Assessment of the Toxic of a Cypermethrin, Deltamethrin and Cyhalothrin Insecticide on the Fingerlings of Clarias gariepinus (Burchell, 1822)

Clarias gariepinus fingerlings of 2.620 ± 0.370g and 6.480 ± 0.598cm mean weight and length were exposed to a Cypermethrin, Deltamethrin and Cyhalothrin insecticide at concentrations of 0.0045, 0.0085, 0.0110, 0.0125 and 0.015ml/L in triplicates with a control (0ml/L) for 96hours. To evaluate the effects on the pH, dissolved oxygen-DO, temperature, salinity, total dissolved solids-TDS, and electrical conductivity-EC of the test media; fish mortality (%), the lethal concentration (96hrLC50) using Probit Plot, the risk of the insecticide, and the oxidative stress indices (the antioxidants- Superoxide dismutase- SOD, Catalase activity- CAT, Glutathione-S-transferase- GST and Malondialdehyde- MDA). The mean ± SD of the data obtained were analyzed and tested using One-way ANOVA. Results obtained showed that, the variations (at p<0.05) in the values of the parameters analyzed were concentration-dependent. The values for the TDS (92.00±1.0 to 124.50±2.50mg/L), EC (183.50±1.50 to 249.00±5.00µS/cm) and salinity (133.76±3.20 to 159.36±3.20mg/L) were most affected by the exposure concentrations compared to the control; the EC values were higher than the WHO Guidelines. Mortality was 6.67, 10.0, 56.67, 30.0 and 63.33% in the concentrations respectively. The 96hrLC50 extrapolated using Probit was 0.00128ml/L, a value that implied high toxicity of the insecticide which was validated by the risk determined to be >1, indicative of high risk. The oxidative stress indicators- SOD, CAT, and GST values determined in the Kidneys and liver of the fish showed reductions with increase in concentration while the MDA had converse values. These values indicated physiological and pathological abnormalities, and oxidative stress in the fish.