Р. С. Мухаммадиев The article presents data on comparative analysis of the productivity, immune status and microbiota of the cecum of broiler chickens when probiotics based on the strains of Lactiplantibacillus plantarum SG66 and/or Bacillus subtilis GA24 were added to the diet. The work used broiler chickens of the Cobb 500 cross, which were raised in floor housing from one day to 42 days of age. The birds of groups 1, 2 and 3 received a balanced diet with the addition of probiotics based on L. plantarum SG66, B. subtilis GA24 and their mixtures, respectively, at dose of 2.70 × 106 CFU/g of feed; group 4 (control) received a complete diet. Live weight gain of the broiler chickens in groups 1, 2 and 3 was higher (p<0.05) than the control by 6.18, 7.02 and 9.81%, respectively; feed conversion was lower by 1.76, 3.53 and 2.94%. Productivity index of the broiler chickens in groups 1, 2 and 3 was higher than in the control by 35.75, 44.93 and 54.66 U, respectively. The broiler chickens in group 3 (97.07%) had the highest safe keeping followed by groups 2, 1 and 4 (96.50, 96.63 and 94.29%, respectively). The observed increase (p<0.05) in the digestibility of nutrients of the diet of the broiler chickens of group 1 was due to the digestibility of dry matter, group 2 – dry matter and fiber, group 3 – dry matter, fiber and protein. Compared with the control, the phagocytic activity of neutrophils, bactericidal and lysozyme activities of blood serum of the broiler chickens in groups 2 and 3 increased (p <0.05). No significant changes in these indicators were observed in the broiler chickens of group 1. According to the results of quantitative PCR, the total number of bacteria in the chyme of the cecum of the broiler chickens of groups 1, 2 and 3 was greater (p<0.05) in 1.12, 1.21 and 1.17 times higher, respectively, than in the control group (p<0.05). An increased Firmicutes/Bacteroidetes ratio in the experimental groups of broiler chickens was positively correlated with an increase in their live weight gain (p=1.0, according to Spearman, p<0.05).
Научная статья 
птицеводство