Solid-state fermented Artemisia argyi residue improves immune response and intestinal integrity of broilers challenged with Clostridium perfringens

Necrotic enteritis (NE) caused by Clostridium perfringens (C. perfringens) in broilers is rising with antibiotic restrictions, severely undermining their health and productivity, and necessitating safe, effective alternatives for control. Artemisia argyi is rich in bioactive compounds, and fermented herbal medicines confer multiple benefits for animal health. However, the potential of solid-state fermented Artemisia argyi residues (AARF) for controlling NE remains underexplored. This study aimed to verify the hypothesis that AARF improves immune responses and intestinal integrity in broilers challenged with C. perfringens. Broilers were assigned into five groups: an uninfected control (Con) group, an infected control (CP) without AARF group, and three infected groups treated with AARF at 15 g/L, 30 g/L, and 45 g/L (AARF-15, AARF-30, AARF-45). From day 14 to day 21 of age, the infected groups received a daily oral gavage of 2 mL (1 × 10⁸ CFU/mL) fresh C. perfringens suspension to induce NE, the Con group received 2 mL sterile cooked meat medium. Broilers supplemented with 30 g/L AARF exhibited enhanced levels of antibodies against C. perfringens alpha toxin (α-toxin), elevated expression levels of hepatic IL-2 and IgA compared with the CP group (all P < 0.05). In the AARF-30 group, body weight (BW), average daily gain (ADG), jejunal villus height (VH), and the activity of jejunal sucrase were all higher than those in the CP group at 21 days of age. The expression level of toll-like receptor 4 (TLR-4) was upregulated in the AARF-30 and AARF-45 groups relative to the CP group, and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were increased in the AARF-30 group, whereas tumor necrosis factor-alpha (TNF-α) was downregulated in the AARF-15 and AARF-30 groups (all P < 0.05). In conclusion, supplementation with an optimal concentration of 30 g/L AARF has been shown to better improve the immune response and intestinal integrity in broilers challenged with C. perfringens. These findings indicate that AARF serves as a promising alternative to antibiotics in poultry production.