Submitted to: Journal of Aquatic Animal Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 5, 2001
Publication Date: June 3, 2002
Citation: DARWISH, A.M., GRIFFIN, B.R., STRAUS, D.L., MITCHELL, A.J. HISTOLOGICAL EVALUATION OF POTASSIUM PERMANGANATE TOXICITY IN CHANNEL CATFISH.. JOURNAL OF AQUATIC ANIMAL HEALTH. 2002. v.14. p.134-144. Interpretive Summary: Potassium permanganate has been used to treat a number of skin and gill diseases of cultured fish for many years. Despite its therapeutic value it is not approved for any aquaculture use in the United States. Currently, the Unites States Food and Drug Administration (FDA) is considering approving potassium permanganate for certain diseases in channel catfish. As part of the FDA approval process, this target animal safety study has been conducted to evaluate the histology or the cellular response of channel catfish exposed to one, three and five times the usual therapeutic dose of potassium permanganate. This research will help the FDA determine the safety margin of potassium permanganate by comparing the toxic dose to the therapeutic dose. This information will be critical in the approval process of potassium permanganate.
Technical Abstract: A histological study was performed to evaluate the effect of waterborne exposure of channel catfish (Ictalurus punctatus) to one, three and five times the therapeutic concentration of KMnO4 (0.438, 1.315 and 2.190 mg KMnO4/L), calculated based on the KMnO4 demand, for 36 h, which is sthree times the therapeutic duration. The organs examined were the gill, liver and trunk kidney. Differential leukocyte counts of neutrophils and monocytes in the blood and plasma enzyme analyses (lactate dehydrogenase and alanine transaminase) were also performed. Gill was the only organ to show lesions. The gills of fish exposed to the therapeutic concentration of KMnO4 for 36 h had mild hypertophy and spongiosis; lesions were not apparent 2 d post-exposure. Gills of fish exposed to three and five times the therapeutic dose had extensive hyperplasia, epithelial hypertophy and necrosis, lamellar fusion, leukocytic infiltration and obliteration of the interlamellar space with an inflammatory exudate containing necrotic epithelial cells. The gills exposed to three and five times the therapeutic dose for 36 h appeared normal at 8 d post-exposure. There was a significant increase in the neutrophil count and the plasma alanine transaminase activity in fish exposed to five times the therapeutic dose. The results demonstrated that exposure to the therapeutic dose at three times the therapeutic exposure time causes mild lesions and recovery occurs within 48 h post-exposure.