Butrylacetycholinesterase Activity in Liver and Plasma, Liver Glycogen and Plasma Glucose Content, Haematology and Behaviour of Clariid Catfish Clarias Gariepinus to Dichlorvos

Abstract

Semi-static bioassay experiment was conducted to ascertain Butrylacetycholinesterase enzyme activity in liver and plasma, liver glycogen and plasma glucose content, haematology as well as behaviour of Clarias gariepinus (mean weight 24.52±1.64 g) to varying concentrations (0, 0.4, 0.8, 1.6 mg L^-1) of Dichlorvos for 96 hours. Butrylacetycholinesterase activity in liver was significantly (P <0.05) inhibited all through the exposure duration to 0.4, 0.8 and 1.6 mg L^-1 of DDVP compared with control group of fish. Similarly, plasma BuChE activity was inhibited all through the exposure duration to 1.6 mg L^-1 DDVP compared to control. There was a significant (P <0.05) inhibition in HB, RBC and MCV of exposed fish after 24,48, 72 and 96h to 1.6 mg L^-1 DDVP compared to the control but PCV and WBC were significantly elevated after 72 and 96h to 1.6 mg L^-1 DDVP compared to the control. Plasma cortisol and liver glycogen were significantly inhibited after 72 and 96 h to 0.8 and 1.6 mg L^-1 compared to the control but plasma glucose was elevated after 24, 48, 72 and 96 h exposure to 0.4, 0.8 and 1.6 mg L^-1 compared to the control group of fish. The 96 h LC₅₀ of DDVP to the exposed fish was found to be 0.66 mg L⁻¹ with safety value estimated to be 0.01 mg L^-1 while lower and upper confidence limits gave 0.29 and 1.49 mg L⁻¹, respectively. The 96 h LT₅₀ values for 0.8 and 1.6 mg L^-1 was shown to be 79.23 and 60.26 hours with safety values of 3.98 and 3.01 hours respectively. WBC value was inversely related to HB (r=-0.997, p <0.05, RBC (r=-0.999, p <0.05) and PCV (r=-0.953, p <0.05). RBC related positively to HB (r=0.998 and PCV (r=0.959), and inversely to MCH (r=-0.996) and MCHC (r=0.995). Plasma BuChE activity related positively to PCV (r=0.979) and inversely to MCHC (r=-0.995 and TBF (r=984). Liver BuChE related positively with plasma BuChE (r=0.978), plasma cortisol (r= 0.970) and liver glycogen (r= 0.975) and inversely to TBF (r=-0.998). Changes in BuChE activity may serve as surrogate information for projecting potential hazards in the health status of C. gariepinus.