The research was realized by an example on 30 chickens aged 1, 10, 20, 30 60-days old, and 10 hens: 4-months, one-year-old and 2-year-old in the conditions of the Republic of Belarus. All poultry stock was maintained in the conditions of industrial production at the Gorodokskaya Poultry Farm of Vitebsk region (Belarus). As a result of the study there was revealed a certain pattern of variation of a quantity of active forms of enzymes in organs chickens of different age. Application of histochemical methods made it possible to reveal different levels of metabolic processes in cellular elements of thyroid gland, which demonstrated the habit of formation and functioning of the organ at different stages of postnatal ontogenesis in hens. Coefficients of acid phosphatase activity in thyrocytes of thyroid gland of hens and indexes of alkaline phosphatase activity in secretion forming cells were analyzed. | Исследование провели на 30 цыплятах в возрасте 1-, 10-, 20-, 30- 60-дней, и 10 курах: 4-месячные молодки, годовалые и 2-летние особи. Все поголовье птицы содержалось в условиях промышленного производства на Городокской птицефабрике Витебской области. В результаты исследований установлена определенная закономерность изменения количества активных форм ферментов в органах птиц разного возраста. Использование гистохимических методов позволило выявить разные уровни метаболических процессов в клеточных элементах щитовидной железы, которые демонстрируют характер становления и функционирования органа на разных этапах постнатального онтогенеза кур. В табличной форме представлены коэффициенты активности кислой фосфатазы в тироцитах щитовидной железы кур и показатели активности щелочной фосфатазы в секретообразующих клетках.

In the conditions of the Republic of Belarus there was realized a comparative studying of immune reactivity of broiler chickens immunized against Marek's disease by means of vaccines of Russian production. In course of the study it was established, that in broiler chickens vaccinated against Marek's disease (by means of cultural dry viral vaccine on the basis a virus of herpes of turkeys FS-126 and by liquid bivalent cultural virus vaccine Bimarek on the basis of strains of a herpes virus of turkeys and a herpes virus of hens) the revealed morphological changes in immune system organs of did not essentially differ and testified to the development of intense postvaccinal immunity. Economic efficiency of immunization of broiler chicken against Marek's disease under production conditions made 4,87 and 2,94 Belarusian roubles per 1 rouble of expenses, respectively. | Целью исследования явилось сравнительное изучение иммунной реактивности организма цыплят-бройлеров, иммунизированных против болезни Марека вакцинами российского производства. В ходе исследований установлено, что у цыплят-бройлеров, вакцинированных против болезни Марека культуральной сухой вирусвакциной из вируса герпеса индеек ФС-126 и жидкой бивалентной культуральной вирусвакциной Бимарек из штаммов вируса герпеса индеек и вируса герпеса кур выявленные морфологические изменения в органах иммунной системы существенно не отличаются и свидетельствуют о выработке напряженного поствакцинального иммунитета. Экономическая эффективность иммунизации цыплят против болезни Марека в производственных условиях составляет 4,87 и 2,94 рубля на 1 рубль затрат соответственно.

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).

In the conditions of the Republic of Belarus there was determined the influence of multi-enzymatic veterinary drug preparations Vitazim (contained a complex of enzymes of carbohydrases: xilanase; cellulose; beta-glucanase) and Ehkosim (universal multi-enzymatic complex: beta-glucanase; endo-xilase; and cellulase) on microbial composition of intestinal bacterial population. Research was realized by an example of layer hens of four-linear cross Highsex white at the age of 34-51 weeks. Regimens of administration of the analyzed preparations were presented. Research results showed promoted the development of the regenerative process of physiological media in intestines of poultry which was necessary for subsisting of normal flora of pathogenic bacteria. The studied preparations Vitazim and Ehkosim can be applied for the preventive treatment and therapy of intestinal dysbacteriosis, normalization of its microbial flora, as well as for the antibacterial therapy.

In the conditions of the Republic of Belarus there was studied the activity of alaninaminotranspherase (AIT) and aspartate aminotransferases (AsT), alkaline phosphatase, lactic dehydrogenase, cholinesterase, alpha amylase in blood serum, liver and pancreas of 130-158-day old replacement chicks vaccinated against Newcastle disease. Research results showed that the most essential changes were observed from such enzymes, as AsT and AIT. Increasing of AIT activity in a liver, pancreas and blood serum of immunized hens was stated on the seventh day after vaccine administration. Character of changes can testify both the increasing of synthesis of the mentioned enzymes, and also their posttransmitting activation which took place due to intensification of transamination processes. Changes of activity of alkaline phosphatase, cholinesterase and alpha amylase were the most expressed on the 14th and 21st days of research. It was possible to assume, that there was a stimulation of synthetic function of hepatocytes under the influence of the vaccine. It was possibly the decreasing of enzymatic functions pancreas.

