Haematological response of the African catfish: Clarias gariepinus (Burchell, 1822) to sublethal concentrations of potassium permanganate

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 wi-dely 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 con-centration, 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 signify-cantly (P< 0.05) lowered from the control value of 25.67
to 23.33% in the sublethal levels after 192 h ex-posure. The mean values of the red blood cell count were also
significantly lowered from the control value of 1.68 million/mm 3
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 perman-ganate 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