Effect of Limosilactobacillus reuteri SBC5-3 Cell-free Supernatant on Growth Performance, Intestinal Inflammation, and Microbiota in Weaned Piglets Challenged With Enterotoxigenic Escherichia coli K88.

The progressive implementation of worldwide restrictions on antibiotic use has necessitated the development of sustainable alternatives for controlling bacterial diarrhea in piglets. This study investigated the effects of a cell-free supernatant (CFS) from Limosilactobacillus reuteri SBC5-3 on growth performance, intestinal inflammation, and microbiota in weaned piglets challenged with enterotoxigenic Escherichia coli K88 (ETEC K88). Forty-eight piglets were randomly assigned to four groups: a control group (CON, basal diet + physiological saline), an ETEC-challenged group (ETEC K88, basal diet + ETEC K88), a prevention group (CFS + ETEC K88, basal diet with CFS supplementation + ETEC K88), and a CFS group (CFS, basal diet with CFS supplementation + physiological saline). The CFS was administered orally at 5 mL/kg body weight for 7 days prior to challenge. Results showed that CFS pretreatment significantly reduced diarrhea rate and fecal scores, improved average daily gain, and alleviated ETEC K88-induced villus damage and lymphocyte infiltration in the jejunum and ileum. Moreover, CFS downregulated the expression of intestinal mucosal pro-inflammatory cytokines (IL1B, IL6, TNFA) and suppressed the activation of the NF-κB pathway by reducing phosphorylation of TAK1, IκBα, and p65. Intestinal microbiota analysis revealed that CFS increased the abundance of Lactobacillus and reduced Escherichia-Shigella. These findings demonstrate that L. reuteri SBC5-3 CFS effectively mitigates ETEC K88-induced diarrhea and intestinal inflammation by inhibiting NF-κB signaling and modulating intestinal microbiota, highlighting its potential as an antibiotic alternative in piglet production.