The thesis is devoted to research of functional state of the of the digestive system of hens – broilers while adding to the basic diet the probiotic supplements «Probion forte» at a dose of 1 g/kg, 0.5 g/kg and "BioPlus2B" at a dose of 0.4 g/kg of feed. It was established that the feeding of hens – broilers with feed of probiotic supplements «Probion forte» at a dose of 1 g/kg and 0.5 g/kg within 42 days promotes: in the glandular stomach of relative increase in the number of lymphoid cells; in the duodenum - credible increasing of the villa height of the mucous membrane 183 micron and 126 micron and the thickness of the muscle membrane - by 175.3 micron and 110.3 micron, that on ultrastructural level it was accompanied with increasing altitude of enterocytes microvilli and in the cytoplasm – the content of ribosome and mitochondria. In jejunum the reliable increase in villus height and crypt depth was noted at the 15th and 30th days, whereas on the 42nd day these figures were approaching to those of the control group, that testifies to rapid activation of digestion and the high intensity of absorption in the jejunum. In liver of research chickens it was also observed the activation of protein synthesized and energy-producing functions. The expressed hyper plastic processes in the digestive tract of chickens – broilers, which received probiotic food supplements with food, were caused by physiological adaptation and were aimed at the functional activity of thin intestines, increased parietal digestion, that was accompanied with increased average daily gain, poultry body mass and slaughter exit of condensing carcasses in the first, second and third experimental groups. In the blind gut mucosa of broilers, which were fed with probiotic supplements «Probion forte» at a dose of 1 g/kg, 0.5 g/ kg and "BioPlus2B" at a dose 0.4 g/kg was established: significant increase of villus height on the 42nd day, in accordance, on 229.3 mcm and 178.4 mcm and 214.9 mcm; crypt depth, in accordance, on 45.0 mcm and 22.36 mcm and 36.8 mcm; increasing the number of microorganisms of genus Lactobacillus, respectively, by 15.3 % and 14 % and 10.7 %, and as well as significant decrease in the number of microorganisms of genus E.coli by 22.9 %, 20.3 % and 16.5 %, respectively. It is established, that the most active hyper plastic and hypertrophy processes took place in structural elements of the broilers digestive tube, which were fed with probiotic supplements «Probion forte» at a dose of 1 g/kg, which caused the activation of mitotic and synthesized cell function, which was aimed at strengthening of the wall digestion and absorption.
