Safety and Effects of Scorpion-Derived Antimicrobial Peptides as an Alternative to Antibiotic Growth Promoters (AGPs) in Broilers: Growth Performance, Immune Function, and Intestinal Development

Mingyang Gao^*Zhengli WangHongfeng ZhaoZihui LiHong Shen^*

• Shihezi University, Shihezi, China

Antimicrobial peptides (AMPs) derived from scorpion venom have gained prominence as environmentally sustainable feed additive candidates due to their favorable biosafety profile, metabolizing into residue-free natural amino acids. This study evaluated the effects of Isalo scorpion cytotoxic peptide (IsCT), a cytotoxic peptide from Isometroides scorpions, on growth performance, immune function, and intestinal development in yellow-feathered broilers. The investigation started with in vitro antimicrobial susceptibility testing against major livestock pathogens, including Staphylococcus aureus ATCC 6538, Salmonella typhimurium ATCC 14028, Escherichia coli ATCC 25922, and Streptococcus agalactiae ATCC 13813, followed by biosafety assessments using chicken erythrocytes and Kunming (KM) mice. Subsequently, a broiler feeding trial assigned 360 birds to six dietary treatments: basal diet control; IsCT-supplemented diets at 25, 50, 100, or 200 mg/kg; and ciprofloxacin control at 50 mg/kg. Results demonstrated concentration-dependent antibacterial activity without hemolytic effects, alongside confirmed biosafety in murine models. During days 1-21 and 22-42, IsCT supplementation enhanced feed conversion efficiency, improved carcass quality, elevated immunoglobulin levels, and promoted intestinal development. These findings establish IsCT as the first scorpion peptide evaluated in poultry, demonstrating broad-spectrum efficacy and growth-enhancing potential for yellow-feathered broiler production systems.