Online Version ISSN: X Volume 4, Number 3 September 2012

Transcription

1 Online Version ISSN: X Volume 4, Number 3 September

2 Editor-inChief Tsanko Yablanski Faculty of Agriculture Trakia University, Stara Zagora Bulgaria Co-Editor-in- Chief Radoslav Slavov Faculty of Agriculture Trakia University, Stara Zagora Bulgaria Editors and Sections Genetics and Breading 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) Scope and policy of the journal Agricultural Science and Technology /AST/ an International Scientific Journal of Agricultural and Technology Sciences is published in English in one volume of 4 issues per year, as a printed journal and in electronic form. The policy of the journal is to publish original papers, reviews and short communications covering the aspects of agriculture related with life sciences and modern technologies. It will offer opportunities to address the global needs relating to food and environment, health, exploit the technology to provide innovative products and sustainable development. Papers will be considered in aspects of both fundamental and applied science in the areas of Genetics and Breeding, Nutrition and Physiology, Production Systems, Agriculture and Environment and Product Quality and Safety. Other categories closely related to the above topics could be considered by the editors. The detailed information of the journal is available at the website. Proceedings of scientific meetings and conference reports will be considered for special issues. Submission of Manuscripts All manuscript written in English should be submitted as MS-Word file attachments via to ascitech@uni-sz.bg. Manuscripts must be prepared strictly in accordance with the detailed instructions for authors at the website and the instructions on the last page of the journal. For each manuscript the signatures of all authors are needed confirming their consent to publish it and to nominate on author for correspondence. They have to be presented by a submission letter signed by all authors. The form of the submission letter is available upon from request from the Technical Assistance or could be downloaded from the website of the journal. All manuscripts are subject to editorial review and the editors reserve the right to improve style and return the paper for rewriting to the authors, if necessary. The editorial board reserves rights to reject manuscripts based on priorities and space availability in the journal. Internet Access This journal is included in the Trakia University Journals online Service which can be found at Address of Editorial office: Agricultural Science and Technology Faculty of Agriculture, Trakia University Student's campus, 6000 Stara Zagora Bulgaria Telephone.: Technical Assistance: Nely Tsvetanova Telephone.: ascitech@uni-sz.bg

