Insecticides induced stress response and recuperation in fish: Biomarkers in blood and tissues related to oxidative damage.

The present research investigated the growth, blood, antioxidant response (liver), AChE (brain and muscle) and Na+/K + ATPase in gills of Clarias batrachus exposed to 0 (control), two insecticides, 1.65 mg L-1 chlorpyrifos (CPF) and 2.14 mg L-1 monocrotophos (MCP) for a fixed interval time of 3, 6, 9, 12 and 15 days and follow up depuration process in fresh water for 30 days (at an interval of 7, 15 and 30 days). The toxicants exposed fish indicated significantly (P < 0.05) lower weight gain and HSI. The RBC, Hb, Hct, plasma total protein, glucose, albumin, globulin and respiratory burst activity was reduced. However, WBC, plasma glucose, serum creatinine, and triglycerides were enhanced. The weight gain, HSI and all haematological parameters were reversed following depuration of CPF and MCP exposed fish. Hepatic superoxide dismutase, catalase, lipid peroxidation, reduced glutathione, and glutathione S-transferase activities were significantly activated whereas glutathione peroxidase was inhibited in both tested groups. All the antioxidant enzymes were reversed on day 15 in MCP concentration, whereas CPF on day 30 of depuration process. The inhibition of acetylcholinesterase (brain, muscle) and gill Na+/K + ATPase activities were more in CPF exposure and early recovery in MCP. The results indicated that depuration process might help in detoxification of fish and improve growth, haematological conditions, oxidative stress and AChE, Na+/K + ATPase activity. However, further studies are needed in different fish species with different toxicants to support this strategy of depuration process in order to detoxify polluted fish.