Evaluation of acute toxicity of triazophos and deltamethrin and their inhibitory effect on AChE activity in Channa punctatus

Pesticides are applied to control the pests indoor and outdoor; however, their remarkable amount reaches to the aquatic system through various routes like run-off, leaching, spray-drift, effluent from factories. These are reported to have negative metabolic impact on different non-target aquatic organisms like fishes. Thus, present study is aimed to evaluate the acute toxicity of two groups of pesticides, organophosphate and pyrethroid, namely triazophos and deltamethrin, respectively. The test was conducted for 96 h period in a freshwater teleost, Channa punctatus. The LC50 values for triazophos and deltamethrin after 96 h treatment was found to be 0.069 mg/L and 7.33 μg/L. The deltamethrin was found to be about ten times more toxic than triazophos to the fish. In treated fish, alterations in various behavioural patterns were observed with increasing concentrations of both the pesticides as compared to control. Further, tissue specific as well as dose dependent inhibition in the acetylcholinesterase (AChE, EC 3.1.1.7) activity was found in brain, muscle and gills in Channa punctatus exposed to both the insecticides. However, the effect was more pronounced in triazophos treated fishes than the deltamethrin. A futuristic approach on biochemical and molecular studies may throw light on the mechanism of action of these pesticides.