Treatment with omega-3-rich fish oil enhances host defense and reduces intestinal colonization by diarrheagenic Escherichia coli.

Escherichia coli is a common intestinal microorganism that can cause a variety of diseases in humans and animals. The aim of this study was to evaluate the therapeutic effects of fish oil rich in omega-3 against intestinal infection caused by enteroaggregative E. coli (EAEC). Minimum inhibitory and bactericidal concentrations were determined, along with toxicity assays using HT-29 intestinal cells and Tenebrio molitor larvae. Swiss mice infected with EAEC 042 were used to assess the in vivo therapeutic potential of fish oil. Histological analyses of the liver, kidney, and colon were conducted to identify tissue alterations such as inflammation and necrosis. Fish oil exhibited a bacteriostatic effect on E. coli and was non-toxic to HT-29 cells at concentrations up to 50 mg/mL. It also enhanced survival in treated larvae. In infected mice, bacterial colony counts were significantly lower in the fish oil-treated group. Histological evaluation showed reduced inflammatory infiltrates in the liver and colon, and no progression of hepatic hydropic degeneration was observed in treated animals, unlike in the untreated infected group. These findings indicated that fish oil rich in omega-3 possesses antimicrobial activity against E. coli, is non-toxic to both cells and animal models, and effectively reduces intestinal infection and associated tissue damage in mice. This suggests its potential as a supportive therapeutic agent for infections caused by pathogenic E. coli.