ISSN 1313 - 8820Volume 5, Number 4

December 2013

2013

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Genetics and Breeding

Atanas Atanasov (Bulgaria)Ihsan Soysal (Turkey)Max Rothschild (USA)Stoicho Metodiev (Bulgaria)

Nutrition and Physiology

Nikolai Todorov (Bulgaria)Peter Surai (UK)Zervas Georgios (Greece)Ivan Varlyakov (Bulgaria)

Production Systems

Dimitar Pavlov (Bulgaria)Dimitar Panaiotov (Bulgaria)Banko Banev (Bulgaria)Georgy Zhelyazkov (Bulgaria)

Agriculture and Environment

Georgi Petkov (Bulgaria)Ramesh Kanwar (USA)

Product Quality and Safety

Marin Kabakchiev (Bulgaria)Stefan Denev (Bulgaria)Vasil Atanasov (Bulgaria)

English Editor

Yanka Ivanova (Bulgaria)

2013

ISSN 1313 - 8820 Volume 5, Number 4December 2013

Comparative investigations on feeding efficiency in growing and fattening DanBred and Topigs hybrid pigs

G. Ganchev, A. Ilchev*

Department of Morphology, Physiology and Animal Nutrition, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

Abstract. A balance trial was performed with two groups of Topigs hybrid pigs (n=4) and DanВred hybrid pigs (n=4). Each trial was of 10-day duration (5 days preliminary and 5 day experimental period, during which urine and faeces were collected). The pigs were fed total mix rations prepared in the Experimental base. DanBred hybrid pigs were fed in compliance to Nutrients Standards for pigs in Denmark, 12-th edition, Copenhagen, July 2005. Feeding of Topigs hybrid pigs was done according to recommendations of Guideline for feeding Topigs sows (Topigs International, BV, 2001). Over the entire fattening period, DanBred hybrid pigs exhibited a higher daily nitrogen retention compared to Topigs pigs – by 5.5% on the average. Because of the higher nutrition norms during the different fattening stages DanBred pigs consumed more expensive compound feeds – by 10% on the average. The average costs for lean meat gain produced from Topigs pigs were by 8% lower than those from DanBred pigs. Provided that the other production costs in farms are identical, the rearing of Topigs hybrid pigs was evaluated as more profitable.

Keywords: topigs pig hybrid, DanВred pigs hybrid, N balance, N excretion, N retention, feeding efficiency

AGRICULTURAL SCIENCE AND TECHNOLOGY, VOL. 5, No 4, pp , 2013400 - 404

Introduction Material and methods

An important feature of Bulgarian pig farming is the Balance trials were performed in the Experimental base of the fundamental change in the genotype of animals. Since 2000, new Faculty of Agriculture, Trakia University, Stara Zagora. As pig breeds and hybrids have being and are still imported, which have experimental animals, castrated male pigs from both hybrids placed almost entirely replaced pigs originating from the Danube White in specially designed individual cages were used. Three balance breed, The new hybrids are characterised with intensive growth rate trials were carried out – during the starter, grower and finisher and a high proportion of carcass lean meat. The feeding norms and periods. Each trial was of 10-day duration (5 days preliminary and 5 feed quality requirements for the novel strains are different. day experimental period, during which urine and faeces were According to data from the Association of industrial pig breeding in collected). The pigs were fed total mix rations prepared in the Bulgaria, the current number of sows from the new genotypes in Experimental base. DanBred hybrid pigs were fed in compliance to Bulgaria is about 35,000. The largest share among them are Nutrients Standards for pigs in Denmark, 12-th edition, DanBred sows – 15.000, followed by Topigs – 10.000, PIC – 5.000, Copenhagen, July 2005. Feeding of Topigs hybrid pigs was done GSR – 1.200, Hermitage – 1.000 and other hybrids. according to recommendations of Guideline for feeding Topigs sows

