Effects of dietary bacteriophage on growth performance, gut health, physiological responses, and cecal microflora in broiler chickens

The aim of this study was to evaluate the effects of dietary bacteriophage on the growth performance, gut health, physiological responses, and cecal microbial populations of broiler chickens. Dietary bacteriophage did not affect growth performance in any phase ( P > 0.05) but improved intestinal morphology (villus height and villus height-to-crypt depth ratio) at 21 and 35 days. The number of S. aureus colonies in the cecal digesta linearly decreased ( P < 0.05) with increasing dietary bacteriophage concentrations at 21 and 35 days of age. Relative percentages of cecal fatty acids also changed at 21 and 35 days of age, with the latter shifting in a beneficial manner. Ig A levels at 21 days increased ( P = 0.044) but IgM ( P = 0.039) and IgY levels ( P = 0.006) at 35days of age decreased with increasing bacteriophage concentrations. Serum catalase activity decreased at 21 ( P = 0.009) and 35 ( P = 0.047) days with the addition of bacteriophage. Glutathione peroxidase activity in liver, thigh meat, and serum samples at 21 days increased. The serum concentration of malondialdehyde, an indicator of lipid peroxidation, decreased ( P = 0.049) at 35 days. These results suggest that dietary S. aureus bacteriophage supplementation can improve gut health and alter biochemical, immunological, and antioxidant responses in broilers.