Effectiveness of copper sulphate, potassium permanganate and peracetic acid to reduce mortality and infestation ofIchthyobodo necatorin channel catfishIctalurus punctatus(Rafinesque 1818)

Abstract

Ichthyobodo necator is a single-celled biflagellate parasite, which in high density can cause significant mortality in young fish. Copper sulphate (CuSO4), potassium permanganate (KMnO4) and peracetic acid (PAA) were evaluated for effectiveness against ichthyobodosis. Treatments were: untreated control, 2.1 mg L−1CuSO4, 3.0 mg L−1 KMnO4, 1.5 mg L−1 PAA and 3.0 mg L−1 PAA, and were applied to flow-through tanks on three consecutive days. The study was designed to simulate the flow-through systems utilized in the commercial rearing of juvenile channel catfish (Ictalurus punctatus). Mortality was monitored daily to compare survival rate among treatments. Parasite intensity was assessed pre chemical exposure and 20–24 h after the third application to determine effectiveness of the treatment. An assessment was also done 7 days post application to investigate possible reoccurrence. Copper sulphate, KMnO4 and PAA (3.0 mg L−1) significantly reduced the infestation rate of I. necator. Copper sulphate significantly improved the survival of I. necator infested channel catfish after three flow-through applications compared with the untreated control. The 3.0 mg L−1 PAA resulted in significantly lower survival than the untreated control, the 1.5 mg L−1 PAA and the KMnO4 were not statistically different from the untreated control.