Digestible energy of a corn-soybean meal-based diet supplemented with xylanase for nursery pigs in metabolism crates and floor pens

Two metabolism trials were conducted in the current study to determine the digestible energy (DE) of a corn-soybean meal-based diet supplemented with xylanase. In trial 1, 32 PIC L1050 barrows (initial body weight (BW) 8.6 ± 0.4 kg) were used. All the barrows were housed individually in metabolism crates (2.0 × 0.8 m2). Daily feed allowance was set at about 3.5% of the average BW of pigs. In trial 2, 32 PIC L1050 × L337 barrows (initial BW 8.7 ± 1.0 kg) were used. Sixteen barrows were kept individually in floor pens (3.0 × 1.8 m2), and the other 16 in metabolism crates (2.0 × 0.8 m2). All the pigs in both pens and crates had free access to feed and water. In trial 1, there were 4 dietary treatments in a 2 by 2 factorial arrangement by combining 2 concentrations of xylanase (0 and 0.2 g/kg feed) with 2 particle sizes of corn: 249 ± 1.7 and 427 ± 2.3 µm. In trial 2, there were 2 concentrations of xylanase (0 and 0.2 g/kg feed) in combination with 2 types of housing conditions (crates and floor pens). In both trials, there were 8 replicates for each treatment and 1 pig in each crate/pen. The results of trial 1 showed that there was no interaction between the particle size of corn and the supplementation of xylanase. Based on both total fecal collection and index methods, the supplementation of xylanase increased dietary DE by 27–29 kcal compared with the unsupplemented treatment (P > 0.05). There was no interaction between the fecal collection method and the supplementation of xylanase. The digestibility of dry matter and gross energy, and DE based on index method were less than those based on total fecal collection method (P < 0.001). In trial 2, there was no interaction between the housing conditions and the supplementation of xylanase. The pigs in the floor pens had a greater average daily feed intake (ADFI; P = 0.021) and a greater average final BW (P = 0.022), but tended to have a less digestibility of DM (P = 0.093). The supplementation of xylanase only tended to improve the ADFI irrespective of the housing conditions (P = 0.055). In conclusion, the supplementation of xylanase released 27–29 kcal DE of a corn-soybean meal-based diet with pigs housed in metabolism crates or floor pens. The supplementation of xylanase could improve the fecal digestibility of DM and increase the feed intake of pigs when allowed a free access to feed.