A phage cocktail targeting multiple receptors reduces Salmonella Enteritidis colonization in chicks and modulates the...

Salmonella Enteritidis is a major pathogen responsible for foodborne illnesses, frequently causing public health issues through the contamination of poultry products and posing a serious threat to the poultry industry. In recent years, phages have emerged as a promising alternative to antibiotics for prevention and control strategies. In this study, a rationally designed phage cocktail from previous research was used, consisting of four phages targeting different receptors: GSP162, GSP193, GSP001, and GSP032. An infection model of chicks infected with S. Enteritidis strain SE006 was established to systematically assess the in vivo protective effects of the phage cocktail. The results demonstrated that the phage cocktail reached high concentrations in the chick ceca and showed a trend toward reduction in the ceca load of S. Enteritidis. In the phage-treated group, the cecal S. Enteritidis load was reduced by an average of 0.75 ± 0.34 log₁₀ CFU/g on day 1 and 1.01 ± 0.33 log₁₀ CFU/g on day 4 post-treatment, respectively. Gut microbiota analysis revealed that the phage cocktail modulated the dysbiosis induced by S. Enteritidis SE006 infection and facilitated the establishment of the early cecal microbial community in chicks. This study provides preliminary experimental evidence supporting the potential of phage-based biocontrol of Salmonella in poultry, laying a foundation for further field validation in commercial settings before practical application.