Dnadamage, Immunotoxicity, And Neurotoxicity Induced By Deltamethrin On The Freshwater Crayfish,Procambarus Clarkii

Pyrethroid pesticides are applied to both agricultural and aquacultural industries for pest control. However, information of their impact on the commercial important freshwater crayfish,Procambarus clarkiiis scarce. Therefore, the present study aimed to characterize to effects of a commonly used pyrethroid pesticide, deltamethrin on DNA damage, immune response, and neurotoxicity inP. clarkii. Animals were exposed to 7, 14, and 28 ng/L of deltamethrin, which correspond to 1/8, 1/4, and 1/2 of the LC50(96 hours) of this pyrethroid toP. clarkii. Significant increase of olive tail moment (OTM) and 8-hydroxy-2 '-deoxyguanosine (8-OHdG) was found after deltamethrin exposure in a dose-dependent way. Total hemocyte counts (THC) and activities of immune-related enzymes including acid phosphatase (ACP), lysozyme (LZM), and phenoloxidase (PO) were all decreased and significantly lower than control at concentration of 28 ng/L after 96 hours exposure. Acetylcholinesterase (AChE) activity, an indicator of neurotoxic effect was investigated and it was decreased significantly in muscles at 14 and 28 ng/L after 24 hours exposure. The level of intracellular reactive oxygen species (ROS) in hemocytes was also measured and the significant increase of ROS was found at 14 and 28 ng/L concentrations. The results revealed that deltamethrin induced DNA damage, immunotoxicity, and neurotoxicity inP. clarkiiby excessive generation of ROS. Because of the dose-dependent responses of all parameters under exposure of deltamethrin at environmentally realistic concentrations, these parameters could be used as sensitive biomarkers for risk assessment of deltamethrin in aquaculture area.