Test vaccines comprised of inactivated water-in-oil emulsions containing various antigen levels were prepared using a non-pathogenic H5N1 avian influenza (AI) virus, A/duck/Hokkaido/Vac-1/04 (H5N1). The potencies of these test vaccines were evaluated by two experiments. In the first experiment, the triangular relationship among the antigen levels of test vaccines, the hemagglutination inhibition (HI) antibody response, and the protective effect against challenge with a highly pathogenic avian influenza (HPAI) virus, A/chicken/Yamaguchi/7/04 (H5N1), was confirmed. Then lasting immunity of chickens after a single-shot vaccination was confirmed in the second experiment. As a result, complete protection after the challenge was observed in chickens immunized by test vaccines with an antigen level of 160 HA units/dose or higher. Thus, it was ascertained that the minimum antigen level in the AI vaccine was 160 HA units/dose, and the minimum HI antibody titer that could protect chickens from HPAI virus infection-related death was considered to be 1:16. Dose-dependent HI antibody responses were observed in chickens after the vaccination. Thus, 640 HA units/dose were thought to be similar to the optimal antigen level. Alternatively, the HI antibody titers of chickens, injected with the vaccine containing 640 HA units/dose, were maintained at 1:181 or higher for 100 weeks after the single-shot vaccination.

Results of studying of therapeutic efficiency of developed in the Republic of Belarus biological preparation of trial series against salmonellosis of animals and birds in the conditions of experimental salmonellosis of calves were presented. Research results showed that dualfold application of multivalent antitoxic serum against salmonellosis of calves, piglets and birds which was caused by association of S. Dublin, S. typhimurium, and S. enteritidis was accompanied by activation of humoral immunity. It was revealed in increasing of agglutinating activity of blood serum against S. enteritidis – in 11,5 times, against S. typhimurium – in 10,5 times, and against S. Dublin – in 10,0 times in 6 days after introduction of infection (4-th day after second application serum). Content of Ig M in blood serum calves which were treated with experimental serum increased in 2,0 times on the 6-th day after introduction of infection. Quantity of Ig G increased in 2,6 times by the 6-th day after introduction of infection. All these changes were typical for the clinical recovery of animals. Treatment efficiency of application of the analyzed serum was 75%

Determination of the optimal doses of monocomponents of the developing vaccine against rotavirus infection and cattle colibacillosis was realized in the conditions of the Republic of Belarus by the example of 80pregnant cows with body weight 400-450 kg. Immunological efficiency of the analyzed preparations was estimated in accordance with ascending rate of titres of specific antibodies before and after vaccination. Research results showed that the highest degree of expressed immunologic response to the monocomponents was stated for cows vaccinated in dose 2,5 cm3. Increasing of dose up to 5,0 cm3 did not render substantial influence on gain of specific antibodies level in blood serum of immunized cows. Decreasing of dose up to 1,0 cm3 caused to less intensive biosynthesis of antibodies, excluding animals which were administrated with antigen E. coli K88. In the majority of experimental groups of cows in blood serum there was stated the increasing of specific antibodies level after the second administration of the components. The obtained results proved the necessity of dualfold administration of the developing biological preparation. In course of study there was determined the choice of monocomponent doses of the vaccine. The optimal dose of monocomponent against cattle rotavirus in case of infection titre 7,0 lg 50% tissue cytopathic dose was 2,5-5 cm3 pr animal. The highest titres of the specific anticolibacillosis antibodies for E.coli with concentration of bacterial cells 10E9/ml for K99 and A20 in the conditions of antigen administration in dose 2,5 cm3, and for E.coli with adhesive antigens K88 - 1,0 cm3

In the conditions of the Republic of Belarus there was produced a trial series of hyperimmune serum against livestock animals colibacillosis and there was realized the quality control of the analysed biological preparation. Research results proved that the developed serum was sterile, safe and had high immunogenetic activity. In course of quality control there were considered the following indexes: determination of physiognomy, colour, presence of visually accessible particulate matters; determination of safety and harnfullness; determination of activity; determination of concentration of hydrogen ions; determination of sterility; determination of serum volume in consumption package. For serum production there were used strains E.coli O9, O78, O0, O117, O26, O139, O15, O41, O55, O115, O141, O8, K88, K99, F41, 987P. For the production of trial series there was realized cultivation of Escherichia on the special nutritive media. There used bulls as serum producers

Research of immune activity of an experimental series of inactivated vaccine against swine pasteurellosis (Pasteurella) with application of adjuvants of Sepptic Montanida ISA 70 and Montanida ISA 206 was realized in the conditions of the Republic of Belarus. In the capacity of water phase there were used serovars A, B, and D Pasteurella multocida. Research results proved the possibility of application of adjuvants of Sepptic company for the development of vaccine against pasteurellosis. The vaccine with the presented adjuvants after its application did not cause after-trouble effects. In course of immunization there was noted the formation long-lived continuous immunity that was proved by high titres of specific anti-bodies in blood serum in all experimental groups of piglets. Single application of the proposed vaccine in doses 2 or 3 ml per animal proved to be effective. Also it was efficient to apply it twice in doses 1 and 2 ml per animal. For the vaccine production it was proposed to use adjuvant Montanida ISA 206 which did not have high reactogenicity

Analysis of manifestation of chlamydial infection of cattle in the conditions of forage affect with mycotoxins was realized in the conditions of the Republic of Belarus. Research results showed that chlamydial infection proceeded in association with aflatoxin, T-2 toxin, deoxynivalenol, zearalenone and ochratoxin. In course of the biochemical analysis there was noted the lowering of carotene on 23%, and vitamin A – in two times; also there was slight lowering of alkaline reserve. The obtained data proved the substantial changes in content of sub-populations of lymphocytes in cow blood in dry and postnatal period. During the immunological study of immunoglobulins in blood serum of cows sick with postpartum chlamydial endometritis it was revealed that titre of immunoglobulin A was on 31% higher. Level of immunoglobulins G and M differed slightl