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硒是一种必需的营养素,在膳食中它的含量正常时可以预防多种动物因缺硒而死亡。但是在膳食中它的含量过多时又可引起中毒,并曾经报导它是一种致癌物质。硒是在150多年前由瑞典化学家Berzelius发现。硒中毒是于1934年在美国达科他州发现,因牧草中含硒过多而引起牛及其它牲畜发生硷土病,其症状为脱毛、蹄和牙的脱落以及麻痹。硒中毒也可引起不育和畸胎。硒的营养需要到了1957年才被Schwarz所证实。大白鼠喂维生素E(以下简称V_E)缺乏饲料时,只需在其中加入0.1 ppm硒即可预防肝坏死。此后证明硒是鸡、猪、牛、羊以及其它动物代谢营养所必需。在预防鸡的渗出性素质、羊及牛
Selenium is an essential nutrient that can prevent many kinds of animals from die of selenium deficiency when its content in the diet is normal. But when it’s too much in the diet it can cause poisoning and it has been reported that it is a carcinogen. Selenium was discovered more than 150 years ago by the Swedish chemist Berzelius. Selenium poisoning was discovered in Dakota in the United States in 1934. It causes alkalescence disease in cattle and other livestock caused by excessive selenium in herbage, and its symptoms are hair loss, shedding of hooves and teeth and paralysis. Selenium poisoning can also cause infertility and teratogenic. The nutritional needs of selenium until 1957 was confirmed by Schwarz. Rats fed vitamin E (hereinafter referred to as V_E) lack of feed, just add 0.1 ppm selenium to prevent liver necrosis. Selenium has since proved that it is necessary for the metabolism of chickens, pigs, cattle, sheep and other animals. In preventing chicken exudative quality, sheep and cattle