Immersion Aeromonas spp. vaccine efficacy and coinfection dynamics in largemouth bass (Micropterus nigricans)

Abstract

The largemouth bass (LMB; Micropterus nigricans) is a North American freshwater fish species. These fish have gained the reputation of being one of North America’s most beloved freshwater sportfish species and, in recent years, have become a species of interest in the aquaculture division. As consumers highly seek after the white fillets of this fish, the demand for retail LMB is increasing exponentially, creating a drive for aquaculturists to expand production operations. Current aquaculture practices involve highly intensive systems with dense populations of fish. Due to the inherent stressors of culture operations compared to naturally extensive systems, LMB become highly susceptible to pathogen outbreaks, often resulting in mass mortality and production losses to farmers. Motile Aeromonas septicemia (MAS) is a devastating disease from one of three species in the genus Aeromonas: A. hydrophila, A. sobria, A. caviae, and A. veronii. Geographically, MAS cases have been documented throughout the United States and globally. As these cases continue to spread and more aquaculturists expand into LMB production, a greater need arises for a solution to prevent further loss. Current therapeutants in LMB culturing involve the use of salt, formalin, prebiotics, probiotics, and emerging vaccination research. While the field of vaccination in Micropterus nigricans is novel, the requirement for remedy increases with the addition of LMB in farms across the United States and internationally.