In the conditions of the Republic of Belarus there was analyzed the influence of diets with different ratio of degradable and by-pass proteins on morphological and biochemical blood composition and productivity of bulls of black-and-white breed. In course of the study there was analyzed the average feeding diet of young stock of cattle in accordance with actually eaten fodders; morphological and biochemical blood indexes; live weight and average daily weight gain; results of a control slaughter. Research results showed the feeding at the finishing period of fattening-off with different ratios of degradable and by-pass proteins in ratio 60-65:40-35 made it possible to obtain 1049-1078 grams of live weight gain of bulls per day in the conditions of fodder expenses of 8,22-8,40 fodder units per 1 kilogram of weight gain. As a result the energy of weight gain was 20,1-21,2 mJ. Conversion of metabolizable energy at weight gain stage was at the level 20,4-21,8%. Expenses of metabolizable energy per 1 mJ at weight gain were 4,83-5,05 mJ, and prime cost of body weight gain lowered on 5% in comparison with control.

In the conditions of the Republic of Belarus there was analyzed the efficiency of application of a whole milk substitute Biomilk-11 and feed additive SFDK-1 (biologically active enzymatic feed additive) for breeding of young stock of cattle, by an example of calves of black-and-white breed. In course of the study there was analyzed the composition of the feed additive SFDK-1 (weight fraction of dry matter; weight fraction of protein; content of amine nitrogen; cellulose fiber activity) as well as the physical and chemical indexes of the whole milk substitute Biomilk-11 (moistness; crude protein; crude fat; crude fibre). There were presented indexes of live weight gain of experimental and control calves as well as the dynamics of average daily weight gains in experimental group. Research results proved the efficiency of application of both additive for calves feeding.

In the conditions of the Republic of Belarus there was determined the efficiency of application of different levels of vitamins and trace elements in feeding of servicing bulls. In course of the study there was analyzed the influence of different levels of supply of servicing bulls with vitamins A, D, E and trace elements (copper; zinc; manganese; iron; cobalt; selenium) on their reproductive ability. On the basis of the experiment there was calculated the economic efficiency of application of the developed vitamin and mineral additive. Research results showed that application of the developed protein and mineral additive in diets of servicing bulls in winter and summer periods made it possible to increase the ejaculate volume on 7,4% and 12,4% (P less than 0,05), sperm activity on 6,7 % (P less than 0,05) and 7,3% (P less than 0,01), concentration of spermium in ejaculate on 6,3% and 7,8% (P less than 0,05). Also, it promoted the lowering of percentage of defective sperm doses.

There were presented data of morphological analysis of blood and tissues from a place of vaccine administration and organs of immune system (thymus and lien) of rats vaccinated against a canicola fever of pigs by a produced in the Republic of Belarus vaccine containing in its structure various adjuvants. The vaccination was realized in combination with immunostimulative drugs. Level of specific antibodies of rats and rabbits after immunization with the analyzed preparations as well as with and without immunostimulative drugs were analysed.

In the conditions of the Republic of Belarus there were analyzed the peculiar features of morphology of bursa of Fabricius of turkeys broad-breasted white turkeys at the stage of postnatal ontogenesis. Research results showed that postnatal ontogenesis of bursa of Fabricius of turkeys developed irregularly with preservation of organ up to 220 days. At turkeys in 300-day old age the organ preserved only in 45% of bird units. Form, colour and consistency of bursa of Fabricius depended on bird age. The absolute weight of the organ increased up to 220 days. The relative weight was maximum at 20-day old age. The sexual peculiar features of the organ morphology were insignificant; they revealed after the beginning of sexual maturity and expressed by some difference in weight and linear dimensions.

In the conditions of the Republic of Belarus there was determined the influence of nutritional medium composition on pathogenic properties of leptospirosis bacteria, by an example of 6 pathogenic strains: Leptospira pomona; Leptospira tarassovi; Leptospira grippothyphosa; Leptospira icterrohaemorragia; Leptospira conicola; Leptospira hardjo. During the study there were used the following media: serum-supplemented vitaminized medium on the basis of buck serum; serum-supplemented medium with a growth factor; serum-supplemented vitaminized medium with antlbody biosynthesis growth factor; semisynthetic Russel's medium. According to the results of realized studies there was developed a correlation between terms of leptospirosis bacteria survivability in laboratory animals depending on cultivation medium. In course of the study there were analyzed terms of Leptospira persistence in guinea pigs.

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 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 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.

Morphological and biological characteristic of isospora and eimeria was realized in the conditions of the Republic of Belarus on the basis of carried out measurements and experimental infection minks (Mustela). Research results showed, that in Belarus at mink breeding farm holdings there were determined four species of eimeria and isospores, one of which I. eversmanni - is registered by researchers from the Vitebsk State Academy of Agriculture in the Republic for the first time. The most widespread species is Е. vison (57,03%) was found out in all analyzed 24 fur breeding farms. Species composition of eimeria and isospores did not depend on a sex and typical coat pattern of minks, as well as on a geographical location area of an analyzed farm. Some distinctions in species composition of the intestinal protozoa were observed at minks of different age. Of all analyzed species the most pathogenic proved to be Е. vison and I. laidlawi which in case of infectioning caused animal mortality. | Дана морфологическая и биологическая характеристика изоспор и эймерий на основании проведенной микрометрии и экспериментального заражения норок. Таким образом, по результатам проведенных нами исследований следует отметить, что в Республике Беларусь у норок, разводимых в хозяйствах, установлено четыре вида эймерий и изоспор, один из которых - I. eversmanni - зарегистрирован нами в республике впервые. Самым распространенным видом является Е. vison (57,03%), обнаруженный во всех обследованных нами 24-х зверохозяйствах. Видовой состав эймерий и изоспор не зависит от пола и типовой окраски норок, а также от географического месторасположения хозяйства. Некоторые различия в видовом составе кишечных простейших наблюдались у норок разного возраста. Из отмеченных видов наиболее патогенными являются Е. vison и I. laidlawi, вызывающие при заражении падеж зверей.