Response of glutathione system and carotenoids to sublethal copper in the postlarvae of Penaeus indicus.

The objective of this study is to determine the effect of sublethal copper on the glutathione system and carotenoids of Penaeus indicus postlarvae (PL) when subjected to short- and long-term exposure in the laboratory. The PL were exposed to 0.1641ppm (sublethal) copper for a period of 30 days with sampling intervals of 24, 48, 96h and 10, 20, 30 days. Variations in the activity of Glutathione reductase (GR), Glutathione peroxidase (GPx) and Glutathione-S-transferase (GSTase) were measured as biomarkers of toxicity. A significant (P<0.05) increase in the GR and GPx activity of the exposed PL till 20 days of exposure and thereafter a significant decrease indicates susceptibility of the PL to oxidative stress upon chronic exposure. Similarly, a significant decrease in GSTase activity during long-term exposures in the exposed PL reflects possible failure of the detoxification system. A possible role of carotenoids to combat oxidative stress against copper toxicity is also discussed. Copyright Â