LAUSR

Abstract BACKGROUND Non‐starch polysaccharides are large complex molecules and are found in cereal grains. This study was conducted to investigate the effect of carbohydrase enzymes or prebiotic oligosaccharides on growth performance, nutrient utilisation and weight of organs associated with the immune system in broilers fed wheat‐ or barley‐based diets. RESULTS In wheat‐based diets, feed intake was lower (P < 0.05) following xylo‐oligosaccharide supplementation, whereas in barley‐based diets feed intake was greater (P < 0.05) following β‐glucanase supplementation. Gross energy digestibility was improved (P < 0.01) when either level of xylanase was added to wheat diets. Ileal digestible energy was greater (P < 0.01) in wheat diets including an additive compared with the control diet. In wheat diets, bursa weight was lower (P < 0.05) following xylo‐oligosaccharide supplementation compared with the control treatment. CONCLUSIONS The current study showed that supplemented carbohydrases or prebiotic oligosaccharides could alter the development of immune organs or small intestine without any significant effect on growth performance in broilers receiving nutrient‐adequate diets. © 2018 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.