Effect of Bacteriophage Cocktail on Growth Performance, Diarrhea Score, and Gut Bacteria of Broilers in Comparison with Bacillus subtilis

This study investigated the efficacy of a bacteriophage cocktail on growth parameters, diarrhea score, and ileal and cloacal bacterial counts of broilers, compared to Bacillus subtilis. A total of 4131 mixed-sex broiler day old chicks (DOCs) were procured from a commercial company and reared for 42 days in cages within a controlled broiler shed. Birds were assigned to three treatment groups: T1 (supplemented with B. subtilis at 200 g/kg of feed), T2 (bacteriophage added to basal feed at 300 g/kg of feed), and T3 (feed sup-plemented with bacteriophage at 500 g/ton of feed). Each treatment was replicated into 81 cages, with 17 broilers per cage. Feed conversion ratio (FCR) was lowest, and the survival rate and European production efficiency factor (EPEF) were highest in the T3 group, with T2 showing intermediate performance. Bacte-riophage-supplemented groups exhibited lower diarrhea scores, as feces appeared normal. Escherichia coli and Salmonella counts were lowest in the T3 group throughout the experiment, followed by T2, while these groups had higher counts of Lactobacillus and Bifidobacterium. The T3 group demonstrated superior over-all performance in comparison with the other two experimental groups. In essence, supplementing a bacte-riophage cocktail at a rate of 500 g/ton of feed could serve as an effective feed additive for enhancing growth performance, overall welfare, and modulation of gut bacteria by increasing beneficial bacteria and reducing targeted pathogens.