Evaluation of the Effect of Bacteriophages and Organic Acids as a Feed Additive to Reduce Salmonella enteritidis in Challenged Chickens

This study aimed to compare the effects of dietary supplementation of bacteriophage (BP) and acidifiers on performance, meat quality, morphology, and intestinal microbiota in chickens challenged and unchallenged with Salmonella enteritidis (SE) and also to investigate the possibility of replacing them in the diet with antibiotics. A total of 1760 male Ross (308) chicks were randomly assigned to 11 dietary treatments (8 pens/with 20 male chickens in each). Dietary treatments were as follows: SE-uninfected (negative control (NC), a basal diet without supplemention; NC+ 500 g/t BP (NBP1); NC+ 1000 g/t BP (NBP2); NC+ 300 mg/kg acidifier A (NAA); NC+ 300 mg/kg acidifier B (NAB)) and SE-infected (positive control (PC), a basal diet without supplemention; PC+ 40 mg/kg Antibiotic enrofloxacin (PA); PC+ 500 g/t BP (PBP1); PC+ 1000 g/t BP (PBP2); PC+ 3000 mg/kg acidifier A (PAA); PC+ 3000 mg/kg acidifier B (PAB)). At 13 D birds in challenged groups were orally gavaged with 1 mL bacterial suspension containing approximately 108 CFU Salmonella enterica. The results indicated that chicks challenged with SE impaired performance so that BWG and FI significantly decreased and FCR increased (p < 0.05). Diets containing a high dose of BP increased BW and improved FCR in challenged and unchallenged chickens. The quality of breast meat showed a decline in oxidation in chickens challenged with SE (p < 0.05). The inclusion of bacteriophage in the diet of chickens (1000 g/t) improved the L*, b*, and oxidation of meat. The use of bacteriophage and acidifier A in the diet significantly increased the Lactobacillus, and LAB count, especially in the challenged groups. The challenge of chickens with SE decreased the villus height and crypt depth in different parts of the small intestine (p < 0.05). The results of the present study suggested that 1000 g/t of BP probably improves chicken performance by increasing beneficial bacteria and decreasing pathogenic bacteria. Also, bacteriophage showed an improvement in the performance reduction of chickens with Salmonella infection. In addition, improved meat quality and beneficial changes in the microbiome and intestinal morphology indicate the effectiveness of BP as an alternative antibiotic growth promoter in broiler diets.