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United States Department of Agriculture

Agricultural Research Service

Research Project: Integrated Aquatic Animal Health Strategies

Location: Aquatic Animal Health Research

Title: Effect of copper sulfate on Aeromonas hydrophila infection in channel catfish (Ictalurus punctatus) fingerlings

Authors
item Bebak, Julie
item Garcia, Julio
item Darwish, Ahmed

Submitted to: North American Journal of Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 9, 2012
Publication Date: September 10, 2012
Repository URL: http://handle.nal.usda.gov/10113/56370
Citation: Bebak, J.A., Garcia, J.C., Darwish, A.M. 2012. Effect of copper sulfate on Aeromonas hydrophila infection in channel catfish (Ictalurus punctatus) fingerlings. North American Journal of Aquaculture. 74(4):494-498.

Interpretive Summary: Motile Aeromonad Septicemia (MAS) results from primary or secondary infection with bacteria from Gram(-) Aeromonas spp., including Aeromonas hydrophila. Since 2009, an emerging strain of A. hydrophila has been associated, as a primary pathogen, with significant morbidity and mortality in the U.S. catfish industry. Two experiments were conducted to evaluate whether application of copper sulfate pentahydrate at a concentration of 1% of total alkalinity can reduce mortality from exposure to this emerging strain of A. hydrophila. In Experiment 1, fingerling catfish received a 48 h continuous bath exposure to copper sulfate after A. hydrophila challenge. In Experiment 2, fish received a four hour pre-treatment with copper sulfate before exposure to A. hydrophila plus a four hour treatment the next day. Under these conditions, this study demonstrated that copper sulfate application at 1% of alkalinity was not beneficial, and actually increased mortality. Further work will elucidate the conditions under which copper sulfate may be beneficial for treatment of A. hydrophila infection in catfish.

Technical Abstract: Motile Aeromonad Septicemia (MAS) results from primary or secondary infection with bacteria from Gram(-) Aeromonas spp., including Aeromonas hydrophila. Since 2009, an emerging strain of A. hydrophila has been associated, as a primary pathogen, with significant morbidity and mortality in the U.S. catfish industry. Two 2 x 2 factorial experiments with five replicates were conducted to evaluate whether application of copper sulfate pentahydrate at a concentration of 1% of total alkalinity can reduce mortality from exposure to this emerging strain of A. hydrophila. In Experiment 1, fingerling catfish received a 48 h continuous bath exposure to copper sulfate after A. hydrophila challenge. Regardless of whether they were exposed to copper sulfate or not, survival in the treatments challenged with A. hydrophila was significantly lower than survival in controls, with p = 0.001 and p = 0.02, respectively. Fish exposed to A. hydrophila and treated with Cu, had the lowest percent survival, at 42.4% (SE = 9.4), p = 0.18 for this treatment compared with the treatment exposed to A. hydrophila and copper sulfate. In Experiment 2 fish received a four hour pretreatment with copper sulfate before exposure to A. hydrophila plus a four hour treatment the next day. In Experiment 2, when fish were exposed to A. hydrophila but not copper sulfate, survival was 80.0% (SE = 5.5%). For fish exposed to A. hydrophila and to copper sulfate, survival was 50.0% (SE = 3.2%). The percent mortality in the treatment exposed to A. hydrophila and to copper sulfate was signficantly different from all of the other treatments (p < 0.001). This study demonstrated that copper sulfate application at 1% of alkalinity was not beneficial, and actually increased mortality when used as a treatment for infection of fingerling catfish with this strain of Aeromonas hydrophila.

Last Modified: 12/20/2014