FFAR2 and Obesity: Consistent with this finding, our results found that transplanted fecal microbiota from NO mice enhanced bone strength and microstructure, as well as decreased relevant osteoclast genes, by altering the microbiome, which was positively correlated with Ffar2. We also identified purines including 5-hydroxyisourate, xanthine and hypoxanthine, as obesity-related metabolites that may reflect bone health.