Two prebiotics are effective in promoting fermentation in rats fed a high fat diet

Resistant starch (RS) and fructooligosaccharides (FOS) are two non‐digestible, fermentable fibers whose break down by intestinal microbiota has been shown to improve gut health. However, previous studies suggest that a high fat diet fed prior to the prebiotic negatively impacted the fermentation process in rodents. The pre‐feeding of the high fat diet may change the microbiota so that the rodents could no longer respond to a dietary prebiotic. The question examined in the current study was: will concurrent feeding of prebiotics with a high fat diet preserve the ability to ferment? This 2×2×2 factorial study in Sprague Dawley rats (n=96) studies the fermentation effects of a high‐amylose corn starch (Hi‐maize® resistant starch) and a short‐chain FOS (NutraFlora®) in low (4% g/kg; 18% of energy) and high (14% g/kg; 40% of energy) levels of dietary fat. Results were significant at p<0.05. Prebiotic diets produced animals with larger full and empty ceca than control diets, and an increase in serum concentrations of GLP‐1 total and PYY, regardless of dietary fat level. Both RS and FOS significantly decreased cecal and colonic pH levels. RS and FOS combined diets caused a further reduction in pH. Feeding the prebiotics concurrently with high dietary fat preserved a significant amount of fermentation that was reduced or lost when pre‐feeding a high fat diet without prebiotics in a previous study. Funding was provided by National Starch LLC and LSU AgCenter. scFOS was provided by GTC Nutrition.