Toxic Effects of Dimethoate (Organophosphate) on Metabolism and Enzyme System of Freshwater Teleost Fish Channa punctatus

摘要

Dimethoate pesticides are frequently used for pest control in agricultural fields, and may leach the surrounding freshwater bodies through irrigation or rain. These pesticides caused severe destructive effects on aquatic fauna. Fishes aie the major component of aquatic fauna, which are the chief source of proteins. Carbohydrate and nitrogenous metabolism of fishes are responsible for proper growth and their development. Dimethoate pesticides are electrophilic in nature and inhibitor of acetylcholinesterase activity and they may attack other enzymes necessary for carbohydrate and nitrogenous metabolism. Freshwater fish Channa punctatus were treated for 24h and 96h with different nominal concentrations (re. 7.16 mg centre dot L and 10.75 rng centre dot L) of dimethoate pesticide and effect on carbohydrate and nitrogenous metabolism was observed by analyzing the different biochemical parameters in muscle, liver and gonad tissues. Carbohydrate and nitrogenous metabolism were significantly affected dueto the hypoxic conditions occurred by the exposure of pesticide, as total protein, nucleic acids (DNA and RNA), glycogen, pyruvate levels and cyto-chrome oxidase activity were significantly decieased, while total free amino acids and lac-tate level and lactic dehydrogenase activity was increased after the sub-lethal exposure. So hypoxic conditions occurred by dimethoate caused severe destructive effects on carbohydrate and nitrogenous metabolism, due to which growth and development of fish was duly affected Fishes with low protein content were not fit for human consumption.