The DanBred strain is created on the basis of four Danish pig (Topigs International, BV, 2001).breeds – Landrace, Yorkshire, Duroc and Hampshire. The breeding Faeces were collected in the morning prior to feed offering. Two schedule allows producing both three-line and four-line hybrids. In samples were collected for analysis on a daily basis. The first (5% Bulgaria, the three-line hybrid is predominating. Topigs is a Dutch from the total amount) was utilized for determination of nitrogen hybrid, obtained by crossing Large White (A-line), Landrace (B-line) content in fresh faeces, and the second (10% from the total amount) and Duroc (D-line). Sometimes, hybridisation schedules include was dried at 60–65 °С in a dryer. Fresh faeces were kept in freezers animals from the Pietrain breed. Topigs has been introduced in our at 17 °С until analyzed. country in 2002. The breeding and distribution of animals is mainly Excreted urine was collected in plastic containers with 100-200 done by the Agroinvest company, Silistra. ml 10% H SO (about 5% of urine amount). The urine volume was 2 4

The farmers in Bulgaria are not completely informed about the measured every morning and 10% was retained for analysis. Urine potential of hybrids for lean meat deposition and the efficiency of samples from each pig were collected in individual plastic bottles utilisation of nutrients from feeds. Therefore, the availability of data and stored in a refrigerator (4ºС) until analyzed. All samples were run about the dietary nitrogen level needed by the different hybrids and in duplicate. The total nitrogen content in feeds, faeces and urine its utilisation are of substantial interest. were assayed as per АОАС (2007).

The aim of the present experiments was to compare two of the Data about feed and water consumption, amounts of faeces most popular pig hybrids in Bulgaria – DanBred and Topigs with and urine, nitrogen retention and output were calculated. Statistical regard to dietary nitrogen retention and utilisation. analysis was performed with Statistica 6 software.

* e-mail: atilbg@abv.bg

400

401

essential amino acids. According to the recommendations for Results and discussionnutrition of both hybrids, there are no significant difference with respect to the first limiting amino acid – lysine. The differences The feeding norms of both hybrids differed mainly with regard to between the growth stages are about 2–3 %. With respect to the the following parameters: other amino acids, controlled in compound feed recipes, the inter-· The content of ME during the different growth periods;hybrid differences vary from 2 to 45 %.· The requirements for some essential amino acids;

The differences in sulfur-containing amino acids levels are · The mineral content.

relatively significant. During the starter period, methionine content The nutrition standards for DanBred hybrid pigs require an

for DanBred pigs is by 23% more as compared to Topigs pigs, energy content of starter compound feed of 13.9 MJ/kg. This is by

whereas methionine + cysteine level is only by 1.6% higher. During about 4% higher than the energy needed for Topigs pigs. During the

the other two periods – grower and finisher – sulfur-containing amino finisher period, energy requirements of DanBred according to norms

acids in nutrition standards for DanBred pigs are by 11–19 % lower are lower than those of Topigs. During the grower period, the

that those of Topigs hybrids. There are also differences with respect requirements of both hybrids are almost identical – 13.1–13.2 MJ/kg

to threonine. During all growth periods, its level is higher for DanBred ME. The different norms for ME during the growth periods influence

hybrid pigs – during the starter period by 9.4 %, during the grower the energy/protein ratio (energy/essential amino acids ratio,

period – by 10.4 %, and during the finisher period – by 17.5 %. These respectively). Also, the different requirements for ME reflect on the

higher norms, according to Danish „Annual reports”, are attributed to amount of fat used in compound feeds and hence, on their

the primary role of this amino acid for muscle tissue synthesis. The production costs (Table 1).

tryptophan dietary levels during all growth periods are higher in All contemporary standards for nutrition of pigs indicate the

nutrition standards for Topigs pigs. During the starter period, the needs for nitrogen through the needed amounts of digestible

