Myostatin gene deletion alters gut microbiota stimulating fast-twitch glycolytic muscle growth

The host genome may influence the composition of the intestinal microbiota, and intestinal microbiota performs an important role in muscle growth and development. Here, we showed that Myostatin (MSTN), a key factor for muscle growth, deletion alters muscularis, plica, and intestinal barrier in pigs. Mice transplanted with MSTN^−/− pig intestinal flora showed increase in the cross-sectional area of myofibers and fast-twitch glycolytic muscle mass. The microbes responsible for the production of short chain fatty acids (SCFAs) were enriched in both MSTN^−/− pigs and recipient mice, and SCFAs levels were elevated in the colon contents. We demonstrated that valeric acid can stimulate type IIb myofiber growth by activation of the Akt/mTOR pathway via GPR43 and improve muscle atrophy induced by dexamethasone. This is the first study to identify the MSTN gene-gut microbiota-SCFA axis and its regulatory role in fast-twitch glycolytic muscle growth.