Effect of dietary supplementation of bacteriophage on performance, egg quality and caecal bacterial populations in laying hens.

1. Bacteriophages (BP) have gained increasing attention as a treatment of bacterial infection for animals. However, the data pertaining to dietary application of BP for laying hens have been limited. 2. This study aimed to investigate the effect of dietary BP on laying performance, egg quality and caecal bacterial populations in laying hens. 3. The dietary BP used in this experiment was a mixture of individual BP targetingSalmonella gallinarum,Salmonella pullorum,Salmonella typhimurium,Salmonella enteritidis,Salmonella derbyandStaphylococcus aureus. 4. A total of 360 Hy-Line Brown laying hens of 32 weeks of age were allotted to one of three dietary treatments with 6 replicates in a completely randomised design. The basal diet was prepared, and 0.4 or 0.8 g/kg BP mixture was supplemented to the basal diet. Diets were fed to hens for 8 weeks. 5. Laying performance and egg quality were not affected by dietary treatments. As inclusion levels of BP mixture in diets were increased, the DNA copy numbers forSalmonellaspp. in the caecal contents decreased linearly, whereas the DNA copy numbers forEscherichia coliin the caecal contents increased linearly. 6. Results indicate that dietary supplementation of BP mixture decreases the targetSalmonellaspp. populations but increasesEscherichia colipopulations in the gastrointestinal tract of laying hens with little impact on laying performance and egg quality. [ABSTRACT FROM AUTHOR]