Extract of Scutellaria baicalensis and Lonicerae flos improves growth performance, antioxidant capacity, and intestinal barrier of yellow-feather broiler chickens against Clostridium perfringens

In this study, we aimed to investigate the effect of Scutellaria baicalensis and Lonicerae Flos (SL) extract on the growth performance and intestinal health of yellow-feather broilers following a Clostridium perfringens challenge. In total, 600 one-day-old yellow-feather broilers were divided into five treatments (6 replicate pens of 20 birds per treatment), including a control (Con) group fed a basal diet and the infected group (iCon) fed a basal diet and infected with Clostridium perfringens, the other three groups receiving different doses of SL (150 mg/kg, 300 mg/kg, and 450 mg/kg) and infected with Clostridium perfringens. The total experimental period was 80 days. When the birds were 24 days old, a subclinical necrotizing enteritis model was induced by orally inoculating the birds with 11,000 oocysts of mixed Eimeria species on day 24, followed by C. perfringens (108 CFU/mL) from days 28 to 30. The birds were evaluated for parameters such as average weight gain (AWG), average daily feed intake (ADFI), mortality, feed conversion ration (FCR), intestinal lesion score, intestinal C. perfringens counts, and villus histomorphometry. Results indicated that C. perfringens infection led to reduced AWG and the levels of tight junction proteins, increased the FCR, ileum E. coli load, and intestinal permeability, causing damage to the intestinal mucosal barrier (P < 0.05). Compared with the infected group, supplementing 300 mg/kg of SL significantly increased AWG at 43–80 days, the ratio of villus height to crypt depth in the jejunum and ileum at 35 days, and the activity of superoxide dismutase (SOD) in serum. It also significantly reduced the FCR at 22–42 days, intestinal lesion score, and the amount of C. perfringens in the ileum (P < 0.05). Additionally, compared with the infected group, the addition of 300 mg/kg SL significantly increased mRNA levels of claudin-2, claudin-3, mucin-2, and toll-like receptor 2 (TLR-2) in the ileum of infected birds at 35 days of age. In conclusion, supplementation with SL extract could effectively mitigate the negative effects of C. perfringens challenge by improving intestinal barrier function and histomorphology, positively influencing the growth performance of challenged birds.