Sessions

In intensive poultry production, in addition to the use of antibiotics, alternative feed additives are gaining increasing attention. These additives may improve production performance and reduce the risk of antimicrobial resistance (AMR) through the maintenance of gut microbiome balance. The aim of the present study was to evaluate the individual and combined effects of a feed-supplemented antioxidant complex and enrofloxacin treatment on the natural production parameters and caecal microbiota composition of broiler chickens.

In the experiment, 1200 Ross-308 male broilers were divided into six treatment groups and reared for 42 days. Treatments included the antioxidant complex administered from either the 1st or 3rd week of age, alone or in combination with enrofloxacin. Sampling was conducted on days 15, 21, and 42. The composition of the gut microbiota was analyzed using the Oxford Nanopore MinION sequencing platform.

The results showed that the treatments had a considerable impact on both the structure of microbial communities and the production indicators. The antioxidant supplementation initiated from the 3rd week (T4 group) resulted in the highest body weight gain, the most favorable feed conversion ratio (FCR), and reduced mortality. At the microbiota level, both the T4 group and the group receiving antioxidants throughout the entire rearing period (T6 group) showed a higher relative abundance of the probiotic Lactobacillaceae family, while the combined antibiotic-treated groups exhibited an increase in opportunistic bacterial families such as Helicobacteraceae and Moraxellaceae.

In conclusion, the standalone use of the antioxidant complex — particularly when initiated from the 3rd week — had a beneficial impact on broiler chickens’ growth performance and gut microbiome stability. These findings support the relevance of antioxidant-based feeding strategies in the context of sustainable livestock production and the mitigation of antimicrobial resistance development.