Carbofuran insecticide induced biochemical alterations in liver and muscle tissues of the fish Clarias batrachus (linn) and recovery response

The effect of carbofuran insecticide on certain metabolites and enzymes of protein and carbohydrate metabolism was evaluated in liver and muscle tissues of the freshwater fish, Clarias batrachus during exposure and following cessation of exposure. Thirty-six fish were exposed to 7.66 mg of carbofuran/l for 6 days. After 6 days, 18 fish were transferred into carbofuran-free water for 6 days (recovery period) in order to study the recovery response. Eighteen fish were kept in clean water as controls. Liver and muscle tissues were isolated from exposed, recovery and control fish at the end of 1, 3 and 6 days in each condition, and used for the estimation of protein, amino acids, ammonia, glycogen, aminotransaminases, glycogen phosphorylase (a and ab) and glutamate dehydrogenase. Total protein showed a delayed decrease in liver and muscle tissues but recovered by the end of the recovery period. 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, and ammonia levels in liver remained elevated during recovery. Glycogen content of liver declined substantially, and rebounded after transfer of fish into clean water. The activity levels of alanine aminotransaminase, aspartate aminotransaminase, glutamate dehydrogenase and glycogen phosphorylase a were found to increase in both tissues during the exposure period. The glycogen phosphorylase ab activity in liver was suppressed on exposure to carbofuran. The enzymes exhibited different recovery pattern in liver and muscle tissues of C batrachus. The patterns of effect of carbofuran on intermediary metabolism suggest avenues to determine the mechanisms by which such effects occur. (C) 2003 Elsevier B.V. All rights reserved.