Evaluation of potassium permanganate against an experimental subacute infection of Flavobacterium columnare in channel catfish, Ictalurus punctatus (Rafinesque)

An experiment was performed to evaluate the efficacy of potassium permanganate (KMnO(4)) as a prophylactic and therapeutic treatment of an experimental subacute infection of Flavobacterium columnare in channel catfish, Ictalurus punctatus. Fish were cutaneously abraded and divided into five treatment groups: (i) challenged by waterborne exposure to F. columnare and not treated with KMnO(4) (positive control), (ii) challenged and simultaneously treated with KMnO(4,) (iii) challenged and treated with KMnO(4) at 1, 6 and 9 days post-challenge, (iv) not challenged and treated with KMnO(4) at 1, 6 and 9 days post-challenge (first negative control) and (v) not challenged and not treated (second negative control). The dosing of KMnO(4) was 2.0 mg L(-1) above the potassium permanganate demand for 2 h duration. The survival of the group challenged and simultaneously treated with KMnO(4) (99%) was significantly higher than the positive control (78%) and was not significantly different from the negative control groups. The challenged fish treated with KMnO(4) post-challenge had 7% higher survival than the positive control (85% compared with 78%), but that difference was not statistically significant. The results demonstrate that KMnO(4) has a clear prophylactic value but probably a marginal therapeutic value once the infection has established.