The response of broilers to xylanase and β-glucanase combination in maize-based diets containing wheat distillers’ dried grain with solubles

Broiler diets containing wheat distillers’ dried grain with solubles (wDDGS) have higher levels of non-starch polysaccharides (NSP) compared to conventional maize-soybean meal-based diets, which can increase intestinal viscosity and impair nutrient utilisation. This study investigated the effects of supplemental xylanase and β-glucanase preparation (XG) on growth performance, ileal flow of soluble NSP constituent sugars, and the gastrointestinal environment in broilers fed maize-based diets with varying wDDGS levels. A total of 768 mixed-sex Cobb 500 d-old broilers were assigned to 6 treatments in a 3 × 2 factorial arrangement, with wDDGS levels (0% (none), 6-12% (medium), 12-20% (high)) and enzyme supplementation (XG: with or without) as factors, across eight replicate pens of 16 birds each, totalling 128 birds per treatment. From d 0-10, XG and wDDGS interacted (P = 0.019) for weight gain, with XG improving weight gain only in broilers fed high wDDGS diets but not in others. High wDDGS worsened (P = 0.014) FCR, while XG tended to improve it (P = 0.079). From d 10-21 (P = 0.006), d 21-35 (P < 0.001), and d 0-35 (P = 0.011), medium and high wDDGS diets impaired FCR, and high wDDGS reduced (P < 0.001) weight gain versus the control diet (no wDDGS). From d 21-35, XG increased (P = 0.001) weight gain and improved (P = 0.006) FCR regardless of wDDGS level. From d 0-35, XG increased (P < 0.001) weight gain and tended to improve (P = 0.097) FCR regardless of wDDGS level. Medium and high wDDGS diets raised ileal viscosity at d 21 (P = 0.020) and high wDDGS at d 35 (P = 0.002). XG lowered ileal viscosity at d 21 (P = 0.006) and d 35 (P = 0.001). Medium and high wDDGS diets resulted in higher ileal flow of soluble NSP constituent sugars, including soluble arabinose, mannose and glucose (all P < 0.001) versus the control. XG reduced soluble arabinose (P = 0.012) and total soluble NSP constituent sugars (P = 0.007). Dietary XG and wDDGS interacted (P = 0.018) for ileal soluble xylose concentration within the NSP fraction, where XG reduced soluble xylose in broilers fed medium and high wDDGS diets but not the control (no wDDGS). High wDDGS diets increased the ileal flow of insoluble NSP constituent sugars (P < 0.001) versus the control diet with no wDDGS. XG supplementation did not affect (P > 0.05) ileal insoluble NSP constituent sugars but tended to elevate (P = 0.053) xylose in the free oligosaccharide fraction in the ileum. XG increased (P = 0.004) caecal propionic acid and tended (P = 0.060) to increase caecal short-chain fatty acids. In conclusion, XG supplementation enhanced broiler performance in maize-based diets with wDDGS by reducing soluble NSP and small intestinal viscosity while promoting hindgut fermentation, though optimised dosing is needed for high wDDGS diets to support sustainable broiler nutrition.