Impact of Bacillus subtilis and enrofloxacin application scheme on biochemical profile of broiler chickens

High metabolic rate of broiler chickens during the early postnatal period requires significant attention from poultry farmers. During this period, physiological functions are formed under significant stress. Furthermore, high risks of infectious diseases can lead to significant economic losses in poultry farming. Enrofloxacin, which is used during the early stages of poultry development, has found wide application in modern broiler poultry farming. The use of bacilli-based probiotics is of particular interest due to their ability to optimize the microbiome and stimulate natural defense mechanisms. The aim of this study was to compare the dynamics of blood biochemical parameters in broiler chickens treated with the antibiotic enrofloxacin, the probiotic strain Bacillus subtilis BKM B-3728D (KE) and their combination. The experiment was conducted on 100 Ross-308 broiler chickens divided into four groups: a control group and experimental groups treated with probiotic, antibiotic enrofloxacin and their combination. Blood biochemical parameters and animal growth were assessed over time, with statistical data processing using the Mann-Whitney test. The probiotic was found to optimize metabolic processes, resulting in a significant reduction in glucose levels by 9-15% and activation of protein metabolism. In contrast, antibiotic therapy caused liver dysfunction (a 32% decrease in bilirubin and 35% decrease in ALT) and a significant disruption of lipid metabolism (a 104% increase in triglycerides). Combined use of the drugs did not demonstrate a synergistic effect and was accompanied by signs of metabolic stress. The obtained results confirm the potential of using Bacillus subtilis strain BKM B-3728D for optimizing the metabolic status of broilers. However, complete replacement of antibiotics with probiotics requires additional research to select compatible strains and develop effective administration regimens.