Effects of dietary inclusion of xylooligosaccharides, arabinoxylooligoscaccharides and soluble arabinoxylan on the microbial composition of caecal contents of chickens

BACKGROUND: Arabinoxylan (AX)-derived preparations have raised particular interest by the suggestion that they exert prebiotic properties. Therefore an in vivo experiment was conducted to study the effects of xylooligosaccharides (XOS), arabinoxylooligosaccharides (AXOS) and soluble AX (S-AX) on several groups of gut bacteria of chickens. Chickens were fed a control diet or the same diet supplemented with 2.S g kg(-1) of XOS (average degree of polymerisation (avDP) of 3, average degree of arabinose substitution (avDS) of 0.09), wheat bran-derived AXOS (avDP 9, avDS 0.34) or wheat endosperm alkali-solubilised AX (:S-AX, avDP > 6000, avDS 0.5). RESULTS: All treatment groups showed an increase in the number of caecal bifidobacteria after 2 weeks of feeding (P < 0.05), while the treatments did not impact numbers of Enterobacteriaceae and aerobic lactobacilli in the caeca relative to the control. XOS led to a tremendous increase in caecal bifidobacteria,counts (10(8) g(-1) for the XOS treatment versus 10(3) g(-1) for the control treatment) after only 1 week of supplementation, while AXOS and S-AX led to similar strong increases in bifidobacteria counts after 2 weeks of supplementation. Addition of S-AX to the diet, but not of AXOS or XOS, led to a significantly decreased (P < 0.05) body weight gain after 2 weeks of feeding relative to animals on the control diet, consistent with its known viscosity-related antinutritive effects in chickens. CONCLUSION: Similar to XOS, AXOS selectively stimulate the presence of bifidobacteria in the caeca of chickens, establishing their bifidogenic effect as a first indicator for prebiotic potential. (c) 2008 Society of Chemical Industry