Use of byproducts as feed ingredients becomes important to reduce feed costs and enhance the sustainable use of feed resources. However, many byproducts that are commonly used in swine diets contain high levels of plant cell wall materials (e.g.,arabinoxylan) that pigs poorly digest (Nortey et al.,2008; Stein and Shurson, 2009). Supplemental xylanase
improves fiber digestibility in wheat-based diets (Atakora et al., 2011) and diets containing corn dried distillers’ grains with solubles (DDGS; Yáñez et al.,2011).However, Woyengo et al. (2008) reported that simultaneous inclusions of xylanase and phytase in wheat-based diets for growing pigs had no synergistic effects in nutrient digestibility. In addition, research on the inclusion of potential energy-releasing enzymes (i.e., xylanase) and phytase to cornbased diets containing multiple byproducts, typical of North American commercial diets, is limited. Therefore, the objective of this study was to evaluate
the effect of increasing xylanase supplementation level on apparent total tract digestibility (ATTD) and energy release for growing pigs fed corn-based,
phytase-supplemented diets containing corn DDGS,
wheat middlings, and corn germ meal.