm animals, Cowey et

al., (1975). The dietary protein and amino acid requirements of fish have been reviewed

by Tacon and Cowey (1985). In general, the dietary protein requirement of fish ranges

between 35 and 55% or an equivalent of 45-75% of the gross energy content of the diet

showed in the form of protein (Tacon and Cowey, 1985) and is synonymous with high

protein quality found at least in part in fishmeal or semi-purified protein sources.

Recent evidences by Norwegian researches indicated that lipid levels of 25 to 30% in

salmon fish diets have a beneficial effect on growth and reduction of dietary protein

needs. Although dietary protein requirement of trout, channel catfish and common carp

have been well documented (Cho et al., 1985; Lovell, 1998; Viola and Ariel, 1982).

The effects of different dietary proteins in the activity of proteolytic enzymes in

freshwater catfish have been reported (Mukhopadhyay, 1977 and Hofer, 1982). A

variety of feed ingredients of both plant and animal origin are used in the preparation of

artificial diets in intensive aquaculture. Since protein is the most important and

expensive ingredient from various sources its inclusion needs a careful assessment of

the nutritive quality. Utilization of protein by the fish is influenced by protein quality

and gross protein level in the diets (Steffens, 1981).

Nowadays chicken intestine, fish waste and silkworm pupae are being used as

the dietary protein sources in fish feed formulation especially for carnivorous fish

species. Carnivorous fish species require good quality and highly digestible protein

sources in their feed. Among plant protein ingredients, soybean meal is considered as

the most nutritive plant protein source and a good alternative to fishmeal in shrimp and

8

fish diets. Use of fish meal as higher dietary protein for optimum fish growth (25 to

65%) in fish feeds induced scarcity with its concomitant raise in rice caused an urgent

need to develop low cost and nutritionally balanced fish diets. The alternative sources

of protein for partial or complete replacements of fish meal with various ingredients

have been studied extensively (Tacon and Jackson, 1985; Wee, 1991; Gomes et al.,

1993).

Fishmeal is an excellent protein source in fish feed due to its balanced amino

acid profile and high digestibility. However, the demand of fish production for human

consumption is increasing and leading to a reduced fishmeal and fish oil productions.

Soybean has been regarded as the suitable plant protein sources with a well balanced

amino acids composition for fish with methionine as first limiting amino acids

Storebakken et al., (2000) a relatively constant amino acid composition (Porter and

Jones, 2003). Studies on digestibility and growth in rainbow trout fed diets in which

soybean meal partly substituted fish meal have shown variable results (Tacon et al.,

1983; 011i and Krogdahl, 1994; Kaushik. et al., 1995; Rumsey et al., 1995; Refsite et

al., 1997, 2000).

1.4. Protein

Proteins are the major organic materials in most fish tissues, and most

necessarily form an important component of the diet. One of the major requirements of

fish culture is the efficient transformation of dietary protein into tissue protein

(Weatherley and Gill, 1987). Since the protein component is the most expensive major

ingredient in animal feedstuff, some investigators claim that this requirement tends to

lessen the advantages of fish as an efficient feed converter (Halver, 1976; Steffens,

1981). Almost in all these studies, investigators have utilized various semi-purified and

purified diets to estimate the protein requirements of fish. Some of the constraints to

overcome the requirement, when the diets have to be prepared are listed in Table 1.1

might have been overestimated and also are difficult to compare due to one or more of

the of the following reasons:

(1) Protein that produces maximum growth does not coincide with maximum

protein utilization. (Tacon, 1993).

(2) Fish fed higher protein levels may have used protein for energy purposes in a

higher proportion than those fish fed the lower protein diets (Cowey, 1995).

