In the development of effective methods of prevention and treatment of poultry today, importance is given to probiotics based on microbial cultures, in particular, lactobacilli, bifidobacteria, yeast, etc. In contrast to antibiotics, the use of probiotics stimulates the immune response of animals, restores the microflora of the gastrointestinal tract, and ensures its optimal ratio. At the same time, livestock products remain safe for the consumer. The purpose of our work was to conduct comparative clinical trials of the efficiency of the probiotic feed additive Probion-forte in terms of productivity, blood indices, and histological structure of immune organs of chicken broilers during fattening. The clinical studies were carried out with broiler chickens of “Cobb-500” cross at the age of 2 days, which were formed into four groups (300 units in each one). In order to determine the efficiency of application, probiotic feed additives were given to chickens in different concentrations during the growing period, together with the main diet. The first group (1st) was given probiotic Probion-forte in the dose of 1 g/kg of feed, the second group (2nd) – Probion-forte in a dose of 0.5 g/kg, the third (3rd) one – a probiotic-analog “Bio plus 2B” in a dose of 0.4 g/kg; the forth (4th) group was a control group – chickens received an essential diet, without adding any feed additives. The compound feed was provided according to norms recommended for the cross “Cobb-500”, considering age. On the 15th, 30th, and 43rd day of the test, 20 units were selected for hematological, pathomorphological and microbiological tests. The productivity of birds of all studied groups was evaluated by the average daily gains, safety, feed conversion, and slaughter output. The stabilized with EDTA chicken blood was used for morphological studies, and blood serum – for biochemical and immunological studies. Comparative clinical studies have shown that adding to the main diet of broiler chickens probiotic feed additive Probion-forte at a dose of 0.5 and 1.0 g/kg throughout the growing period increases the safety and improves feed digestibility, and increases the bird’s European Efficiency Index. Based on the obtained hematological, biochemical, and immunological parameters of blood, it can be argued about the activating effect on the body of broiler chickens probiotic feed additives, namely the intensification of reanimation of free amino acids, which increases the content of the studied metabolites of lipid metabolism, which chickens use as energy and plastic material. Stimulating cellular and humoral protection, nonspecific resistance is established, confirmed by a high level of lysozyme activity in blood serum and significantly higher content of T- and B-lymphocytes, NK-cells, and γ-globulins. The macro- and microscopic structure of the studied immune organs is preserved in all groups of broiler chickens. Compared with the control group, morphometric examination in the immune organs of broiler chickens of the first and second groups revealed an increase in the area and density of lymphoid elements, an increase in the number of plasmablasts and plasma cells, much higher structural and functional capacity of cells, which was reflected at the ultrastructural level. The most significant difference was found in the 1st group of chickens fed with the feed additive Probion-forte at a dose of 1.0 g/kg of feed.

An important feature of living organisms, acquired in the process of evolution, is the ability to adapt to various external influences and changes in the environment, to maintain homeostasis and regulatory processes in organs, systems and the body as a whole. However, with modern breeding technologies, the physiological capabilities of the animal's body are often unable to change as quickly as required by the conditions of industrial maintenance, which leads to stress. Vitamin preparations and biologically active feed additives are widely used by veterinary medicine specialists to increase resistance to stressful situations, disease prevention, increase resistance, safety and productivity of farm animals. Preparation L-tsyn, solution for injection (manufactured by BIOTESTLAB LLC), is a drug, the action of which is due to the prescription combination of active substances, namely: butaphosphane, B vitamins (vitamin B12, vitamin B3) and L-carnitine. The aim of the study was to investigate the effectiveness of the drug L-tsyn on horses under the influence of stressors of various natures. Two experiments on working horses with constant, excessive physical activity with chronic exercises and with complex therapy of intoxication with signs of acute renal failure in horse were conducted. Clinical trials of the drug were performed on working horses aged 5–15 years, of different sexes. The drug was administered in a dose of 20–25 ml per animal, 1 time per day for 5 consecutive days. The clinical condition of the experimental animals was observed for 21 days from the start of the drug. The morpho-functional state of the animal's body before and after the drug was established according to the indicators of the clinical condition, morphological and biochemical parameters of the blood, which were determined according to generally accepted methods. In working horses under excessive load the drug L-tsyn activated the processes of hematopoiesis, improved the physiological state of the body and contributed to the increase the general tone of the body. The drug as part of complex therapy in the treatment of intoxication, showed hepato- and nephroprotective properties, reduced the manifestations of intoxication, helped to restoration of the animal’s normal physiological state. According to the results of clinical, hematological and biochemical studies, it can be concluded that the drug L-tsyn has a stimulating effect on metabolic processes in the animals’ body, shows tonic properties, increases the body's resistance to toxins and adverse environmental factors and can be used as monotherapy and for the complex treatment of diseases of various etiologies in horses.

