Title: Evaluation of a 4-h static copper sulphate treatment against experimental infection of Flavobacterium columnare in channel catfish (Ictalurus punctatus) Authors
Submitted to: Journal of Fish Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 15, 2011
Publication Date: April 2, 2012
Citation: Darwish, A.M., Mitchell, A.J., Straus, D.L. 2012. Evaluation of a 4-h static copper sulphate treatment against experimental infection of Flavobacterium columnare in channel catfish (Ictalurus punctatus). Journal of Fish Diseases. 43:688-695. Interpretive Summary: Columnaris disease, caused by the bacterium Flavobacterium columnare, exists worldwide and affects a wide variety of fish. Columnaris is one of the two most costly diseases to the channel catfish industry in the US. Because of the serious losses attributed to the disease, therapeutants are needed to control columnaris. The present study was designed to assess the therapeutic potential of copper sulfate against an acute columnaris infection. The results demonstrated that one application of copper sulfate at concentration of 2.1 or 4.2 mg/L can significantly reduce the mortality of acutely infected fish. Further research will be warranted to evaluate copper sulfate as columnaris treatment in pond water.
Technical Abstract: The efficacy of copper sulfate (CuSO4) against early stages of an experimental acute infection of Flavobacterium columnare in channel catfish (Ictalurus punctatus) was evaluated. Fish were challenged, by waterborne exposure to F. columnare in an ultra-low flow-through water delivery system, and treated with CuSO4 at 4.2 and 2.1 mg/L at 5.5 h post challenge for 4 h. Bacterial challenged non-treated fish acted as positive control and non-challenged non-treated fish acted as a negative control. Fish challenged with F. columnare and treated with CuSO4 at 4.2 and 2.1 mg/L post challenge had mortalities of 6.4 and 18.3%, respectively, compared to the positive control that had 90.2% mortality. The mortality of challenged fish treated with CuSO4 at 4.2 and 2.1 mg/L was significantly different from the positive control. There was no significant difference between the mortalities of the 4.2 and 2.1 mg/L treatments. The results suggest that CuSO4 has clear therapeutic value against columnaris infections.