In the conditions of the Republic of Belarus there was studied the influence of various doses of dolomite on productivity, egg quality and a mineral metabolism of laying hens. The research was realized by an example of laying hens of Highsex Brown. The experimental hens at the age of 250 days old were divided into 4 groups on 60 heads in each by means of analog method. Laying hens of the first (control) group were fed with a basic diet including 5% of a soya cake (cockle-shell), and hens of the second, third and fourth (experimental) groups instead of a soya cake were fed with a mixed fodder with addition of a mineral additive of dolomite. Hens of the second group were fed with the additive at a rate of 2%, the third group - 3%, and the fourth group - at a rate of 5% of weight of dry matter of forage. During the experiments there were maintained optimum parameters of microclimate, recommended temperature and light regimes and a sufficient ultra-violet irradiation. As a result of the realized research it was established, that use of the mineral dolomite additive in feeding of laying hens proved to be possible as a substitute of an expensive import cockleshell. Use of various doses of dolomite promoted improvement of mineral metabolism, increasing of productivity and improvement of egg quality of laying hens.

Determination of influence of combined feed with carnitine and 3% lipids on digestibility of nutrients in ration of fattening stores was realized in the conditions of the Republic of Belarus by an example of 8 castrated male pigs of Belarusian meaty breed with body weight of 60-65 kg. Piglets were divided into 2 groups in accordance with analogue pair principle. Selected animals were kept in single cages specially equipped for fecal and urina gathering. Both groups of animals were given the same combined feed SK-26 which included 3% lipids. Experimental piglets were fed with combined feed with carnitine in dose of 50 g/t of mixed fodder. The mixed fodder contained the following ingredients: wheat; triticale; grain mixture; sunflower oil cakes; liprot SG; tricalcium phosphate; calcium carbonate; salt; premix KS-4; vegetable oil. Research results showed that enriching of combined feed carnitine rendered positive influence on digestibility and absorbency of nutrients. It made it possible to increase the digestibility of dry matter on 2,1%, organic matter on 2,0%, crude protein on 3,1%, crude fat on 7,4%, crude fiber on 8,6%, free-nitrogen extract on 1,1%, as well as to increase nitrogen, calcium and phosphorus absorbency. Quantity of saved nitrogen in the experimental group (with carnitine additive) was on 21,1% than in control one. Quantity of saved nitrogen and absorbed with feed was on 9,8% and 5,6% respectively higher than the same indexes for the control group; calcium - on 15,5% and 2,6%, phosphorus - on 23,3% and 3,7%, respectively

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).

Development of new compositions of premixes for cows with milk yield of 4-5 thousands kg per lactation depending on lactation stage and pregnancy was realized in the conditions of the Republic of Belarus. Efficiency of application of premixes in comparison with the standard ones was estimated. Experiment was realized by an example of 3 groups of cows of white-and-black breed; experimental period included beginning milking period (90 days) and the main lactation period (142 days). Cows of the first control group were given premix P60-6M with combined feed. Animals of the second group were fed with premixes created on the basis of carotene and microelements content. Cows of the third group were given premixes in accordance with recommended standards. The refined standards of cow vitamin and trace elements consumption were presented. Formulas of premixes for high-producing cows were presented. The research results showed that the developed formulas corresponded to the physiological needs and their application influenced on metabolism and milk producing ability. Application of experimental premixes made it possible to increase the digestibility of nutritive substancesoin 2,3-7,5%. Application of vitamins and trace elements in heightened doses (on 10-30%) caused the increasing of their uptake and increasing of cuprum, zinc, manganese and cobalt content in blood on 11,6-40,8%