In the conditions of the Republic of Belarus there were studied the influence of different levels of glucosinolates of rape (Brassica napus) seeds on metabolic processes and productive qualities of lying hens for the determination of an optimal dose of administration into their diets of ground rape seeds of the national Belarusian selection in spite of extraction cakes of other crops. Research results showed that addition into mixed fodder of 8-13% of rape seeds increase in their share in a lying hen diets caused the decreasing of the basic zootechnical indexes and did not render essential influence on production quality. However, introduction 6% rapeseeds into diets of lying hens of commercial stock instead of oil-seed meal of other crops did not render essential negative influence on productive indexes and production quality. Feeding of 6% of rapeseeds in spite of oil-seed meal of other crops in course of ten months of technological use of poultry caused the increasing of total yield of eggs on 2,9%, egg production - on 1,8%, average weight of eggs - on 1,7%. Also, it made it possible to reduce the daily consumption of forage on 2,6%, forage expenditures per 10 eggs - on 5,5% and per kilogram of egg weight - on 5,8%. The obtained results assume the possibility of inclusion into lying hens diets of 6% milled rapeseeds of national selection with a level of glucosinolates up to 44,7 mkmol/g.

Analysis of the optimal scheme of doses and rates of combined administration of probiotic Dialakt and immunostimulant Alveozan was realized in the conditions of the Republic of Belarus by the example of 1500 broiler chickens of cross Kobb- 500. Chickens of the first (controlled) group were given only total ration, balanced with the main nutrients. For the chickens of the second group were administrated with immunostimulant Alveozan with water starting from one day old age, every day in dose of 10 mkg/kg of body weight once a day in course of 5 days successively and with 7 days interval till the end of growing period; and probiotic Dialakt was administrated with water in dose of 0,1-0,2 ml/head (10,0-20,0 mln microbial bodies) starting from one day old age, once a day in course of 5 days successively and with 6 and 14 days intervals till the end of growing period. Chickens of the third group were administrated Alveozan in dose of 10 mkg/kg of body weight with drinking water once a day in course of 5 days with 10 days interval till the end of growing period; and Dialakt in dose of 0,1-0,2 ml/head with drinking water starting from one day old age, every day in course of 5 days with 6 and 14 days interval till the end of growing period. The research results showed the following optimal regime of complex application of the analyzed preparations: immunostimulant Dialakt - in dose of 0,1-0,2 ml/head with drinking water starting from one day old age, once a day in course of 3 days successively with 6 and 14 days intervals till the end of growing period; and immunostimulant Alveozan - in doze of 10 mkg/kg of body weight with drinking water once a day in course of 5 days with 10 days interval till the end of growing period. Complex application of Dialakt and Alveozan promoted the increasing of organometric indexes, specific volume and size of thymus in 1,5-1,8 times (P less than 0,01), Fabritsiya bursa - in 2 times (P less than 0,01) and lien - on 11,1% (P less than 0,05)

Investigation of influence of complex probiotic preparation Laktimet obtained by means of cultivation of bifidus bacteria and lactic acid bacillus on morphological indexes of pancreatic gland of laying hens was realized in the conditions of the Republic of Belarus. Two groups of laying hens of 121-130 days old were used in the experiment. The experimental hens were given probiotic Laktimet with water in dose of 1 ml/head every day in 4 cycles during 7 days and with 7 days intervals. Total condition, dynamics of body weight, and egg production were estimated. Research results showed that body weight of experimental hens increased on 6,4 % on the 10-th day; on 12,1% - on the 24-th day; on 6% - on the 40-th day; and 7,5% - on the 50-th day of experiment. Pancreas weight of experimental hens increased on 4-9%. Acinus size increased on 11%. Morphological indexes in exocrine pancreatic cells showed that altitude of basal pole increased on 3-7%. Application of probiotic Laktimet rendered positive influence on laying hens that was evident in increasing of their productivity (there was an increasing of live weight on 4-8%, and egg-laying capacity – on 18-33%). The positive dynamics of the majority of morphofunctional indexes of exocrinous and endocrine parts of pancreatic gland proved its significant role in maintenance of general state of laying hens and metabolic processes

Application of antiviral preparation Mixoferon for poultry is studied. It is established, that Mixoferon application does not influence negatively on organism of hens, increases intensivity of protein metabolism, including the maintenance of antibodies in blood whey. Mixoferon in dozes of 2,5 ml (500000 МЕ), 1,5 ml (300000 МЕ), 0,5 ml (100000 МЕ) can be used for preventive maintenance and therapy of virus infections of hens

Application zoned bare-grained oats grades in a diet of chickens and hens-layers of egg breeds makes positive impact on efficiency of a bird, forage conversion, reduces expenses of forages for manufacture of eggs that allows to receive additional profit. The maximum norm – 40 % bare-grained oats in mixed fodders of hens is defined