Bioeconomic Analysis of Flavobacterium columnare Vaccine Pond Trials with Channel Catfish

Abstract

AbstractWhile Flavobacterium columnare is a well‐known fish pathogen that has been studied for over 100 years, columnaris disease remains poorly controlled and is in need of improved management solutions for U.S. catfish producers. Outside of therapeutants, the disease remains relatively unchallenged in the commercial catfish industry. Attempts to improve the management of this disease have led to the development of a live‐attenuated genetic group 2 F. columnare vaccine (hereafter, “17‐23 vaccine”) administered via immersion to fingerling‐stage Channel Catfish Ictalurus punctatus. The 17‐23 vaccine was confirmed to protect against F. columnare in Channel Catfish fry during previous studies. In the present study, we investigated and compared the efficacy of the 17‐23 vaccine in Channel Catfish fingerlings versus nonvaccinated (control) fingerlings grown to food‐size fish in earthen ponds. Data were collected from the two treatments (n = 5 ponds/treatment) to evaluate impacts on survival, growth, feed conversion, antibody development, and economic benefit. There were no natural outbreaks of columnaris disease observed during the trial and no significant difference in survival of vaccinated versus control fish. Indirect enzyme‐linked immunosorbent assay results determined that the anti‐F. columnare 17‐23 antibody concentrations were significantly higher in vaccinated fish at 4 weeks postvaccination but not at 12 weeks. Vaccinated fish had a significantly higher average weight at harvest (mean ± SE = 357.5 ± 30 g) than control fish (289.3 ± 20 g), and the feed conversion ratio of vaccinated fish (1.35) was significantly better than that of control fish (2.13). Partial budget analysis of changing production from use of nonvaccinated fingerlings to use of 17‐23 vaccinated fingerlings for grow out resulted in a net benefit of US$1,443/ha. Based on these results, the vaccine appears to show potential economic benefit to producers but should be further substantiated under both research and commercial settings.