(3) Energy requirements are expressed as GE, ME or DE accessing to their specific

usage and estimate. Various investigators have used estimated gross energy

(GE) values in formulating their diets (Davis and Stickney, 1978; Jauncey,

1982a; Dc Silva and Perera, 1985; Daniels and Robinson, 1986; Degani et al.,

1989; Khan and Jafri, 1990); others used estimated metabolisable energy (ME)

values (Garling and Wilson, 1976; Machiels and Henken, 1985; Archdekin et

al., 1988; Fagbenro, 1992; Hassan et al., 1995); and few estimated digestible

energy (DE) values (Winfree and Stickney, 1981; Jantrarotai et al., 1996;

Samantaray and Mohanty, 1997).

(4) Most experiments have been carried out on fry and fingerlings which should be

growing rapidly, and may not be extrapolated to larger fish. The protein sources

may not contain an adequate balance of essential amino acids.

(5) Fixed feeding regime may favour the growth of those fish fed the higher protein

diets, as fish eat to satisfy their energy requirements (Cowey and Sargent,

1979). Protein digestibility coefficients may vary as different protein sources

are employed (Hunt, 1980; Tacon and Cowey, 1985; Wilson, 1985; De Silva

and Anderson, 1995).

10

The dietary protein requirement of various cultured fish species have been

investigated by a number of authors (Lim et al., 1979; Jauncey, 1982; Wee and Tacon

1982; Wee and Ngamsnae; 1987; Santiago and Laron; 1991; Singh and Bhanot, 1988)

and these studies showed that the dietary protein requirement for fish varied from

species to species due to feeding habit, size and water temperature. Dietary protein

requirement of cuneate drum appears to be similar to that of other Sciaenids. Extending

the comparison to other carnivorous fish species, protein requirement of cuneate drum

is similar to that for small mouth bass (44% to 45% cp) (Ballestrazzi et al., 1994; Perez

et. al., 1997) and Cobia (45% cp (Chou et al., 2001). Protein requirement of C.

batrachus fingerlings have been studied by Cruz and Laudencia, (1976) and reported

that ration containing 36 to 38% crude protein gave optimum results in terms of weight

gain and feed conversion.

The gross protein requirement of C. carpio as estimated from the dose-response

curve indicated a higher requirement for the smaller for the smaller fish (40% crude

protein) than for the larger fish (35% crude protein) this clearly points to the fact that,

as in many other fish species, that the protein requirement of the fish decreases with

increasing size and age has been observed for several other warm - water fish species

(NAS- NRC, 1983 ; Page and Andrews, 1973 ; Balarin and Haller, 1982). Many

authors obtained conflicting results from their studies on the effect of dietary protein

level on the growth of Nile tiiapia. The dietary protein requirements of several species

of tilapia ranged between 20% and 56% (El-Sayed and Teshima, 1991). The dietary

protein requirement for fish fry is high which ranged from 35% to 56% (Jauncy and

Ross, 1982). Further Wilson, (1989), Pillay, (1990) and El-Sayed and Teshima, (1991)

found that dietary protein requirements decreased with increasing fish size and age.

11

Most of the researchers concluded that higher levels of protein (40% and more)

are required for small fish, while lower levels (25% -35) are adequate for larger fish

(Jauncy and Ross, 1982; Luquet, 1991). This value is within the range of 40 -55%

reported for a variety of carnivores' fish species (NRC, 1983; Steffens, 1989; Wilson,

1989; Jobling, 1994.). Several authors have reported on the effect of dietary protein

levels in various air breathing fishes (C/arias gariepinus). In catfish Mystus nemurus

40% of protein level in diet produced best results (Khan et al., 1993).

The optimum dietary protein requirement in fish diets is influenced by fish

species, protein quality (digestibility, available essential amino acid profile), dietary

protein to energy ratio, the amount of non-protein energy in the diets, the physiological

state of the animal (size / age, reproductive state), environmental status (water

temperature, salinity, etc.), and the level of food intake (Tacon and Cowey, 1985;

Steffens, 1989; Cowey, 1995; Jauncey, 1998).

