The extract of Gentiana macrophylla exerts anti-bacterial effects on groupers infected by vibrio harveyi via suppressing inflammatory responses.

Abstract

Vibrio harveyi has emerged as one of the primary bacterial pathogens affecting grouper (Epinephelus spp.) aquaculture in recent years. However, effective control measures remain elusive. Gentiana macrophylla Pall. (GM), a traditional Chinese medicinal herb with over 2000 years of documented use exhibits anti-inflammatory, antioxidant, antibacterial and antiviral properties. However, its application for controlling aquaculture diseases remains unexplored. Therefore, this study aimed to investigate the anti-Vibrio harveyi activity of GM extract (GME). Results indicated that GME inhibited Vibrio harveyi growth by suppressing protein synthesis and disrupting cell membrane integrity, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 62.5 mg/mL and 125 mg/mL, respectively. Furthermore, 1% and 1.5% GME supplements significantly reduced mortality rates in vitro during Vibrio harveyi infections and alleviated inflammatory responses and pathological damage to major organs in vivo. These findings provide scientific support for developing GME as a fisheries drug or feed additive to prevent or treat infectious diseases in aquaculture.