title: Effects of chronic exposure of methomyl on the antioxidant system in liver of Nile tilapia (Oreochromis niloticus).
abstract: The chronic effect of methomyl on the antioxidant system in tilapia (Oreochromis niloticus) was investigated. Fish were exposed to sub-lethal concentrations of 0.2, 2, 20 and 200μgL(-1) for 30 days, and then transferred to methomyl-free water for 18 days. Hepatic antioxidant parameters, including Glutathione-S-transferase (GST), Glutathione peroxidase (GPx), Glutathione reductase (GR), Reduced glutathione (GSH) and oxidized glutathione (GSSG), were measured at 10min (day 0), 6, 12, 18, 24 and 30 days after starting the experiment and at 18 days after transferring to methomyl-free water. There were no significant changes in enzymatic activity and content of antioxidants in liver of tilapia exposed to 0.2μgL(-1) methomyl compared to controls. However, the results showed significant increases in activities of GST, GR, GPx and levels of GSSG accompanied by a decrease in GSH levels following methomyl exposure in tilapia to 2, 20 or 200μgL(-1) over the 30-day exposure period and the highest induction rates in GST, GR, GPx and GSSG were 150.87%, 163.21%, 189.76%, and 179.56% of the control respectively, and the highest inhibition rate in GSH was 50.67% of the control, suggesting the presence of oxidative stress. Thus it would appear that the 0.2μgL(-1) methomyl might be considered as the no observed adverse effect level (NOAEL). Recovery data showed that the effects produced by lower concentration of methomyl 20μgL(-1) were reversible but not at the higher 200μgL(-1) concentration.
authors: Wuxi Fishery College, Nanjing Agricultural University, Wuxi 214081, Jiangsu, China; Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences; Scientific Observing and Experimental Station of Fishery Resources and Environment in the Lower Reaches of the Changjiang River, Wuxi 214081, China.
authors: Shun Long
authors: SL
authors: Meng
authors: Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences; Scientific Observing and Experimental Station of Fishery Resources and Environment in the Lower Reaches of the Changjiang River, Wuxi 214081, China.
authors: Jia Zhang
authors: JZ
authors: Chen
authors: Wuxi Fishery College, Nanjing Agricultural University, Wuxi 214081, Jiangsu, China.
authors: Geng Dong
authors: GD
authors: Hu
authors: Wuxi Fishery College, Nanjing Agricultural University, Wuxi 214081, Jiangsu, China.
authors: Chao
authors: C
authors: Song
authors: Wuxi Fishery College, Nanjing Agricultural University, Wuxi 214081, Jiangsu, China.
authors: Li Min
authors: LM
authors: Fan
authors: Wuxi Fishery College, Nanjing Agricultural University, Wuxi 214081, Jiangsu, China.
authors: Li Ping
authors: LP
authors: Qiu
authors: Wuxi Fishery College, Nanjing Agricultural University, Wuxi 214081, Jiangsu, China; Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences; Scientific Observing and Experimental Station of Fishery Resources and Environment in the Lower Reaches of the Changjiang River, Wuxi 214081, China. Electronic address: xup@ffrc.cn.
authors: Pao
authors: P
authors: Xu
mesh_terms: D000818:Animals; D023681:Cichlids / Q000502:physiology*; D004781:Environmental Exposure; D004789:Enzyme Activation / Q000187:drug effects; D004798:Enzymes / Q000378:metabolism; D008099:Liver / Q000187:drug effects*; D008297:Male; D008724:Methomyl / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects; D011897:Random Allocation; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D004798:Enzymes; D014874:Water Pollutants, Chemical; D008724:Methomyl
keywords: Antioxidants; Liver; Methomyl; Recovery; Tilapia