Antimicrobial Activity of Black Soldier Fly (Hermetia illucens) Larva Hemolymph against Six Animal Pathogenic Bacteria

Purpose: As concern about antimicrobial resistance has increased, finding alternatives is necessary in the animal industry. Black soldier fly (Hermetia illucens, BSF) has an innate immune system, which induces antimicrobial peptide (AMP) expression when infection occurs. Our study aimed to investigate the antimicrobial activity of BSF larvae (BSFL) hemolymph containing AMPs produced by Escherichia coli challenge against six animal pathogenic bacteria. Methods: Fifth instar BSFL were challenged with E. coli, and their hemolymph was collected. Antimicrobial activities of BSFL hemolymph were evaluated using agar well diffusion test. The electrophoresis analysis of the BSFL hemolymph was conducted. Results: Antimicrobial activities of BSFL hemolymph were evaluated using agar well diffusion tests. E. coli-challenged hemolymph (100 and 200 mg/mL) significantly (p<0.005) inhibited growth of Aeromonas salmonicida, Lactococcus garviae, Salmonella Typhimurium, Staphylococcus aureus, and Vibrio alginolyticus. In addition, significant (p<0.005) positive correlation was found between antimicrobial activity and hemolymph concentration. Electrophoresis analysis showed expressed protein bands with approximately 15 kDa. Conclusion: AMPs from immunized BSFL may become an alternative to antimicrobial to improve animal health and productivity by controlling pathogenic bacterial infections in animal industry.