Effects of Lactobacillus reuteri LR1 on the growth performance, intestinal morphology, and intestinal barrier function in weaned pigs.

The objective of this study was to investigate the effects of Lactobacillus reuteri LR1, a new strain isolated from the feces of weaned pigs, on the growth performance, intestinal morphology, immune responses, and intestinal barrier function in weaned pigs. A total of 144 weaned pigs (Duroc × Landrace × Yorkshire, 21 d of age) with an initial BW of 6.49 ± 0.02 kg were randomly assigned to 3 dietary treatments with 8 replicate pens, each of per treatment and 6 pigs. Pigs were fed a basal diet (CON, controls), the basal diet supplemented with 100 mg/kg olaquindox and 75 mg/kg aureomycin (OA) or the basal diet supplemented with 5 × 1010 cfu/kg L. reuteri LR1 for a 14-d period. At the end of study, the ADG, ADFI, and G:F were calculated, and 1 randomly selected pig from each pen was euthanized for sample collection. The LR1 increased ADG (22.73%, P < 0.05) compared with CON. The villus height of the ileum was increased (P < 0.05) and crypt depth in duodenum was reduced (P < 0.05), along with increased (P < 0.05) villus height to crypt depth ratio of the jejunum and ileum by LR1 compared with CON and OA. LR1 increased (P < 0.05) ileal mucosal content of IL-22 and transforming growth factor-β compared with OA. Compared with CON, LR1 increased (P < 0.05) and OA decreased (P < 0.05) the ileal content of secretory immunoglobulin A (sIgA), and the abundance of transcripts of porcine β-defensin 2 and protegrin 1-5. Compared with CON, LR1 increased (P < 0.05) tight junction protein zonula occludens-1 and occludin transcripts in the mucosa of the jejunum and ileum, and those of mucin-2 in ileal mucosa. The relative expression of toll-like receptor 2 (TLR2) and TLR4 were increased (P < 0.05) in ileal mucosa in pigs fed LR1 compared with CON. In conclusion, these data indicated that dietary LR1 supplementation at 5 × 1010 cfu/kg improved growth performance, intestinal morphology, and intestinal barrier function in weaned pigs.