Probiotic Enterococcus faecium (M74) as an alternative to antibiotics for controlling necrotic enteritis in broiler chickens.

Necrotic enteritis caused by Clostridium perfringens remains a major challenge in broiler production, particularly under restrictions on antibiotic use. This study evaluated the prophylactic and therapeutic effects of Enterococcus faecium (M74) as a probiotic alternative to antibiotics in broiler chickens experimentally challenged with C. perfringens. Birds were allocated into negative control, positive control, prophylactic, and therapeutic groups, and growth performance, bacterial counts, hematological and biochemical indices, immune responses, intestinal morphometry, and histopathology were assessed. Supplementation with E. faecium (M74) markedly reduced intestinal bacterial load, with C. perfringens and total coliform counts decreased by approximately 88% and 84%, respectively, in the prophylactic group compared with the infected control. Final body weight and body weight gain were improved by approximately 30-31%, while feed conversion ratio was improved by about 25%. Villus height increased by approximately 43%, accompanied by a marked reduction in histopathological lesion scores (up to 82% decrease in degeneration score). Renal and hepatic function markers were significantly ameliorated, and immune parameters were markedly enhanced in treated birds. The prophylactic regimen consistently showed superior efficacy compared with therapeutic application. Although the study was limited to a single probiotic strain and experimental conditions, these findings indicate that E. faecium (M74) is a promising probiotic candidate for mitigating necrotic enteritis in broilers and may represent a viable alternative or complementary strategy to antibiotics.