difference is 25 %, while during the grower and finisher periods – 45

Table 1. Ingredients content and nutritive value of used compound feeds

Feedrecipe Starter Grower Finisher

1 kg compound feed contains

Digestible amino acids, %

Starter Grower Finisher

Corn

Wheat

Barley

Soybean meal

Sunflower meal

Wheat bran

Fish meal

Sunflower oil

L - Lysine

DL - Methionine

L - Threonine

Salt

Limestone

Dicalcium phosphate

Vitamin premix

Total

ME MJ/kg

CP, %

CF, %

Ca, %

P available, %

Lysine

Methionine+ Cystine

Threonine

Tryptophan

Costs per 1 t feed, BGN

1.06

0.64

0.63

0.20

576.94

0.82

0.54

0.54

0.17

479.90

0.74

0.50

0.49

0.15

437.28

1.07

0.61

0.64

0.29

497.62

0.85

0.57

0.48

0.27

443.99

0.71

0.50

0.40

0.22

422.86

14.00

19.50

3.50

1.00

0.34

13.40

16.80

4.60

0.80

0.25

13.00

15.60

4.50

0.70

0.23

13.20

20.10

3.10

0.80

0.33

13.10

17.00

4.30

0.70

0.23

13.10

15.10

4.90

0.60

0.18

23.00

24.00

10.00

20.30

5.00

5.00

3.00

5.20

0.30

-

0.22

0.28

1.40

1.55

0.75

100.0

19.22

20.00

20.00

14.30

8.00

10.00

-

4.60

0.30

0.08

0.26

0.34

1.20

1.20

0.50

100.0

19.87

22.00

22.00

10.30

9.00

10.00

-

3.00

0.30

0.06

0.24

0.33

1.30

1.10

0.50

100.0

27.48

24.00

10.00

21.00

5.00

5.00

3.00

0.80

0.30

0.03

0.12

0.42

1.30

1.05

0.50

100.0

21.16

20.00

20.00

15.00

8.00

10.00

-

2.60

0.30

0.07

0.07

0.30

1.00

1.00

0.50

100.0

22.15

22.00

22.00

9.00

9.00

10.00

-

3.20

0.30

0.04

0.04

0.22

1.10

0.45

0.50

100.0

Hybrids DanBred Topigs

402

and 41 %, respectively. reflected upon the amount of excreted faeces, which was also Inter-hybrid differences exist also with respect to dietary statistically significantly higher in DanВred pigs. Pigs from both

mineral content. According to nutrition norms, the compound feed of hybrids excreted 0.67 and 0.51 kg faeces per 1 kg consumed feed. DanBred pigs during the starter period should contain almost 1% Са, There was not a considerable difference with regard to drinking i.e. almost by 23% more than is required by Topigs. During the next water consumption. However, the differences in urine output were growth stages, the calcium requirements are also higher, but the significant. DanBred pigs excreted almost twice more urine than difference decreased from starter to finisher periods. The norms for Topigs (Р<0.001).digestible phosphorus during the starter period are almost identical – During the grower period, DanBred pigs consumed more feed 0.33–0.34 %. The differences appear during the grower (difference compared to Topigs (by 8% on the average). The amount of excreted 21.7 %) and particularly the finisher period (difference 33.3 %). Most faeces was also higher. Both hybrid pigs excreted an equal amount probably, the lower requirements of the Topigs hybrid are related of faeces – 0.6 kg per 1 kg consumed feed. The amount of consumed rather to environmental protection issues (a considerable part of the water also differed significantly – the average amount of water drank Dutch territory is under the sea level and excess phosphorus by DanBred pigs was by 37% higher (Р<0.05). This could be contaminates underground waters) than to animal needs. This is attributed on one hand to the greater feed intake by this hybrid. On especially valid for the finisher period, when more than 70% of total the average, DanBred pigs consumed 2.6 L more water, which was nutrients undigested by pigs are excreted. by 0.1 L more than the recommended amount fro this category pigs

Inter-hybrid differences are present also with regard to the (NRC, 1998). The average water consumption in Topigs pigs was macroelement sodium during the starter and finisher periods. During 2.1 L, i.e. 0.4 L less than recommended amount. On the other hand, the starter stage, dietary sodium requirements of Topigs are by 29 % the existing difference between hybrids could be explained by higher higher than those of DanBred, whereas during the finisher period – dietary nitrogen requirements and the need of more water for by 33% lower. The latter could also be attributed to environmental nitrogen output. This thesis is supported by the higher amount of protection. excreted urine in DanBred pigs.

On the basis of feeding requirements, compound feed recipes Data obtained during the finisher period showed that feed for the three pigs' growth stages have been developed. The recipes intake was almost identical in both hybrids. Similar were the differ mainly with respect to the amount of corn, soybean meal and amounts of excreted faeces. During that growth period, there were supplemental fat (Table 1). The nutritional value of each ration is statistically significant differences between the amounts of excreted compliant to the requirements of the respective hybrid and urine. The water consumed by DanBred pigs was by 20% more, and development stage. the urine output – almost twice higher (Р<0.01) than Topigs pigs. In

our belief, the enhanced diuresis was due to the dietary nitrogen Balance trials excess, which needs more water to be excreted. The results from balance feeding trials are presented in Tables The higher feed intake during the starter period in DanBred pigs

2 and 3. During the starter period, feed intake of DanBred hybrid pigs reflected upon the nitrogen intake, which was by 12% higher was by 12% more than that of Topigs (Р<0.05) (Table 2). This compared to that in Topigs pigs (Table 3). The faecal nitrogen output

a – equal letters designate statistically significant differences P < 0,05.

