Anemoside B4 attenuates intestinal damage in chickens infected with Eimeria tenella: Mechanisms involving antioxidant defense, immune modulation, and barrier repair

This study aimed to investigate the reparative effects and underlying mechanisms of Anemoside B4 (AB4) on intestinal damage induced by Eimeria tenella (E. tenella) infection in chickens. Eighty 14-day-old broilers were allocated into four groups: control (CON), E. tenella-infected (E. tenella), AB4-treated (E. tenella+AB4), and diclazuril-treated (E. tenella+DC). Infected birds were orally inoculated with 4 × 10⁴ sporulated oocysts, followed by oral administration of AB4 (40 mg/kg BW) or Diclazuril (1 ml/bird, 0.2 mg/mL) at 12 hours post-infection. Key findings demonstrated that AB4 exhibited significantly superior radical scavenging activity (82.7-93.1 %) against superoxide anion, 2,2-diphenyl-1-picrylhydrazyl (DPPH), and hydroxyl radicals compared to Diclazuril (<16.3 %) . The Anticoccidial Index (ACI) for the AB4 group (163.05) indicated moderate efficacy and was comparable to the diclazuril group (161.69) (P>0.05), with significantly reduced cecal lesion scores. Concurrently, AB4 downregulated serum pro-inflammatory cytokines (IFN-γ, IL-6) and upregulated IL-10, enhanced the splenic CD4⁺/CD8⁺ ratio (with superior restoration to Diclazuril at D14, P<0.01), and promoted expression of tight junction genes (ZO-1, P<0.01; Occludin, P<0.05 at D7/D14), corroborated by histopathological evidence of intact cecal villus architecture. These results establish that AB4 effectively mitigates coccidial enteritis through a tripartite synergistic mechanism involving potent antioxidant activity, immune homeostasis restoration, and intestinal barrier repair, offering comparable efficacy to conventional anticoccidials with enhanced safety as an eco-friendly alternative.