Effects of dietary xylanase plus β-glucanase levels on total-tract nutrient and energy digestibility and N balance of growing pigs fed diets containing corn distillers dried grains

Abstract

The addition of corn distillers dried grains (corn-DDG) to pig diets has been limited due to concerns about fiber content. The aim of the present study was to determine the metabolizable energy of corn-DDG (Exp. I) and the dose-response effects of dietary xylanase plus β-glucanase on the nutrient and energy digestibility of growing pigs fed diets containing 25% corn-DDG (Exp. II). Pigs in individual cages were subjected to feeding periods of 5 days for voluntary feed intake quantification followed by 5 days for collection of feces and urine. In Exp. I, 10 castrated male pigs with 61.10 ± 3.25 kg BW distributed in a randomized complete block design experiment with five replications were fed a reference diet or a test diet (75% reference diet plus 25% corn-DDG). In Exp. II, 10 castrated male pigs with 29.69 ± 3.57 kg BW distributed in a Latin square design (two squares with four replicates in time) experiment were fed with 5 dietary xylanase plus β-glucanase levels (0, 50, 100, 200, or 400 mg/kg) added to diets formulated with 25% corn-DDG. The corn-DDG had 26.5% crude protein, 5.94% ether extract, 55.5% neutral detergent fiber (NDF), and 4.248 kcal/kg gross energy. The metabolizable energy of corn-DDG was 3.657 ± 189 kcal/kg. Increasing dietary xylanase plus β-glucanase quadratically influenced (P < 0.05) the NDF digestibility and digestible energy in growing pigs fed diets containing 25% corn-DDGS. Compared to the control, dietary xylanase plus β-glucanase addition increased digestibility and reduced metabolizability of crude protein. The addition of dietary xylanase plus β-glucanase to growing pig diets containing corn-DDG increased NDF digestibility, allowing for additional dietary energy and protein availability.

Keywords: Carbohydrase enzymes; Digestible protein; Metabolizable energy; N balance; Nonstarch polysaccharides.