In the conditions of the Republic of Belarus the was studied the age-specific dynamics of content of total lipids, triglycerides, total cholesterol, phospholipids, total iron and catalase activity in spleen of broiler chicken during the incubation period (1-46 days). The content of total lipids, total cholesterol, and phospholipids was at maximal level at one day-old age, and gradually lowered by the end of growing period. The amount of total iron in ontogeny increased till the 30 day-old age and a bit lowered by the end of growing period. In broilers with lower live weight the iron content in spleen was lower during the whole growing period. The catalase activity had a wave-like character and depended on prophylactic vaccinations undertaken and the amount of lipids in tissues.

In the conditions of the Republic of Belarus there was analyzed the influence of inclusion into broiler chickens diets of probiotoc preparation Bifidoflorin zhidkij (liquid) and prediotic veterinary drug Biofon AIL on the natural resistance, hematopoiesis, growth, metabolic function, development and viability of broiler chickens. In course of the study there was analyzed the dynamics of total haemoglobin, total protein of blood serum, albumins and globulins of broiler chickens which were fed with veterinary drugs probiotoc Bifidoflorin zhidkij and prediotic Biofon AIL. Indexes of chicken viability and life weight gain were marked. Research results showed that application of the presented veterinary preparations rendered the growth promoting action, lowering of disease incidence, increasing of chicken viability, increasing of live weight gain and stimulation of metabolic processes in the most intense period of poultry growing. All these factors were expressed in highest degree after the combined application of the probiotic and prebiotic veterinary drugs.

In the conditions of the Republic of Belarus there was analyzed the efficiency of bactericidal action of tartaric acid aerosol for air sanitation of poultry buildings and increasing of broiler chickens viability. The bactericidal action was analyzed by the example of Staphylococcus aureus, Eschericia coli and Proteus vulgaris. In course of study there were analyzed biochemical indexes of blood and blood serum, lymphoid tubercle in proper mucous plate of trachea of broiler chickens after 6-time treatment with tartaric acid and Ekotsid C preparation. Research results showed that the analysed preparations did not render negative influence on metabolic indexes of broiler chickens and increase poultry viability. Application of tartaric acid did not cause pathomorphologic changes in tissues and organs of birds, stimulated the active proliferation of leucocytes in immune system organs (thymus gland; spleen; and lymphoid tissue).

In the conditions of the Republic of Belarus there was realized a morphological analysis of pectoral and leg muscles of broiler chickens of cross Cobb-500 in the process of administration of metabolic activator Catosal. Research results showed the positive influence of catosal on the myogenesis: diameter of muscle fiber, the amount of bigger diameter muscles fibers in the first order strand and homogeneity of muscle strands. Under the influence of Catosal preparation there was stated the increasing of the amount of muscle tissue in pectoral and leg parts of chicken carcass. | Приведены данные морфологических исследований грудных и ножных мышц цыплят-бройлеров кросса Кобб-500 при применении активатора метаболизма катозал. Установлено, что катозал активизирует миогенез за счет увеличения диаметра мышечных волокон, содержания в пучках первого порядка мышечных волокон большей толщины, а также большей однородности мышечных пусков. Под действием препарата происходит увеличение содержания мышечной ткани как в грудной части тушки, так и в окороках.

In the conditions of the Republic of Belarus there were determined types of transferrins of 46-day old broiler chickens and their relation with indexes characterizing ferrum transport fund. In broilers of Smena-2 cross there were stated four transferrin phenotypes, which revealed at a electrophoregram in a form of two fractions with various mobility and intensity. The quantity of the found out phenotypes should be considered as a minimum one because it was possible to find out the infrequent forms only after realization of a very big number of research studies (for example, occurrence of some phenotypes can be 1:1000 and even lower). Perfection of electrophoresis techniques or application of other carriers (for example, polyacrylamide gel) can also increase a number of phenotypes owing to high resolving power and division of homogeneous transferrin fraction into several sub-factions. The type of transferrin actually did not render influence on the content of haemin proteins, while the indices of ferrum transport fund showed out such kind of dependence. Taking into account that total iron binding capacity (TIBC) was caused by transferrin presence in blood serum, the distinction in this indicator characterized both the transferrin content, and its transport possibilities in relation to iron. The highest content of total iron and TIBC was observed at a slow phenotype of CD tranferrin type (formed by fractions with the least mobility). Fast type of tranferrin АВ (formed by the most mobile fractions) had high enough content of the totaliron but possessed the least iron-binding ability that specifies to the worst performance capabilities of transportation of iron ions. Taking into consideration the transferrin value in formation of antibacterial immunity, it is possible to assume, that broilers with phenotype СD should be more resistant to infections.

In the conditions of the Republic of Belarus there was analyzed the efficiency of application of an adsorbent mycotoxins Toxfin Dry (Belgium) for lowering of toxicity load on broiler chickens. In the course of the study there was given attention to poultry productivity, viability and forage expenses for broiler chickens breeding. There was developed a scheme of Toxfin Dry preparation feeding to broiler chickens. There were presented the results of weighing of control and experimental broiler chickens during the breeding periods; the basic zootechnical indices in the conditions of introduction Toxfin Dry; economic efficiency of its application. Research results showed that introduction of a mycotoxin adsorbent Toxfin Dry into diets of broiler chickens promoted the improvement of digestion and absorption of mixed fodder nutrients in a gastroenteric tract, that in its turn promoted the increasing daily average weight gain on 4,3%, broiler stock viability - on 2,6%; and to decrease the expenses for forages on 13,9%. On the basis of obtained experimental data it was recommended to include the mycotoxin adsorbent Toxfin Dry into rations of broiler chickens as a dry mix with mixed fodder in a dose of 5 g/kg of forage dry matter.