Improvement in adiposity with oligofructose is modified by antibiotics in obese rats

Given the intimate link between gut microbiota and host physiology, there is growing interest in understanding the mechanisms by which diet influences gut microbiota and affects human metabolic health. Using antibiotics and the prebiotic oligofructose, which has been shown to counteract excess fat mass, we explored the gut microbiota-dependent effects of oligofructose on body composition and host metabolism. Diet-induced obese male Sprague Dawley rats, fed a background high-fat/sucrose diet, were randomized to one of the following diets for 6 wk:1) high-energy control; 2) 10% oligofructose; 3) ampicillin; 4) ampicillin + 10% oligofructose; 5) ampicillin/neomycin; or 6) ampicillin/neomycin + 10% oligofructose. Combining oligofructose with ampicillin treatment blunted the decrease in adiposity seen with oligofructose. Although ampicillin did not affect total bacteria, ampicillin impeded oligofructose-induced increases in Bifidobacterium and Lactobacillus. In contrast, the combination of ampicillin and neomycin reduced total bacteria but did not abrogate the oligofructose-induced decrease in adiposity. Oligofructose-mediated effects on host adiposity and metabolic health appear to be in part dependent on the presence of specific microbial species within the gut.