Compound bioengineering protein improves growth performance and intestinal health in broiler chickens under high-temperature conditions

In recent years, more frequent and prolonged periods of high ambient temperature in summer compromised poultry production worldwide. This study was conducted to investigate the effects of compound bioengineering protein (CBP) on the growth performance and intestinal health of broilers under high ambient temperatures. A total of 400 one-day-old Arbor Acres birds were randomly distributed into five treatment groups: control group (CON) with basal diet, or a basal diet supplemented with CBP 250, 500, 750, and 1,000 mg/kg, respectively. The trial lasted 42 d, all birds were raised at normal ambient temperature for the first 21 d and then subjected to the artificial hyperthermal condition with the temperature at 32 ± 2 °C and relative humidity at 60 ± 5% during 22 to 42 d. Dietary CBP supplementation improved the growth performance and serum antioxidant capacity (total antioxidant capacity and total superoxide dismutase), and decreased serum cortisol, aminotransferase, and alkaline phosphatase of broilers. Dietary CBP inclusion enhanced intestinal barrier function by promoting intestinal morphology and reducing intestinal permeability (diamine oxidase), increased the intestinal antioxidant capacity by elevating glutathione peroxidase activity in the duodenum, reducing malondialdehyde content in the jejunum. Dietary CBP supplementation also alleviated intestinal inflammation by decreasing interleukin (IL)-6 content in the jejunum and ileum, promoting IL-10 levels in the ileum, down-regulating the mRNA abundance of intestinal inflammatory-related genes interferon-gamma (IFN-γ) in the duodenum and up-regulating IL-10 in the jejunum. Additionally, CBP increased the population of total bacteria and Lactobacillus in cecal chyme. Collectively, dietary CBP inclusion exerts beneficial effects on the broilers, which are reflected by enhancing antioxidant capacity, promoting intestinal barrier function, ameliorating intestinal immune response, and regulating intestinal bacteria, thus improving the growth performance of broilers under high-temperature conditions. In general, 750 mg/kg CBP supplementation is more effective.Extreme high ambient temperature in summer occurs frequently around the world, which causes severe economic losses in the broiler industry, and impairs food safety. Improving the high-temperature resistance of broilers is beneficial to the sustainable development of the broiler industry. Dietary supplementation of anti-stress additives is an effective way to prevent high-temperature stress in broilers. Antimicrobial peptides are excellent anti-stress additives that exhibit multiple biological functions, such as against microbial infection, improving antioxidant capacity and immune function, and perfecting the intestinal health of broilers. In the present study, we added the compound bioengineering protein (CBP) (two bioengineering proteins containing functional fragments of antimicrobial peptides) in diets to investigate the potential protective effects of CBP for broilers under high temperatures. Our present results indicate that dietary CBP supplementation enhances the growth performance of broilers exposed to high temperatures. This improvement is attributed to the increased antioxidant capacity, improved intestinal barrier function, ameliorated intestinal immune function, and improved intestinal bacteria. These results provide a theoretical foundation for CBP utilization in diets to ameliorate growth performance and intestinal health of broilers under high temperatures.