Digestibility responses of growing pigs fed corn plus corn distiller grains or wheat plus wheat coproduct-based diets without or with supplemental xylanase

We evaluated efficacy of xylanase (X) on apparent ileal (AID) and total tract digestibility (ATTD) of energy, nutrients, and fiber in growing pigs fed corn- or wheat-based diets. The corn diets had 40% corn DDGS and wheat diets had 25% wheat middlings. Diets were fed without or with 2,000 X U/kg to individually housed ileal cannulated growing barrows (n=6). All diets contained phytase (500 FTU/kg) and celite (0.3%) as indigestible markers. Pigs were fed a daily amount of feed equivalent to 3% of BW, equally divided into 2 feedings at 0800 and 1600 h. The experiment lasted for 9 d: 5 d for adaptation, d 6 and 7 for fecal samples, and d 8 and 9 for ileal digesta sample collection. Interaction between diet and X was only observed for the neutral detergent fiber (NDF) digestibility such that X improved ATTD (P = 0.04) of NDF in corn diets only. Xylanase effects were observed for digestible energy (DE) such that pigs fed X had higher DE (3,732 vs. 3,644 kcal/kg, P = 0.04) that corresponded to higher AID (P < 0.05) of nitrogen and fat than non-X-fed pigs. Generally, wheat diets had higher (P < 0.05) AID of DM, nitrogen, and NDF than corn diets. Although diet type impacted digestibility, xylanase improved DE independent of diet types as a result of improved nutrients digestion in the ileum.