Effects of xylanase on growth performance, nutrients digestibility and intestinal health in weaned piglets.

• Dietary xylanase improves growth performance of weaned piglets. • Different levels of xylanase increases nutrient digestibilities in vitro. • Dietary xylanase improves intestinal physical barrier and immune barrier functions in piglets. Supplementation of xylanase is an effective way to relieve anti-nutritional effects of dietary non-starch polysaccharides. Besides, the hydrolysis product xylo-oligosaccharides could affect intestinal microecology as prebiotics in pigs. However, whether there are other effects of xylanase on pig intestinal health is unclear. Two experiments were conducted in the present study to investigate the effects of xylanase on growth performance, nutrients digestibility and intestinal barrier function in piglets, and to explore whether the prebiotic effect of xylanase was related to the antioxidant function of NSP hydrolysates using an in vitro digestive system. In experiment 1, a total of 54 weaned pigs [Duroc × (Landrace × Yorkshire)] with an average body weight of 7.76 ± 0.10 kg were randomly assigned to one of three diets (corn-soybean meal diets with xylan content of 3.33%) supplemented with 0, 30, 60 mg/kg (0, 24000, 48000 BXU/kg) xylanase, respectively. The trial lasted for 28 days to investigate the effects of xylanase on growth performance, nutrient digestibility and intestinal health of piglets. In experiment 2, an in vitro study was conducted to simulate the digestion process of corn-soybean meal diets (the basal diet was same as that in experiment 1) in pig stomach and small intestine. Xylanase was supplemented in 0, 30, 60, 90 mg/kg (0, 24000, 48000, 72000 BXU/kg), respectively, to investigate the nutrient digestibility and system anti-oxidant ability (n = 6). In experiment 1, average daily gain (ADG) of piglets and viscosity of stomach digesta were quadratically decreased (P < 0.05), while the feed/gain ratio (F/G) was linearly decreased by xylanase (P < 0.05). The diarrhea rate (P = 0.066) and diarrhea index (P < 0.05) were quadratically affected by xylanase. Gene expression of zonula occludens-1 (ZO-1) and B-cell lymphoma/leukaemia-2 (Bcl-2) were linearly up-regulated by xylanase (P < 0.05). Also, xylanase linearly increased the contents of secretory immunoglobulin A (SIgA) in the jejunum of piglets (P < 0.05). In experiment 2, xylanase quadratically increased the in vitro dry matter digestibility (IVDMD) (P < 0.05), and linearly increased the glucose release rate of diets (P < 0.05). Dietary xylanase improves intestinal physical barrier and immune barrier functions in piglets, and increases nutrient digestibilities in vitro. [ABSTRACT FROM AUTHOR]