The effects of xylo-oligosaccharides on performance and microbiota in broiler chickens.

In broiler chickens, feed additives, including prebiotics, are widely used to improve gut health and to stimulate performance. Xylo-oligosaccharides (XOS) are hydrolytic degradation products of arabinoxylans that can be fermented by the gut microbiota. In the current study it was aimed to analyze the prebiotic properties of XOS when added to the broiler diet. Administration of XOS to chickens, on top of a wheat/rye-based diet, significantly improved the feed conversion ratio. XOS significantly increased villus length in the ileum. It also significantly increased numbers of lactobacilli in the colon and Clostridium cluster XIVa in the caeca. Moreover, the number of gene copies encoding the key bacterial enzyme for butyrate production, butyryl-CoA:acetate CoA-transferase, was significantly increased in the caeca of chickens administered XOS. In this group of chickens, at species level, Lactobacillus crispatus and Anaerostipes butyraticus were significantly increased in abundance in the colon and caecum, respectively. In vitro fermentation of XOS revealed cross-feeding between L. crispatus and A. butyraticus. Lactate, produced by L. crispatus during XOS fermentation, was utilized by the butyrate-producing Anaerostipes species. These data show the beneficial effects of XOS on broiler performance when added to the feed, which potentially can be explained by stimulation of butyrate-producing bacteria through cross-feeding of lactate and subsequent effects of butyrate on gastrointestinal function.