Arabinoxylans are the predominant fiber component in cereal grains and cereal co-products. They have a backbone of β-(1− 4) linked xylose units with side chains of arabinose, glucuronic acid, acetyl, and phenolic acids. Xylanase hydrolyzes the β-(1− 4) glycosidic bonds between xylose units in the backbone and releases a mixture of xylose and xylo-oligosaccharides that can be either absorbed or fermented by pigs. Previous data indicate that xylanase increased the degradation of dietary fiber and increased energy digestibility in diets for growing pigs and lactating sows. Xylo-oligosaccharides improve growth performance of nursery pigs because they serve as prebiotics that modulate gut microbiota. A stimbiotic (i.e., xylanase in combination with xylo-oligosaccharides) may improve growth performance of weanling pigs to a greater extent than either additive alone by shifting the intestinal microbiome to favor fiber fermentation. However, there are no data on possible effects of xylanase in sows diets on growth performance and intestinal health of the offspring or on the impact of the stimbiotic on digestibility of nutrients when fed to nursery pigs. Therefore, an experiment was conducted to test the hypothesis that xylanase or a stimbiotic improves growth performance and the apparent total tract digestibility (ATTD) of dry matter (DM), gross energy (GE), and total dietary fiber (TDF), and the concentration of digestible energy (DE) of diets for weanling pigs, but that the effect is greater in offspring of sows fed xylanase in lactation than in offspring of sows not fed xylanase.

Experimental design

A total of 46 Camborough sows bred to Line 800 boars (Pig Improvement Company, Hendersonville, TN, USA) were allotted in a randomized complete block design and randomly assigned to 2 dietary treatments 7 days after breeding (i. e., a control diet without xylanase and the control diet with 16,000 beechwood xylanase units (BXU) per kg of an exogenous xylanase. Therefore, there were a total of 24 replicated sows for the control treatment and 22 replicated sows for the xylanase treatment. Sows were fed the diets during 2 reproductive cycles. After the second lactation period, 240 newly weaned pigs were used (initial body weight: 5.81 ± 0.50 kg); 120 pigs were weaned from sows fed a diet without xylanase, and 120 pigs were weaned from sows fed a diet containing xylanase. Pigs were allotted to a 2 × 3 factorial with two sow groups (sows fed a 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 and 8 replicate pens per treatment. Pigs were fed experimental diets during phase 1 (d 0 to 14 postweaning), phase 2 (d 15 to 28), and phase 3 (d 29 to 42). Average daily gain (ADG), average daily feed intake (ADFI), and gain:feed (G:F) were calculated. Fecal samples were collected at the end of phases 2 and 3.

Results

No interactions were observed for the overall experiment between sow group and diet, and sow lactation diet treatment did not impact any post-weaning growth or digestibility parameters on the offspring of sows. In phase 2, the ADG, G:F, ATTD of DM, GE, and TDF, and concentration of DE were greater (P < 0.05) for pigs fed the diet with stimbiotic than pigs fed the xylanase or the control diet, but pigs fed the xylanase diet had greater (P < 0.05) ADG, G:F, ATTD of DM, GE, and TDF, and concentration of DE than pigs fed the control diet (Table 1). In phase 3, pigs fed diets with xylanase or the stimbiotic had greater (P < 0.05) ADG, ATTD of DM, GE, and TDF, and concentration of DE than pigs fed the control diet. In conclusion, pigs fed diets containing xylanase or a stimbiotic had greater digestibility of nutrients and DE, resulting in greater growth performance and greater body weight at d 42 post-weaning. However, feeding sows with xylanase during lactation did not have any impact on pig growth performance.

Key Points

• Xylanase or the stimbiotic increased the digestibility of nutrients and DE, resulting in greater growth performance and greater final body weight at d 42 post-weaning.
• Inclusion of xylanase in lactation diets with xylanase did not influence pig growth performance.

Table 1. Growth performance of weanling pigs fed experimental diets, and apparent total tract digestibility (ATTD) of gross energy, insoluble dietary fiber (IDF), soluble dietary fiber (SDF), total dietary fiber (TDF), and concentrations of digestible energy in experimental diets fed to weanling pigs^{1, 2.}

¹Pigs (n = 240) were weaned from sows that had received a lactation diet without or with xylanase, but there was no impact of sow lactation treatment on growth performance of the offspring or on energy and nutrient digestibility by the offspring and no interactions between sow diet and post-weaning dietary treatments were observed. Therefore, only main effects of post-weaning dietary treatments are shown.

²Data are means of 16 observations per dietary treatment.

³Xylanase (Econase XL; AB Vista, Marlborough, UK).

⁴Stimbiotic = Xylanase in combination with xylo-oligosaccharides (Signis; AB Vista, Marlborough, UK).

⁵ADG = average daily gain; ADFI = average daily feed intake; G:F = gain to feed ratio; ATTD = apparent total tract digestibility; IDF = insoluble dietary fiber; SDF = soluble dietary fiber; TDF = total dietary fiber.

^a-cWithin a row, means without a common superscript differ (P < 0.05).