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Effectiveness of Copper Sulfate and Potassium Permanganate on Channel Catfish Infected with Flavobacterium columnare

Farmer, Bradley D., Beck, Benjamin H., Straus, David L.
North American Journal of Aquaculture 2012 v.74 no.3 pp. 320
Flavobacterium columnare, Ictalurus punctatus, aquaculture tanks, bacteria, bacterial infections, copper sulfate, disease control, fins, fish, fish diseases, gills, liver, microbial load, polymerase chain reaction, potassium channels, potassium permanganate, potassium sulfate, quantitative analysis, stocking rate, therapeutics
Copper sulfate (CuSO ₄) and potassium permanganate (KMnO ₄) were evaluated for their effectiveness to curtail mortality and decrease bacterial load in fish tissues and water in channel catfish Ictalurus punctatus infected with Flavobacterium columnare , the causative agent of columnaris. Fish (average size, 16.6 g and 13.7 cm) were obtained from a single culture tank undergoing an epizootic of columnaris and were stocked at a density of 30 fish per tank in each of 12 tanks. The study consisted of three treatments (n = 4 replicates per treatment): an untreated control group, a CuSO ₄-treated group, and a KMnO ₄-treated group. Treatment rates were 2.1 mg/L CuSO ₄ and 3.0 mg/L KMnO ₄ and were applied on three consecutive days at 24-h intervals. Caudal fin, gill, and liver samples were taken from one fish of each replication 24 h after the last treatment for analysis by quantitative real time PCR. A significant improvement in survival was noted among fish treated with CuSO ₄ (72.7%) compared with the control fish (38.5%) and the KMnO ₄-treated fish (52.2%). Survival of the KMnO ₄-treated fish was not significantly different from the control. Quantitative PCR indicated a significant reduction of bacteria in the water after the first and second treatments of both therapeutants; no difference was detected in fish tissues. Histological analysis of gill samples 24 h after the last treatment indicated that CuSO ₄-treated fish exhibited significantly less gill damage than untreated controls and there was no difference in KMnO ₄-treated fish. Copper sulfate therapy significantly improved survival, reduced the number of bacteria in the water, and reduced gill pathologies associated with F. columnare infection in channel catfish. Received August 23, 2011; accepted November 22, 2011