Microencapsulated Propionate and Butyrate Improved Energy Balance and Gut Microbiota Composition in Diet-Induced Obese Rats

Short-chain fatty acids (SCFA), particularly propionate and butyrate, reduce food intake, body weight, and modulate gut microbiota composition. However, it is unclear whether encapsulation of propionate and butyrate enhances their delivery to distal gut to improve energy balance and gut microbiota composition in obesity. Objectives: We determined the effects of microencapsulated propionate and butyrate on energy balance, gut microbiota and metabolite composition in obese rats. Methods: In experiment-1, obese male Sprague-Dawley rats were fed microencapsulated propionate and butyrate (5&ndash:10% wt/wt) or control high-fat diet. In experiment-2, obese rats were fed 10% microencapsulated propionate and butyrate, non-encapsulated butyrate (10% wt/wt), and pair-fed to non-capsulated butyrate. Food intake, energy expenditure (EE), sympathetic-mediated EE changes by propranolol, body composition, gut microbiota and fecal and plasma metabolites were analyzed. Results: Microencapsulated propionate decreased caloric intake, weight and fat mass, while microencapsulated butyrate had modest effects. Non-encapsulated butyrate reduced intake and prevented weight gain beyond pair-fed controls. Microencapsulated propionate and non-encapsulated butyrate reduced respiratory quotient suggestive of a shift towards lipid utilization, and enhanced &beta:-adrenergic-mediated EE. Microencapsulated propionate and butyrate altered alpha and beta diversity metrics, microencapsulated propionate increased Verrucomicrobiae, microencapsulated butyrate increased Lactobacillaceae, and microencapsulated propionate and butyrate reduced Erysipelotrichia. Microencapsulated propionate and butyrate increased fecal amino acids and altered select plasma metabolites: microencapsulated propionate increased fecal and plasma propionate, supporting distal gut delivery. Conclusions: Dietary supplementation with microencapsulated propionate and butyrate improved energy balance, enhanced lipid utilization, beneficially modulated gut microbiota composition, and altered metabolite profiles in obese rats.