Protective effect of phage pSal-4 on chicken intestinal epithelial cells injured by Salmonella Enteritidis

Abstract

Abstract Salmonella Enteritidis (SE) is one of the most important pathogens posing a huge threat to the poultry industry, bacteriophages are used as an alternative antibiotic product for the treatment of SE due to their specific bactericidal effect and safety. This study aimd to investigate the protective effect of bacteriophage against SE infection of chicken intestinal epithelial cells. Chicken intestinal epithelial cells were treated with different concentrations of bacterial suspension, and cell damage was assessed by measuring the changes of cell viability and observation by transmission electron microscopy. In the phage protection experiment, the phages were co-incubated with SE for 2, 4, and 6 h, the adhesion rate and invasion rate of bacteria and gene transcription levels of Occludin, Claudin-1, ZO-1, NF-κB p65, TNF-α and IL-6 in cells were determined. The results showed that the transcription level of immune factor gene in chicken small intestinal epithelial cells was significantly decreased, and the transcription level of tight junction protein gene was significantly increased. Phages could decrease the infection of bacteria to chicken intestinal epithelial cells. Furthermore, phages were able to alleviate inflammation and barrier integrity disruption inflicted by bacteria in the co-culture. Based on these observations, phages seemed to be promising candidates for the prevention and treatment of gastrointestinal bacterial infections.