Evaluation of the effect of selected alternatives to antibiotics on broiler production performance.

This study investigated the effects of dietary supplementation with lincomycin, bacteriophages, and tributyrin, alone or in combinations on growth performance, carcass characteristics, immunity, and mortality of broiler chickens. A total of 900 one-day-old Aviagen Ross-308 chicks were allocated to six dietary treatments: Negative Control (NC, basal diet without additives), Positive Control (PC, basal diet with 100 g lincomycin/ton), BAC (basal diet with 500 g bacteriophage/Ton), TRB (basal diet with 500 g tributyrin/Ton), BAC*AB (basal diet with 250 g bacteriophage + 50 g lincomycin/ton), and BAC*TRB (basal diet with 250 g bacteriophage + 250 g tributyrin/Ton). Birds were reared under standard management practice for 35 days. Birds were reared under standard management practice for 35 days. Results revealed that BAC*AB significantly improved feed conversion ratio (FCR) compared to other treatments, achieving the highest European Production Efficiency Factor (EPEF) of 459. Carcass yield and organ weights varied, with TRB exhibiting the highest liver percentage (2.51%) and BAC enhancing spleen weight (0.24%). Immunological parameters, including IgA and IgG levels, were significantly enhanced in the TRB and BAC*TRB groups, reflecting improved immune responses. Mortality rates were lowest in BAC*AB (2.00%) and BAC (2.67%) groups. Additionally, the BAC and TRB groups demonstrated improved cytokine and interferon profiles. Dietary treatments significantly increased IFN-γ mRNA expression compared to the NC group, with the TRB and BAC groups showing the highest levels, indicating enhanced immune activation. All treatment groups improved immune marker expression compared to NC. In conclusion, the combined use of bacteriophages with either lincomycin or tributyrin offers benefits in improving feed efficiency, immune parameters, and overall production efficiency in broilers. These findings support the integration of alternative feed additives into poultry diets to enhance productivity while reducing reliance on traditional antibiotics.