3 Online Version ISSN: X Volume 4, Number 3 September

4

5 AGRICULTURAL SCIENCE AND TECHNOLOGY, VOL. 4, No 3, pp , 2012 Effect of dietary supplementation of dried distillers grains with solubles (Zarnela) on some rumen fermentation parameters in yearling sheep V. Radev* Department of Morphology, Physiology and Animal Nutrition, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria Abstract. The investigation was carried out with five yearling sheep, Stara Zagora meat type and Pleven Blackhead crosses. The average live body weight of animals at the beginning of the experiment was 55.4 кg. The effect of dietary supplementation of dried distillers grains with solubles (DDGS) on rumen fermentation in sheep was studied. Zarnela dried distillers grains with solubles (DDGS) is a by-product of wheat ethanol production made by the еthanol producing enterprise at Gorna Oryahovitsa, Bulgaria. The experiment consisted of two periods control and experimental. During the control period, animals were fed a ration consisting of kg meadow hay and kg barley. During the experimental period, the ration contained kg barley mash, kg DDGS and kg meadow hay. The following parameters were investigated: hydrogen ion concentration (рн), ammonia concentration, total volatile fatty acid (VFA) concentration.the effects of supplementing the feed of yearling sheep with DDGS were as followed:1) DDGS resulted in statistically significant reduction (p<0.01) of rumen ph before feeding. Two and a half hours after feeding, rumen ph was insignificantly higher in the experimental group. 2) The inclusion of DDGS in the animal ration during the experimental period resulted in increased total VFA concentrations (p<0.05) in the rumen before the feeding hours. The trend for higher rumen total VFA was also preserved after feeding during the experimental period. 3) After the supplementation of the diet with DDGS, rumen ammonia concentrations were significantly higher (p<0.01) in experimental animals after feeding. Keywords: rumen fermentation, sheep digestion Abbreviations: DDGS dried distillers grains with solubles, VFA volatile fatty acid Introduction Cellulose and crude fibres make up a major part of nutrients in ruminant rations. During the evolutionary development of ruminants, their digestive system has evolved and improved in such a manner as to be able to maximally degrade and utilise rough plant feeds, which contain high percentages of cellulose and crude fibre. Under the influence of microbial enzymes, an intense fermentation in fore stomachs of ruminants is occurring. Here, the initial degradation of carbohydrates takes place. That is why the events in fore stomachs of ruminants are essential for the supply of energy to their organisms. The fermentation in the fore stomachs of ruminants could be modified by dietary nutritional supplements (enzyme preparations, probiotics, prebiotics, products from biotechnological, food and distillery industries). The addition of these supplements aims at optimising fermentation processes and achieving a more complete degradation of complex carbohydrates, increased rate of bacterial and infusorial biomass synthesis in the rumen, and increased utilisation of dietary proteins. Apart from their effect on rumen digestion, nutritional supplements influence the degradation and absorption of nutrients in intestines as well (Morgavi et al., 2001). The dried distillers grain is increasingly used as an ingredient of ruminant rations. According to Carvalho et al. (2005) dried distillers grain has high energy value, good digestibility of fat and crude fibres. The nutritional supplement based on dried distillers grain with solubles (DDGS) combined with cereals (wheat or corn is appropriate for combination with low-quality roughages in sheep rations, as it improves its nutritional value (Archibeque et al., 2008). A number of studies on the effect of DDGS on the fattening performance, weight gain and meat quality in small ruminants have been performed. Estrada-Angulo et al. (2007) did not observe a statistically significant difference in the weight gain and feed utilisation after substitution of 15 to 35% of corn and soybean meal in yearling sheep rations by DDSG. The addition of DDSG to the diet of yearling rams at the end of the fattening period did not influence their weight (Held, 2006). Shauer et al. (2006) suggested that DDSG mixed with cereals could be added to finishing lambs at a level of >22.5%. No negative impact on feed intake, growth or carcass traits was reported. Despite the numerous research conducted on both national and international scale, the effect of DDSG on digestive processes in ruminant fore stomachs and its aftereffects on digestion in general are not adequately studied. The present experiment aimed at establishing the influence of the feed supplement Zarnela on some parameters related to rumen fermentation in yearling sheep. The results are a part of a large-scale research on the effect of Zarnela on rumen fermentation in fore stomachs, fattening traits, weight gain and some blood parameters in small ruminants. Material and methods To evaluate the effect of the nutritional supplement Zarnela on the studied parameters, a physiological trial was performed at the Experimental Base of Animal Physiology Unit at the Faculty of Agriculture, Trakia University, Stara Zagora. The experiment was conducted with five yearling sheep, Stara Zagora meat type and Pleven Blackhead crosses. The average live body weight of animals * vradev@uni-sz.bg 241

