Abstract

Potassium permanganate (KMnO₄) is a widely used freshwater aquaculture chemotherapeutant for the treatment and prevention of waterborne parasitic and fungal diseases. The goal of this research is to determine the toxicological effects of potassium permanganate on haematological parameters of the widely consumed African catfish, Clarias gariepinus. Advanced juveniles C. gariepinus were exposed to a sublethal concentrations (0.0, 2.0, 6.0 and 10.0 mg/L) of potassium permanganate for 12, 24, 48, 96 and 192 h adopting the static renewal bioassay technique and subjected to analyses. Blood samples were obtained from the caudal circulation and used for the measurement of haematocrit, haemoglobin concentration, red and white blood cell counts. Empirical data of the results obtained were subjected to statistical analysis using two-way analysis of variance (ANOVA) to test for level of significance between the various sublethal concentrations of KMnO₄ and the exposure periods. Haemoglobin concentrations were significantly (P< 0.05) decreased to values between 19.25 and 13.60 mg/dL in all sublethal levels compared to the control value of 19.65 mg/dL at zero time.  Haematocrit values were similarly significantly (P< 0.05) lowered from the control value of 25.67 to 23.33% in the sublethal levels after 192 h exposure.  The mean values of the red blood cell count were also significantly lowered from the control value of 1.68 million/mm³ to between 1.64 and 1.15 million/mm³ in 2.0, 6.0 and 10.0 mg KMnO₄/L. Similar trends were observed in the mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) which decreased significantly (P< 0.05) with an increase in exposure time, but the level of the mean corpuscular volume was increased. The results suggest that potassium permanganate can negatively affect the haematology of fish, causing various disturbances in its health and wellbeing. It is hereby recommended that potassium permanganate widely used in controlling external fungal, bacterial and protozoan infections of fish should not be used indiscriminately.

Key words: Potassium permanganate, haemoglobin, haematocrit, erythrocyte count, haematological indices, Clarias gariepinus, Nigeria.