ISSN Volume 6, Number 2 June 2014

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1 ISSN Volume 6, Number 2 June

2 Editor-in-Chief 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 Breeding Atanas Atanasov (Bulgaria) Nikolay Tsenov (Bulgaria) Max Rothschild (USA) Ihsan Soysal (Turkey) Horia Grosu (Romania) Bojin Bojinov (Bulgaria) Stoicho Metodiev (Bulgaria) Nutrition and Physiology Nikolai Todorov (Bulgaria) Peter Surai (UK) Zervas Georgios (Greece) Ivan Varlyakov (Bulgaria) Production Systems Dimitar Pavlov (Bulgaria) Bogdan Szostak (Poland) Dimitar Panaiotov (Bulgaria) Banko Banev (Bulgaria) Georgy Zhelyazkov (Bulgaria) Agriculture and Environment Georgi Petkov (Bulgaria) Ramesh Kanwar (USA) Martin Banov (Bulgaria) 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 manuscripts written in English should be submitted as MS-Word file attachments via to editoffice@agriscitech.eu. 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. Manuscripts submitted to this journal are considered if they have submitted only to it, they have not been published already, nor are they under consideration for publication in press elsewhere. 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. The journal is committed to respect high standards of ethics in the editing and reviewing process and malpractice statement. Commitments of authors related to authorship are also very important for a high standard of ethics and publishing. We follow closely the Committee on Publication Ethics (COPE), elines The articles appearing in this journal are indexed and abstracted in: EBSCO Publishing, Inc. and AGRIS (FAO). The journal is accepted to be indexed with the support of a project BG051PO Science and business financed by Operational Programme Human Resources Development of EU. The title has been suggested to be included in SCOPUS (Elsevier) and Electronic Journals Submission Form (Thomson Reuters). 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.: editoffice@agriscitech.eu

3 Volume 6, Number 2 June 2014 ISSN

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5 AGRICULTURAL SCIENCE AND TECHNOLOGY, VOL. 6, No 2, pp , 2014 Effect of the dietary supplement Zarnela on some duodenal chyme parameters in yearling rams V. Radev*, I. Varlyakov, T. Slavov, R. Mihaylov 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 supplementation of animal rations with dried distillers grains with solubles (DDGS) on duodenal chyme ph, total volatile fatty acid and ammonia concentrations was studied. Zarnela dried distillers grains with solubles is a by-product of wheat ethanol production manufactured by the еthanol producing enterprise at Gorna Oryahovitsa, Bulgaria. The experiment was conducted in two periods control and experimental. During the control period, animals were fed a ration consisting of kg meadow hay and kg barley mash. During the experimental period, the ration contained kg barley mash, kg DDGS (Zarnela) and kg meadow hay. The dietary supplementation with Zarnela at kg had the following effects on studied duodenal chyme parameters: duodenal chyme ph increased both before (p<0.05) and 2.5 hours (p<0.01) after feeding, an insignificant increase in duodenal chyme total volatile fatty acid concentrations, both before and after feeding was established and duodenal chyme ammonia concentrations became higher before (p<0.05) and after feeding (p<0.01). Keywords: Sheep digestion, duodenal chyme Abbreviations: DDGS dried distillers grains with solubles, DM dry matter, VFA volatile fatty acids Introduction In the fore stomachs of ruminants, intense fermentation takes place under the influence of microbial enzymes. The initial degradation of carbohydrates, proteins and fat occurs here. Therefore, the metabolic events in the fore stomachs are essential for providing energy to ruminants. Fermentation in fore stomachs, as well as the next digestion events in the small intestine could be largely modulated by dietary inclusion of the so-called nutritional supplements. Modern approaches in ruminant nutrition are characterised with broad application of exogenous enzyme preparations, probiotics, prebiotics, as well as supplements and ingredients originating from the biotechnological, food and distillery industries. The supplementation of ruminant rations is directed towards optimisation of fermentation, more complete degradation of complex dietary carbohydrates, protection of feed proteins and prevention of their degradation in the rumen, increase in bacterial and ciliate ruminal flora and higher conversion rate of plant proteins. Dietary supplements influence not only rumen degradation, but also nutrient degradation in intestines and the extent of their absorption (Morgavi et al., 2001). Dried distillers grains with solubles (DDGS) witnesses an increasing use as a supplement to ruminant rations. DDGS is characterised with high energy value, good fat and crude fibre conversion (Carvalho et al., 2005). Also, dried distillers grains with solubles is an adequate protein replacer as it possesses a relatively high percentage of rumen undegradable protein (Spiehs et al., 2002). In combination with cereal-base feed (wheat or maize) DDGS is appropriate as part of low-quality roughages in sheep nutrition. Supplemented to small ruminant diets, DDSG improved their nutritional value (Archibeque et al., 2008). In a number of research reports, the effect of DDSG supplementation on fattening performance, weight fain and meat quality of small ruminants was investigated. 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 with DDSG. According to Shauer et al. (2006) DDSG fed with cereals could be added to finishing lambs at a level of more than 22.5%. No negative impact on feed intake, growth or carcass traits was reported. The addition of DDSG to the diet of yearling sheep at the end of the fattening period did not exert a negative influence on their weight and could be used as a supplement decreasing feed costs (Held, 2006). At the same time, there are no studies in available scientific literature showing the effect of the DDSG on fermentation processes in ruminant fore stomachs and concentrations of metabolites in the small intestine as well as their general effect on ruminant digestion and metabolism. The purpose of the present study was to establish the effect of the feed supplement Zarnela wheat-based dried distillers grains with solubles added at kg to yearling sheep ration on duodenal chyme hydrogen ions, volatile fatty acid and ammonia concentrations Material and methods The results reported in this study are a part of a large-scale survey on the effects of wheat-based dried distillers grains Zarnela, on rumen fermentation, some small intestinal indices, fattening performance, weight gain and haematological parameters (blood from v. jugularis) in yearling sheep. To this end, a physiological trial was performed at the Experimental Base of Animal Physiology Unit to 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 * vradev@af.uni-sz.bg 179

