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 0.1641 ppm (sublethal) copper for a period of 30 days with sampling intervals of 24, 48, 96 h 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.

► Effect of sublethal Cu on glutathione system, carotenoids of P. indicus postlarvae.
► GSTase, GPx and GR activity decreases in exposed postlarvae upon chronic exposure.
► This indicates susceptibility of PL to oxidative stress upon chronic exposure.
► Decrease in GSTase activity reflects possible failure of the detoxification system.
► Carotenoids can be used as biomarker; P. indicus PL as bioindicator of Cu pollution.