The Acute Toxicity Study Of Sodium Selenite On Chanel Catfish (Ictalurus Punctatus)

In this paper, the toxic effects of sodium selenite to Channel Catfish (Ictalurus Punctatus) were studied.The purposes of this study were to identify the toxic mechanisms of selenium and offer some indexes of detecting and preventing enviromental pollution, and provide more detail theory on basic biology for food chain safety and individual health. Main study contents and conclusions were concluded as following:1.The acute toxicity of sodium selenite to Channel Catfish embroy, larval and fry were studied by biological hydrostatic toxic test respectively. The results showed the semi-lethal concentrations of sodium selenite to Channel Catfish embroy, larval and fry were 8.37mg/L,1.35mg/L,5.12mg/L respectively.The safe concentrations were 0.83.7 mg/L,0.135mg/L,0.512mg/L respectively.2.According to result of acute toxicity test, six sub-lethal concentrations to Channel Catfish were put up in the range of 0-96h LC50, the test lasted for 24h, Then related enzyme activities of gill, hepatopancreas, muscle tissue were measured.The results showed when the sub-lethal concentration increased, the AchE,Na+K+-ATPase, ACP,AKP activities of gill went up generally; The ACP,AKP activities of hepatopancreas showed higer generally,but the ACP,AKP activities of hepatopancreas treated with 2.4mg/L Se4+ went down. The SOD and GST activities of hepatopancreas first rised and then declined generally; The SOD activity of muscle was inhibited slowly. However, the GST activity of muscle first rised and then declined.3.Channel Catfish was infected by 2.4mg/L sodium selenite through water bath.Then microtome section of gill, hepatopancreas, muscle tissue were made by paraffin slicing respectively after the acute toxic test lasted for 24h. The results of microscopic observations showed the damage of sodium selenite to the hepatopancreas tissue exhibited pancreas tissue shrinking obviously and part of liver cell aggregating; The injury contained also gill lamellae became necrotic and disintegrated,The colour of HE staining took on deeper; The nuclear of muscle fiber became almost disappeared,but the influence of sodium selenite to muscle fiber was not obvious.4. We treated Channel Catfish with 2.4mg/L sodium selenite leaded to significant change of enzyme activity for 24h. In order to investigate the toxicity of sodium selenite to Channel Catfish, These proteins from liver tissue were extracted,quantified and separated by 2-DE.The gels were stained by Coomassie blue and analyzed by Imagemaster software. More than 700 protein were detected. Of which,28 proteins with at least two-fold difference through Imagemaster software analysis and manual check.15 proteins were identified by mass spectrometer, proteins such as protein disulfide-isomerase, alpha-actinin, enolase 1 alpha maybe related to cell oxidation reduction, internal environment balance, energy metabolism.