EartEarthworm hydrolysate alleviates Escherichia coli-induced enteritis by suppressing MAPK pathway activation, enhancing intestinal barrier integrity, and modulating gut microbiota

Escherichia coli enteritis causes substantial economic losses in animal husbandry, while antibiotic treatments face challenges of resistance and residue. This study investigated earthworm hydrolysate (EH) as a potential antibiotic alternative. In vitro assays demonstrated potent antibacterial activity of EH against E. coli, with an inhibition zone diameter of 12.24 ± 0.45 mm, a minimum inhibitory concentration (MIC) of 375 μg/mL, and a minimum bactericidal concentration (MBC) of 750 μg/mL. An in vivo enteritis model was established via intraperitoneal injection of E. coli (1 × 107 CFU/mL). Three-day EH treatment effectively alleviated intestinal injury, improved mucosal architecture (increased villus height/crypt depth ratio), and upregulated tight junction protein (ZO-1, Occludin, Claudin-1) expression. Mechanistically, EH downregulated the levels and expression of pro-inflammatory cytokines (TNF-α, IL-6, IL-2) and inhibited the activation of the MAPK signaling pathway (reduced p-p38, p-JNK, and p-ERK). Furthermore, EH modulated gut microbiota composition, increasing the Firmicutes/Bacteroidetes ratio and beneficial genera (Bacteroides, Lactobacillus), while reducing Proteobacteria and pathogenic genera (Helicobacter, Desulfovibrio). In conclusion, EH exerts therapeutic effects against E. coli enteritis through multi-target mechanisms involving antibacterial action, MAPK-mediated anti-inflammatory activity, intestinal barrier restoration, and microbiota modulation, offering a promising antibiotics alternative for managing intestinal infections.