Carbohydrases or prebiotic oligosaccharides influenced growth performance and the expression of genes related to immune function in 28 day old broilers raised on clean or dirty litter.

Title- Carbohydrases or prebiotic oligosaccharides influenced growth performance and the expression of genes related to immune function in 28 day old broilers raised on clean or dirty litter. Authors- Allison Craig1,3, Farina Khattak1, Peter Hastie3, Mike Bedford2 and Oluyinka Olukosi1, 4.1Monogastric Science Research Centre, SRUC, Edinburgh, EH9 3JG, UK²AB Vista, Marlborough Business Park, Marlborough, Wiltshire, SN8 4AN, UK3 McCall Building, School of Veterinary Medicine, Glasgow University, Glasgow, G61 1QH, UK4 Department of Poultry Science, University of Georgia, Athens, GA 30602, USAKey words- broiler, toll-like receptors, xylanase, β-glucanase, XOSThe aim of this experiment was to evaluate the effect of carbohydrase or xylo-oligosaccharide (XOS) supplementation on growth performance, energy utilization and the expression of immune-related genes in broilers. Six hundred and forty Ross 308 broilers were used in this 28-d study. The study employed a randomised complete block design to investigate 2 environments (dirty or clean litter) and 4 additives (control, xylanase alone (XY), xylanase and β-glucanase (XY+BG) or xylo-oligosaccharide (XOS)) in a 2×4 factorial arrangement. The birds were allocated to 8 treatments; each treatment had 8 replicates and 10 birds per replicate. Feed and birds were weighed on d-14 and d-28. On d-28, two birds per pen were euthanized; tissue samples from the caecal tonsil and bursa of fabricius were collected and fixed in RNA later. The remaining birds were euthanized and ileal digesta was collected. On d-14, body weight gain (BWG) and feed intake were greater (P < 0.05) in birds on clean litter compared with those on dirty litter. On d-28, BWG was (P < 0.05) lower in diets supplemented with XOS or the XY+BG compared with the control. Ileal digestible energy (IDE) was greater (P < 0.001) in birds on both litter types and receiving the XY+BG compared to other treatments. IL1β expression was greater (P < 0.05) in birds raised on dirty litter compared to those raised on clean litter. TLR4 expression was greater (P < 0.05) in birds raised on dirty or clean litter and receiving the XY diet compared to birds raised on dirty litter and receiving the control treatment or birds raised on clean litter and receiving XY+BG. There were no treatment effects on IL10 or TLR21 expressions. In conclusion, the lack of positive effect of additive supplementation on growth performance in the current study, is contrary to our previous and subsequent studies using similar diets and the observation of positive effect of the additives on energy utilization. In addition, the effect of additive supplementation on the expression profiles of immune-related genes shows potential for carbohydrases or XOS to positively modify immune responses in broilers.