| Dietary fats and gut microbes are regarded as environmental factors for the onset of obesity. However, whether there is a direct association between dietary fat type and gut microbiome that promotes obesity remains unclear. In this study, we tested the effect of modulation of the gut microbiome by antibiotics on energy balance in Sprague Dawley rats fed a 45% high fat diet containing primarily saturated fatty acids (SFA) vs. polyunsaturated fatty acids (PUFA). Antibiotic treatment successfully decreased the gut microbiome as evidenced by decreased microbiome &agr;-diversity and beta-diversity. We found that food intake was decreased by antibiotic treatment irrespective diet. PUFA-fed rats gained less weight and consumed less food than those fed SFA independent of microbiome composition. No differences were seen in energy expenditure among the 4 groups. Gut hormone and adipokine gene and protein expression was measured in ileum, colon, white adipose tissue (WAT) and blood serum. Compared with SFA, PUFA fed rats had less ileum peptide YY, colon glucagon-like peptide-1, WAT sterol regulatory element binding transcription factor 1 and more ileum beta-defensins, WAT adiponectin gene expression. However, no differences were seen in serum protein expression among the 4 groups. In conclusion, SFA are more obesogenic and promote food intake as compared to PUFA and this positive energy balance is independent of the gut microbiome. The mechanisms by which SFA modulate body weight and food intake warrant further investigation. |
