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Effect of timing of post-weaning supplementation of xylanase on growth performance, nutrient digestibility and fecal microbial composition in weanling pigs
The study was conducted to investigate the effect of timing of xylanase (Econase XT) supplementation to weanling pigs fed a corn-soybean meal based diet, and its effect on growth performance, nutrient digestibility and gut microbial composition. A total of 128 weanling pigs ([Hampshire × Duroc] × [Yorkshire × Landrace]; barrows: gilts = 1:1; 6.2 ± 0.6 kg BW; weaning age: 21 d) were randomly assigned to 4 treatments, 8 replicate pens with 4 pigs per pen based on their BW at weaning. The 4 treatments were a combination of 2 dietary treatments (Xylanase added at 0 or 16,000 BXU/kg) and 2 feeding time points [period 1 (d 0-14) and period 2 (d 14-42)]. Treatments were; xylanase-xylanase, xylanase-control, control-xylanase and control-control. The study lasted 42 d with a 3-phase feeding program: d 0 to 14, d 14 to 28 and d 28 to 42. Chromic oxide marker was included in the diets at 0.5% from day 28. BW and feed intake were recorded every two weeks. On d 41, fecal samples were collected from each pig for determination of microflora diversity and apparent total tract nutrient digestibility (ATTD). Ileal digesta were also collected on d 42, for determination of apparent ileal nutrient digestibility (AID). From d 0-14, pigs had lower BW, ADG and feed efficiency when xylanase was included in the diets. The final BW and overall ADG was higher (P < 0.05) when xylanase was supplied from d 14 compared with that from d 0. The AID and ATTD of DM, energy, N and phosphorus was increased (P < 0.05) by xylanase and not impacted by timing of xylanase inclusion. The overall bacterial community structure was not influenced by different treatments. However, xylanase significantly decreased (P < 0.05) Veillonellaceae and tended to decrease (P < 0.08) Megasphaera abundance in period 2 compared to the control group. Therefore, timing of xylanase inclusion in weanling pig diets has an effect on performance in the nursery.
Keywords: Key words: weaning pigs, xylanase, digestibility, gut microbial profile