Intervention of antimicrobial peptide usage on antimicrobial resistance in aquaculture

Antibiotic resistance genes (ARGs) widely exist in diverse matrices to pose potential risks and attract global attention. This study performed tilapia-cultivation experiment to discuss the intervention of antimicrobial peptide usage on antimicrobial resistance in aquaculture by analyzing 29 target ARGs in water, residue, and fish muscle samples. The sul1 gene was the dominant ARG in most of samples while absolute abundances of total ARGs were in the range of 1.5 × 10²-2.3 × 10⁷ copies/mL in water samples and 2.1 × 10⁸-3.9 × 10⁹ copies/g in the residue and fish muscle samples. Compared with antibiotic treatment, the cecropin treatment could significantly reduce the absolute abundance of ARGs and intI1 in all samples. Proteobacteria were the dominant phylum for most of samples while Aeromonas/Cetobacterium served as the dominant genus for samples with antibiotic/cecropin treatment. Network analysis showed that cecropin treatment could significantly reduce occurrence of multi-drug resistant bacteria and the correlation between genera and ARGs. Results of partial least squares structural equation modeling which was used to discuss the influential factors of ARGs exhibited that antibiotics could increase ARGs, further proving that cecropin peptide could effectively reduce ARGs in aquaculture. This study will provide important information on controlling ARGs in aquaculture in terms of antimicrobial peptide application.