Commercial feed manufactures currently utilize high quality fishmeal as the

major portion of the protein source in fish diets. Unfortunately, attempts by nutritionists

to replace the fishmeal component of practical fish feeds by alternative sources have

met with only limited success. Protein sources which have been considered include

meat and bone meal, blood meal, soy bean meal, silk worm pupae, various oil cakes,

cotton seed meal, poultry by-product meal, dried brewers yeast, hydrolyzed feather

meal, corn gluten meal and fish silage. These proteins have generally been termed

secondary protein sources and as such are commonly incorporated at low levels in

practical fish diets (Tacon and Jackson, 19851).

Fishmeal is generally rich in protein (essential amino acids), lipid

(polyunsaturated fatty acids), minerals, and vitamins and low in fibre and carbohydrate.

Apart from fishmeal there are no animal feed proteins available to the fish diet

12

0.5- 1.00.0240.560.3- 0.52.5 - 7.51.3 - 3.5

Fish mealFish mealCasein- gelatinSoy/fish mealCasein/albuminCasein

3.0 - 4.0 Casein/gelatin1.0 - 1.5 Casein/gelatin0.06- 1.3 Casein

0.01-7.0 Casein4.0- 10.0 Casein

0.2

40-12010 - 122.5

13-1526323.0-4.0

200.0

10— 12

6.9

1.5- 5.0

3.0

16-45

5.5

655246

2.5

Casein

CaseinFish mealFishmealSoybean mealCasein / gelatinFish mealFish mealFish mealWhole eggprotein

Fish mealFish mealCasein/gelatin

Casein, fish -protein conc.

Casein

Casein / gelatinSand eel andfish mealMenhadenMeal / CaseinFish meal andSoy proteinate

Table 1.1 Estimated dietary protein requirement of selected fish species (for maximum

growth and expressed as a percentage of the diet)

InitialSpecies body Protein source Requirement Reference

wt.(g) (% dry wt.)

Tilapia:Oreochromis mossambicusOreochromis niloticusOreochromis niloticusOreochromis aureusOreochromis aureusTilapia zuluMajor carp:Cirrhinus mrigalaCatla catlaLabeo rohitaCommon carp:Cyprinus carpioCyprinus carpioGrass carp:Ctenophaiyngodon idellaCatfish:Clarias gariepinusClarias gariepinusClarias macrocephalus xClarias gariepinusClarias batrachusClarias batrachusClarias isheriensisHeteropneustesfossilisChannel catfish:Ictalurus punctatusSnakehead:Channa striataRainbow trout:Oncorhynchus mykissChinook salmon:Oncorhychus tschawytschaGilthead sea bream:Pagru.s aurataRed sea bream:Chrysophrys majorEuropean sea bass:Dicentrarchus labraxYellow tail:Serbia quinqueradiataRed drum:Sciaenops oceliatusStriped bass:Morone saxatilis

40 Jauncey (1982a)

28 - 30 De Silva and Perera (1985)35 Teshima et al., (1985b)36 Davis and Stickney (1978)34 Winfree and Stickney (1981)35 Mad et al., (1979)

40 Hassan et al., (1995)

30-35 Seenappa and Devaraj (1995)45 Sen et al., (1978)

45

Sen et al., (1978)32

Takeuchi et al., (1979)

41 -43

Dabrowski (1977)

40 Machiels and Henken (1985)40 Degani et al., (1989)40 Jantrarotai et al., (1996)

40 Khan and Jafri (1990)40 Singh and Singh (1992)40 Fagbenro (1992)39 Sakthivel (1994)

32-36 Garling and Wilson (1976)Samantaray and Mohanty

40 (1997)

40

Satia (1974)

40

Archdekin et al., (1988)

40

Sabaut and Luquet (1973)

55

Yone (1976)

40

Alliot et al., (1979)

55

Takeda et al., (1975)35

Daniels and Robinson (1986)44

55

Millikin (1982)

Table 1.2 Optimum protein : energy ratios (PIE ratios) in the diets for various fishspecies. (CP = Crude protein; GE = Gross energy; DE = Digestible energy; ME =Metabolizable energy, as the basis of calculation)

