Effects of a fiber-degrading enzyme on ileal digestibility of amino acids and fiber and total tract digestibility of energy and fiber in growing pigs fed diets with high level of corn distillers grains with solubles

Abstract

Dietary enzyme supplementation may enhance the digestibility and utilization of non-starch polysaccharides (NSP) in fiber-rich feedstuffs, which are increasingly being used in swine diets. The objective of this study was to evaluate the efficacy of a carbohydrase enzyme containing xylanase and cellulase on apparent total tract digestibility (ATTD) and apparent ileal digestibility (AID) of nutrients and fiber fractions in growing pigs. Twelve ileal-cannulated pigs (initial body weight (BW) = 31.7 ± 3.04 kg) were allocated to one of 2 experimental groups differing on carbohydrase enzyme (CE; cellulase and xylanase) supplementation to a corn-soybean meal (SBM)-corn distillers grains with solubles (cDDGS) diet in a completely randomized design. Pigs were housed in individual metabolic crates for 21 d (Period 1) and subsequently transferred to individual floor pens for an additional 28 d (Period 2). Thus, experimental treatments included a corn-SBM-based diet with 30% cDDGS without (Control) or with CE at a dose of 0.2 g/kg of the diet. The diets were fed to pigs at three times their maintenance energy requirements based on their BW, which contained 0.3% titanium dioxide as an indigestible marker. In Period 1, pigs had 14 d of adaptation, followed by 4 d of fecal and urine collection using the total collection method and 2 d of ileal digesta collection. In Period 2, pigs had 23 d of adaptation, followed by 2 d of fecal collection and 2 d of ileal digesta collection. Data were subjected to ANOVA using the MIXED procedure of SAS, and the model included the Period as a repeated term. Dietary CE supplementation improved (P<0.05) the AID of Ile (77.3 vs. 80.0%), Thr (73.8 vs 77.8%), Trp (83.2 vs. 86.6), crude protein (CP, 71.1 vs 75.9%), gross energy (GE, 61.5 vs. 67.6%), neutral detergent fiber (22.0 vs. 29.1%), insoluble dietary fiber (30.9 vs 37.9%), total dietary fiber (29.2 vs 37.1%), and cellulose (12.5 vs. 22.0%). The CE also improved (P<0.05) the ATTD of dry matter (75.4 vs 78.9%), organic matter (80.3 vs. 82.8%), CP (80.8 vs. 85.7%), crude ash (44.4 vs. 57.0%), calcium (58.5 vs. 66.1%), GE (76.5 vs. 79.4%), acid detergent fiber (40.7 vs. 48.2%), and total NSP (49.3 vs. 53.0%). In conclusion, supplementing a corn-SBM-30% cDDGS diet with carbohydrase enzyme with xylanase and cellulase activities increased the availability of nutrients and fiber fractions at the ileum, enhancing further the degradation in the total tract of growing pigs.