Improving sorghum digestion in broilers by targeting fermentation of xylan

Abstract

<p>This study was to examine if it is possible to accelerate sorghum digestion in broiler chickens by targeting fermentation of the xylan. Cobb 500 broilers (<i>n</i> = 960, 80 birds per treatment) were fed 12 sorghum-soybean meal-based dietary treatments fed as 3 phases (starter d 0 to 12, grower d 13 to 23, finisher d 24 to 35), with 8 replicate pens of 10 birds per treatment. For half of the treatments (<i>n</i> = 6), 10% of the sorghum in the diet was directly replaced with 10% wheat bran, as a source of fermentable fibre. The diets were supplemented with either 0, 50 or 2,000 mg/kg xylo-oligosaccharides (XOS), with or without xylanase application. Body weight gain (BWG), feed intake (FI) and feed conversion corrected for mortality (cFCR) was determined at d 0 to 35, and male and female body weight were measured on d 35. On d 35, ileum and caeca samples were collected from 2 birds per pen, for determination of caecal cellulase and xylanase activity, microbiota composition and short chain fatty acid (SCFA) concentration, and ileal XOS concentration. Supplementation with 2,000 mg/kg XOS caused increased BWG at d 0 to 35 (<i>P</i> = 0.007) and enhanced caecal propionic, valeric and succinic acid concentration (<i>P</i> < 0.05). Wheat bran increased FI (<i>P</i> = 0.018) and BWG (<i>P</i> = 0.016), as well as caecal Bifidobacteria concentration (<i>P</i> < 0.001). Ileal XOS concentration was greatest when feeding combined wheat bran, 2,000 mg/kg XOS, and xylanase, resulting in increased caecal total SCFA, acetic acid and butyric acid concentration, and xylanase and cellulase activity (<i>P</i> < 0.05). Results from this study present that feed efficiency in birds fed sorghum-based diets is improved as a consequence of supplementing with fermentable fibre, xylanase and XOS.</p>