Table 2. Feed and water intake and amounts of excreted faeces and urine

ParametersStarter Grower Finisher Starter Grower Finisher

Feed intake, kg/day

Water intake, l/day

Faeces, kg/ day

Urine, l/ day

a2.08 ± 0.06

3.75 ± 0.46a1.40 ± 0.14a2.97 ± 0.25

a3.05 ± 0.04a7.95 ± 0.52

1.82 ± 0.16

3.29 ± 0.40

3.25 ± 0.11

7.08 ± 0.43

1.89 ± 0.14a3.90 ± 0.32

a1.85 ± 0.05

3.90 ± 0.31a0.94 ± 0.05a1.49 ± 0.12

a2.82 ± 0.09a5.80 ± 0.40

1.72 ± 0.13

2.37 ± 0.31

3.09 ± 0.03

5.88 ± 0.33

1.96 ± 0.13a2.05 ± 0.17

Mean ± SEM MEAN ± SEM Mean ± SEM Mean ± SEM Mean ± SEM Mean ± SEM

DanВred, n = 4 Topigs, n = 4

a – equal letters designate statistically significant differences P < 0,05.

Table 3. Nitrogen balance

ParametersStarter Grower Finisher Starter Grower Finisher

Intake N, g/day

Fecal N, g/ day

Digestibility N, %

Urinary N, g/ day

Total excreted N, g/ day

Retened N, g/ day

Retention N, %

57.66 ± 1.62a10.85 ± 0.52

81.05 ± 1.21

20.80 ± 1.79

31.65 ± 1.45

26.01 ± 0.34

45.11 ± 1.03

69.19 ± 0.87a10.50 ± 0.81a84.81 ± 1.18

31.34 ± 0.96

41.84 ± 0.65

27.35 ± 0.37

39.53 ± 0.36

73.44 ± 0.85

11.99 ± 0.45

83.62 ± 0.77

36.06 ± 2.62

48.05 ± 2.56

25.39 ± 0.83

34.57 ± 1.69

51.33 ± 2.47a9.00 ± 0.21

82.39 ± 0.64

17.93 ± 1.40

26.93 ± 1.54

24.40 ± 0.97

47.54 ± 0.59

67.08 ± 4.16a13.77 ± 0.78a79.25 ± 1.72

26.27 ± 3.45

40.04 ± 3.38

27.04 ± 1.32

40.31 ± 1.64

65.85 ± 3.49

11.55 ± 0.57

82.40 ± 0.57

30.45 ± 2.82

42.00 ± 3.35

23.85 ± 0.94

36.22 ± 2.06

Mean ± SEM Mean ± SEM Mean ± SEM Mean ± SEM Mean ± SEM Mean ± SEM

DanВred, n = 4 Topigs, n = 4

403

was by 20% higher in DanBred pigs that accounted for the lower digestibility of nitrogen in this pig hybrid. Substantial differences were established with respect to nitrogen excreted with urine – by 16% higher in DanВred. It is acknowledged that the excessive nitrogen, digested but not included in protein synthesis is excreted with urine; therefore, it could be assumed that in DanBred pigs the poorer nitrogen utilisation indicated the dietary nitrogen set in nutrition standards was higher than the really necessary level.

