摘要
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(n=960,80 birds per treatment)were fed 12 sorghumsoybean 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(n=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(P=0.007)and enhanced caecal propionic,valeric and succinic acid concentration(P<0.05).Wheat bran increased FI(P=0.018)and BWG(P=0.016),as well as caecal Bifidobacteria concentration(P<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(P<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.
