Dietary resistant starch increases Bifidobacterium spp./ Lactobacillus spp. and Clostridia spp. in the gut of mice fed low and moderate fat diets

Abstract

Our previous work showed that resistant starch (RS) failed to reduce obesity in rodents fed a high fat diet. The high fat diet (41% dietary energy) prevented fermentation of RS and reduced bacterial populations in the gut compared to a low fat diet (18% dietary energy). The current 10‐wk study used thirty‐six C57Bl/6J mice to determine the effects of RS with low vs. moderate fat diets (18% vs. 28% dietary energy) on growth of bacterial populations. We measured three types of bacteria involved in RS fermentation and butyrate production. The study was analyzed as a 2x2 factorial with control versus RS diets and moderate versus low fat diets (significance at p<0.05). Ceca with contents were aseptically collected with an anaerobic gas pack. After serial dilutions, populations of Bifidobacterium spp./Lactobacillus spp. and Clostridia spp. in cecal contents were determined using appropriate media to enumerate Colony Forming Units (CFU). Moderate dietary fat did not diminish the growth of bacterial populations. The presence of RS in the diet promotes increased growth of bacterial populations in low and moderate fat diets, but not in high fat diets. This is important in formulating diets that support healthy gut microflora and reduced obesity. Supported by the NIH and the LSU AgCenter.