摘要This study was to evaluate the effect of xylanase supplementation and the addition of live yeast,Saccharomyces cerevisiae,on growth performance and intestinal microbiota in piglets.One hundred and eighty commercial crossbred 23-d-old piglets(PIC 417)were sorted by initial BW and allocated to 3 treatments:control(CTR)diet,CTR diet supplemented with xylanase at 16,000 birch xylan units/kg(XYL)and XYL diet supplemented with live yeast(2 × 1010 CFU/g)at 1 kg/t(XYL+LY).Each treatment had 10 replicates,with 6 animals each.A sorghum-based diet and water were available ad libitum for 42 d of the study.Average daily gain(ADG)and average daily feed intake(ADFI)were measured from 0 to 42 d(23-to 65-d-old)and feed conversion ratio(FCR)calculated.At the end of the study,bacterial identification through 16S rRNA(V3 to V4)sequencing of the ileal and caecal digesta from one piglet per replicate was performed.No treatment effects were observed on ADFI.Pigs offered the live yeast in addition to the xylanase had increased ADG compared with those supplemented with xylanase alone(XYL+LY vs.XYL;P = 0.655).FCR was improved with XYL and XYL+LY compared with CTR(P = 0.018).Clostridiaceae counts in the ileum tended to reduce by 10％with XYL and 14％with XYL+LY compared to CTR(P=0.07).XYL and XYL+LY increased the counts of Lactobacillaceae in the caecum compared with CTR(P＜0.0001).Dietary supplementation of live yeast combined with xylanase improved growth perfor-mance and microbial balance of piglets during the nursery phase.