Ovomucin and its hydrolysates differentially influenced colitis severity in Citrobacter rodentium-infected mice

Egg white protein ovomucin and its hydrolysates were previously reported to exhibit anti-inflammatory and anti-adhesive activities. However, their potential to regulate pathogen colonization and disease severity has not been fully characterized. To investigate the effects of ovomucin (OVM) and its hydrolysates including ovomucin-Protex 26L (OP) and -pepsin/pancreatin (OPP) on host resistance to pathogen infection, a well-documented colitis model in mice for attaching and effacing E. coli pathogens, Citrobacter rodentium, was used in the current study. C57Bl/6J female mice were fed on a basal diet supplemented with OVM or its hydrolysates for 3 weeks prior to the C. rodentium challenge, with the dietary treatments continued for seven days. Body weight was not affected throughout the experimental period. OP supplementation resulted in lower (P < 0.05) pathogen loads at 7 dpi. Attenuated colitis severity was observed in mice that received OVM and OP, as indicated by reduced colonic pathological scores and pro-inflammatory responses compared with the infected control group. In contrast, OPP consumption resulted in enhanced C. rodentium colonization and disease severity. Notably, reduced microbial diversity indices of the gut microbiota were observed in the OPP-supplemented mice compared with the OVM- and OP-supplemented groups. This study showed the potential of OVM and OP to alleviate the severity of colitis induced by infection while also suggesting the opposite outcome of OPP in mitigating enteric infection.