Lactobacillus amylovorus Alleviates Escherichia coli-Induced Growth Retardation and Intestinal Dysfunction in Weaning Piglets

Lactobacillus amylovorus has been reported to inhibit Escherichia coli growth in vitro and to modulate intestinal function and microbial composition. However, whether L. amylovorus can protect weaning piglets from E. coli-induced growth retardation and intestinal dysfunction remains unclear. In the present study, we challenged weaning piglets with E. coli K88 and supplemented their diet with L. amylovorus. Our results demonstrated that L. amylovorus supplementation improved growth performance and reduced diarrhea incidence in E. coli-challenged piglets. Furthermore, it enhanced plasma antioxidant capacity and reduced levels of pro-inflammatory cytokines. L. amylovorus alleviated E. coli-induced villus atrophy and disruption of villus architecture, as evidenced by improved histological morphology. Microbiota profiling showed that L. amylovorus improved gut microbial composition, characterized by increased abundance of Muribaculaceae and Lactobacillaceae. Ileal transcriptome analysis indicated that L. amylovorus restored the expression of genes primarily involved in nutrient metabolism. Notably, L. amylovorus-derived extracellular vesicles (EVs), but not EV-free supernatant, inhibited E. coli growth in vitro. Collectively, these findings suggest that L. amylovorus supplementation enhances growth performance, attenuates inflammation, and improves intestinal morphology, function, and microbial homeostasis in E. coli-challenged weaning piglets, potentially mediated by its EVs.