Dietarytrans-10,cis-12-conjugated linoleic acid alters fatty acid metabolism and microbiota composition in mice

The main aim of the present study was to investigate the effects of dietarytrans-10,cis-12-conjugated linoleic acid (t10c12-CLA) on intestinal microbiota composition and SCFA production. C57BL/6 mice (n8 per group) were fed a standard diet either supplemented witht10c12-CLA (0·5 %, w/w) (intervention) or with no supplementation (control), daily for 8 weeks. Metabolic markers (serum glucose, leptin, insulin and TAG, and liver TAG) were assessed by ELISA commercial kits, tissue long-chain fatty acids and caecal SCFA by GC, and microbial composition by 16S rRNA pyrosequencing. Dietaryt10c12-CLA significantly decreased visceral fat mass (Pt10c12-CLA intake. Caecal acetate, propionate and isobutyrate concentrations were higher (Pt10c12-CLA-supplemented group than in the control group. The analysis of the microbiota composition following 8 weeks oft10c12-CLA supplementation revealed lower proportions of Firmicutes (P= 0·003) and higher proportions of Bacteroidetes (P= 0·027) compared with no supplementation. Furthermore,t10c12-CLA supplementation for 8 weeks significantly altered the gut microbiota composition, harbouring higher proportions of Bacteroidetes, including Porphyromonadaceae bacteria previously linked with negative effects on lipid metabolism and induction of hepatic steatosis. These results indicate that the mechanism of dietaryt10c12-CLA on lipid metabolism in mice may be, at least, partially mediated by alterations in gut microbiota composition and functionality.