Xylanase increased the energetic contribution of fiber and improved the oxidative status, gut barrier integrity, and growth performance of growing pigs fed insoluble corn-based fiber

Abstract

The experimental objective was to investigate the impact of xylanase on the bioavailability of energy, oxidative status, and gut function of growing pigs fed a diet high in insoluble fiber and given a longer adaptation time than typically reported. Three replicates of 20 gilts with an initial body weight (BW) of 25.43 ± 0.88 kg were blocked by BW, individually housed, and randomly assigned to 1 of 4 dietary treatments: a low-fiber control (LF) with 7.5% neutral detergent fiber (NDF), a 30% corn bran without solubles high-fiber control (HF; 21.9% NDF), HF + 100 mg/kg xylanase (HF+XY; Econase XT 25P), and HF + 50 mg/kg arabinoxylan-oligosaccharide (HF+AX). Gilts were fed ad libitum for 36 d across 2 dietary phases. Pigs and feeders were weighed on d 0, 14, 27 and 36. On d 36, pigs were housed in metabolism crates for a 10-d period, limit fed (80% of average ad libitum intake) and feces and urine were collected the last 72 h to determine digestible energy (DE) and metabolizable energy (ME). On d 46, serum and ileal and colonic tissue were collected. Data were analyzed as a linear mixed model with block and replication as random effects, and treatment, time, and treatment × time as fixed effects. There was a significant treatment × time interaction for BW, average daily gain (ADG), and gain to feed (G:F; P<0.001). By design, BW at d 0 did not differ, at d 14 pigs fed LF were 3.5% heavier, and pigs fed HF+XY, when compared to HF, were 4% and 4.2% heavier at d 27 and d 36, respectively (P <0.001). From d 14 to 27 and d 27 to 36, when compared to HF, HF+XY improved ADG by 12.4% and 10.7% and G:F by 13.8% and 8.8%, respectively (P<0.05). Compared to LF, HF decreased DE and ME by 0.51 and 0.42 Mcal/kg, respectively, but xylanase partially mitigated that effect increasing DE and ME by 0.15 and 0.12 Mcal/kg, over HF, respectively (P<0.05). Pigs fed HF+XY had increased total antioxidant capacity in the serum and ileum (P<0.05) and tended to have less circulating malondialdehyde (P=0.098). Pigs fed LF had increased ileal villus height, and HF+XY and HF+AX had shallower intestinal crypts (P<0.001). Pigs fed HF+XY had increased ileal messenger ribonucleic acid abundance of claudin 4 and occludin (P<0.05). Xylanase, but not AX, improved the growth performance of pigs fed insoluble corn-based fiber. This was likely a result of the observed increase in ME, improved antioxidant capacity and enhanced gut barrier integrity, but it may require increased adaptation time to elicit this response.

Xylanase supplementation in corn-based swine diets: a review with emphasis on potential mechanisms of action

“…A study by Laerke et al (2015) found that xylanase increased the xylose concentration in the liquid phase of ileal digesta from pigs fed wheat by nearly 4-fold, but not in pigs fed rye. Moreover, an increase in urine GE in pigs fed corn bran with xylanase supplementation was observed by Petry et al (2020b) ; this is perhaps indicative of xylose absorption as it has been reported that free xylose increases urine GE due to the excretion of xylose itself or threitol ( Huntley and Patience, 2018 ). There is a dearth of in vivo evidence to support xylose release from corn-based AX by xylanase, and in vitro research would suggest that it is quite marginal ( Dale et al, 2019 ).…”

“…Recently, there has been an increase in the evidence supporting xylanase supplementation for purposes that extend beyond the logical improvement in fiber utilization. The aforementioned reductions in mortality are one of the more consistent responses observed commercially with this enzyme, and recent research suggests that xylanase likely modulates intestinal health through mechanisms that improve gut barrier integrity, mitigate oxidative stress, and alter immune function ( Li et al, 2018 ; Duarte et al, 2019 ; Petry et al, 2020b ). These improvements observed in the systemic and gut health of the pig are most plausibly a result of the interplay between xylanase and the microbiome.…”

“…However, if one looks past this variability, there is some evidence to suggest that adaptation time may play a role in xylanase efficacy. A study by Petry et al (2020b) found that xylanase improved ADG and G:F in pigs fed a corn-based diet with 30% corn bran without solubles after 14 d of supplementation, and these metrics were even greater after day 27. This work is in agreement with Fang et al (2007) , Myers and Patience (2014) , and Lan et al (2017) who found that xylanase improved performance in later phases of supplementation in pigs fed largely corn-based diets.…”

“…This is likely due to the increased lignification in corn bran ( Akin and Rigsby, 2008 ). Interestingly, corn bran appears to be susceptible to xylanase in the pig ( Petry et al, 2020b ). Moreover, the structure of AX is often described and portrayed in a linear unidimensional fashion, but the reality is the more substituted and complex AXs, like those in corn, form complex three-dimensional structures that are intertwined with other components in the plant cell wall ( Jeremic et al, 2014 ).…”

“…Economically, relative to improving G:F by 2 points, reducing wean-to-finish mortality from 4% to 2.4%, as observed by Zier-Rush et al (2016) , is nearly four times more profitable. Moreover, recent research in corn-based diets has suggested that xylanase may improve pig health through altering intestinal morphology ( Duarte et al, 2019 ; Li et al, 2019 ; Chen et al, 2020 ), increasing gut barrier integrity ( Tiwari et al, 2018 ; Petry et al, 2020b ), altering immune function ( Chen et al, 2020 ), and mitigating localized and systemic oxidative stress ( Duarte et al, 2019 ; Petry et al, 2020b ). The efficacy of xylanase to improve pig health and reduce mortality is clearly an added, and until recently unexpected, benefit of using this enzyme.…”