49 Effects of xylanase or a stimbiotic on growth performance and total tract digestibility of nutrients by pigs weaned from sows fed a lactation diet without or with xylanase

Abstract Two hypotheses were tested 1) the offspring of sows fed xylanase in lactation have greater growth performance after weaning than offspring of sows fed no xylanase, and 2) xylanase and a stimbiotic (i.e., xylanase in combination with xylo-oligosaccharides) improve growth performance, apparent total tract digestibility (ATTD) of gross energy (GE) and total dietary fiber (TDF), and digestible energy (DE) of diets for weanling pigs. A total of 120 newly weaned pigs from sows fed a lactation diet without xylanase and 120 pigs from sows fed a lactation diet containing 16,000 beechwood xylanase units (BXU) per kg of an exogenous xylanase were used [initial body weight (BW) = 5.81 ± 0.50 kg]. Pigs were allotted to a 2 × 3 factorial with two sow groups (lactation diet without or with xylanase) and three dietary treatments (i.e., control, control plus 100 g/t of xylanase, or control plus 100 g/t of stimbiotic). The xylanase (Econase XT) and the stimbiotic (Signis) were procured from AB Vista, Marlborough, UK. Pigs were weaned in 4 blocks and allotted to 12 pens per block, with 5 pigs per pen for a total of 8 replicate pens per treatment. Pigs were fed phase 1 diets from d 1 to 14, phase 2 diets from d 15 to 28, and phase 3 diets from d 29 to 42 post-weaning. Average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G:F) were calculated. Fecal samples were collected at the end of phases 2 and 3. Data were analyzed using the MIXED procedure of SAS. Sow group, diet, and the interaction between sow group and diet were fixed effects, and block and replicate within block were random effects. Results indicated that for the overall experiment, there were no interactions between sow group and diet, and sow lactation diet treatment did not impact any post-weaning growth or digestibility parameters in the weaned pigs (Table 1). However, weaned pigs had greater (P < 0.05) ADG, G:F, ATTD of GE and TDF, and DE in phase 2 if fed the diet with stimbiotic than if fed the xylanase diet or the control diet, but pigs fed the xylanase diet had greater (P < 0.05) ADG, G:F, ATTD of GE and TDF, and DE than pigs fed the control diet (Table 2). In phase 3, pigs fed the diet with xylanase or stimbiotic had greater (P < 0.05) ADG, ATTD of GE and TDF, and DE than pigs fed the control diet. In conclusion, pigs fed diets containing xylanase or stimbiotic had greater nutrient digestibility and DE, resulting in greater overall ADG, G:F, and final body weight on d 42 post-weaning, but feeding sows xylanase in lactation did not influence post-weaning growth performance.