Investigation of acute and subchronic (chronic) toxicity of complexinates of trace elements in experiments with calves was realized in the conditions of the Republic of Belarus. The realized experiments were based on developed in Belarus veterinary preparations for the treatment and prevention of diseases connected with disorders of trace elements exchange containing chelate compounds of trace elements with sodium ethylene diamine acetate: Cuprovet (on the basis of CuNa); Cobalvet (on the basis of CoNa), Zinkovet (on the basis of ZnNa), and Feravet (on the basis of FeNa). There were the following indexes of ferrum in nephros - 55,3 +/- 2,26, in muscles - 134 +/- 26,6 mkg/g, and in liver - 565 +/- 35,5 mkg/g after administration of Feravet. There were the following index of zinc in nephros - 56,3 +/- 2,64, in muscles -25, 8 +/- 1,23 and in liver - 84,4 +/- 3,29 mkg/g after administration of Zinkovet. There were the following indexes of cuprum in nephros - 4,1 +/- 0,325, in muscles - 2,33 +/- 0,117, and in liver - 12,3 +/- 1,12 mkg/g after administration of Cuprovet. There were the following indexes of cobalt in nephros - 40,35 +/- 2,29, in muscles - 12,5 +/- 0,98, and in liver - 126,5 +/- 10,45 ng/g after administration of Cobalvet. Parameters of toxicity of all preparations were by the example of laboratory mice, rats and calves given. Content of trace elements in blood of calves in dynamics of the experiment was analyzed. There were determined parameters of acute toxicity of the analyzed preparations: they all could be referred to substance hazard category 4 (low-hazardous substances). The determined parameters of acute toxicity made it possible to recommend them for treatment and prophylaxis of microelementoses of cattle, as well as to use them as feed additives taking into consideration that defect action levels of the analysed preparations exceed the deficiency needs of cattle in case of their limited cumulation

Evaluation of pathogenicity of Paenibacillus alvei culture obtained from a dead bee brood from Berezinsky Biosphere Nature Reserve was realized in the conditions of the Republic of Belarus by an example of 30-day old white male mice with body weight of 16-18 grams. Experimental animals were infected with European foul brood (Paenibacillus alvei) intraperitoneally. Research results showed that bacteria Paenibacillus alvei after the intraperitoneal infection with various amount of microbial cells did not cause mouse death; i.e. it was not pathogenic for white mice. In course of the realized observations over the laboratory mice after introduction of infection there were stated no changes in mice behavior and overall condition. There were no visible pathologicoanatomic changes in internal organs. After the bacteriologic examination of internal organs and blood there were isolated pure cultures of Paenibacillus alvei