Initial Crude protein (CP, %);Species body PIE ratio Energy (kJ.g') as the Reference

Wt-(g) (mg P. kJ') basis of calculationTilapia:Oreochromis aureus 2.5 29 56% CP; 19.2 kJ.g' DE Winfree and Stickney (1981)

Oreochromis aureus 7.5 26 34% CP; 13.4 kJ.g' DE Winfree and Stickney (1981)

Oreochromisniloticus 6.0 16-17 30% CP; 19.6 kJ.g' DE Wang etal., (1985)

Oreochromis niloticus 12.0 mg 26 45% CP; 16.7 kJ.g' GE El-Sayed and Teshima (1992)

O.niloticus x 0. aureus 1.6 25 24% CP; 10.8 kJ.g ME Shiau and Huang (1990)

Major carp:Cirrhinus mrigala 3.0-4.0 26.6 40% CP; 15.0 kJ.g' ME Hassan etal., (1995)Common carp:Cyprinus carpio 6.0-20.0 20-25 32-37% CP; 14 kJ.g' DE Watanabe etal., (1987)

Cyprinus carpio 3.0 24 34% CP; 14 kJ.g' DE Murai etal., (1985)Cyprinus carpio 4.0-10.0 21-23 32% CP; 12.2 kJ.S 1 DE Takeuchi el al., (1979)

Catfish:C/arias gariepinus 1.0-14.0 26-29 40-42%CP; 14-1 6kJ.g'DE Uys (1989)Clarias gariepinus 40-120 31 40% CP; 13 kJ.g' ME Machiels and Henken (1985)C/arias batrachus 13-15 25 40% CP; 16 kJ.g" GE Khan and Jafri (1990)C/arias batrachus - 23-31 40%CP; 13-17 kJ.g' GE Patra and Ray (1988)C/arias isheriensis 32 28-31 37-40%; 13 kJ.g' ME Fagbenro (1992)Hybrid catfish:C/arias macrocephalus 2.5 34.0 40% CP; 11.7 kJ.g DE Jantrarotai etal., (1996)

x C/arias gariepinusC/arias macrocephalus 2.0 25.7 35% CP; 13.6 kJ.g' DE Jantrarotai. et al., ( 199 8)

x C/arias gariepinus 4.0 34.7 40% CP; 11.52 kJ.g1 DE Jantrarotai etal., (1998)

Channel catfish:Ictaluruspunctatus 60 20 26% CP; 12.9 kJ.g DE Li and Lovell (1992)Ictaluruspunctatus 200 21-28 32-36% CP; - kJ.g' ME Garling and Wilson (1976)

Snakehead: Samantaray and Mohanty

Channastriata 10-12 21.7 40%CP; 18.4 kJ.g' DE (1997)

Rainbow trout:Sa/mogairdneri 15 19 35%CP; 18kJ.g' DE Takeuchi etal., (1978b)

Salmogairdneri 15 18 35% CP; 18 kJ.g' DE Watanabe etal., (1979)Oncorhynchus mykiss 10-15 22 33% CP; 15 kJ.g' DE Cho and Kaushik (1985)

Red drum:Sciaenops ocellatus 52 21 35% CP; 17 kJ.g' GE Daniels and Robinson (1986)

Gilthead sea bream: 46 26 44% CP; 17 kJ.g' GE Daniels and Robinson (1986)

Sparus aurata 3.0 23 GE Kissil and Groop (1984)

Striped bass:Morone saxati/is 11-16 28 52% CP; 19 kJ.g 1 ME Berger and Halver (1987)

Yellow tail:Serio/a quinqueradiata 65 34 55% CP; 16 kJ.g 1 ME Takeda etal., (1975)

Seriolaquinqueradiata 89 38 57% CP; 15 kJ.g' ME Shimeno etal., (1985)

compounded with essential amino acid (EAA) profile approximating the dietary EAA

requirements. However, chicken intestine, fish waste and silk worm pupae used as a

protein source in fish diets is often necessary to avoid nutrient deficiencies and / or to

enhance palatability of diets, so ensuring good growth and nutritional performance of

the fish.