6 at the beginning of the experiment was 55.4 kg. The sheep were housed in individual pens indoors, with constant access to drinking water and salt licks. Twenty days prior to the experiment, cannulae were surgically placed on the dorsal sac of the rumen of all animals as per Aliev (1960). The tests began after a 10-day period of adaptation of animals to the rations fed. The experiment comprised two periods: control and experimental. During the control period, animals were fed a ration consisting of kg meadow hay and kg barley. During the experimental period the ration contained kg barley mash and kg meadow hay. Also, the experimental ration was supplemented with the feed ingredient Zarnela at kg. The rations were offered twice daily at 8.00 AM and 1.00 PM. According to manufacturer's data, Zarnela contains 90% dry matter, 33% crude protein, 7.6% crude fibre, 4.2% crude fat and 3.2% ash. The chemical composition of rations given throughout this experiment and of feed ingredients was obtained by proximate (Weende) analysis, and was performed in the Animal Nutrition Lab at the Faculty of Agriculture, Stara Zagora. The chemical composition and the amount of feed constituents of both rations are presented in Tables 1, 2 and 3. Zarnela - dried distillers grains with solubles (DDGS) is a feed supplement, by-product of wheat-based ethanol production in the еthanol producing enterprise at Gorna Oryahovitsa, Bulgaria. According to manufacturers, Zarnela is a valuable feed ingredient appropriate for small ruminants, poultry and fish. It contains minerals, vitamins from group B (vitamin В 1, vitamin РР, riboflavin, pantothenic acid and biotin). The content of starch is low, and it is produced by carbohydrate-rich sources. The starch has fermented as a result of ethanol production. The content of amino acids, fats, vitamins and minerals in Zarnela is almost 3 times higher than that of source feeds. The fibre content of Zarnela is high, and it is a rich source of energy for the animal organism. According to the manufacturer, Zarnela could efficiently replace the high-protein sunflower meal in rations, as well as a part of grain in compound feed recipes. Ruminal content for analysis was collected thrice daily via the cannula for 4 consecutive days before feeding, 2.5 and 5 hours after feeding. The following parameters were determined: hydrogen ion concentration (рн), ammonia concentration, total volatile fatty acid (VFA) concentration.routine methods of analysis, as described in previous studies of ours (Radev, 1999) were used. The results were statistically processed by statistical software (Statistica for Windows, Stat. Soft. Inc.,1994). Results and discussion Ruminal ph is closely related to the molar ratios of volatile fatty acids. It is also influenced by the extent of carbohydrate and dietary organic matter fermentation in the rumen (Sutton, 1981). Figure 1 presents hydrogen ion concentration (рн) of ruminal content in experimental animals. Before feeding, ph values were the highest 6.45 (control period) and 6.14 (experimental period). After feeding, consequently to enhanced fermentation events in the rumen and VFA production, ph values decreased (p<0.05, p<0.01) 2.5 h after feed intake in both control and experimental sheep. Five hours after feed intake, ph remained relatively low as compared to pre-feeding values 5.71 and 5.92 for control and experimental periods, respectively. The supplementation of Zarnela resulted in ruminal ph reduction (p<0.01) before feeding.by post feeding hour 2.5, ruminal ph in sheep fed the experimental ration was higher, but statistically insignificant. The increased efficacy of fermentation of easily digestible carbohydrates in the ration results in higher concentrations of volatile fatty acids in the ruminal content, and thus, on altered ph values.the high ph values are beneficial for the development of ruminal microflora and stimulated the metabolic activity of microbial colonies, which reflects on the extent of dietary dry matter degradation. According to Russel and Wilson (1996), the reduction in ruminal ph values has a considerable effect on the activity of cellulolytic bacteria in the rumen. Table 1. Chemical composition of feeds Table 2. Daily ration fed to sheep during the control period Feed DM(%) Crude protein Chemical composition (%) Crude fibre Crude fat Ash Feed kg DM intake kg Crude protein Daily intakes, g Crude fibre Crude fat Ash Meadow hay Barley mash DDSG Meadow hay Barley mash Total Table 3. Daily ration fed to sheep during the experimental period Feed kg DM intake kg Crude protein Crude fibre Daily intakes, g Crude fat Ash Meadow hay Barley mash DDSG Total

7 Control Zarnela ph Before feeding 2,5 h after feeding 5 h after feeding Figure 1. ph level mmol/l Before feeding 2,5 h after feeding 5 h after feeding Control Zarnela Figure 2. Volatile fatty acid concentrations (mmol.l-1) Amonia mg/100 ml Before feeding 2,5 h after feeding 5 h after feeding Control Zarnela Figure 3. Ammonia concentration (mg/100 ml) 243

