133 Supplementing xylanase increased the digestibility of non-starch polysaccharides, particularly arabinoxylan, in diets high in insoluble corn fiber fed to swine with a 36-d dietary adaptation period

Abstract

Abstract Xylanase should increase arabinoxylan digestibility in swine, but the responses in corn-based diets are inconsistent. The experimental objective was to investigate xylanase efficacy 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 (25.4 ± 0.9 kg BW; L337 × Camborough), were blocked by weight, housed individually, and randomly assigned to one of four dietary treatments: a low-fiber control [LF; 6.9% non-starch polysaccharides (NSP)], a 30% corn bran high-fiber control (HF; 17.6% NSP), HF + 100 mg xylanase/kg (HF+XY; Econase XT 25P; AB Vista, Marlborough, UK), and HF + 50 mg arabinoxylan-oligosaccharide/kg (HF+AX; 3-7 degrees of polymerization). Diets contained 0.5% CrO3. Gilts were fed ad libitum for 36 d, followed by 10-d of limit feeding (80% of average ad libitum intake) and were housed in metabolism crates. On d 46, pigs were necropsied and ileal, cecal, and colonic digesta were collected; ileal digesta was pooled within replicate for NSP analysis (n=6 per treatment). Data were analyzed as a linear mixed model using replicate and block as random effects, and treatment as a fixed effect. Compared to LF, the HF diet reduced (P< 0.01) apparent ileal digestibility (AID) of total NSP (32.7 vs. 16.3%), insoluble NSP (50.0 vs. 21.5%), and insoluble arabinoxylan (29.8 vs. 15.4%). Xylanase (HF+XY vs. HF) increased (P< 0.01) AID of total NSP by 39.8% (27.1 vs. 16.3%) and insoluble NSP by 34.0%. This may be attributed to xylanase increasing AID of total arabinoxylan by 54.5% over HF, 44.5% over LF, and 56.9% over HF+AX (33.0, 15.1, 18.3, and 14.2%, respectively; P=0.02). In conclusion, increasing insoluble fiber reduces NSP digestibility, but xylanase can increase AID of arabinoxylan and NSP. Supplementing an arabinoxylan-oligosaccharide, a potential release product of the xylanase, did not increase NSP digestibility.