Effects of xylanase supplementation and feeding method on nutrient digestibility in pigs fed diets containing corn dried distillers grains with solubles or wheat middlings

Abstract Text:

The objective was to determine the effect of endo-1,4-β-xylanase supplementation (Xyl; with or without) and feeding method (dry or liquid) on apparent total tract digestibility (ATTD) and apparent ileal digestibility (AID) of nutrients in growing pigs fed diets containing 30% of corn dried distillers grains with solubles (DDGS) or 30% of wheat middlings (Midds). Sixty-four pigs (BW 25.9±0.38 kg) were blocked by BW and sex, placed in individual pens, and randomly assigned to 8 dietary treatments. Within each feedstuff, diets were fed either liquid or dry, without or with Xyl (24,000 BXU/kg feed). Diets contained 3.25 Mcal/kg ME and 1.05% SID lysine. Pigs were fed restricted at 3 times maintenance energy requirements (197 kcal ME/kg BW^0.60) in 2 equal meals. Liquid diets were prepared by steeping DDGS or Midds with water (1:3 w:v) with or without Xyl for 24 h, followed by mixing with the respective basal diet and water to achieve a final DM concentration of 25%. Following a 13 d adaptation, fecal samples were collected for 3 d. When DDGS was included, Xyl increased AID of NDF in liquid diets (48.4% vs. 31.6%), but not in dry diets (interaction, P=0.03). Pigs fed liquid diets with DDGS had decreased (P<0.05) ATTD of GE (81.1% vs. 83.0%) and NDF (64.8% vs. 72.1%) compared to pigs fed dry diets. When Midds were included, Xyl increased AID of NDF in pigs fed dry diets (52.9% vs 31.7%) but not in pigs fed liquid diets (interaction, P=0.09). Pigs fed liquid diets with Midds had greater AID of N (P=0.01) than pigs fed dry diets (77.7% vs. 72.0%). The AID of GE tended to be greater (P=0.09) for pigs fed Midds with Xyl (63.7% vs. 57.3%). Pigs fed dry diets with Midds and Xyl had increased ATTD of NDF; however it was reduced when pigs were fed liquid diets with Xyl (interaction, P<0.01). The ATTD of GE (80.4% vs. 78.1%) and N (80.2% vs. 78.0%) was improved (P<0.05) in pigs fed Midds with Xyl compared to diets without Xyl. This study indicates that Midds based diets with Xyl in liquid feeding did not improve nutrient digestibility. However, addition of Xyl improved ATTD of GE, N and NDF in dry diets with Midds. Furthermore, DDGS based diets with Xyl in liquid feeding improved only AID of NDF. Results suggest that the addition of Xyl appears to be more beneficial in Midds than DDGS based diets.

Keywords: enzyme, nutrient digestibility, pigs