The regulatory effects of solid-state fermented Rosa roxburghii Tratt. pomace on serum metabolism and intestinal microbiota in rats

This study investigated the in vivo physiological effects of solid-state fermented (SSF) Rosa roxburghii Tratt. pomace (F-RRTP) on host metabolism and gut microbiota. Rats were fed diets supplemented with 1% ( w/w , total diet basis) unfermented RRTP or F-RRTP. Compared with unfermented RRTP, F-RRTP showed a relative increase in serum HDL-C and improved antioxidant-related parameters, as indicated by higher serum SOD and hepatic T-AOC activities. Gut microbiota analysis showed that F-RRTP altered the microbial community structure, including a reduced Firmicutes / Bacteroidetes ratio and a lower relative abundance of Proteobacteria , a taxon commonly associated with gut dysbiosis. Notably, F-RRTP enriched putative butyrate-producing genera, including Ruminococcus and Allobaculum , as well as Bifidobacterium , and this was accompanied by a higher fecal butyrate level. Serum metabolomics further revealed distinct metabolic alterations in the F-RRTP group, including changes in flavonoid-related metabolites, tryptophan metabolites such as serotonin and indole-3-lactic acid, and several metabolites associated with antioxidant status. It suggested coordinated associations among gut microbiota, serum metabolites, and host physiological indices, implying that fermentation-induced changes in pomace properties may contribute to the observed effects. Collectively, these findings indicate that SSF may enhance the functional potential of RRTP and support its further development as a value-added food or feed ingredient with potential metabolic health benefits.