Sodium-containing preparations have antimicrobial, anti-inflammatory and wound-healing activity, which determines their use in veterinary medicine. This effect is due to a wide range of physiological effects of sodium ions on animals metabolism. The article presents the results of experimental studies of the irritant effect of sodium-containing drugs: known – 2 % glycetinate, its analogues – 2 % ovocid, 3 % ovocid, 1.5 % potassium-sodium drug (Na / K, 1.5%). Studies of irritant and skin-resorptive action of drugs were performed by immersing the tail of animals in a test tube with the substance on white rats weighing 250–270 g. Four groups of rats were formed with 3 animals each: rats of I group (control) tails were immersed in test tubes with 2 % glycetinate, animals of II group – in test tubes with 2% oocide, III group – in test tubes with 3 % oocide, and in IV group rats – with Na / K, 1.5% drug. The exposure time was 4 hours. The animals were subjected to clinical observations, assessing their general condition and the reaction of the tail’s skin. The effect of drugs on the morphological and biochemical parameters of the rats blood was studied. The study of the local irritant effect of the studied drugs in rats from I, II and III groups showed a moderate local irritant reaction, as evidenced by the appearance of redness and thickening of the skin, and in group IV animals appeared only slight redness on the skin of the tails. This indicates a weaker local irritant effect of potassium-sodium-containing drug (1.5% K, Na), compared with other studied drugs. According to hematological studies, in the rats’s blood of groups III and IV, a reliable increase, within normal limits, the number of leukocytes and a decrease in hemoglobin content, compared with those of animals of group I. It was found that at 4 hours of the experiment under the action of the studied potassium-sodium drugs increases the permeability of Sodium and Potassium through the rats’s skin into the blood. In particular, in serum of animals from groups II and IV there was a reliable increase of Potassium content by 2.1 times, respectively, and a significant increase in Sodium content in the blood of animals from groups III and IV, compared with control group. In animals of groups II and IV there was a reliable increase of serum aspartate aminotransferase activity, and in rats of group III – increase of serum alanine aminotransferase, alkaline phosphatase activity and in triacylglycerol’s content, compared with rats of group I, which indicates the effect of 2 % glycecin analogues on metabolic processes in animals.

Doxycycline is a bacteriostatic antibiotic from the group of tetracyclines, a semi-synthetic derivative of chloretracycline. It is a broad-spectrum antibiotic that is active in gram- positive and gram- negative bacteria, including some anaerobes. Therefore, the use of doxycycline drugs is relevant to solve the problem of treatment and control of mono- and polyinfections, which are caused by doxycycline sensitive and other antibiotics resistant to other antibiotics. The article presents the results of clinical studies of a new veterinary drug Doxal (water-soluble powder for oral administration), production of PJSC “Technologist” (Ukraine), an active pharmaceutical ingredient of which is doxycycline, in the treatment of acute intestinal disease in broiler chickens. A high level of therapeutic efficacy and safety of the Doxal studied drug in the treatment of chickens 25 daily age with colibacteriose-claspidiosis infection was established. The diagnosis was made on the basis of anamnestic data, a clinical picture of the disease, the results of pathoanatomical section and bacteriological examination. Microorganisms – pathogens of infection, their level of sensitivity to doxycycline were selected and identified. Therapeutic efficiency of the tested drug was not inferior to the drug-comparison of Doxatib®, production of KRKA DD Novo-Mesto (Slovenia), similar in dosage form and the content of the active substance. According to the results of laboratory tests, a positive effect of Doxal on the morpho-functional state of the body of chickens in the treatment of acute colibacteriosis-claspidiosis infection was revealed, which is confirmed by normalization with a high percentage of the reliability of morphological and biochemical blood indicators to the values of clinically healthy bird. Comparative clinical studies have confirmed that Doxal drug is effective chemotherapeutic agent for the treatment of bacterial infections in chickens caused by microorganisms sensitive to doxycycline, and is analogous to Doxatib® by it’s action.

The article presents the results of clinical trials on pigs of the veterinary medicinal product Vetaseptol (powder for oral use), manufactured by “Ukrvetrompostach LLC”. The drug was used orally with feed for the treatment of acute respiratory infection in 2-month-old piglets in the dosage recommended by the manufacturer. Before the experiment, microbiological studies were conducted on selection and identification of microorganisms, pathogens of respiratory infection in pigs, and establishing of their sensitivity to the active substances of the drug (oxytetracycline and erythromycin). During the experiment, constant observation of the clinical condition and physiological parameters of the body of the experimental animals were performed. Evaluation of hematological and biochemical indicators was carried out according to recognized methods. The therapeutic efficiency was compared with the data obtained before the treatment and after using the comparator drug. On the basis of obtained data and their statistical analysis, conclusions about the effeciency of Vetaseptol in the treatment of pigs, suffering from streptococcosis, and its effect on their organism were made. According to the evaluation of the animal’s clinical condition and the results of laboratory tests obtained, it was established that the tolerability of the studied drug for the treatment of respiratory infection of young pigs was good. During the experimental period and two weeks after the use of the drugs, no side effects were detected and no changes in the behavior of the piglets were observed. The therapeutic effectiveness of the test drug was 100%, and the recovery time was almost 5 days. A comparative analysis of piglet’s hematological indicators showed a reliable decrease of monocytes number in the animal’s leukogram after antibiotic therapy. The normalization of the piglet’s leukogram indicated the termination of inflammatory processes and the improvement of the physiological state of animals. The serum biochemical profile of experimental animals hasn’t changed significantly. Laboratory studies did not reveal hemo- and hepatotoxic effects of the antimicrobial drug.