During the grower period, the nitrogen balance demonstrated that regardless of the different feed intake, the difference in nitrogen intake between hybrids was small – about 3%. There was however a statistically significant difference in faecal nitrogen output (Р<0.05). The higher concentrations of nitrogen in the faeces of Topigs pigs showed a lower digestibility of this element – by 7% lower compared

between hybrids was 7.5 % in favour of DanBred pigs. The to that in DanBred pigs. The urinary nitrogen output was relatively difference is mainly due to the higher feed intake, but also to the high – DanBred pigs excreted by 19% more nitrogen with urine than dietary nitrogen content, especially during the finisher period. There Topigs pigs. These data together with results about water intake were no inter-hybrid differences with regards to faecal N output and pointed towards the assumption for inefficient nitrogen utilisation by N digestibility. Differences in urinary nitrogen output were relatively DanBred pigs. As a whole during the grower period, the daily large. According to summarised data, Danish hybrid pigs excreted nitrogen output with faeces and urine in pigs from both hybrids was about 15% more nitrogen with urine than Topigs pigs. This the same. Almost identical amounts of nitrogen deposited in the determined the higher total nitrogen output in the Danish DanВred body and its utilisation were also established.pigs. The results from nitrogen balance during the finisher period

The main differences between hybrids are visible from nitrogen have shown that the nitrogen intake in DanBred pigs was by 11.5% retention parameters. The average nitrogen deposition for the three higher than that in Topigs pigs. The difference resulted from the growth stages was 26.3 g N/day (DanBred) and 24.9 g (Topigs). IN higher feed intake and higher protein content of compound feeds for terms of lean meat gain, the respective values were 418 g and 397 g. DanBred hybrid pigs. There was no substantial difference as to the The difference of 5.2 % was not statistically significant, but the higher faecal nitrogen output and nitrogen digestibility. Relatively lean meat gain is a main advantage of DanBred pigs. At the same significant differences (18.5 %) were observed in urinary nitrogen time, Topigs pigs have utilised less efficiently dietary nitrogen (39.32 output. These data confirm the aforementioned hypothesis for vs 40.16 %).excess of dietary nitrogen in finisher rations of DanВred pigs. Again,

the total nitrogen output was higher in the Danish pig hybrid (by 14.5 Economic efficacy of nutrition%). Data about nitrogen balance did not demonstrate definitely the The most intriguing results were about nitrogen retention.

advantages of any of studied hybrids. With respect to nitrogen Nitrogen deposition in DanBred pigs was 25.4 g N/day vs 23.9 g for retention, DanBred pigs were better than the Topigs hybrid. With the Topigs hybrid. Calculated as amount of lean meat gain (as per respect to compound feed costs and N utilisation, Topigs pigs were NRC, 1998), the daily lean meat gain of animals from the first hybrid better than DanBred pigs. was 405 g, and that of Topigs pigs – 380 g. The difference is about

We believe that more accurate information about the 6.5 % in favour of the Danish hybrid. The greater duration of the advantages and disadvantages of a pig hybrid could be obtained by finisher period should also be taken into consideration. IN Bulgaria, calculating the economic efficiency of nutrition. For this purpose, the is it usually from about 55-60 kg live weight to about 110-120 kg live parameter costs per 1 kg lean meat gain was used. It combines the weight. The association between this period's duration and the production and economic indices that determine the efficacy of pork higher protein retention outlines the considerable advantages of the production. The feed recipes were calculated using the price of DanBred hybrid pigs. These advantages are compensated at a ingredients in February 2012. The costs of one tonne feed are certain extent by nitrogen utilisation (deposited N, in % from dietary presented in Table 1. Then, we calculated the economic efficiency of N intake). The results from balance trials shower that with respect to lean meat growth (Table 5).this parameter, the Danish hybrid was inferior to the Dutch hybrid.

According to results, during the starter period, feed costs for The data about the nitrogen balance for the entire production DanBred pigs were 1.20 BGN vs 0.92 BGN for Topigs pigs. The period (Table 4) showed that the difference in nitrogen intake

Table 4. Nitrogen balance starter – finisher

Intake N, g/day

Fecal N, g/day

Digestibility N, %

Urinary N, g/day

Total excreted N, g/day

Retened N, g/day

Retention N, %

66.76 ± 1.81

11.11 ± 0.37

83.16 ± 0.69

29.40 ± 1.86

40.51 ± 1.89

26.25 ± 0.36

39.32 ± 1.17

62.05 ± 2.67

11.45 ± 0.59

81.50 ± 0.66

25.68 ± 2.07

37.13 ± 2.45

24.92 ± 0.68

40.16 ± 1.58

DanВred, n = 12

Mean ± SEM Mean ± SEMMean ± SEM

Topigs, n = 12

Table 5. Economic efficacy of nutrition of pigs according to age

Parameters

Feed intake, kg/day

Compound feed costs BGN/tonne

Feed costs per pig, BGN/day

Weight gain, kg

Costs per 1 kg weight gain, BGN

2.08

576.94

1.20

0.415

2.89

3.05

479.90

1.46

0.436

3.36

3.25

437.28

1.42

0.405

3.51

1.85

497.62

0.92

0.389

2.37

2.82

443.99

1.25

0.431

2.90

3.09

422.86

1.31

0.380

3.44

Lean meat gain (muscle tissue only)

