Effect of xylanase and xylo-oligosaccharide supplementation on growth performance and faecal bacterial community composition in growing pigs

Abstract

This study was conducted to investigate the effects of xylanase (XYL) and xylo-oligosaccharide (XOS) supplementation on the growth performance and faecal bacterial community composition in growing pigs over time. In this 35-day trial, a total of 464 grower pigs with an average initial body weight (BW) of 14.5 kg (SD ±1.56 kg) were blocked into mixed sexed pens of 4–5 pigs balanced for BW, sex and litter origin. Pens were randomly allocated to 1 of 4 dietary treatments in a 2 × 2 factorial treatment arrangement with 2 concentrations of supplementary XYL (0 and 0.15 g/kg) and XOS (0 and 0.20 g/kg). On a weekly basis, pen feed intake and pigs were weighed to calculate pig performance. Faecal samples from 32 male pigs were collected on days 1, 14 and 35 of the trial and analysed to profile the bacterial communities through 16S ribosomal ribonucleic acid (rRNA) sequencing of the V4 region on the MiSeq platform (Illumina). There was no effect of XYL on pig performance, nor was there an interaction between XYL and XOS. Pigs supplemented with XOS had a poorer gain to feed ratio during the first week (Day 1–7) of the trial (P < 0.01). During the second week of the trial (Day 8–14), pigs fed XOS showed an improved average daily gain compared to those without XOS (P < 0.01), but there were no performance effects in the overall trial period (Day 1–35). Alpha diversity increased over time (P < 0.05), and as an index of bacterial community compositions, beta diversity also changed over time (P < 0.05), but there was no overall effect of treatment on alpha or beta diversity. Despite no overall treatment effect, certain operational taxonomic units (OTUs) associated with Muribaculaceae_ge and Prevotellaceae NK3B31 group were higher in all 3 dietary treatments compared to the unsupplemented control diet (P < 0.05). In summary, XYL and XOS had limited effect on pig performance in this trial. Faecal bacterial communities significantly changed over time but despite influencing certain OTUs, treatment had no overall effect on faecal bacterial community composition. Supplementation of XYL or XOS, individually or simultaneously, increased the abundance of OTUs belonging to the Muribaculaceae and Prevotellaceae families which are associated with carbohydrate metabolism, indicating that these bacteria are likely involved in the mechanistic pathways of XYL and XOS.