Mouse Selenium Accumulation Of Toxicity Tests And Residue Determination Study

The emergence of a large number of selenium-enriched feed,selenium-rich foods, as well as man-made to add selenium are widely spread recently both at home and abroad.According to this situation,the Kun Ming mice was taken as animal models and the intragastric administration was used to study on selenium.Firstly the LD₅₀ for selenium was determined in the acute toxicity test,and then the 30d accumulative toxicity test was performed.By systematically study on the effects of selenium on the animals' growth performance,physiology function,selenium residue in tissue and blood,some scientific evidence and reference were provided for the non-polluted meat products and the by-products even for the food supervision department.The method of acute toxicity test:The 60 rats were divided into 6 groups which were named as control division,Ⅰ,Ⅱ,Ⅲ,Ⅳ,Ⅴ.The number of males and female rats was same in every group.Taked the Na₂SeO₃·5H₂O as the selenium source,the five groups were given dose concentration as 9.93mg/kg,12.42mg/kg,15.52mg/kg, 19.40mg/kg,24.25mg/kg by intragastric administration once in the acute toxicity test. Rats in the control group were given equivalent Ultra-pure water as other groups.The apperance of clinical symptoms and death numbers of rats was recorded.And the observation of dead rats's pathological anatomy and biopsy were performed.The results of the acute toxicity test showed that:The LD₅₀ was 15.86mg/kg,and 95%confidence interval range was 14.04～17.92mg/kg.The reasons of the rats'death were cardiac failure and respiratory weakness according to the observation of dead rats's pathological anatomy and biopsy.As a result,the liver and heart were the main target organ in acute selenium poisoning of mice.The method of the 30d accumulative toxicity test:The 40 rats were divided into 4 groups named as control group,Ⅰ,ⅡandⅢ(the number of males and females was same in every group.).Taken the Na₂SeO₃·5H₂O as the selenium source,selenium was exposured by intragastric administration.The three groups were given dose concentration as 0.317mg/kg,1.586mg/kg,7.93mg/kg by intragastric administration.The control group was given equivalent Ultra-pure water as other groups.In the test,the main contents were as follows:determination of the rats' growth performance,different count of white blood cell of blood samples which were collected form the tail vein each 10 days,pathological observations of organs and tissues in all rats after 30d,calculation of the viscera index and test of the blood biochemical index and detecting the selenium residue in liver, kidney,muscle and blood.The results of the 30d accumulative toxicity test showed that:The level of selenium at 0.317mg/kg could significantly improve the rats' growth performance.The total weight gain of this group's rats was 12.19g,while the control group's level of selenium was at 11.00g and the weight gain rate was 47.00%(control group 43.64%).The total feed intake was 195.65g(control group 180.81g).The total F/G was 16.05(control group 16.44).The 1.586mg/kg,7.93mg/kg selenium level could significantly reduce the mouse's growth performance.Compared with the control group,the total weight of these groups sperately reduced 1.82g and 5.56g each rat.The total feed intake reduced 20.32g and 63.09g each rat.The total F/G increased 1.04 and 5.20.The results showed that when the selenium reached a certain degree,the more selenium pollution to the rats,the more serious situation on the growth of rats appeared.In a word,appropriate amount of selenium would promote animal growth,but high levels of selenium had a significantly impediment on the growth of animals.The activities of AST,ALT,LDH,AKP of mice had significantly increased in the 7.93mg/kg group,which proved a high level of selenium would have toxicity on animals' liver and kidney.This result was as well as swelling of the liver significantly change the color line in observation and dissection.The 7.93mg/kg selenium levels could damage the heart,liver and kidney in different degrees which were risen along with the increase of dose.There were cells cloudy swelling,cytoplasm of osteoporosis,granular degeneration and vacuolar degeneration in cells of liver.And glomerular volume,capillary bleeding and eosinophilic cytoplasm of tubular epithelial cells increased.Vacuolar degeneration in kidney.It proved the liver and kidney were the main target organs for injury in the accumulative toxic of selenium.The results of residue test by the atomic fluorescence spectrophotometer showed that:There were 0.087mg/kg and 0.145mg/kg in the liver and kidney in control group's rats.There were 0.125mg/kg and 0.257mg/kg in the liver and kidney inⅠgroup(0.317mg/kg)'s rats which were 1.44 times and 1.77 times than the control group.The results explained the 0.317mg/kg was closer to the daily demand of rats.There were 0.240mg/kg and 0.381 mg/kg in the liver and kidney inⅡgroup(1.586mg/kg)'s rats which were 2.76times and 2.63 times than the control group.The results explained the 1.586mg/kg was more than the daily demand of rats.There were 0.993mg/kg and 1.257mg/kg in the liver and kidney inⅢgroup(7.93mg/kg)'s rats which were 11.42times and 8.67 times than the control group,the results explained the 7.93mg/kg was far more than the daily demand of rats.These results also explained the liver and kidney were the main targets for accumulation of selenium.The accumulation factor of Selenium in rats was 5.5,which explain the selenium have a mild accumulation.The low level of selenium could promote growth on the body and it was inhibited the growth of the body with the level of selenium increased and there were abvision damage in the liver,kidney and other organizations when the level of selenium too high and the selenium would accumulate in organizations of body by above-mentioned results.Selenium is an essential and trace element in animals,but humen can not intake it too much,wich would cause damage to the body.