PV4 medicated baths treats skin ulcer syndrome of Apostichopus japonicus by eliminating surface bacteria, modulating gut microbiota, and enhancing host immune responses

Skin ulceration syndrome (SUS) is a major threat to Apostichopus japonicus aquaculture, particularly in Fujian in 2024, where it has shown high mortality rates and infectious potential. Traditional antibiotic treatments often lead to challenges such as antibiotic resistance. Antimicrobial peptides (AMPs), as key components of innate immunity, represent a promising alternative for treating SUS. In this study, we identified a novel AMP, Pv4, from Litopenaeus vannamei, which exhibited strong antibacterial activity against multiple Vibrio species responsible for SUS and demonstrated bacteriostatic effects in seawater.