In the physiological experience spent on male pigs-manufacturers, we had been studied influence of various doses of selenium (10 mg, 20 and 30 mg) in structure premix on nutrients. It is established, that increase of level of selenium in mixed fodders for male pigs-manufacturers to 30 mg/kg especially promotes increase in degree of use in their organism of fat to 58,7%; (P less than 0,05), the digested nitrogen to 62,1%, calcium – to 78,3% and phosphorus – to 72,5%

Determination of chronic toxicity of a new selenium-containing preparation Aesel was realized in the conditions of the Republic of Belarus. There was realized endermatic administration of the experimental preparation to laboratory white mice. Studying of sensitivity of some organs and systems of mice and revelation of a degree of reversibility of processes caused by active substances of the drug was realized. The main clinical, pathomorphologic, biochemical, hematological changes in the organism of laboratory animals with induced chronic toxicity were determined.

Application in diets of breeding bull calves of an optimum dose of selenium (0,4 mg on 1 kg of a solid of a diet) renders positive influence on formation of reproductive ability of bull-calves: promotes increase daily average gains live weight on 7,1%, indicators of natural resistance – on 0,6-6,7% and to improvement of quality sperm production – on 16,4% during the winter period. During the summer period daily average gains live weight on 6,8%, indicators of natural resistance – on 0,5-13,9% and to improvement of quality sperm production – on 15,7% accordingly

This article is devoted to a problem of biochemical interaction of selenium and antioxidational system of animals and people organism. The problem we have touched is about the efficiency of influence of organic and inorganic taking place on subcellular level. The advantages of organic selenium are proved, the degree of its bjochemical influence on an antioxidationi status of health are indicated.