6 weight of animals at the beginning of the experiment was 55±4 kg. All animals were of uniform age and origin. During the experiment they were housed indoor in individual pens equipped with individual feed troughs. Sheep had a constant access to drinking water and salt licks. Twenty days prior to the experiment, they were surgically prepared in a way such that to enable collection of duodenal chyme samples. Intestinal cannulae were surgically placed on the proximal part of the duodenum, 4 6 cm from the pyloric sphincter of the rumen. The surgical procedure was described by Aliev (1960). The experiment was designed and performed in compliance to animal welfare regulations. The tests began after a 10-day period of adaptation of animals to rations fed. The experiment comprised two periods: control and experimental. During the control period, animals were fed a ration consisting of kg barley and1.000 kg meadow hay. 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. The chemical composition and the amount of feed constituents of both rations are presented in Tables 1 and 2. Table 1. Chemical composition of feeds Feed Meadow hay Barley mash DDSG Chemical composition (%) Feed Crude protein Crude fibre Crude fat Ash Table 2. Daily ration fed to sheep during the study periods Control period Daily intakes, g Feed Meadow hay Barley mash Total kg DM intake kg Crude protein Crude fibre Crude fat Ash Crude fibre Crude fat Ash Experimental period Daily intakes, g Feed Meadow hay Barley mash DDSG Total kg DM intake kg Crude protein Zarnela represents DDGS. During the last years, it is commonly used as a feed supplement. DDSG is a by-product of wheat-based ethanol production in the еthanol producing enterprise at Gorna Oryahovitsa, Bulgaria. According to manufacturers, Zarnela is a relatively valuable feed ingredient appropriate for ruminants, poultry and fish. It contains minerals, vitamins from group B (vitamin В1, 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. Because of its high dietary protein and fat contents, Zarnela could efficiently replace the high-protein sunflower meal in rations, as well as a part of grain in compound feed recipes. Duodenal content for analysis was collected via the cannula for 4 consecutive days before feeding, and 2.5 hours after feeding. The following parameters were determined: hydrogen ion concentration (рн), total volatile fatty acid (VFA) concentration, ammonia concentration. Routine methods of duodenal chyme analysis are described in previous studies of ours (Varlyakov et al, 2001). The results were statistically processed by statistical software (Statistica for Windows, Stat. Soft. Inc.,1994). Results and discussion Hydrogen ions concentrations in ruminant fore stomachs depends on a number of factors such as extent of dietary carbohydrate fermentation, nutrients' evacuation rate, extent of VFA absorption through the ruminal wall, amount of ingested saliva etc. The dietary amount of easily digestible carbohydrates is essential for ph. The addition of starch, sugar or molasses to the ration reduces the rate of cellulose conversion. The probable cause is the increased rumen acidity and lower metabolic activity of rumen microflora. Neutral ph provides the optimum conditions for cellulose lysis.

