Skip to main content
ARS Home » Southeast Area » Stoneville, Mississippi » Warmwater Aquaculture Research Unit » Research » Publications at this Location » Publication #330768
Research Project: Health Management, Disease Prevention and Control Strategies in Catfish Aquaculture

Location: Warmwater Aquaculture Research Unit

Title: Oral vaccination of channel catfish against enteric septicemia of catfish (ESC) using a live attenuated Edwardsiella ictaluri isolate

Author
item WISE, DAVID - Mississippi State University
item GREENWAY, TERRENCE - Mississippi State University
item BYARS, TODD - Mississippi State University
item GRIFFIN, MATT - Mississippi State University
item KHOO, LESTER - Mississippi State University

Submitted to: Journal of Aquatic Animal Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/15/2015
Publication Date: 3/16/2015
Citation: Wise, D.J., Greenway, T.E., Byars, T.S., Griffin, M.J., Khoo, L.H. 2015. Oral vaccination of channel catfish against enteric septicemia of catfish (ESC) using a live attenuated Edwardsiella ictaluri isolate. Journal of Aquatic Animal Health. 27(2):135-143.

Interpretive Summary: A oral live-vaccine against Edwardsiella ictaluri was developed and used in pond trials. This research proved that this method of delivery of a single dose of the oral vaccine is possible in a commercial setting.

Technical Abstract: Enteric septicemia of catfish (ESC), caused by Edwardsiella ictaluri, is the most problematic bacterial disease affecting catfish aquaculture in the southeastern United States. Efforts to develop an effective ESC vaccine have had limited industrial success. In commercial settings, ESC vaccines are typically administered by immersion when fry are transferred from the hatchery to rearing ponds. While this approach is a practical method of mass delivery, this strategy administers vaccines to very young fish, which lack a fully developed immune system. To circumvent this limitation, an oral vaccination strategy was evaluated as a means of immunizing catfish at the fingerling stage of production, when fish possess a more complete immune arsenal. A virulent E. ictaluri isolate (S97-773) was attenuated by successive passage on media containing increasing concentrations of rifamycin. In laboratory trials, cultured vaccine was diluted and mixed with feed (100 mL diluted vaccine/454 g feed). This mixture was then fed to Channel Catfish Ictalurus punctatusfingerlings. Two separate dilutions of cultured vaccine (1:10 and 1:100) were used to create the vaccine–feed mixture, equating to estimated doses of 5E+07 and 5E+06 CFU/g (1of feed, respectively. After 30 d, catfish were exposed by immersion (1e+06 CFU/ml) to the virulent parental strain of E. ictaluri. The target dose (1:100 dilution, ~5E+06 CFU/g feed) offered exceptional protection (relative percent survival = 82.6–100%). In addition, negligible deaths occurred in fish vaccinated at 10 times the target dose (1:10 dilution, ~5E+07 CFU/g of feed) ). In pond trials, antibody production increased 18-fold in orally vaccinated fish. When compared with nonvaccinated controls, vaccination significantly improved survival, feed fed, feed conversion, biomass produced, and total harvest. This research demonstrates Channel Catfish can be successfully immunized in a commercial setting against E. ictaluri with a single dose of an orally delivered, live attenuated, E. ictaluri vaccine.