Many authors suggested that the high protein requirement is an artifact of the

low energy requirement in fish (Cowey, 1979, 1980; Wilson, 1989). In addition, if the

dietary protein to energy ratio is unbalanced so that non-protein energy became

inadequate, where as the dietary protein may be catabolised and used as an energy

source to satisfy maintenance before growth (Cowey and Sargent, 1979; Shepherd and

Bromage, 1988; NRC, 1993). In contrast, excessive dietary energy can reduce feed

consumption and thus lower the intake of the necessary amount of protein and other

essential nutrients for maximum growth. Excessively high ratios of energy to nutrients

can also lead to deposition of large amounts of body fat, which can be undesirable in

food fish (NRC, 1993; Jauncey, 1998). As the use of protein as an energy source is

wasteful from the both nutritional and economical point of view, it seems worthwhile to

supply as much as possible of the required non-protein energy as carbohydrates and

lipids rather than protein and thus reduce the proportion of protein in the diet to the

level needed for growth (NRC, 1993).

The beneficial effects of the incorporation of protein-sparing nutrients have

been widely studied and optimal ratios between energy and protein (E/P ratio) have

been proposed for some species of fish. The most favorable or optimal PIE ratios (in

mg of protein / kJ of energy) in the diets for selected fish species are shown in Table

1.2. These results are based on experiments where dietary lipid was the main source of

non-protein energy and fish were fed diets containing a range of dietary protein levels

13

(in all of them but in those from Takeuchi et al., 1978b; Watanabe et al., 1979; where

all diets contained a fixed dietary protein level), combined with a range of dietary lipid

levels. The energy content of the diets was calculated using typical nutrient energy

contents, except in those by Daniels and Robinson, (1986).

1.5 AIR BREATHING FISHES:

The air breathing fishes constitute a unique group of fishes belonging to diverse

genera which have developed accessory respiratory organs to utilize atmospheric air for

respiration to enable them to thrive in oxygen depleted waters. They form about 15% of

the marketable surplus of freshwater fishes in India (Prasad et al., 1993). Among the air

breathing fishes, the families Channidae form a unique group of food fishes in inland

fisheries in India (Dehadrai et al., 1973). The culture of air breathing fish species has

been popularized because of the need to exploit vast swampy areas and derelict water

bodies for immediate benefit to the people without involving expensive process of their

reclamation. Unlike gill breathing fish, the air breathing fish can be easily stored and

supplied alive to the consumers. The commercially important air breathing fishes of

India are Heteropneustes fossilis (Singhi), Anabas testudineus (Kowai), Clarias

batrachus (Magur), Notopterus chitala (Chital), Channa striatus ((Striped murrel),

Channa marulius (Giant murrel) and Channa punctatus (Spotted murrel).

The air breathing fishes represent the transitional stage in the evolution of

vertebrates, while changing from the aquatic to the terrestrial mode of life. The biology

of air breathing fishes has also received much attention due to their interesting

adaptations especially with regard to respiration. Although they have not successfully

achieved structural and functional modifications for a life on land, they can easily

withstand the hypoxic conditions of water by utilizing their air breathing organs to meet

the adequate supply of oxygen from air. However, elimination of carbon dioxide by the

14

air breathing organs remains the greatest problem for the fish (Rahh and Howell, 1976).

Nevertheless, in order to overcome this difficulty the air breathing teleosts have

succeeded in developing the neomorphic organs for carbondioxide elimination on the

inner side of their operculum (Singh et al., 1990). It is generally a freshwater inhabitant

preferring from clean running stream water to stagnant muddy pond water, weedy

derelict swamps, canals, paddy fields, lakes, reservoirs rivers, beds and baors. They

dwell also in the hilly streams with rocky beds (Hora, 1921). They can even thrive with

the help of its accessory respiratory organ in shallow oxygen depleted waters (Dass,

1940) and in polluted waters mildly or loaded fairly with obnoxious gases.