7 Parallelly with increasing easily carbohydrate level, an increase in the counts of degrading microorganisms is observed, together with utilisation of nitrogen compounds needed for the growth and development of cellulolytic bacteria. It is reported that the holotrich ciliates D. ruminantum and Isotricha also possess amylolytic enzymes (Williams et al., 1984). Тhese ciliate species are able to convert starch to volatile fatty acids, lactate, hydrogen and carbon dioxide. The composition of the diet is a limiting factor with regard to cellulolysis in the rumen of ruminants. The higher the share of compound feeds, the lower the rumen ph is. The ph values usually increase with time after feeding. This is due to the increased relative share of ingested saliva (Sivkova, 1979) and the advanced nutrient evacuation to the small intestine. Figure 1 presents duodenal chyme ph levels in experimental animals. Hydrogen ion concentration changed according to the period after feeding. Similar changes in duodenal ph in small ruminants were reported after and before dietary supplementation of exogenous enzymatic preparations (Nedeva, 2009). During the control period, pre-feeding ph was 1.81 and continued to increase (p<0.01) to attain hours after feeding. The observed duodenal chyme increase was most probably due to the absorption of metabolic products, especially VFA through the rumen wall and the fore stomachs in post feeding hours and evacuation of content with higher ph towards the duodenum. The secretion of alkaline pancreatic juice which is enhanced after feeding, is also important. The same tendency towards statistically insignificant increase in post-feeding ph values was observed during the experimental period. Pre- and post feeding (2.5 h) ph values were 2.25 and 2.61, respectively. After feed supplementation with Zarnela, duodenal chyme ph increased both before (p<0,05) as well as 2.5 hours after feeding (p<0.01) of experimental sheep. A similar tendency was present with respect to the influence of Zarnela on ruminal fluid ph in a previous study of ours (Radev, 2012). Dietary sugars have a different extent and rate of fermentation, therefore, they alter at a various extent primary parameters of rumen content as рн, ammonia and VFA concentrations (Chamberlain et al., 1985). Many data are reported in the literature concerning the effect of dietary carbohydrate levels on rumen fermentation and the general metabolism of ruminants. According to Oh et al. (1999) the addition of carbohydrates to the feeds improved the utilisation of crude protein and ammonia through changes in the rumen mmol/l 2 fermentation. The extent of dietary carbohydrate fermentation and their absorption through the mucosa of fore stomachs determines their concentrations in duodenal content. The VFA level in duodenal chyme is also influenced by the content evacuation rate from fore stomachs to intestines. Duodenal chyme VFA level is also influence by the inclusion of different supplements as probiotics (Varlyakov et al., 2001), multienzyme preparations (Sivkova, 2007), and diets with different carbohydrate level and structure (Sivkova, 2007). Figure 2 depicts duodenal chyme VFA level in experimental sheep. In pre-feeding hours during the control period, total VFA content was mmol/100 ml and did not change considerably 2.5 hours after feeding VFA values were mmol/100 ml. During the experimental period, the same tendency was present. Before feeding, total duodenal chyme VFA concentration was 19.5 mmol/100 ml and 25 hours after feeding increased up to mmol/100 ml. The addition of the feed supplement Zarnela resulted in statistically insignificant elevation of duodenal chyme VFA both before and after feeding. In a previous experiment (Radev, 2012) changes occurring in total rumen VFA content in yearling rams receiving Zarnela were comparable. The addition of DDGS in the ration of experimental animals increased (p<0.05) total VFA in the rumen before feeding. The observed tendency was also preserved during post feeding hours. According to Sutton (1980), numerous factors influence the production of VFA in the digestive tract of ruminants. Limiting factors are the diet composition, the amount of easily fermentable carbohydrate, the frequency of feeding, the presence of various nutritional supplements etc. The so-called endogenous factors as рн, rumen ammonia concentrations, metabolic activity of rumen microflora, and the size of ciliate colonies are also influencing VFA levels. It was found out that protein hydrolysis in ruminant fore stomachs occurs at two stages. First, dietary proteins are hydrolysed to relatively large protein molecules composed of not less than 2 amino acids. The formed polypeptides are degraded to amino acids and then to ammonia at a later stage (Wallace and McKain, 1990). The proteolysis extent in the fore stomachs depends on a number of factors as diet structure, protein solubility, level of provided nitrogen and energy for microorganisms etc. The metabolism of proteins results from the metabolic activity of rumen ciliates. The protein structure is a key factor for the activity of рн Before feeding Control 2.5 h after feeding Zarnela Figure 1. Hydrogen ions concentration (ph) in the duodenal chyme of experimental animals 0 Before feeding Control 2.5 h after feeding Zarnela Figure 2. Total volatile fatty acid concentrations in the duodenal chyme of experimental animals 181