DanBred

Starter StarterGrower GrowerFinisher Finisher

Topigs

404

difference of about 30% was mainly due to the higher nutrition The average costs for lean meat gain produced from Topigs standards of DanBred, hence the more expensive ingredients of pigs were by 8% lower than those from DanBred pigs. Provided that compound feeds for this hybrid. With age, the difference between the other production costs in farms are identical, the rearing of the hybrids decreased, it was 16.8% during the grower and 8.3% Topigs hybrid pigs was evaluated as more profitable.during the finisher periods. The lean meat gain (protein retention multiplied by a coefficient 2.55) was also different during the growth stages. For all stages, DanBred pigs exhibited a higher weight gain.

ReferencesDuring the starter and the finisher periods the difference was about 6.5%, and during the grower period – 1.2 %.

АОАС International, 2007. Official Methods of Analysis of AOAC The calculation of the costs for production of lean pork meat International (18 Edition, Rev. 2), Association of Official Analytical showed that during the starter period, 1 kg weight gain in DanBred Chemists International, Gaithersburg, MD, USApigs was by 0.52 BGN (21.9 %) more expensive than in Topigs pigs. Ilchev A, Ganchev G, Pavlov D, Valkova P and Nikiforov I, 2008. During the grower stage, the difference was 0.46 BGN (15.8 %), and A study on the effect of different protein levels in the diet on the nitrogen retention and excretion in growing pigs. Journal of Animal Science, 45, 5, 54-59 (Bg).Ilchev A, Ganchev G, Pavlov D and Chobanova S, 2008. Investigation of the effect of different levels of protein in diets on retention and excretion of nitrogen at pig through growing period. International Scientific Conference, Stara Zagora, June 5-6, CD, Proceeding book, Animal studies, 3, 1-7 (Bg) .Ilchev A, Ganchev G, Pavlov D, Valkova P and Nikiforov I, 2008. Investigation of the effect of different levels of protein in diets on retention and excretion of nitrogen at pig through finishing period. International Scientific Conference, Stara Zagora, June 5-6, CD, Proceeding book, Animal studies, 3, 1-7 (Bg).Ilchev A, Pavlov D, Miteva Ch and Nikiforov I, 2008. A study on water intake of growing and fattened pigs depending on the live

during the finisher period – 0.07 BGN (2.0 %). Average for the entire weight and the diet composition. Journal of Animal Science, 45, 5, period, the difference between costs per 1 kg lean weight gain was 54-59 (Bg).over 8% in favour of Topigs pigs (Table 6). Ilchev A, Petkova M, 2008. Effect of the nutritional additive Genex

Pig on the compound feed for piglets. Journal of Animal Science, 45, 3, 86-90 (Bg).

Conclusion Ilchev A, 2010. Balance of nitrogen in growing and fattened pigs depending on the amino acids level in the ration. Journal of Animal Over the entire fattening period, DanBred hybrid pigs exhibited Science, 45, 1, 63-68 (Bg).

a higher daily nitrogen retention compared to Topigs pigs – by 5.5% Ilchev A, 2010. Investigation of the effect of different nitrogen levels on the average. Because of the higher nutrition norms, during the in the rations on the economic parameters of oig farming from different fattening stages DanBred pigs consumed more expensive DanBred hybrid. Journal of Animal Science, 45, 1, 69-73 (Bg).compound feeds – by 10% on the average. www.topigs.com, www.danbred.com.

Table 6. Economic efficacy of nutrition for the entirerearing period.