The air breathing teleosts are bimodal breathers with gill and / or skin

functioning in aquatic gas exchange and neomorphic air breathing organs variously

structured and developed for direct aerial gas exchange (Lenfant et al., 1970). During

ontogenetic development, these fishes change from purely gill-breathers during larval

or juvenile stages to obligate air breathers when become adult.

The reclamation of swamps for carp culture would require considerable

expenditure, yet a waste of valuable food sources it will be if these vast areas are not

better utilized for the culture of air breathing fishes. Realization of these objectives

would have considerable significance in the augmentation of fish production, especially

in the rural areas (Dehadrai, 1972; 1978; Dehadrai and Thakur, 1980). But, at present,

fish collection from wild is declining every year. So far, limited attempts have been

made in air breathing fish culture when compared to Indian major carps and minor

carps.

15

;:4

4 IN "9W'?

4 !ur—_ -

NATARAJ bfl

NATABAJ S2

-..

C. Channa punctatus d. Channa inicropeltes

PLATE.1

a. Channa marulius b. Channa striatus

1 IlL .1 il.l 1..._ ..- -, IjJ - IL ! l!ilIllIl III 1111.iflUItI1IlIt Illijilil IHjlIfl II!

-

e. Chaiinagac/iva

1.6 Channa striatus (Stripped murrel)

Murrels commonly called stripped munel (Channa striatus) belonging to the

family Channidae (Ophiocephalidae) constitute the most common and dominant group

of air breathing fishes and highly regarded food fish in the South and South East Asian

countries (Wee, 1982). Their ability to breathe atmospheric oxygen makes them

suitable to survive for longer periods out of water. Besides the high quality flavour and

texture of their flesh, murrels are specially regarded as diet for valid and recuperating

patients (Khanna, 1978). There are over 28 species of murrels distributed in tropical

Asia including northern China and Africa. Studies made during the All India Co-

coordinated Research Project on Air breathing Fish culture (ICAR final report 1975-

1985) reported that among the ten species of murrels as described by Day (1878) only

the following eight are valid.

1. Channa marulius (Hamilton, 1822) (plate La)

2. Channa striatus (Bloch, 1793) (plate 1.b)

3. Channapunctatus (Bloch, 1793) (plate 1.c)

4. Channa orientalis (Bloch and Schn, 1801)

5. Channa stewartii (Play fair, 1867)

6. Channa micropeltes (Kuhl & Val, 1822) (plate 1.d)

7. Channa barba (Hamilton, 1822)

8. Channa gachua (Hamilton, 1822) (plate 1.e)

Among these C. striatus (Striped munel) C. marulius (Giant murrel) C.

micropeltes grow to a length of 1.2 m, whereas the other two species C. punctatus and

C. gachua are smaller in size, reaching 22-30 cm. Though adult murrels have a market

value in Asian countries, the preferred weight is 100-1000 g. Murrels are a group of

carnivore and belong to the genus Channa. They are known for their predatory habit

16

and serpent like head. The stripped murrels are commonly considered pest fishes in the

culture ponds because of their predatory habit. Murrels are very hardy and can tolerate

unfavorable conditions, if kept moist; they can live out of water for long periods and

are known to survive droughts by aestivating for months in moist mud. Stripped murrel

can survive in harsh environments with low dissolved oxygen and high ammonia (Ng

and Lim 1990; Qin et al., 1997 a) and therefore, are often cultured in grow out ponds at

densities of 40-80 fish/m2, with annual yields ranging from 7-156t ha (Wee, 1982).