8 Volatile fatty acids are end products of carbohydrate digestion resulted in a marked increase in ruminal ammonia concentrations in the fore stomachs. A small amount originates from the residues of 2.5 hours after feeding but five hours after feeding, they declined deaminated amino acids when ruminants are fed protein-rich rations again. This could be due to the beneficial effect of the DSGS (Leng and. Phillipson, 1970). The great importance of VFA for the supplement on metabolic activity of ruminal proteolytic microflora ruminant organism consists in their function for energy supply and and hence on the extent of dietary protein hydrolysis. The addition of building purposes. The effect of the individual fatty acids on the Zarnela resulted in substantially increased (p<0.01) ruminal different production types is also proved.figure 2 depicts the VFA ammonia concentrations in sheep after feeding. concentrations in the ruminal content of experimental animals.before feeding, the total VFA content during the control -1 period was mmol.l. The inclusion of Zarnela in the ration during the experimental period resulted in increased total VFA Synopsis -1 content (p<0.05) in the rumen up to mmol.l. The tendency Zarnela - Dried Distillers Grains with Solubles from wheat, is a towards higher VFA levels with the experimental ration was feed ingredient with relatively high carbohydrate, mineral, protein preserved in post feeding intervals too. By post feeding hour 2.5, the -1 and fat contents. The supplementation of small ruminant rations total VFA content was mmol.l. The addition of Zarnela -1 (yearling sheep) with Zarnela influenced some primary indices of resulted in post feeding VFA concentrations of mmol.l at the fermentation in fore stomachs. The addition of Zarnela to rations same interval. The tendency was still present five hours after -1 altered ruminal ph, the total concentration of volatile fatty acids and feeding, when ruminal VFA concentrations were mmol.l and -1 ammonia in ruminal content of supplemented animals.added to mmol.l during the control and experimental periods, small ruminant rations, Zarnela altered the direction and intensity of respectively, with insignificant differences. The time course of rumen fermentation and thus, could have an impact on digestion and ruminal VFA was compliant with the classic increase following the absorption of main feed nutrients. morning feeding. Five hours after feeding, the total VFA content in the rumen was statistically significantly higher in both tested rations (p<0.01). The concentrations of volatile fatty acids in the fore stomachs of Conclusion ruminants are influenced by multiple factors. Limiting factors are the composition of the ration, the amount of easily fermentable Zarnela resulted in statistically significant reduction (p<0.01) of carbohydrates, the feeding frequency, dietary supplementation, etc. rumen ph before feeding. Two and a half hours after feeding, rumen The so-called endogenous factors (ruminal content ph, ammonia ph was insignificantly higher in the experimental group. concentration, metabolic activity of rumen microflora, the size of The inclusion of Zarnela in the animal ration during the colonies) all have an impact on VFA content (Sutton, 1980). experimental period resulted in increased total VFA concentrations Proteins in ruminant rations are hydrolysed by microbial (p<0.05) in the rumen before the feeding hours. The trend for higher enzymes, produced by proteolytic ruminal bacteria. The total rate of rumen total VFA was also preserved after feeding during the protein lysis in the fore stomachs is determined by several factors, experimental period. most important of which are the size and metabolic activity of the After the supplementation of the diet with Zarnela, rumen proteolytic bacterial colonies, the amount of easily degradable ammonia concentrations were significantly higher (p<0.01) in proteins in the ration, the rate of nutrients evacuation towards the experimental animals after feeding. more distant parts of the alimentary system (Kopenci and Wallase,1982). The authors suggest that non-soluble proteins are also lysed by bacteria, but in this case, the activity of ruminal infusoria is essential as their vitality in fore stomachs facilitates the References penetration of extracellular proteolytic enzymes in feed protein particles. Dietary proteins are degraded in ruminant fore stomachs Aliev AA, A modification of the fistula method for study of at several stages. The end products of protein lysis occurring in the digestion in the divisions of the ruminant stomach, Sechenov rumen are amino acids and ammonia. The ammonia concentration Journal of Physiology, Soviet union, SSSR, 46, (Ru). in the rumen is a parameter of the extent of protein degradation and Archibeque SL, Freetly HC and Ferrell CL, Feeding absorption in fore stomachs of ruminants. The ruminal ammonia distillers grains supplements to improve amino acid nutriture of concentrations of sheep during both periods of the experiment are lambs consuming moderate-quality forages. Journal of Animal presented on Figure 3. During the control period, pre-feeding Science, 86, ammonia concentration was mg/100ml. After feeding (2.5 and Estrada-Angulo A, Contreras G, Perez A, Gamer G, Lozano O, 5 h) ammonia levels decreased (p<0.05) to 7.74 mg/100ml and 6.41 Rios FG and Vazquez E, Effect of dried distillers grains mg/100ml, respectively. The reduction in ruminal ammonia substituting for corn-soybean meal on growth and feed intake of concentrations after feeding was most probably due to its rapid Pelibuey sheep. Journal of Animal Science, 85, 572. absorption through the wall of the rumen and the utilisation of Carvalho LPF, Melo DSP, Pereira CRM, Rodrigues, MAM, ammonia nitrogen by protein-synthesizing bacteria. Cabrita ARJ and Fonseca AJM, Chemical composition, in A different time course of ruminal ammonia concentrations was vivo digestibility, N degradability and enzymatic intestinal observed with the ration supplemented with Zarnela. Before feeding, digestibility of five protein supplements. Animal Feed Science and th ruminal ammonia was mg/100 ml. By the 2.5 hour after Technology, 119, feeding, ammonia levels increased up to mg/100 ml (p<0.01), Held J, Feeding soy hulls and dried distillers grain with whereas 5 hours after feeding, it was again lower (p<0.05) up to solubles to sheep. Sauth Dakota State University, Cooperative mg/100 ml. Unlike the control ration, the addition of Zarnela Extension Service, ExEx 2052 Access at edu/articles/exex2052.pdf. 244