8 mg 100/ml microbial proteases. Rumen proteolytic activity varies with the type of ration (Hvelplund, 1991). Bacterial activity is dependent on the type and solubility of proteins (Bach et al., 2005). Ammonia is the primary metabolite of proteins and non-protein nitrogen compounds in the rumen, and also a product of rumen microflora (Broderik et al., 1991). Each type of feed is characterised with a specific level and production dynamics of ammonia. Rumen ammonia content depends not only on dietary protein quality, but also on their solubility. It is found out that almost all microorganisms colonising the rumen, use ammonia nitrogen for microbial protein synthesis. The need of rumen bacterial populations for nitrogen is rather variable. Antagonistic relationships among populations are also possible. Bacteria which could satisfy all their needs from ammonia nitrogen inhibit the development of microorganisms needing a supply of amino acids or polypeptides. With this regard, the degree of ammonia nitrogen utilisation from rumen microflora is an essential factors for duodenal chyme ammonia concentrations (Awawdeh et al., 2004). The flow of metabolic products from protein degradation in the small intestine is determined by the enzyme activity of the abomasum, as well as ammonia and nitrogen compounds absorption rate through the mucosa of fore stomachs. Figure 3 presents ammonia concentrations in duodenal chyme of experimental animals. During the control feeding period, it decreased from 7.10 mg/100 ml pre-feeding to 6.00 mg/100 ml 2.5 h after feeding (p<0.05). During the experimental period, there were no statistically significant differences in the studied parameter with The feed supplement Zarnela dried distillers grains with solubles, has a relatively high carbohydrate, mineral, protein and fat content, Studies performed so far indicate that it could be successfully used as a dietary supplement to replace a certain proportion of compound feed. It could be fed to ruminants of various productive type. After being added to the ration of small ruminants (yearling sheep), this feed ingredient influences the main parameters of fermentation in fore stomachs. Zarnela alters the hydrogen ion concentration, total volatile fatty acid amount and duodenal chyme ammonia level in supplemented animals. In the diet of small ruminants, DDGS alters the direction and intensity of rumen fermentation, the subsequent metabolic processes in fore stomachs and small intestine and thus, influences the entire process of digestion and utilisation of main feed nutrients. Conclusion The addition of Zarnela to the diet of small ruminants (yearling sheep) at kg resulted in increased duodenal chyme ph both before (p<0.05) and 2.5 hours (p<0.01) after feeding. The inclusion of Zarnela to the ration during the experimental period resulted in insignificant increase in total VFA amount in the duodenal chyme of experimental sheep at both studied time intervals. Added to the ration of sheep, Zarnela resulted in higher (p<0.05, p<0.01) duodenal chyme ammonia concentrations both before and after feeding References Before feeding Control 2.5 h after feeding Zarnela Figure 3. Ammonia concentration in the duodenal chyme of experimental animals respect to feeding. The respective pre- and post feeding values were 8.47 mg/100 ml and 9.42 mg/100 ml. The supplementation of the diet of experimental sheep with Zarnela resulted in higher (p<0.05; p<0.01) duodenal chyme ammonia levels. According to Spiehs et al. (2002) Zarnela contains a relatively high proportion of rumen undegradable protein, which is converted in the abomasum and the small intestine. Probably, the increased chyme ammonia concentrations were related to increased dietary crude protein level after the addition of Zarnela. The reason of obtained values could also be sought in the extent of ammonia nitrogen utilisation by rumen microflora and ammonia absorption through the mucosa of fore stomachs. 182 Synopsis Aliev AA, A modification of the fistula method for study of digestion in the divisions of the ruminant stomach, Sechenov Journal of Phisiology, Soviet union, USSR, 46, (Ru). Archibeque SL, Freetly HC and Ferrell CL, Feeding distillers grains supplements to improve amino acid nutriture of lambs consuming moderate-quality forages. Journal of Animal Science, 86, Awawdeh MS, Titgemeyer EC, Mc Cuiston KC and Gnad DP, Effects of ammonia load on methionine utilization by growing steers. Journal of Animal Science, 82, Balch A, Calsamiglia S and Stern MD, Nitrogen Metabolism in the rumen. Journal of Dairy Science, 88, Broderick GA, Wallace RJ and Ørskov ER, Control of rate and extern of protein degradation. In Physiological Aspects of Digesta and Metabolism in Ruminants eds T.Tsuda, Y Sasaki and Kawashima, Academia Press, Tokyo, Carvalho LPF, Melo DSP, Pereira CRM, Rodrigues MAM, Cabrita ARJ and Fonseca AJM, Chemical composition, in vivo digestibility, N degradability and enzymatic intestinal digestibility of five protein supplements. Animal Feed Science and Technology, 119, Chamberlain DG, Thomas PC, Wilson W, Newbold CJ and Mac Donald JC, The effect of carbohydrate supplements on ruminal concentrations of ammonia in animal given diets of grass silage. Journal of Agricultural Science, 104, Estrada-Angulo A, Contreras G, Perez A, Gamer G, Lozano O, Rios FG and Vazquez E, Effect of dried distillers grains

