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 there was studied rumen digestion of ruminants after their feeding with green mass of buckwheat (Fagopyrum esculentum) and buckwheat haylage. Special attention was given to studying of enzymatic processes taking place in rumen. The experiments were realized in vitro with application of simulator Rusinec (Rumirant Simulation Technique) for the imitation of digestion processes taking place in cattle rumen. On the Rusinec (n=4/diet) stimulator there were analyzed 5 rations on the basis of hay with buckwhear addition in dose of 0,300 or 600 g/kg on the form of green mass and haylage. None of the above mentioned forms of buckwheat in vitro experiments rendered negative influence on rumen digestion and concentration of volatile fatty acids. Application of buckwheat green mass made it possible to lower the quantity of bacterium in rumen content; while buckwheat haylage – the number of protozoon organisms. There was marked a tendency to lowering of fleshed methane.

In the conditions of the Republic of Belarus there was studied the influence of various doses of kizelgur on metabolic processes and natural resistance of poultry by an example of lying hens. Use of the mineral additive rendered the positive influence on protein, carbohydrate, lipidic and mineral metabolism in hens. It was marked that in blood the content there was an increasing of crude protein on 11,5-11,7% (Р less than 0,05), crude lipids - on 1,9-5,3%, glucose - on 25,1-54,6% (Р less than 0,01), calcium - on 0,8-12,4%, phosphorus - on 8,9-15,9%, iron - on 9,2-24,6% (Р less than 0,01) and magnesium - on 9,3-21,6%. The laying hens which were fed with the mineral kizelgur additive were characterized by better resistance reactions. Bactericidal activity of blood serum of the experimental hens was higher on 2,7-15,3% (Р less than 0,01), lysozymic activity - on 1,3 22,5% (Р less than 0,05).

In the conditions of the Republic of Belarus there were analyzed the efficiency of 13-18-month old young stock of cattle bred for meat in the conditions of various energy value nutrition levels with the determination of nutrients intake of a diet. It was established that use of rations with various level of metabolic energy and protein breakage rendered the positive influence on nutrient digestibility of rations. This made it possible to improve the digestibility of dry and organic substances, nitrogen-free extractive substances and fibre at the bull calves which were fed with 63% of cleavable protein, as well as to increase the metabolic energy up to 10% in the ration, surpassing the control indexes respectively on 3.1; 2.5; 2.8; and 2.9 items. Adjournment from the acquired nitrogen considerably increased and made up to 64-70%. Productivity of fattening young cattle stock made it possible to obtain 977.7-1011.0 gram of live weight gain. As a result, the growth energy was stated at the level of 15,90-17,33 МJ in the conditions of conversion of metabolic energy into growth of 13,81-14,26% and expenses of metabolic energy of the ration per 1 MJ in live weight gain of 4,72-5,46 MJ.

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 studied the efficiency of application of forage chemical preservatives Kormoplyus-1, Kormoplyus-2, and Kormoplyus-3 for grass fodder conservation. The analyzed preservatives contained acetous acid, urotropine and sodium acetate (only in Kormoplus-2). In course of the study there were established experimental batches with the studied sreservative; there was determined a chemical composition of prepared forages; in physiological and scientifical and economic experiment there was analyzed the feeding efficiency of cereal ensilage. Research results showed that application of preservatives Kormoplyus-1 and Kormoplyus-2 2 for preparation of cereal ensilage made it possible to receive a high quality ensilage and to increase the dry matter safety on 4,2-8,7% and protein on 12-9,4% on comparison with storage without preservatives. Also, it made it possible to increase the digestibility of dry matter in cattle diets respectively on 5.5% and3.7%; organic substance - on 5.5% and 4.0%; fibre - on 16,5% and 15,0%, and also to increase nitrogen deposition on 17,4 and 20,8%. Feeding with forages preserved with Kormoplyus-1 and 2 did not render negative influence on a health state and biochemical indices of animal blood.

The recipe of mixed fodder is developed for cows with a 6-8 thousand kg yield of milk for a lactation during the period yield of milk, different the raised maintenance of a crude protein (18%) that allows to increase a yield of milk of animals by 6,6% (22,5 kg instead of 21,1 kg of 4% milk a day) to reduce the expense of forages on production unit to 6,4% (0,73 fodder units against 0,78 fodder units per 1 kg of milk). At the expense of additional production economic benefit makes 104,4 thousand rbl. counting on 1 head

It is determined that diets with protein digestibility of 61-66% in organism of a calve activate fermentative processes in rumen, increase digestibility of nutrients at 3,8-10,1% that allows to obtain the average weigh gains of 1036-1075 g, that is at 4,2-8,1% higher than that of control group at forage spends of 6,79-7,04 forage units

The research in RUP Scientific and Practical Center of Animal Breeding of National Academy of Sciences on such parameters as consumption of forages, processes of rumen digestion, morphological and biochemical structure of blood has shown that usage of wet grain preserved with Kormoplus for young cattle fattening has a positive effect on physiological condition and digestibility of nutrients and promotes nitrogen usage by animals that increases at 7,0 and 1,6%