PSVII-10 Xylanase improved the nutrient and energy digestibility of diets high in insoluble corn fiber fed to swine following a 36-d dietary adaptation period

The efficacy of xylanase in practical swine diets is inconsistent and poorly understood. The experimental objective was to investigate the efficacy of xylanase in growing pigs fed a diet high in insoluble corn fiber and afforded a longer adaptation period than typically reported in the literature. Sixty gilts (25.43 ± 0.88 kg BW; L337 X Camborough, PIC, Hendersonville, TN; n = 15 per treatment), were blocked by weight, housed individually, and randomly assigned to one of four dietary treatments: a low-fiber control (LF; 8.45% NDF), a 30% corn bran high-fiber control (HF; 24.5% NDF), HF + 100 mg/kg of xylanase (HF+XY; Econase XT 25P; AB Vista, Marlborough, UK), and HF + 50 mg/kg of arabinoxylan-oligosaccharide (HF+AX; 3-7 degrees of polymerization). Diets contained 0.5% chromium (III) oxide. Gilts were fed ad libitum for 36 d, followed by a 7-d period of adaptation to limit feeding (80% of average ad libitum intake) and housing in metabolism crates, followed by 3 d of urine and fecal collection. Data were analyzed using PROC MIXED (SAS; 9.4) as a randomized complete block design with pig as the experimental unit, block and replicate as random effects, and treatment as a fixed effect. Compared to the LF diet, the HF diet reduced the apparent total tract digestibility (ATTD) of DM (88.7 vs. 75.6%), GE (89.0 vs. 77.4%), CP (87.2 vs. 81.8%), NDF (63.3 vs. 44.4%), ADF, and hemicellulose (P = 0.01). Xylanase supplementation, but not arabinoxylan-oligosaccharide, when compared to the HF control diet, improved the ATTD of DM by 3.3% (78.2 vs. 75.6%), GE by 2.2% (79.1 vs. 77.4%), CP by 2.9% (84.2 vs. 81.8%), NDF by 17.5% (53.9 vs. 44.4%), ADF by 16.3% (52.1 vs. 42.9%), and hemicellulose by 16.4% (P < 0.05). These data indicate insoluble fiber reduced nutrient and energy digestibility, but xylanase was effective in partially mitigating that effect.