# Feline-Derived Ligilactobacillus agilis ZY25 and Ligilactobacillus salivarius ZY35 Alleviate Enteropathogenic Escherichia coli-Induced Intestinal Injury and Microbial Dysbiosis in Mice

## TL;DR

Feline-derived probiotics reduce intestinal damage and inflammation caused by EPEC in mice, suggesting potential for treating gut infections in cats.

## Contribution

Demonstrates the protective effects of feline-derived Ligilactobacillus strains against EPEC-induced gut injury in mice.

## Key findings

- Probiotic treatment improved intestinal morphology and reduced serum markers of barrier permeability.
- Immune balance was restored with increased anti-inflammatory cytokines and decreased pro-inflammatory markers.
- Gut microbiota was modulated with enrichment of beneficial taxa and suppression of harmful ones.

## Abstract

Enteropathogenic Escherichia coli (EPEC) disrupts intestinal barrier integrity, induces inflammation, and alters gut microbial balance, leading to diarrhea and growth impairment. Probiotics are considered promising alternatives to antibiotics for managing enteric infections, yet the functional properties and underlying mechanisms of feline-derived strains remain unclear. This study evaluated the protective effects of Ligilactobacillus (L.) agilis ZY25 and L. salivarius ZY35, isolated from healthy cats, against EPEC-induced intestinal injury in C57BL/6 mice, with a focus on barrier function, immune modulation, and microbial homeostasis. In this 21-day experiment, 48 mice were assigned to six groups (n = 8/group): control, EPEC model (MOD), chlortetracycline treatment (CTC), probiotic treatment (PRO-T; post-infection only), probiotic pre-treatment (PRO-P; pre-infection only), and continuous probiotic supplementation (PRO; pre- and post-infection). EPEC challenge (0.2 mL; 1 × 109 CFU/mL) was performed daily during experimental days 8–14. EPEC challenge resulted in weight loss (p < 0.05), increased (p < 0.05) diarrhea incidence, elevated (p < 0.05) serum D-lactate, diamine oxidase, and lipopolysaccharide levels, impaired intestinal morphology, immune imbalance, and microbial dysbiosis. Probiotic administration alleviated these alterations, as evidenced by restored intestinal morphology, reduced serum markers of barrier permeability (D-lactate, DAO, LPS), enhanced systemic immunoglobulins (IgA, IgG, IgM), a balanced cytokine profile (increased IL-4, IL-10; decreased TNF-α, IL-6, IL-1β, IFN-γ, CRP), and modulation of the gut microbiota (enrichment of beneficial taxa such as Lachnospiraceae_NK4A136_group and suppression of pro-inflammatory Desulfovibrio). The continuous supplementation regimen (PRO) produced the most consistent improvements among the three intervention strategies tested. These findings suggest that feline-derived probiotics mitigate EPEC-induced intestinal dysfunction, accompanied by improved barrier-related indices, immune rebalancing, and microbial stabilization, thereby providing proof-of-concept evidence for their further evaluation in feline gastrointestinal health.