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Effect of Copper Sulfate on Aeromonas hydrophila Infection in Channel Catfish Fingerlings
Author(s) -
Bebak Julie,
Garcia Julio C.,
Darwish Ahmed
Publication year - 2012
Publication title -
north american journal of aquaculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 41
eISSN - 1548-8454
pISSN - 1522-2055
DOI - 10.1080/15222055.2012.685212
Subject(s) - aeromonas hydrophila , catfish , ictalurus , copper sulfate , biology , ictaluridae , microbiology and biotechnology , aeromonas , vibrionaceae , alkalinity , fish farming , pathogen , aquaculture , bacteria , veterinary medicine , fish <actinopterygii> , zoology , copper , fishery , chemistry , medicine , genetics , organic chemistry
Motile Aeromonas septicemia results from primary or secondary infection with bacteria from 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 × 2 factorial experiments with five replicates were conducted to evaluate whether copper sulfate pentahydrate (CuSO 4 ) at a concentration of 1% of total alkalinity (total alkalinity = 98 mg/L as CaCO 3 ; total hardness = 60 mg/L as CaCO 3 ; pH = 7.4) can reduce mortality of channel catfish Ictalurus punctatus after their exposure to this emerging strain of A. hydrophila . In experiment 1, fingerling channel catfish received an 18‐h continuous bath exposure to CuSO 4 after A. hydrophila challenge. Survival in the treatments challenged with A. hydrophila , both when exposed or unexposed to CuSO 4 , was significantly lower than survival in sham‐exposed controls. Fish exposed to A. hydrophila and treated with copper sulfate had the lowest percent survival, at 18% (SE, 7.0), and survival was significantly different from the treatment in which fish were exposed to A. hydrophila but not treated with copper sulfate. In experiment 2, fish received a 4‐h pretreatment with CuSO 4 before exposure to A. hydrophila plus a 4‐h treatment the next day. In experiment 2, when fish were exposed to A. hydrophila but not CuSO 4 , survival was 80.0% (SE, 5.5). For fish exposed to A. hydrophila and to CuSO 4 , survival was 50.0% (SE, 3.2). The percent mortality in the treatment exposed to A. hydrophila and to CuSO 4 was signficantly different from all of the other treatments. This study demonstrated that, under these experimental conditions, CuSO 4 application reduced survival when used as a treatment for infection of fingerling channel catfish with this strain of A. hydrophila .