9 Kopenci J and Wallase RJ, Cellular location and some Russel JB and Wilson DB, Why are cellulolytic bacteria properties of photolytic enzymes of rumen bacteria. Applied and unable to digest cellulose at low ph?. Journal of Dayry Science, Environmental Microbiology, 43, , Morgavi DP, Beachemin KA, Sereco LV, Rode LM, McAlister TA, Schauer CS, Berg PB, Stamm M, Stecher DM, Pearson D and Iwaasa AD and Yang WZ, Resistance of feed enzymes to Drolc D, Influence of dried distillers grains of feedlot photolytic inactivation by rumen microorganisms and performance and carcass characteristics of finishing lambs. gastrointestinal proteases, Journal of Animal Science, 79, Western Dakota Sheep and Beef Day, 47, Sutton JD, Digestion and end product formation in the rumen Leng RD and Phillipson AT, In: Physiology of Digestion and from product in ration. In Digestive Physiology and metabolism in Metabolism in Ruminants". Ed. by A. T. Phillipson. Newcastle upon ruminants, Eds. Y. Ruchebush and P. Thivent. MTP-press, pp Tyne. England. Oricl. Press Radev V,1999. Influence of the Yeast culture (Yea-Sacc 1026) on Sutton JD, Concentrate feeding and milk composition. In the rumen metabolism in sheep. Bulgarian Journal of Agricultural Recent advances in animal nutrition. Ed. W. Haresing. Butterworths, Science, 5, London,

10

11 AGRICULTURAL SCIENCE AND TECHNOLOGY, VOL. 4, No 3, 2012 CONTENTS 1 / 3 Genetics and Breeding Genetic polymorphism of the melatonin receptor MT1 gene in four Bulgarian sheep breeds D. Hristova, S. Georgieva, Ts. Yablanski, S. Tanchev, R. Slavov, G. Bonev Biochemical investigations on sunflower lines (Helianthus annuus L.) and their hybrid combinations N. Nenova, E. Penchev, M. Drumeva Development and testing of experimental sunflower hybrids obtained by using doubled haploid lines M. Drumeva Stability of productiveness and technological qualities of diploid and triploid sugar beet varieties and hybrids G. Kikindonov Morphometric characteristic of European perch (Perca fluviatilis) related to sex dimorphism I. Sirakov, Y. Staykov, E. Ivancheva, G. Nikolov, A. Atanasov Correlations between grain yield and yield related traits in barley mutant lines B. Dyulgerova Nutrition and Physiology Pharmacokinetics of tilmicosin in calves after single subcutaneous application D. Dimitrova, P. Petkov, D. Tsoneva Pharmacokinetics of pefloxacin in pigs after single intramuscular application D. Dimitrova, V. Katsarov, D. Tsoneva Age-related morphometric and weight parameters of third-eyelid (Harderian) gland in common bronze turkeys (Meleagris meleagris gallopavo) D. Dimitrov Effect of dried distillers' grains with solubles from corn (ddgscc) fed on fattening lambs M. Yossifov, L. Kozelov, K. Dimov Research on the stimulating effect of Tribulus terrestris on the oviparous activity of the queen bees I. Hristakov Ethological parameters as markers of sheep welfare І. Varlyakov, T. Slavov Effect of dietary supplementation of dried distillers grains with solubles (Zarnela) on some rumen fermentation parameters in yearling sheep V. Radev Production Systems Performance of three commercial hybrid layers housed in conventional and enriched cage systems H. Lukanov, D. Alexieva 246

