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 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.

Scientific and production examination of feed additive Semerik-Vita containing iodine and selenium was realized in the conditions of the Republic of Belarus by studying of its influence on production and economic indexes of laying hens and their products, as well as by studying of its influence on clinical state and biochemical blood indexes of poultry. Research results showed that application of feed additive Semerik-Vita made it possible to increase of egg producing ability intensity on 1,8 %, egg yield - on 2,4 % in the conditions of lowering of feeding expenses on 1,4 %. Application of the analyzed feed additive made it possible to obtain a new kind of eggs fortified with iodine, selenium, beta-carotene and vitamins (A, E, C, PP, B1, B2, pantothenic acid and folic acid). In eggs of poultry of experimental group the content of selenium increased in 2,1 times, iodone - in 1,5 times, vitamin E – in 3,9 times, beta-carotene – in 1,4 times, vitamin A – in 1,3 times, pantothenic acid – in 1,2 times, vitamin C – in 1,17 times, vitamin PP – in 1,4 times, vitamin B1 – in 1,5 times, vitamin V2 – in 1,4 times, folic acid - in 1,5 times in comparison with eggs of laying hens from the control group. Research results proved that application of Semerik-Vita did not render negative effect on the clinical indexes of laying hens. It made it possible to lower the content of urea acid in 1,7 times, as well as to increase the content of triglycerides in 2 times, cholesterol - in 2,4 times, magnesium - in 1,28 times

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)

Scientific experiments on determination of the optimal doses kizelgur for import substitution of shells in poultry diets was realized in the conditions of the Republic of Belarusby an example of 4 groups of laying hens of Khajseks korichnevyj cross. Hens of the first (controlled) group were given full ration applied at the tested poultry farm which included 5% of shells. Hens of the other three experimental groups were given complete feedstuffs with inclusion of mineral feed kizelgur: hens of the second group – in dose 2% out of dry matter mass; third group - 3%; for the fourth group - 4%. The research results showed that application of mineral feed additive kizelgur increased hen productivity in experimental groups on 2,8%; 5,9%; 7,2%, respectively. In the experimental groups there was an increasing of egg yields on 2,8%; 5,9%; 7,2%, respectively. The best indexes of poultry livability were stated in the third group (on 5,5% higher than in control). The similar tendency was stated in course of analysis of egg weight, shell thickness and calcium content of shell. Kizelgur application led to increasing of egg mass in tested groups: on 0,46% (2 group), 1,6% (3 group) and 2,4 % (4 group). At the age of 340 days shell thickness in experimental groups was on higher 3,3% (2 group), 0,7% (3 group) and 8,7 % (4 group) than in control. The analyzed additive increased the natural resistance of hens that was proved by indexes of bacterial growth-inhibitory activity of blood serum and lysozyme activity. There noted tendency of total protein increasing. Studying of immunological indexes showed that they were the most evident in the fourth experimental group

Determination of productivity and natural resistance indexes of laying hens after application of dry multienzyme preparation Vitazim (xylanase, 3600 units/g; cellulose, 3000 units/g; beta-glucanase, 7000 units/g); as well as the specification of optimal doses the enzyme were realized in the conditions of the Republic of Belarus. Research results showed that the best indexes of egg yields of laying hens were obtained after application in the main poultry diet of enzyme preparation Vitazim in dose 500 g/t that made it possible to increase the productivity in the experimemtal group on 12%. Application of Vitazim also promoted the increasing of natural resistance level of laying hens. There was stated the positive effect of Vitazim on bactericidal activity of blood serum. Before the beginning of test this index was the level of 44,35+/-0,92 – 56,52 +/-1,63. By the 300-th day of life the bactericidal activity of blood serum in experimental group administrated Vitazim in dose 300 g/t exceeded the control idexes on 3,8%; in the second experimental group (Vitazim in dose of 500 g/h) – on 29,5%; in the third experimental group (/vitazim on dose of 700 g/h) – on 23,7%.Vitazim administration also exercised positive influence on lysozyme activity in blood serum of lying hens

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

Into the programme hen selection of Belarus Autoseksnyj cross there was introduced the indeks of the so-called quality of eggs which is defined by removal defective on quality of a shell of eggs in 30 and 52-week age. The size of variability of an indicator of 16,0-25,4% and hehtability 0,3-0,4 allows to lead selection on increase in an exit of qualitative eggs. Influence on quality of eggs with defects of a shell of age of hens, intensity eggs, weights of eggs, a linear accessory is established

In the conditions of the Republic of Belarus there was studied the influence of various doses of dolomite on productivity, egg quality and a mineral metabolism of laying hens. The research was realized by an example of laying hens of Highsex Brown. The experimental hens at the age of 250 days old were divided into 4 groups on 60 heads in each by means of analog method. Laying hens of the first (control) group were fed with a basic diet including 5% of a soya cake (cockle-shell), and hens of the second, third and fourth (experimental) groups instead of a soya cake were fed with a mixed fodder with addition of a mineral additive of dolomite. Hens of the second group were fed with the additive at a rate of 2%, the third group - 3%, and the fourth group - at a rate of 5% of weight of dry matter of forage. During the experiments there were maintained optimum parameters of microclimate, recommended temperature and light regimes and a sufficient ultra-violet irradiation. As a result of the realized research it was established, that use of the mineral dolomite additive in feeding of laying hens proved to be possible as a substitute of an expensive import cockleshell. Use of various doses of dolomite promoted improvement of mineral metabolism, increasing of productivity and improvement of egg quality of laying hens.