A study was conducted to determine the effect of different nutrients i.e. metabolizable energy (ME) and crude protein (CP) content of ration on the egg production and egg weight of rural layers. For the purpose six different experimental rations containing 2700, 2900 kcal/kg ME and 14, 16, 18 percent CP were offered to the birds. The results indicated that egg number increased with proportional adversely affected as the CP of the ration was increased weight of the layers was proportionally increased with ration at constant ME level, while increase in ME level egg weight. increase in ME, while it was at constant ME level. The egg increase in CP content of the did not significantly affect the egg weight.

In the present study, effects of different doses of dietary Cu and Zn suplementation on plasma biochemical parameters in broilers were investigated. In this study, a total of 430 avian broiler chicks were used and divided into 12 groups as control and treatment groups in which different doses of Cu, Zn and Cu+Zn supplemented

In the conditions of the Republic of Belarus it was determined that application of monocalcium phosphate in a dose of 10 gram per 1 kilogram of mixed fodder and specified doses of trace elements (cuprum; zink; cobalt; manganese; iodine) in diets of growing pedigree bull calves made it possible to increase indices of body weight of young cattle stock of the third experimental group in comparison with animals of the first and the second groups on 18,3 and 11 kg or respectively on 3,9 and 2,3%; as well as to increase the intensity of their growth. The highest daily average live weight gain was noted at animals of the third experimental group – 1062 grams. It was higher than at bull calves of the first and the second groups respectively on 31,3 and 12,8 grams, or on 3 and 1,2%. Application of monocalcium phosphate in a dose of 10 gram per 1 kilogram of mixed fodder favorably affected the formation of desirable type of sexual behavior and indices of semen production quality. Thus, in the third experimental group in comparison with animals of the first and the second groups the volume of ejaculate was on 0,2 and 0,1 ml higher (or on 5,8 and 2,9%); quantity of sperm in ejaculate - on 0,7 and 0,3 billion, or on 35 and 15%.

In the conditions of the Republic of Belarus there was studied the efficiency of application of granulated and extruded lupine (Lupinus) in feeding of bull claves. It was determined that after lupine extruding the quantity of sugar in it increased on 45% due to lowering of starch content. The inclusion of extruded lupine into bull calves diets made it possible to increase the digestibility of dry and organic substances, protein and nitrogen-free extractive substances. The highest average daily weight gain (842 gram) was stated at claves which were fed with mixed fodder with 15% of extruded lupine; this was on 7,5% than in a control group. In the conditions of feeding with the granulated lupine the average daily weight gain increased on 5,3% in comparison with crushed one. In course of study there was analyzed the dependence chemical composition of lupine on the processing method; blood composition of the studied animals; diets of experimental animals; digestibility of nutrient substances of forages; balance and intake of nitrogen; biochemical blood composition; changes of live weight and average daily weight gain.

In the conditions of the Republic of Belarus there were determined the doses of application of siliceous sapropel as well as there were studied the indexes of ruminal digestion and digestibility of diet nutrient substances by bull calves. The studied siliceous sapropel of the lake Pribylovichi (Belarus) occurence on 42% consisted of organic substances and on 58% - of mineral substances: calcium, phosphorus, magnesium, potassium, sodium, iron, zinc, manganese, and copper. The studied sample of sapropel did not render toxic action on test objects of infusorian Tetrahymena pyriformis in the conditions of its addition into the basic forage in number of 1%; 3%; 5%; and 10%. However, its higher concentrations (10%) retarded the development of Protozoa. Feed additives with the content of siliceous sapropel in mixed fodder in dose of 1%, 3% and 5% increased the relative biological value of forage in the experiments on test objects of infusorians Tetrahymena pyriformis in the average respectively on 5,4%, 5,0 and 2,6%. Higher concentrations of sapropel in mixed fodder (5 and 10%) lowered its nutritional value. Inclusion of siliceous sapropel in bull calve rations activated the enzymatic processes in farding bag and increased the digestibility nutritive elements on 2,3-3,6% except for protein, digestibility which was practically at identical level at animals of all groups.

In the conditions of the Republic of Belarus there was analyzed the productivity of 13-18-month old young stock of cattle which was bred for meat with various levels of energy value nutrition. Also, there were noted their slaughter qualities and chemical composition of meat. Administration of diet rations with an increased level of exchange energy and the best indices of protein fissility rendered a positive influence on productivity of young stock of fattening cattle and made it possible to obtain 1103-1100 gram of body weight gain. As a result, the energy value gain was 22,9-22,6 MJ along with conversion of metabolizable energy at a gain - 24,7-25,3%. Consumption of metabolizable energy per 1 MJ along with body weight gain were within 4,7-5,0 MJ. Feeding of rations with various levels of the studied factor rendered the positive influence on slaughter qualities, made it possible obtain slaughter yield of 53,6-54,6% at an optimum ratio of nutrients in meat. Feeding of bull calves with diets with excessive content (up to 10%) of metabolizable energy made it possible to lower the prime cost of obtained breeding products on 0,55%.

In the conditions of the Republic of Belarus there was analyzed the efficiency of application multi-enzyme preparations (drugs) Ehkozim (contained beta-glucanases; endo-xilanase; cellulose) and Vitazim (contained complex of enzymatic carbohydrases: xylanase; cellulose; beta-glucanases) in diets of lying hens. Vitazim was applied for destruction of complex structures: dietary fibre, protein, starch. Ehkozim was applied for albuminolysis of the main nonstarch polysaccharides of fodders. It was established that application of preparations in feeding of lying hens promoted the increasing of biological value of poultry meat, and prove to be economically expedient. Poultry meat of analyzed samples in accordance with physical, chemical and bacteriological indices, as well as in accordance with biological value and harmlessness was not worse than meat of control samples. As a result of the realized bacteriological research of all experimental samples of meat and internal organs there were not stated microorganisms Е. coli, S. aureus, bacteria of sort Proteus, B. сеreus and sulfate-reducing clostridium, salmonellas.

Research on working out of a new fodder additive on the basis of rape (Brassica napus) phospholipids which included mineral substances necessary for normal functioning of cattle was realized in the conditions of the Republic of Belarus. Results of biochemical analysis of 35240 blood samples revealed that 15-40% of studied animals had abnormalties in vitamin, protein and mineral metabolism and lowering of immunobiological disease resistance. There was correlation dependence between the degree of metabolic orders and the state of forage reserve of a forage reserve. The lowering of forage reserve caused the increasing of metabolic disorders. As a whole forages of the surveyed farms were low in content of copper, zinc, cobalt and selenium and could not provide physiological requirements of animals without introduction into rations of specialized additives

While studying biochemical values that characterize rumen digestibility based on research agricultural experiment some results were obtained. These results prove that studied diets with increase of energy and raw protein concentration levels in dry matter influence positively at nitrous substances concentration activate micro flora motions and promote bio-synthetic processes in rumen fluid of experimental animals

Increase of diets nutrition energy in our experiment showed no significant effect on usage of nitrogen in feeds. Diets with different energy levels have no negative effect on hematological indices of animals