Dietary eggshell membrane modulates gut microbiota and alleviates AOM/DSS-induced colonic inflammation in mice

Persistent intestinal inflammation and gut dysbiosis are key drivers of the progression from inflammatory bowel disease (IBD) to colitis-associated colorectal cancer (CAC). Eggshell membrane (ESM) has shown beneficial effects in alleviating IBD symptoms; however, its impact on inflammation-driven CAC remains unclear. This study investigated the effects of dietary ESM supplementation in an azoxymethane/dextran sulfate sodium (AOM/DSS)-induced CAC mouse model. Mice were fed either a control or ESM-supplemented diet for one month prior to CAC induction and continuing throughout the experiment. ESM supplementation significantly improved survival rates in AOM/DSS-induced CAC mice and reduced colitis severity, indicated by the down-regulation of the pro-inflammatory cytokines and M1-like macrophage markers in the colonic mucosa. In addition, ESM conferred systemic protective effects by alleviating liver inflammation and tissue damage, as evidenced by preserved hepatic structure and reduced immune cell infiltration. Importantly, ESM significantly restored cecal microbiota composition disrupted by AOM/DSS, reducing pathogenic bacteria such as Escherichia-Shigella, while enriching beneficial bacteria such as Firmicutes and Muribaculaceae. These compositional shifts were accompanied by predicted correction of dysregulated microbial metabolic pathways, reflecting a restoration of microbial functional balance. Overall, these findings demonstrate that ESM alleviates multi-organ inflammation and restores microbial balance in CAC, highlighting its potential as a dietary strategy to mitigate chronic inflammation and its systemic consequences.