They are highly predaceous and cannibalistic; murrels are generally preferred for

monoculture practices considering the stock of the same size group (Josmon et al.,

1994). Recent experimental work in India shows the possibility of culturing C.

marulius, C. striatus, and C. micropeltes in ponds together with tilapia as forage fish

(Ebanesar et al., 1995). Though intensive culture of murrels is lacking in India due to

non- availability of seeds. Saxena, (1993) to reported that the main constraint in the

culture of murrels is the non-availability of seeds.

Channa striatus are stripped murrel widely distributed in Africa and Asia (Ng

and Lim, 1990). It is commercially cultured in Thailand, Taiwan, Philippines and India

(Wee, 1988). Recently attempts have been made to develop culture techniques for

snakehead in Hawai and USA (Qin and Fast, 1996). Production and maintenance of

natural feed organism for snakehead in the culture pond have been widely reported as

one of the main factors contributing to the successful of snakehead production (Qin and

Fast, 1997). The desirable characteristic of this fish includes high market value, rapid

growth, tolerance and high stocking rate (Sampath, 1985). Most commercial snake

head culture rely on capture of wild fry which are then trained to accept formulated

feed consisting of fish waste paste, rice bran, wheat flour (Diana et al., 1985). The

importance of dietary protein level in relation to energy for snakehead fingerlings was

17

found earlier for several other fresh water fish species. (Garling and Wilson, 1976;

Lovell 1989; Dass et al., 1991; De silva ; 1991; Garcia etal., 1993). Previous studies

have shown that snake head fingerlings require about 50% crude protein for maximum

growth (Wee and Tacon, 1982), whereas fry require about 55% crude protein for

maximum growth (Mohanty and Samantaray, 1996).

They support economically important fisheries and aquaculture industry in

many Asian countries (Ling 1977, Chen, 1990). Among murrels C. striatus forms a

significant role in capture fisheries of India. Characteristics of this fish that make it

desirable cultivable food fish include rapid growth and the ability of the fish to store

and use atmospheric oxygen for respiration in waters with low dissolved oxygen and

they can withstand higher stocking densities also. It has been estimated that out of

18,000 tons of marketable surplus air breathing fishes caught from natural resources in

India, murrels account for nearly 12,000 tons (Jhingran, 1975) with major part of them

constituted by Channa marulius, Channa striatus and Channa punctatus.

The fish farmers therefore depend on wild collection, which are unpredictable.

Further, the rearing of hatchlings, post larvae and fry of C. striatus is a complicated

process unlike the raising of carp fry, which has been standardized to some extent.

Recently attempts have been made on larval nutrition of Channa striatus by (Qin et al.,

(1997) and Samantaray and Mohanty, 1997). But these authors have provided

formulated pelleted feeds (instead of live feed) to the larvae resulting in poor survival

and growth.

In India, culture of murrels is still not practised in a systematic way. Their

availability in the market is also very limited. The main reason for their poor

availability is, that the culture is not being encouraged because of their high predatory

carnivorous feeding habit also the fish farmers in India are mainly engaged in carp

18

culture. Moreover, unlike the carps and other fresh water teleost, Channa species do not

accept their feeds in pelleted forms. Hence utilization of animal protein diets for the

monoculture is highly desirable. No systematic culture practice of this species has been

recorded so far, though extensive culture of murrels is practiced in Tamil nadu, Andra

pradesh, Karnataka and Kerala. When compared to the giant munel, the stripped murrel

is more delicate and susceptible to infection and death due to change in the

environment. So the present investigation deals with the utilization of biowaste by

Channa striatus for commercial murrel culture. The optimal dietary protein level

required for channel cat fish and other freshwater fishes on growth have been

demonstrated by several investigators. (Nail and Shell, 1962; Hastings, 1969; Hastings

and Dupree, 1969). But there is no published work available in the candidate species

using the different biowaste optimum dietary requirements and larval rearing protocol

etc.

The following are the objectives of the present study:

1. To study the effect of different live diets on growth and survival of

Channa striatus larvae.

2. To study the effect of different diets on the growth and survival of

Channa striatus fry

3. To study the effect of different level of dietary protein on growth of

Channa striatus fry and fingerlings.

