Fructooligosaccharides alter profiles of fecal short-chain fatty acids and bile acids in rats

We investigated the effects of fructooligosaccharides and chicory inulin on the profiles of cecal and fecal short-chain fatty acids (SCFAs) and fecal bile acids in rats. Thirty-six Sprague Dawley male rats weighing about 190 g were randomly divided among four treatments control diet, control diet + 6%(w/w) fructooligosaccharide (FOS), control diet + 6% chicory inulin oligosaccharide(CIOS), and control diet + 6% chicory inulin(CI). The rats were pair-fed and experimental diets were maintained for 5 weeks. Cecal and fecal pH was significantly decreased in rats that were fed fructooligosaccharides and chicory inulin. Cecal propionate was significantly elevated in rats fed CIOS diets, and butyrate was lower in rats fed FOS and CI than control values. Cecal lactate was significantly higher in the FOS group than in the control group. The fecal excretions of acetate and total SCFA were 200-300% higher in rats that were fed fructooligosaccharides and chicory inulin than in the control group. Lactate excretion was highest in rats that were fed FOS, followed by those fed CIOS and Cl. The cholic acid and total bile acid concentrations in feces were significantly lower in the rats that were fed fructooligosaccharides and chicory inulin. The deoxycholic acid concentrations in wet feces were significantly lower in the groups of rats that ate CIOS (0.186 mM), FOS (0.274 mM), and CI (0.362 mM) than in the control group (0.595 mM). Among the fructans, short-chain fructooligosaccharide was snore effective at decreasing colonic pH and lactate production, but medium-chain chicory inulin oligosaccharide was snore effective at increasing fecal butyrate and lowering the fecal secondary bile acid concentration.