Stimbiotic and wheat bran inclusion in maize or wheat-based diets for broiler chickens; effects on jejunal histomorphology, digesta oligosaccharides and caecal short-chain fatty-acids profiles.

1. A stimbiotic (STB) is any feed additive that stimulates caeca fibre fermentation, although the additive itself contributes little to the caeca short-chain fatty acid (SCFA) production. A 42 d experiment investigated the interactive effects of STB and wheat bran (WB) in broiler chickens receiving maize or wheat-based diets.2. The treatments were arranged in a 2 × 2 × 2 factorial (eight replicates each), the dietary factors being diet (maize-SBM or wheat-SBM), STB (with or without) and WB (0 or 50 g/kg). Jejunal tissue, gizzard, jejunal and ileal digesta and caecal contents were collected on d 18 and 42.3. Gizzard pH tended to decrease with STB ( p  = 0.06) supplementation and was lower in birds fed wheat- compared to maize-based diets on d 18 ( p  < 0.05). Birds receiving diets with WB had higher jejunum pH on d 18 ( p  < 0.05).4. Total short-chain fatty acids (SCFA) in the caeca on d 18 and isobutyrate on d 42 were higher ( p  < 0.05) for maize compared with wheat-based diets. However, on d 42, acetate, butyrate and total SCFA were higher ( p  < 0.05) for wheat-based compared with maize-based diets.5. On d 18, STB and WB inclusion increased villi height (VH; p  < 0.05) and VH to crypt depth ratio (VH/CD), respectively ( p  < 0.05). On d 42, VH ( p  < 0.05) and VH/CD were higher in wheat-based diets ( p  < 0.05). The VH/CD ratio was lower with STB supplementation ( p  < 0.05). Marker-corrected pentose oligosaccharides (Pent) 4 and (Pent) 5 concentrations in the ileal digesta were reduced ( p  < 0.05) with STB supplementation. In addition, STB decreased (Pent) 3 concentration in maize-, but not wheat-based diets ( p  < 0.05).6. In conclusion, both WB and STB influenced gastrointestinal pH and jejunum histomorphology of broilers without increasing oligosaccharide concentration in the ileum and SCFA in the caeca.