12 AGRICULTURAL SCIENCE AND TECHNOLOGY, VOL. 4, No 3, 2012 CONTENTS 2 / 3 The evolution and current situation of sheep breeding in Romania I. Răducuţă Effect of soil compaction on nodulation of common bean (Phaseolus vulgaris L.) G. Milev, P. Yankov Effect of biostimulator Aveikan on growth manifestations yield and phytosanitary status in leek variety Starozagorski 72 S. Masheva, N. Valchev, V. Yankova Influence of mineral fertilization on the harmful soil acidity and chemical composition of wine grape varieties V. Valcheva, K. Trendafilov, S. Todorova Studying the effect of irrigation furrows in maize grain A. Stoyanova, M. Georgiev, L. Plescuta Chemical composition, nutritive value, energy yield and feed units of the winter pea grain grown after different predecessors using conventional and organic production M. Gerdgikova, M. Videva, D. Pavlov, A. Dobreva Agriculture and Environment Assessment of the physical-chemical status of surface water in lower part of Toundja river, Bulgaria G. Mihaylova, G. Kostadinova, G. Petkov Change of some chemical properties of alluvial-meadow soil (Mollic fluvisol) after long term fertilization S. Todorova, N. Simeonova, K. Trendafilov, V. Valcheva Investigation on the effect of the environment on some new common winter wheat varieties E. Penchev, K. Kostov, I. Stoeva, V. Dochev Chemometrical analyses of Zn distribution between water and soil of dams in Chirpan Municipality, Bulgaria N. Georgieva, Z. Yaneva, M. Todorova, R. Ivanova, N. Nizamov, P. Neicheva Comparative ecological analysis of the types of pasture and swards in Sakar and Strandzha region V. Vateva, K. Stoeva Product Quality and Safety Physico-chemical quality characteristics of royal jelly from three regions of Bulgaria R. Balkanska, I. Zhelyazkova, M. Ignatova Microscopic method for qualification of the cut surface of white brined cheese P. Boyanova, P. Panayotov, V. Ganchovska, A. Bosakova Ardenska Characterization of enzyme with carboxymethyl cellulase activity produced by Trichoderma reesei NRRL 3652 B. Zhekova, G. Dobrev, V. Dobreva, M. Hadjikinova

13 AGRICULTURAL SCIENCE AND TECHNOLOGY, VOL. 4, No 3, 2012 CONTENTS 3 / 3 Investigations on production traits of mulard ducks with experimentally induced aflatoxicosis I. Valchev, N. Grozeva, L. Lazarov, D. Kanakov, Ts. Hristov, R. Binev, Y. Nikolov Study on levels of some heavy metals in water and liver of carp (Cyprinus carpio L.) from waterbodies in Stara Zagora region, Bulgaria V. Atanasov, E. Valkova, G. Kostadinova, G. Petkov, N. Georgieva, Ts. Yablanski, G.Nikolov Comparative electronmicroscopical study of the enterocytes of the duodenum of the Japanese quail (Coturnix japonica) and the wild type (Coturnix coturnix) R. Mihaylov, R. Dimitrov, V. Yordanova

14

15 Instruction for authors Preparation of papers Papers 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 authors The 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 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 experiment 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 consequences 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, Responses to selection for lean growth in sheep. Animal Science, 74, Books: Author(s) surname and initials, year. Title. Edition, name of publisher, place of publication. Example: Oldenbroek JK, Genebanks and the conservation of farm animal genetic resources, Second edition. DLO Institute for Animal Science and Health, 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, C3- variants and diverse phenotypes of unconverted and converted C3. In: Provides of the Biological Fluids (ed. H. Peters), vol. 22, , Pergamon Press. Oxford, UK. Todorov N and Mitev J, Effect of level of feeding during dry period, and body condition score on reproductive perforth mance in dairy cows,ix International Conference on Production Diseases in Farm Animals, Sept.11 14, Berlin, Germany, p. 302 (Abstr.). Thesis: Penkov D, 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.

16 Volume 4, Number 3 September 2012