Feed intake, kg/day

Compound feed costs BGN/tonne

Feed costs per pig, BGN/day

Weight gain, kg

Cost per 1 kg weight gain, BGN

Cost per 1 kg weight gain, %

2.80

498.04

1.39

0.418

3.32

100.00

2.66

454.82

1.21

0.397

3.05

91.86

Lean meat gain (muscle tissue only)

DanBred TopigsParameters

Genetics and Breeding

Nutrition and Physiology

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Comparative morphological study of new Burley tobacco linesT. Radoukova, Y.Dyulgerski

Effect of genotypic and environmental factors on the inheritance of the main characters in chickpea and relationships between themR. Sturzu, T. Nistot, Cr. Melucă, Fl. Bodescu, A. Stoilova

Evaluation of double haploid lines of winter malting barley using selection indicesB. Dyulgerova, D. Valcheva

Evaluation of the combining ability of grain yield of mutant maize lines M. Ilchovska

Comparative study of some biochemical indicators in Karakachan and Copper-Red Shumen sheep breedsG. Angelov, I.Dimitrova, T. Mehmedov, P. Stamberov, N. Stancheva, S. Georgieva, Zh. Nakev

Impaired pancreatic function in mulard ducks with experimental aflatoxicosis I. Valchev, N. Grozeva, D. Kanakov, Ts. Hristov, L. Lazarov, R. Binev, Y. Nikolov

Comparative investigations on feeding efficiency in growing and fattening DanBred and Topigs hybrid pigsG. Ganchev, A. Ilchev

Blood parameters in yearling sheep fed Paulownia (Paulownia spp.) leavesI. Varlyakov, V. Radev, T. Slavov, G. Ganchev

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Changes in some blood parameters in yearling rams fed diets with different protein and lipid levelsV. Radev, T. Slavov, I. Varlyakov

Effect of the sowing norm and nitrogen fertilization on the yield from dry bean (Phaseolus vulgaris L.) cultivar Beslet G. Milev

Evapotranspiration of corn crop for silageR. Bazitov, A. Stoyanova

Productivity and economic traits of winter oilseed rape (Brassica napus var. biennis) under the conditions of DobrudzhaG. Georgiev, G. Georgiev, P. Chamurliyski

Feasibility of the use of heat energy from alternative sources for air conditioning in sows facilityK. Peichev, R. Georgiev

Productivity of green beans, irrigated at different pre-irrigation soil moistureR. Petrova, A. Matev, K. Koumanov, B. Harizanova-Petrova

Comparative assessment of plant resources as substrates for bioshlam productionZ. Shindarska, V. Kirov, G. Kostadinova, B. Baykov

The influence of organic carbon on bioremediation process of wastewater originate from aquaculture with use of microalgae from genera Botryococcus and Scenedesmus I. Sirakov, K. Velichkova, G. Beev, Y. Staykov

Sanitary hygienic assessment of drinking water from underground source at a pig farmG. Kostadinova

Study of bee honey by spectral analysis in the near infrared spectrumI. Zhelyazkova, S. Atanasova , K. Elencheva – Karaneycheva

Comparative GC/MS analysis of lavender (Lavandula angustifolia Mill.) inflorescence and essential oil volatilesT. Zagorcheva, S. Stanev, K. Rusanov, I. Atanassov

Influence of key factors on the time of initial coagulation of cow's milk using milk-clotting enzyme of camel originP. Panayotov, K. Yoanidu, P. Boyanova, B. Milenkov

Production Systems

Agriculture and Environment

Product Quality and Safety

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Instruction for authors

Preparation of papersPapers shall be submitted at the editorial office typed on standard typing pages (A4, 30 lines per page, 62 characters per line). The editors recommend up to 15 pages for full research paper ( including abstract references, tables, figures and other appendices)The manuscript should be structured as follows: Title, Names of authors and affiliation address, Abstract, List of keywords, Introduction, Material and methods,Results, Discussion, Conclusion, Acknowledgements (if any), References, Tables, Figures.The title needs to be as concise and informative about the nature of research. It should be written with small letter /bold, 14/ without any abbreviations. Names and affiliation of authorsThe names of the authors should be presented from the initials of first names followed by the family names. The complete address and name of the institution should be stated next. The affiliation of authors are designated by different signs. For the author who is going to be corresponding by the editorial board and readers, an E-mail address and telephone number should be presented as footnote on the first page. Corresponding author is indicated with *.Abstract should be not more than 350 words. It should be clearly stated what new findings have been made in the course of research. Abbreviations and references to authors are inadmissible in the summary. It should be understandable without having read the paper and should be in one paragraph. Keywords: Up to maximum of 5 keywords should be selected not repeating the title but giving the essence of study. The introduction must answer the following questions: What is known and what is new on the studied issue? What necessitated the research problem, described in the paper? What is your hypothesis and goal ?Material and methods: The objects of research, organization of experiments, chemical analyses, statistical and other methods and conditions applied for the experiments should be described in detail. A criterion of sufficient information is to be possible for others to repeat the experi-ment in order to verify results.Results are presented in understandable

