Roux-en-Y gastric bypass surgery (RYGB) improves glycemic control in severely obese individuals beyond weight loss effects. This study investigated gut microbiota's role using a preclinical RYGB model. 16S rRNA sequencing revealed altered fecal microbiota composition in RYGB-treated Zucker fatty rats, including lower Erysipelotrichaceae. This species correlated with glycemic control in RYGB rats, with Longibaculum muris showing positive correlation with glucose intolerance. Fecal microbiota transplant partially transferred improved glucose tolerance from RYGB rats to germfree mice. L. muris supplementation further improved glucose tolerance in RYGB recipients. These findings indicate gut microbiota contributes to weight-loss independent glycemic improvements after RYGB, highlighting the complexity of microbiota-host interactions.

Mohammed K Hankir, Petia Kovatcheva-Datchary, Rebecca Springer, Annett Hoffmann, Jörg Vogel, Florian Seyfried, Tulika Arora