From association to intervention: Muribaculaceae driven SCFAs production enhances boar semen quality via inflammation...

The gut microbiota plays a vital role in host reproduction, yet its contribution to semen quality in boars remains unclear. In this study, we analyzed 556 boars from three commercial breeds and identified Muribaculaceae as a key microbial taxon positively associated with sperm quality, with the effect mediated by short-chain fatty acids (SCFAs). This association was validated in Yorkshire boars with extreme semen phenotypes. Fecal microbiota transplantation in mice confirmed that enrichment of Muribaculaceae improved semen quality, likely through enhanced SCFA production and reduced inflammation in the gut and reproductive tract. Furthermore, in vitro fermentation and mouse experiments demonstrated that a designed functional fiber selectively promoted Muribaculaceae, increased SCFA levels, and improved sperm quality. These findings suggest a functionally supported and potentially translational association between gut microbiota and boar fertility, suggesting that targeted dietary modulation of Muribaculaceae may represent a novel strategy to enhance reproductive performance in livestock.