Obesity is a major global lifestyle disorder associated with gut microbiota. The health benefits of eggshell membrane (ESM) have been shown in previous reports, particularly as regards gut microbiota composition. Here, we investigated whether ESM improves lipid metabolism and alters gut microbiota in high‐fat diet‐fed mice. A total of 20 C57BL/6J mice aged 6 weeks were given either a control diet (CON), high‐fat diet (HFD), or high‐fat diet + 8% ESM powder (HESM) for 20 weeks. ESM supplementation in HFD‐fed mice reduced plasma triglycerides (TG) and liver total cholesterol (TC) and upregulated the expression of lipid metabolism genes carnitine palmitoyltransferase 1A and suppressor of cytokine signaling 2. Microbiota analysis showed increased relative abundance of the anti‐obesity bacterium, Lactobacillus reuteri, at 4, 12, and 16 weeks and reduced the abundance of inflammation‐related Blautia hydrogenotrophica, Roseburia faecis, and Ruminococcus callidus at 12 and 20 weeks. ESM‐supplemented mice had increased cecal isobutyrate, negatively correlated with B. hydrogenotrophica and Parabacteroides goldsteinii abundance. The results indicate that ESM supplementation in HFD‐fed mice reduced plasma TG and liver TC, possibly through alteration of lipid metabolism gene expression and gut microbiota composition, suggesting that ESM may be effective in obesity management.

Inflammatory bowel disease (IBD) is a multifactorial immunomodulatory disorder. In relative nosogenesis, gut microbiota has been the focus of research on IBD. In our previous study, we demonstrated the ameliorating effect of zeolite‐containing mixture (Hydryeast^®, HY) on dextran sodium sulfate (DSS)‐induced colitis, through transcriptomics and proteomics. In the present study, we performed further investigation from the perspective of metagenomics using the gut microbiota. C57BL6 mice were provided an AIN‐93G basal diet or a 0.8% HY‐containing diet, and sterilized tap water for 11 days. Thereafter, colitis was induced by providing 1.5% (w/v) DSS‐containing water for 9 days. DNA was extracted from the cecal contents and pooled into libraries in a single Illumina MiSeq run. The resulting sequences were analyzed using Quantitative Insights Into Microbial Ecology (QIIME) software. According to the alterations in the relative abundance of certain bacteria, and the related gene and protein expressions, HY supplementation could improve the gut microbiota composition, ameliorate the degree of inflammation, inhibit the colonic mucosal microbial growth, and, to some extent, promote energy metabolism in the colon compared with the DSS treatment. Thus, we believe that HY may be a candidate to prevent and treat IBD.