4. To study the effect of different animal protein sources on growth and

survival Channa striatus fingerlings.

5. To study the growth performance of Channa striatus reared in earthen

ponds fed with different animal bio-wastes.

19

40-42

40

C/arias batrachus

40

40

40

14-16 DE

11-13 GE

13-17 GE

16 GE

Table1.3. Dietary protein requirement of air breathing Channa species and Asian

cat fish

Species Protein requirement

Size

(%)

Asian cat fish:

Clarias batrachus

Clarias macrocephalus/gariepinus

Pan gasius hypophthalmus

Pangasius larnaudii

40

Fry

35

Fingerlings

27-29

Fingerlings

35

Fingerlings

20

Juveniles

Snake head: 43

Fry

Channa sp. 36

Fingerling

Information summarized from Jantrarotai, (1996), Takeuchi et al., (2002), Murthy

(2002), Shiau, (2002) and Paripatananont, (2002).

Table 1.4. Dietary protein and energy requirements of air breathing fishes

Protein (%) Energy (Kj/g) P/E (Mg/Kj) Reference

Clarias gariepinus

>40 13 ME 31 Machiels and Henken

(1985)

26-29 Uys (1989)

31-36 Degani et al., (1989)

23-31 Patra and Ray (1988)

25 Khan and Jafri (1990)

Singh and Singh

(1992)I I xx? I flO'1

30 - unuapocnu W. ioi

Clarias islieriensis

37-40 13 ME 28-31 Fagbenro(1992a)a GE = gross energy: DE = digestible energy; ME = Metabolizable energy.b PE protein-energy ratio.

- no data.

20

Table.1.5. Recommended dietary nutrient levels for carnivorous fish species.

Nutrient level

Fish size classFingerling Juvenile Grower Brood fish

Crude lipid % minimum 16

14 14 12

10Fish: plant lipid

7:1

7:1 7:1 7:1

7:1Crude protein % minimum 52

49 47 45

47

Amino acids % minimumLysine 308

2.90 2.78 2.66

2.78

Methionine 1.00

0.94 0.90 0.87

0.90Cystine 0.36

0.34 0.33 0.31

0.33

Carbohydrate %max 15

20 25 25

25Major minerals %Calcium %max 2.5

2.5 2 2

2

Available phosphorus %min 1.0

0.8 0.8 0.7

0.8Manesium % mm. 0.08

0.07 0.07 0.06

0.07

Data from Tacon, (1990).

21

Table. 1.6. Estimated protein requirement of juvenile fish

Species

Channel catfish(Ictalurus punctatus)Estuary grouper(Epinephelus salmoides)Gilthead bream(pagrus aurata)Japanese eel (Anguilla japonica)Large mouth bass(Micropterus salmooides)Plaice(Pleuronectes platessa)Puffer fish (Fugu rubripes)Red sea bream(Chrysophrys major)SalmonidsChinook salmon(Oncorhynchus tshaiytscha)Coho salmon(Oncorhynchus kisutch)Rainbow trout(Oncorhynchus mykiss)

Sockeye salmon(Oncorhynchus nerka)

Smalimouth bass(Micropterus dolomieui)Snakehead(Channa micrppeltes)Stripped bass(Morone saxatilis)

Yellowtail(Seriola quinqueradiata

Source: Wilson, (1989).

Protein sources Estimated

requirements(%)

Whole egg protein

32-36

Tuna muscle meal

40-50

Caesin,FPC a and amino

40acidsCaesin and amino acids

44.5Caesin and FPC

40

Cod muscle

50

Caesin 50

Caesin

55

Caesin,gelatin and amino 40acids

Caesin

LUO

Fish meal 40Caesin and gelatin 40Caesin and gelatin and amino 45acidsCaesin and gelatin and amino 45acids

Caesin and FPC

45

Fish meal

52

Fish meal and SP b

47

Sand eel and fish meal

55

IN