9 substituting for corn-soybean meal on growth and feed intake of Pelibuey sheep. Journal of Animal Science, 85, Held J, Feeding soy hulls and dried distillers grain with solubles to sheep. Sauth Dakota State University, Cooperative Extension Service, ExEx 2052 Access at edu/articles/exex2052.pdf. Hvelplund T, Volatile fatty acids and protein production in the rumen. In: Rumen Microbial Metabolism and Ruminant Digestion. Ed. J. P. Jouany, INRA, Paris, Morgavi DP, Beachemin KA, Sereco LV, Rode LM, McAlister TA, Iwaasa AD and Yang WZ, Resistance of feed enzymes to photolytic inactivation by rumen microorganisms and gastrointestinal proteases, Journal of Animal Science, 79, Nedeva N, Slavov Т, Radev V, Tоdorova P, Sivkova K and Еnev Е, Effect of the multienzymatic preparation Hostazym C 100 on some rumen, duodenum and blood parameters of protein metabolism in yearling sheep. Bulgarian Journal of Veterinary Medicine, 12, Supplement 1, Oh YG, Kim KH, Chong JJ and Chamberlein DG, The effect of the forme nitrogen in the dieton ruminal fermentation in the yield of microbial protein in sheep consuming diet of gras silage supplementation with starch or sucrose. Animal Feed Science and Technology, 78, Radev V, Effect of yeast-based biotechnological products on rumen fermentation in sheep. Thesis for PhD, Trakia University, Stara Zagora (Bg). Radev V, Effect of dietary supplementation of dried distillers grains with solubles (Zarnela) on some rumen fermentation parameters in yearling sheep. Agricultural Science and Technology, 4, Schauer CS, Berg PB, Stamm M, Stecher DM, Pearson D and Drolc D, Influence of dried distillers grains of feedlot performance and carcass characteristics of finishing lambs. Western Dakota Sheep & Beef Day, 47, Sivkova K, Digestion process by the ruminants in the dependence of diet composition and structure. Thesis for DSc, Trakia University, Agricultural Faculty, Stara Zagora (Bg). Sivkova К, Some parameters of rumen fermentation, saliva secretion, feeding behaviour and blood composition in sheep after intake of feeds with different physical structure. Thesis for PhD, Sofia (Bg). Sivkova К, Еnev Е, Radev V, Nedeva N and Slavov T, Effect of diet structure on some rumen, duodenal and blood parameters of protein metabolism in sheep. Journal of Mountain Agriculture on the Balkans, (Bg). Spiehs MJ, Whiteny MH, and Shurson GC, Nutrient database for distiller's dried grains with solubles produced from new ethanol plants in Minnesota and South Dakota. Journal of Animal Science, 80, Sutton JD, Digestion and end product formation in the rumen from product in ration. In Digestive Physiology and metabolism in ruminants, Eds. Y. Ruchebush and P. Thivent. MTP-press, Pp Varliakov IS, Radev VD and Otouzbirov RI, 2001.Influences of a Yea-Sacc 1026 as a ration supplement оn level of duodenal metabolites.first joint meeting of Departments of Animal Science of the Balkan countries Balnimalcolm, Tekirdag, Turkey. Wallace RJ and McKain N, Acomparison of methods for determining the concentration of extracellular peptides inrumen fluid of sheep. Journal of Agricultural Science, Cambridge University, 114, Williams AG, Withers SE and Coleman GS, Glucoside hidrolasis of rumen bacteria and protozoa. Current Microbiology, 10,

