Evaluation of Potential Probiotic Properties of Limosilactobacillus fermentum Derived from Piglet Feces and Influence on the Healthy and E. coli-Challenged Porcine Intestine

In this work, we evaluated the probiotic properties of Limosilactobacillus fermentum strains (FL1, FL2, FL3, FL4) isolated from feces of healthy piglets. The in vitro auto-aggregation, hydrophobicity, biofilm-forming capacity, survival in the gastrointestinal tract, antimicrobial activity and anti-oxidation capacity were evaluated. Four strains were resistant to simulated gastrointestinal conditions, including low pH, pepsin, trypsin and bile salts. They also maintained strong self-aggregation and cell surface hydrophobicity. Limosilactobacillus fermentum FL4, which had the strongest adhesion ability and antimicrobial effect on Enterotoxigenic Escherichia coli K88 (ETEC K88), was then tested in porcine intestinal organoid models. The in vitro experiments in basal-out and apical-out organoids demonstrated that L. fermentum FL4 adhered to the apical surfaces more efficiently than basolateral surfaces, had the ability to activate the Wnt/beta-catenin pathway to protect the mucosal barrier integrity, stimulated the proliferation and differentiation of the intestinal epithelium, and repaired ETEC K88-induced damage. Moreover, L. fermentum FL4 inhibited inflammatory responses induced by ETEC K88 through the reduced expression of pro-inflammatory cytokines (TNF-alpha, IL-1 beta and IFN-gamma) and higher levels of anti-inflammatory cytokines (TGF-beta and IL-10). These results show that L. fermentum FL4 isolated from feces of healthy Tunchang piglets has the potential to be used as an anti-inflammatory probiotic and for mitigation of intestinal damage in piglets.

Automated summary

In this study, the probiotic properties of Limosilactobacillus fermentum strains isolated from healthy piglets were evaluated. The strains exhibited resistance to gastrointestinal conditions and maintained self-aggregation and cell surface hydrophobicity. L. fermentum FL4 showed strong adhesion ability and antimicrobial effect against Enterotoxigenic Escherichia coli K88. In vitro experiments demonstrated that L. fermentum FL4 efficiently adhered to the apical surfaces of intestinal organoids, activated the Wnt/beta-catenin pathway, stimulated intestinal epithelium proliferation and differentiation, and inhibited inflammatory responses induced by ETEC K88. These findings suggest that L. fermentum FL4 has the potential to be used as a probiotic to mitigate intestinal damage and inflammation in piglets.