Location: Warmwater Aquaculture Research UnitTitle: Efficacy of a live attenuated Edwardsiella ictaluri oral vaccine in channel and hybrid catfish
|GREENWAY, TERRENCE - Mississippi State University|
|BYARS, TODD - Mississippi State University|
|WISE, DAVID - Mississippi State University|
Submitted to: Journal of the World Aquaculture Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/2/2018
Publication Date: 8/1/2018
Citation: Chatakondi, N.G., Peterson, B.C., Greenway, T.E., Byars, T.S., Wise, D.J. 2018. Efficacy of a live attenuated Edwardsiella ictaluri oral vaccine in channel and hybrid catfish. Journal of the World Aquaculture Society. 49(4):686-691.
Interpretive Summary: Channel x blue hybrid catfish are increasing raised in production ponds in US farm-raised catfish industry largely because of their superior production characteristics and their suitability to intensive production systems. Enteric Septicemia of Catfish (ESC) and columnaris are two of the most economically important bacterial diseases affecting the production of farm-raised catfish. The current methods to control the disease have inherent limitations leading to production losses. Effective and practical methods to control disease losses in production ponds are needed Efficacy of a live attenuated Edwardsiella ictaluri oral vaccine against ESC in channel catfish and hybrid catfish was evaluated under controlled conditions. Patented oral vaccine (Wise et al. 2015) was delivered at four doses 4 X 106 to 3.2 X 107 viable vaccine cells/g wet commercial feed to fish held in replicated aquaria. After 35 days, vaccinated and non-vaccinated channel catfish and hybrid catfish were challenged with a virulent E. ictaluri following standard procedures. Unvaccinated channel catfish (73%) and hybrid catfish (85%) was significantly higher than the vaccinated channel catfish (14.1 to 26.6%) and hybrid catfish (10.4 to 14.1%).
Technical Abstract: This study evaluated the efficacy of an oral live-attenuated Edwardsiella ictaluri vaccine against enteric septicemia of catfish (ESC) in channel and hybrid catfish. The vaccine was delivered orally by feeding fish a diet coated with an attenuated E. ictaluri isolate at four doses to deliver between 4x10+6 to 3.2x10+7 viable vaccine cells/g wet feed. Thirty five days post vaccination, control and vaccinated fish were challenged with virulent E. ictaluri and mortality was examined for 30 days post-challenge. Mortality of non-vaccinated hybrids (85%) and non-vaccinated channel catfish (73%) was similar but significantly greater than all groups of vaccinated fish. In channel catfish, a trend towards increasing mortality with decreasing dose was observed. Mortality of channel catfish vaccinated with the lowest dose (26.6%) was significantly higher than fish vaccinated with the highest dose (14.1%) but similar to fish vaccinated at the intermediate doses (17.5 and 19.4%). In contrast, mortality of all vaccinated hybrid catfish was similar and ranged between 10.4 and 14.0 %. The data demonstrates that the attenuated E. ictaluri vaccine at all four doses tested is effective at reducing ESC related mortalities in hybrid and channel catfish.