Effects of dietary inulin on the intestinal short chain fatty acids and microbial ecology in broiler chickens as revealed by denaturing gradient gel electrophoresis

Inulin can stimulate the growth of the intestinal bacteria as well as alter the ratio among various short chain fatty acids (SCFA) produced. In the present study, we analyzed the effect of dietary inulin on the intestinal bacterial community as determined by denaturing gradient gel electrophoresis analysis of universal 16S rDNA after amplication with PCR and SCFA profile. Broilers were fed a diet primarily composed of corn-soybean meal or same diet with 1% inulin for 42 d. The relative weight of digesta-filled ceca of the inulin-fed group was higher (P < 0.01) than in the control group. Amongst SCFA, only acetate could be detected in the jejunal digesta, which tended to be higher (P = 0.09) in inulin-fed group compared with the control group. Inulin did not affect the total concentration of SCFA in the cecal digesta. The relative proportion of n-butyrate was elevated (P = 0.05) with a concomitant decrease in the concentration of n-valerate (P < 0.05) in the inulin-fed group compared with the control group. Dietary inulin did not affect the number of PCR-denaturing gradient gel electrophoresis bands nor their diversity in the jejunal and cecal digesta. Intragroup similarities were not different between the groups, nor were any differences between intra and intergroup similarities in the jejunal and cecal samples. In conclusion, inulin altered the cecal microbial metabolic activity without any major impact on the composition of intestinal bacterial communities as measured by the present techniques.