Effect of Lactobacillus reuteri Postbiotics on Growth Performance and Intestinal Health of Escherichia coli-Infected Broilers.

Avian pathogenic Escherichia coli (E. coli) impairs poultry production and causes substantial economic losses. This study investigated the effects of Lactobacillus reuteri postbiotics (LR) on growth performance and intestinal health of broiler chickens challenged with E. coli. A total of 180 one-day-old Arbor Acres+ broilers were allocated into three groups (six replicates per group and 10 chicks each replicate): CTR, control group; E. coli-infected group, orally challenged with a mixture of E. coli O1, O2, and O78 at a dose of 109 CFU/mL; LR + E. coli-infected group, challenged with E. coli and fed a basal diet supplemented with 100 mg/kg LR. The results showed that dietary LR significantly improved the average daily gain (ADG) in the LR + E. coli group compared to the E. coli-infected group from days 1 to 18 (p < 0.05). However, no significant differences in average daily feed intake (ADFI) or feed conversion ratio (FCR) were observed among the CTR, E. coli, and LR + E. coli groups. Infection with E. coli led to lower total antioxidant capacity in jejunum and activity of total superoxide dismutase in ileum. Moreover, dietary LR significantly alleviated the down-regulation of Mucin2 and Aquaporin-3 gene expression in jejunum and ileum caused by E. coli infection and up-regulated the gene expression of Claudin-1 and Zonula occludens 1 in the ileum. In addition, dietary LR treatment led to the up-regulation of interleukin-10 mRNA transcripts in the jejunum. Further analysis demonstrated that dietary supplementation with LR reshaped the ileal flora of birds challenged with E. coli via elevating the relative abundance of Romboutsia and Bacteroidota, while reducing the abundance of Candidatus_Arthromitus and Escherichia-Shigella. In conclusion, dietary LR supplementation improved the expression of intestinal barrier and anti-inflammatory genes and reshaped the intestinal flora in E. coli-infected broilers.