Effects of lead nitrate on glutathione production levels in Clarias gariepinus (Burchell, 1822) post juveniles

The effects of lead nitrate on glutathione (GSH) production levels in Clarias gariepinus post juveniles were investigated. The 96 hours LC 50 of the toxicant was determined. Six samples of the fish were exposed to sub-lethal concentrations of 0 mg/L, 28 mg/L, 43 mg/L and 57 mg/L with replicate in each case for a period of 28 days. Two samples of the fish were randomly selected from the treatments and control for the bioassay of GSH production levels in the kidney, liver and gill of the fish on the 14th and 28th day respectively. The results showed that 96 hours LC 50 for C. gariepinus exposed to lethal concentrations of lead nitrate was 284.189 mg/L. The GSH production levels were significantly lower (P≤0.05) in the kidney of the fish exposed to treatments 28 mg/L and 43 mg/L and in the liver of the fish exposed in all the treatments on both days 14 and 28, respectively. The GSH production levels were also significantly lower in the gill of the fish exposed in all the treatments. The liver of C. gariepinus exhibited a better control of the toxicant and therefore, a better biomarker of oxidative stress due to lead nitrate. Key Words : Glutathione, lead nitrate, 96 hours LC 50 , oxidative stress, Clarias gariepinus