Field efficacy of enterotoxigenic Escherichia coli-specific phage (ΦCJ19) as a feed additive was evaluated in weaning piglets. Fifty-four piglets at 3~4 weeks old were allocated in three different groups and two of them were fed with bacteriophage at different concentrations (106 PFU/kg feed and 108 PFU/kg feed, respectively) for 30 days. Body weight and feed intake were measured at 10 days interval and body condition and fecal score were inspected every day. Based on the measurement, feed conversion rate (FCR) and average daily gain (ADG) of each group during 30 days were analyzed. The analysis suggests that the bacteriophage may help the improvement of FCR and ADG at 108 PFU/kg of bacteriophage feeding group in 30 days. A result from analysis of fecal score indicates that the bacteriophage also may help to relieve the intermittent diarrhea in post-weaning stage. Those results suggest that bacteriophage might help the growth of piglets in post-weaning stage.

In the conditions of the Republic of Belarus there was realized a complex of studies of quality swine slaughter products against the background of combine applications of the albuminous-vitamin-mineral additive Immovit and an extract of hill-growing saltwort for the preventive maintenance and treatment of a toxic dystrophy of liver. Research results showed the analysed preparations did not render negative influence on quality and safety of produced meat products. Against the background of application of the albuminous-vitamin-mineral additive Immovit in combination with an extract of hill-growing saltwort there was stated the improvement of swine slaughter product quality. In products from the animals which were administrated with a complex of examined preparations there was stated an optimized moisture content, the increasing of a relative biological value of a product (101,3-103,8%), and according to the indexes of bacterial safety the experimental pork considerably surpassed the meat indexes from animals of control groups. At the same time, in slaughter animal products of control groups there were revealed coliform bacillus bacteria.

In the conditions of the Republic of Belarus there was studied the activity of hepatic specific enzymes of blood serum of bull calves of black-and-white breed in course of application of various doses of zinc-containing preparations. Application of zinc-containing preparations led to multidirectional change of activity of hepatic specific serum enzymes. Application of Zinkovet preparation in dose of 1,8 g/100 kg of live weight made it possible to essentially grade the indexes of hepatic tissue affect. In the experimental group at animals there was marked the lowering in activity alanine-aminotransferase, serum glutamic oxalacetic transaminase and gamma-glutamyl transpeptidase. At the same time, there was noted the increasing of zinc-containing enzymes activity (sorbitol dehydrogenase and glutamate dehydrogenase). All these processes were caused by zinc inclusion into the metabolic process.

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 studied the veterinary and sanitary quality and safety of poultry slaughter products after application of a natural biological corrector VitoLAD produced in Belarus on the basis of cultivation of nonpathogenic strain of fungi Fusarium sambuninum MKF-2001-3 used for restoration of dysfunction disorders. As a result of the realized bacteriological research there were marked no pathogenic and opportunistic organisms in all experimental samples of meat and internal organs. Indices of biological value of meat of three experimental and control group had no authentic differences. Displays of toxicity for infusorians were not marked. Poultry meat of investigated samples in control, and all three experimental groups (doses of 0,25 ml/head - the second experimental group, a dose of 0,5 ml/head - the third experimental group and a dose of 1 ml/head - the fourth experimental group) in diets of which there was added the natural biological corrector VitoLAD, proved to be good-quality and harmless. In accordance with organoleptic, physical and chemical, bacteriological indexes, as well as biological value and harmlessness did not concede to meat of the control group. The complex veterinary and sanitary estimation of bird carcasses of three experimental and control groups did not show any deviations from existing standards that made it possible to organize production realization without restriction.

In the conditions of the Republic of Belarus there was analyzed the efficiency of application of organic form of selenium Sel-plex in feeding of producer bulls. In course of the study there was showed the dynamics of live weight and average daily weight gain of producer bulls; blood indexes of analimals by the end of the experiment; sperm quality of experimental bulls. As a result of research it was established, that application of organic form of selenium Sel-plex in feeding of breeding bulls during the summer and winter periods in a dose of 0,4 mg/kg of dry matter of a ration promoted the increasing of daily average live weight gain on 6,4-8,1%, improvement of morphological and biochemical blood structure, increasing of indices of natural resistance on 0,5-6,1% and sperm production quality - on 7,3-28,0%.

In the conditions of the Republic of Belarus there was realized a scientific and economic experiment on studying the influence of a multi-enzyme feed additive on productivity, viability, growth and development of calves. The multi-enzyme additive contained in its formula xilanaza; glucanase; cellulose; and dolomite (as a filling agent). It was determined that young growth of cattle which were fed with the multi-enzyme additive in dose 1 gram per 6 kilogram of milk by the end of the experiment had a live weight gain on 13,6% higher than in a control group. Calves which were fed with the additive were characterized by more stretched constitution, had well developed thorax and good development of skeleton in comparison with analogues from the control group.

In the conditions of the Republic of Belarus there was analyzed the efficiency of administration of nonconventional feed materials in diets of highly productive cows and its influence of indexes of natural resistance at different physiological stages of animals. In the process of studying of adaptation processes of highly productive cows at different stages of lactation it was determined that feeding with nonconventional melanoidin-humic additives at different physiological periods rendered a positive influence of highly productive cows, promoted the increasing of natural resistance of animals and improvement of immuno-humoral blood indexes. Administration of an additive Ehkolin in a ration of highly productive cows with stimulation for increasing milk flow in a dose of 100 ml per head promoted the increasing of blood serum bactericidal activity on 5,2%, beta-lysine activity - on 7,2%. Feeding of animals at a basic lactation period with 50 ml of preparation Ehkolin-2 provided the maximum increasing of lysozyme activity of blood serum (on 6,2%) and beta-lysine activity of blood serum (on 12,7%), and also promoted the activation of leukocytopoiesis. Addition of Ehkolin-3 in ration structure of dry cows in a dose of 750 ml increased the indexes of lysozyme activity of blood serum on 7-8,6%, bactericidal activity of blood serum - on 2,2-3,6% and beta-lysine activity of blood serum - on 2,2-3,6%.

In the conditions of the Republic of Belarus there were determined the doses of application of siliceous sapropel as well as there were studied the indexes of ruminal digestion and digestibility of diet nutrient substances by bull calves. The studied siliceous sapropel of the lake Pribylovichi (Belarus) occurence on 42% consisted of organic substances and on 58% - of mineral substances: calcium, phosphorus, magnesium, potassium, sodium, iron, zinc, manganese, and copper. The studied sample of sapropel did not render toxic action on test objects of infusorian Tetrahymena pyriformis in the conditions of its addition into the basic forage in number of 1%; 3%; 5%; and 10%. However, its higher concentrations (10%) retarded the development of Protozoa. Feed additives with the content of siliceous sapropel in mixed fodder in dose of 1%, 3% and 5% increased the relative biological value of forage in the experiments on test objects of infusorians Tetrahymena pyriformis in the average respectively on 5,4%, 5,0 and 2,6%. Higher concentrations of sapropel in mixed fodder (5 and 10%) lowered its nutritional value. Inclusion of siliceous sapropel in bull calve rations activated the enzymatic processes in farding bag and increased the digestibility nutritive elements on 2,3-3,6% except for protein, digestibility which was practically at identical level at animals of all groups.