10 AGRICULTURAL SCIENCE AND TECHNOLOGY, VOL. 6, No 2, 2014 CONTENTS 1/2 Reviews Selection for linear traits for legs and feet and its significance for dairy cattle breeding I. Marinov 115 Genetics and Breeding Morphological analysis of spikes and grouping of accessions of Triticum turgidum ssp. dicoccon H. Stoyanov 124 Crops from Cucurbitaceae in collection of the Maritsa Vegetable Crops Research Institute, Plovdiv local cultivars and their application in breeding programme N. Velkov, V. Petkova 134 Study of chickpea seed size heredity (Cicer arietinum L.) R. Sturzu, T. Nistor, F. Bodescu, C. Melucă 143 Egg quality traits in layers from different production types H. Lukanov 148 Evaluation of Bulgarian winter common wheat varieties of yield stability in South Bulgaria Z. Uhr, G. Rachovska, G. Delchev 152 Study of opportunities for effective use of varieties from Ukraine for creating early winter wheat lines II.Grain quality N. Tsenov, D. Atanasova, I. Stoeva, E. Tsenova 156 Anther culture response of Winter Barley (Hordeum vulgare L.) B. Dyulgerova, D. Vulcheva, D. Dimova 162 Evaluation of grain yield in advanced lines two-rowed winter barley M. Dimitrova-Doneva, D. Valcheva, D. Vulchev, B. Dyulgerova, M. Gotcheva, T. Popova 165 Nutrition and Physiology Haematology and some serum parameters of broilers fed decorticated fermented Prosopis africana seed meal D. Hassan, N. Yusuf, M. Musa, I. Musa-Azara, R. Barde, D. Ogah, A. Yakubu, M. Ari 170 Comparative age related weight and morphometrical investigation of the intraorbital glands in the common bronze turkey (Meleagris Meleagris Gallopavo) D. Dimitrov 175 Effect of the dietary supplement Zarnela on some duodenal chyme parameters in yearling rams V. Radev, I. Varlyakov, T. Slavov, R. Mihaylov 179 Production Systems 13. Variations of maize yield and some quality indices of grain depending on the type of main soil tillage P. Yankov, M. Drumeva, D. Plamenov 184

11 AGRICULTURAL SCIENCE AND TECHNOLOGY, VOL. 6, No 2, 2014 CONTENTS 2/2 Behavior, sexual maturity and productive traits in gilts reared under different floor area M. Kirov, V. Doychev. 187 Influence of organic fertilizers Aminobest and Greenfol on the initial stages of growth of wheat (Triticum aestivum L.) М. Pashev, D. Yakimov, V. Budаeva 190 Algorithm for determining the type of turns carried out by the unit in shuttle movement in the field while using precision farming systems K. Trendafilov 194 Correlations between morphological and productive parameters in Burley tobacco Y. Dyulgerski, Tz. Radoukova 197 Growth and fruiting of the apple sort Braeburn 7926 grafted on M9 Pajam2 and MM106 G. Dobrevska 199 Agriculture and Environment Theoretical model of biogas production from cattle slurry with different additive of maize silage K. Peychev, R. Georgiev 202 New data about Agaricus (Section Minores, Agaricaceae) in Bulgaria M. Lacheva, Tz. Radoukova 206 Changes of the humus status of Pellic Vertisol (FAO) soil type under long-term growing of filed crops in a stationary trial without fertilization V. Koteva, S. Kostadinova 211 Non-fish marine resources and their exploitation along the Bulgarian Black Sea coast E. Petrova Pavlova 215 Productivity and grass density of the main types of pastures in Sakar and Strandja region V. Vateva 219 Product Quality and Safety Automatic measurement of Loin eye urea with computer vision system Z. Zlatev, S. Ribarski, M. Mladenov 224 Influence of the kinetics of salting for Bulgarian white brined cheese, produced by mechanized and traditional technology on the starter and adjunct microflora during ripening P. Panayotov, V. Mihailov, D. Rakov 228 Effect of season, lactation period and number of lactation on mastitis incidence and milk yields in dairy cows T. Penev, Zh. Gergovska, I. Marinov, V. Kirov, K. Stankov, Y. Mitev, Ch. Miteva 231

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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, C3variants 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 performance in dairy cows,ixth International Conference on Production Diseases in Farm Animals, September 11 14, Berlin, Germany. Thesis: Hristova D, Investigation on genetic diversity in local sheep breeds using DNA markers. Thesis for PhD, Trakia University, Stara Zagora, Bulgaria, (Bg). The Editorial Board of the Journal is not responsible for incorrect quotes of reference sources and the relevant violations of copyrights. Animal welfare Studies 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.

13 Volume 6, Number 2 June