Long-term endurance exercise influences exercise capacity in mice through modulation of the intestinal microbiota by fecal microbiota transplantation.

Background: Exercise alters intestinal microbiota composition; however, it remains unclear whether these alterations induced by long-term endurance exercise can be transferred by fecal microbiota transplantation (FMT) to improve recipient exercise capacity. Methods: Mice were divided into control (Group C), exercise (Group E), PBS transplantation (Group PT), and FMT (Group MT) groups. Group E underwent 14 weeks of treadmill training, and Groups PT and MT were transplanted with PBS or fecal microbiota from Group E, respectively. Subsequently, exhaustive exercise tests and 16S rRNA sequencing were performed, and blood glucose levels, glycogen reserves, and antioxidant indices were assessed. Results: Compared with Group C, Group E had significantly higher hepatic/muscle glycogen levels and superoxide dismutase activity, and lower liver malondialdehyde content. After transplantation, Group MT showed significantly higher Conclusion: Exercise-induced increases in glycogen reserves and antioxidant capacity, associated with altered intestinal microbiota composition, can be partially transferred to recipient mice via FMT. The gut microbiota acts as a partial mediator of improvements in exercise capacity, rather than the sole driver.