In the conditions of the Republic of Belarus there were analyzed data on studying the species specificity of anatomic and topographic characteristics of the most important component of neuroimmunoendocrine system providing body homeostasis - thymus gland of 5-6 year-old European beavers (Myocastor coypus). As a result of studies taking into consideration the sexual dimorphism there was formed a database of morphometric indexes characterizing the degree of development of left and right lobes of thymus gland of European beavers, as well as to reveal their species-specific anatomic and topographic characteristics correlating with processes typical for age-specific and accidental involution.

In the conditions of the Republic of Belarus there was determined the influence of different rates of lithium addition into mixed fodders for sows feeding on hematological indexes and their reproductive qualities. In course of the study there was analyzed the dynamics of body weight of sows over the reproductive period; indexes of productivity of sows (number of born piglets; weight of 1 piglet; litter weight; weight of weanling piglets; number of weanling piglets; etc.); hematological indexes of sows; state of humoral factors of immunity of sows. Research results showed that in case of lithium application in diets of sows there was stated an improvement of hematological indexes and immunity functions and resistance. The optimal level of lithium in rations was 15 milligram per 1 kilogram of dry matter of a diet. This dose essentially promoted the increasing of reproductive performance, piglets weight and milking capacity of sows as well as better viability of piglets.

Determination of adaptation and compensation abilities of larval forms of cestodes (cysticercus and echinococci) was realized by means of evaluation of biochemical composition of their internal environment. There was realized the following estimation of biochemical composition of internal environment: Cysticercus tenuycollis from sheep - 34, Cysticercus tenuycollis from swine - 17, Echinococcus granulosus L. from swine - 23. Estimation of biochemical composition of custodies larvaceous forms was realized on the basis of the standard veterinary methods. Research results revealed that osmotic volumetric concentration of internal environment of custodies larval forms was lower than of osmolarity of blood serum. The average value of osmolarity of blood serum for both sheep and swine was 296,63 mmol/l. Research results showed presence of large quantity of specific lipo- and glycoproteins in custodies larva forms. Cysticercotic liquid administrated into suspended matter of microorganism Micrococcus lysadeicticus and leads to lyzing up to 5% of microbal bodies. It was possible to testify the presence of lyzing activity in liquid of larval forms of cestodes. The research results showed that the analyzed larval forms of cestodes had a lot of different and strong defense mechanisms. Adaptation and compensation abilities of larval forms of cestodes had nonspecific character and contained the following: physical mechanisms; humoral immunocompetent factors; and biochemical adaptation

Determination of influence of long acting antihelminthics (Aversictini boluses and boluses with albendazole) and influence of usual antihelminthics (farmatsin, alverm, fenbendavet) on first stomachanimal digestion, as well as on quantity and quality composition of microflora and microfauna in first stomach and large bowel was realized in the conditions of the Republic of Belarus. In course of the experiment there were used 6 groups of calves infested with helminths (Neoascaris vitulorum, Strongylata sp.). Research result showed that different antihelminth preparations to a greater or lesser degree rendered negative influenced on quantity and quality composition of microorganisms in first stomach and large bowel of cattle. Alverm and boluses with albendazole rendered the least influence on microflora and microfauna that could be explained by low toxicity of active substance (albendazole) of the above preparations. Aversictini boluses, fenbendavet, and farmastin changed the composition of microorganisms. It could be explained by high toxicity of preparations containing aversictini which rendered influence not only of gastro-intestinal tract but also on the whole organism. Active ingredient of mentioned above preparations (Aversektin C), being the product of microbial synthesis, rendered the antagonist action on the normal microflora of digestive tract. Negative influence of fenbendavet was caused by the chemical composition of the preparation and neurotoxic action of fenbendazol