tables and figures, accompanied by the statistical parameters needed for the evaluation. Data from tables and figures should not be repeated in the text.Tables should be as simple and as few as possible. Each table should have its own explanatory title and to be typed on a separate page. They should be outside the main body of the text and an indication should be given where it should be inserted.Figures should be sharp with good contrast and rendition. Graphic materials should be preferred. Photographs to be appropriate for printing. Illustrations are supplied in colour as an exception after special agreement with the editorial board and possible payment of extra costs. The figures are to be each in a single file and their location should be given within the text. Discussion: The objective of this section is to indicate the scientific significance of the study. By comparing the results and conclusions of other scientists the contribution of the study for expanding or modifying existing knowledge is pointed out clearly and convincingly to the reader.Conclusion: The most important conse- quences for the science and practice resulting from the conducted research should be summarized in a few sentences. The conclusions shouldn't be numbered and no new paragraphs be used. Contributions are the core of conclusions. References:In the text, references should be cited as follows: single author: Sandberg (2002); two authors: Andersson and Georges (2004); more than two authors: Andersson et al.(2003). When several references are cited simultaneously, they should be ranked by chronological order e.g.: (Sandberg, 2002; Andersson et al., 2003; Andersson and Georges, 2004).References are arranged alphabetically by the name of the first author. If an author is cited more than once, first his individual publications are given ranked by year, then come publications with one co-author, two co-authors, etc. The names of authors, article and journal titles in the Cyrillic or alphabet different from Latin, should be transliterated into Latin and article titles should be translated into English. The original language of articles and books translated into English is indicated in parenthesis after the bibliographic reference (Bulgarian = Bg, Russian = Ru, Serbian = Sr, if in the Cyrillic, Mongolian =

Мо, Greek = Gr, Georgian = Geor., Japanese = Jа, Chinese = Ch, Arabic = Аr, etc.)The following order in the reference list is recommended:Journal articles: Author(s) surname and initials, year. Title. Full title of the journal, volume, pages. Example:Simm G, Lewis RM, Grundy B and Dingwall WS, 2002. Responses to selection for lean growth in sheep. Animal Science, 74, 39-50Books: Author(s) surname and initials, year. Title. Edition, name of publisher, place of publication. Example: Oldenbroek JK, 1999. Genebanks and the conservation of farm animal genetic resources, Second edition. DLO Institute for Animal Science and Heal th, Netherlands.Book chapter or conference proceedings: Author(s) surname and initials, year. Title. In: Title of the book or of the proceedings followed by the editor(s), volume, pages. Name of publisher, place of publication. Example: Mauff G, Pulverer G, Operkuch W, Hummel K and Hidden C, 1995. C3-variants and diverse phenotypes of unconverted and converted C3. In: Provides of the Biological Fluids (ed. H. Peters), vol. 22, 143-165, Pergamon Press. Oxford, UK.Todorov N and Mitev J, 1995. Effect of level of feeding during dry period, and body condition score on reproductive perfor-

thmance in dairy cows,IX International Conference on Production Diseases in Farm Animals, Sept.11 – 14, Berlin, Germany, p. 302 (Abstr.).Thesis:Penkov D, 2008. Estimation of metabolic energy and true digestibility of amino acids of some feeds in experiments with muscus duck (Carina moshata, L). Thesis for DSc. Agrarian University, Plovdiv, 314 pp.

The Editorial Board of the Journal is not responsible for incorrect quotes of reference sources and the relevant violations of copyrights.EthicsStudies performed on experimental animals should be carried out according to internationally recognized guidelines for animal welfare. That should be clearly described in the respective section “Material and methods”.

Volume 5, Number 4December 2013