Toxicity bioassay of lead acetate and effects of its sublethal exposure on growth, haematological parameters and reproduction in Clarias gariepinus

The African catfish, Clarias gariepinus, was exposed to different concentrations of lead acetate for 96 h, and the value of LC₅₀ for the exposure period was registered as 122 mg/L. The effects of sub-lethal exposure on growth, reproduction and haematological parameters were also investigated in C. gariepinus. Lead exposure at all concentrations reduced growth rate, and was inversely related to growth. There were significant effects of lead exposure on erythrocyte count, haemoglobin concentration and haematocrit values. Lead exposure time and dose increased the plasma glutamicoxaloacetic transaminase (PGOT) and plasma glutamic-pyruvic transaminase (PGPT) activity levels. No significant effect of lead acetate was noticed on fecundity and ovum size. Sperm motility was reduced in all concentrations of lead acetate after 4 weeks of exposure. The present investigation indicates that the lead acetate is less toxic to fish than other metals as the LC₅₀ value is comparatively high.