Efficacy of xylanase on growth performance, nutrients digestibility and digesta fermentation metabolites in nursery pigs fed wheat based diets

Abstract Text: Two experiments were conducted to investigate the efficacy of supplemental xylanase on growth performance, ileal and total tract digestibility of nutrients (AID and ATTD) and ileal short chain fatty acids (SCFA) concentrations in pig fed wheat based diets. Two basal diets were prepared using either hard or soft wheat as the major cereal grain and met the NRC (1998) nutrient specifications, with the exception of DE which was 95% of recommendations. Diets were formulated for two phase feeding (phase I, weaning to 15kg BW and phase II, 15-25kg BW) and fed with or without 2,000 U of xylanase (Danisco, Marlborough, UK). All diets included 1% celite as an indigestible marker. In Exp.1, 96 pigs (~7.0kg) were assigned to 1 of 4 diets giving 6 pens/diet (4 pigs/pen). Feed intake and BW were measured weekly and at the end of each phase, fresh fecal samples were collected on a pen basis for determination of ATTD. In Exp.2, phase II diets used in Exp.1 were fed to 4 ileal cannulated barrows (~27kg) in a 4x4 Latin square design with one added column to give 5 observations per diet. Each period lasted for 7 d; d 1-5 for adaptation and d 6-7 for digesta collection for determination of AID and SCFA concentration. All data were analyzed as a 2×2 factorial with main effects of wheat, xylanase and the associated 2-way interactions. In Exp.1, there was no interaction (P>0.10) between xylanase and wheat type. Xylanase increased (P<0.05) ADFI and nutrients digestibility whilst pigs fed hard wheat had improved (P<0.05) ADG, ADFI and nutrients digestibility compared to pigs fed soft wheat. In Exp.2, an interaction between wheat and xylanase was observed for AID of DM and leucine (P<0.05) with xylanase increasing AID of DM and leucine in soft but not hard wheat. The main effects were such that xylanase increased AID of energy, NDF and N and ileal lactic acid whereas pigs fed soft wheat had greater (P<0.05) AID of energy, N, leucine and threonine than pigs fed hard wheat. However, pigs fed hard wheat had higher AID of NDF (P=0.04) than pigs fed soft wheat. Although wheat types impacted growth performance and nutrients digestibility, xylanase was efficacious across wheat types on feed intake and utilization of energy and fiber. These data indicate that degradation of dietary fibrous components using xylanase may stimulate feed intake and nutrient digestibility in weaned pigs.

Keywords: pigs, wheat, xylanase