Effect of active yeast on productive traits of chicken-livers
The results of the studying of active yeasts Saccharomy cescerevisiae influence on the egg-laying capacity and morphological characteristics of the hens "NOVOgen brown" breed eggs are presented. 250 laying hens were divided into five groups of 50 birds. In scientific and economic experiment laying hens of experimental groups were fed with combined feed containing active yeast in the amount of 0.02, 0.04, 0.06 and 0.08% instead of a similar amount of soybean meal. The feeding of experimental hens was carried out twice a day with complete combined feed. The poultry was kept in triple- deck cages. During the study period, which continued 180 days, all groups received complete combined feed mainly from cereal. The results of the determination of the chemical composition of active yeast showed that they contain raw protein 46.77% by Kjeldahl method and 41.64% by Barstein method, non-protein nitrogen - 5.13%, raw fat - 2.96%. As a result of the research it was found that the level of exchange energy in 1 kg of active yeast Saccharomy cescerevisiae was 362.9 MJ/kg. The amino acid composition of active yeasts was characterized by the advantage of nonessential amino acids such as glutamic acid (14.5 %), aspartic acid (8.09%) and essential amino acid as leucine (9.2 %), lysine (8.9 %), phenylalanine (8.63%), isoleucine 5.6 %), threonine (5.5%) and serine (5.3 %). The high level of glutamic acid in the yeast improves the taste of the feed, which resulted in increased appetite and better in taking of the feed. Thus, during the entire period of scientific and economic experiment the egg-laying capacity of hens of experimental groups in relation to the control group increased: in the 2nd group by 3.69%; in the 3d group by 4.26%, in the 4th group by 6.63% and in the 5th group by 5.21%, and more eggs were received in the experimental groups from both the primary and the average laying hen. Despite the fact that in the 5th experimental group where hens received Saccharomy cescerevisiae in the amount of 0.08 % in the combined feed, the productivity of the poultry was slightly lower, but the egg mass, the yolk mass, the Haugh unit and the energy value were higher by 1.1; 11.6 (P<0.001); 1.9 (P<0.001) and 6.6 % (P<0.001) respectively. This is related to the best using of amino acids from this feed supplement.