Fisheries Lab, Department of Zoology, Panchsheel College of Education, Nirmal-504 106, A.P, INDIA
Department of Zoology, Kakatiya University, Warangal – 506 009, A.P. India.
The effect of triazophos insecticide on certain metabolites and enzymes of protein and carbohydrate metabolism was evaluated in liver and muscle tissues of the freshwater fish, Channa punctatus during exposed to sublethal concentration (0.006 ppm) of triazophos for 24h, 48h, 72h and 96h exposure periods. The harmful toxic effect of this chemical is investigated by measuring enzymes in protein and carbohydrate metabolism. Liver and muscle tissues were isolated from exposed and control fish at the end of 24h, 48h, 72h and 96h in each condition, and used for the estimation of protein, amino acids, ammonia, glycogen, aminotransaminases and glutamate dehydrogenase. Total protein showed a delayed decrease in liver and muscle tissue. Free amino acid content was affected little in liver, but was elevated in muscle, and ammonia levels were elevated in both tissues throughout the exposure period. Glycogen content of liver declined substantially. The activity levels of alanine aminotransaminase, aspartate aminotransaminase and glutamate dehydrogenase were found to increase in both tissues during the exposure period. The patterns of effect of triazophos in intermediary metabolism suggest avenues to determine the mechanisms by which such effects occur.
Key words: Triazophos toxicity. Protein. Amino acids. Ammonia. Glycogen. Transaminases. Glutamate dehydrogenase. Liver. Muscle.
The aquatic environment is continuously being contaminated with toxic chemicals from industrial, agricultural and domestic activities. Pesticides are one of the major classes of toxic substances used in India for management of pests in agricultural lands and control of insect vectors of human disease. The runoff from treated areas enters the rivers and aquaculture ponds that are supplied by rivers. Such rivers and the adjacent aquaculture ponds are likely to be contaminated by pesticides.
Aquatic animals inhabiting polluted water bodies tend to accumulate many chemicals in high concentrations even when the ambient environmental contamination levels are low (Colombo et al. 1995) a potentially hazardous situation for the entire food chain. Once a toxicant enters an organism, several biochemical and physiological responses occur which may be adaptive or may lead to toxicity. The biochemical processes represent the most sensitive and relatively early events of pollutant damage. Thus, it is important that pollutant effects be determined and interpreted in biochemical terms, to delineate mechanisms of pollutant action, and possibly ways to mitigate adverse effects.
Work has been done on biochemical effects of pesticides on aquatic animals in India (Begum and Vijayaraghavan, 1999; Bhavan and Geraldine, 2001; Tripathi and Singh, 2002), but there is a dearth of information relating to the comprehensive effects of pesticide during exposure and following cessation of exposure. In a continuation of this work, we have studied the levels of certain important metabolites and enzymes in liver and muscle tissues of the fish Channa punctatus (Bloch), during commercial triazophos (O, O - diethyl, 0.1 phenyl, 1H, 1, 2, 4, Triazol 3yl – phosphorothio) exposure and withdrawal from exposure. C. punctatus are valuable food fish often cultivated in paddy in a “paddy-cum fish” culture program in India, and thereby are often chronically exposed to insecticides. The metabolites and enzymes examined are concerned with important biological functions viz., metabolism of proteins and carbohydrates.
Materials and Methods
The fish Channa punctaus, weight (50±1.30g) and length (25.5±1.21 cm) were collected from the lake of Nirmal,...