Eggshell membrane, a resistant protein, possesses prebiotic-like properties in improving gut microbiota composition and gut-liver axes in chronologically aged C57BL/6J male mice

Aging-induced gut dysbiosis may contribute to inflammation and obesity, potentially elevating the risk of age-related chronic diseases. In this study, we aimed to investigate the effects of diet supplemented with 8% eggshell membrane (ESM) on gut microbial composition in chronologically aged C57BL/6J male mice (53-week-old) compared to those of young (8-week-old) and age-matched control mice. After a 24-week dietary intervention, the ESM-fed group exhibited an increased abundance of butyrate-producing and valerate-producing bacteria, accompanied by a significant increase in the cecal concentrations of isobutyrate, isovalerate, and valerate. Furthermore, the ESM-supplemented diet led to reduced expression of Srebf1 , Acaca , Elovl6 , and Scd1 , suggesting a potential role for short-chain fatty acids in the suppression of hepatic lipogenesis. Additionally, reduced hepatic triglyceride levels showed an association with the downregulation of Atgl and Cpt1a , two key lipolysis-associated genes. These findings highlight the potential of ESM as a functional food ingredient that can support healthy aging. • The effect of ESM on the gut microbiota composition of aged mice was examined. • ESM diet increased the SCFA-producing bacteria, and hence the cecal SCFA levels. • Hepatic TG levels were significantly reduced in the ESM-fed mice. • Daily ESM intake could ameliorate aging-induced gut dysbiosis and aid healthy aging.