Abstract

Gut microbiota plays a pivotal role in host immunity and overall health. Enterococcus faecium HDRsEf1 (Ef1), a novel potential probiotic, has been reported to enhance immune defense against pathogenic invasion; however, its effects on inflammation and gut microbiota remain poorly understood. This study aimed to evaluate the impact of Ef1 on host health, gut microbiota, and fecal metabolite profiles using DSS-induced colitis in mice and nursery pig models. In mice, Ef1 effectively mitigated growth retardation and organ damage caused by DSS-induced inflammation. In nursery pigs, Ef1 administration reduced markers of inflammation and oxidative stress, including IL-1β, IL-6, TNF-α, and MDA, while increasing the anti-inflammatory cytokine IL-10 and the antioxidant enzyme SOD. Furthermore, Ef1 modulated gut microbiota composition, promoting beneficial genera such as Ruminococcus and Acetobacter , while suppressing potentially harmful genera like Acinetobacter . Metabolomic analysis revealed that Ef1 enriched anti-inflammatory metabolites in the gut. Collectively, these findings indicate that Ef1 can beneficially modulate gut microbiota and metabolite profiles, thereby enhancing host health.