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日粮硒水平对猪机体代谢及人类健康的多重影响 总被引：1，自引：0，他引：1
硒(selenium)为半金属元素,最先被瑞典科学家Berzelius于1817年发现,并被命名为月亮女神(Selene)。近200年来,人类对硒的探索如同彩云追月,充满了梦想和变幻。最初,硒一度被认为只是一种有毒元素和致癌剂,直到20世纪50年代, 相似文献
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20世纪30-40年代是营养学研究的黄金时代.其标志是发现、分离、鉴别及合成了多种维生素,也发现了大量的必需微量元素,并改进了研究方法和进行了饲料分析.这些工作为以后25(1954-1979)年进行的科学养鸡打下了基础.营养学家获得的成就有:(1)制定代谢能与蛋白比率;(2)制定氨基酸需要量;(3)确定各种维生素和必需矿物质元素需要量;(4)对各种饲料中氨基酸、维生素和矿物质有效性的进一步了解;(5)发现了硒、硒的 相似文献
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硒是一种必需营养素,也是所有微量元素中毒性最大的。一个世纪之前,就知道了它的毒性。但直到1957年,才发现它在畜禽日粮中的作用。70年代,美国食品和药物管理局(FDA)批准硒可做为牛、羊、猪、 相似文献
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硒的生物学作用与生物转化 总被引：4，自引：0，他引：4
硒是1818年瑞士化学家Berzelius发现的。上世纪50年代以前，硒一直被认为是一种毒性很强的元索。1957年，Schwarz发现硒能使大鼠免于饮食性肝坏死，并指出硒是机体不可缺少的微量元素，此后国内外许多学者已对其进行了广泛的研究。硒是人体红细胞谷胱甘肽过氧化物酶和磷脂过氧化氢谷胱甘肽过氧化物酶的组成成分，其主要作用是参与酶的合成，保护细胞膜的结构与功能免遭过度氧化和干扰，具有许多重要的生理功能。 相似文献
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纳米硒对仔猪生长和抗氧化的影响 总被引：5，自引：0，他引：5
将纳米硒和亚硒酸钠2种硒源分别以0.1、0.2、0.3、0.4、0.5、1.0 m g/kg 6个硒水平添加到基础日粮中,配制成12种试验日粮,研究纳米硒和亚硒酸钠对断奶仔猪生长和抗氧化的影响。结果显示:硒源添加浓度在0.1￣0.3 m g/kg时,亚硒酸钠和纳米硒对仔猪生长性能、总抗氧化能力(T-AO C)、丙二醛(M D A)和活性氧含量的影响无显著差异(P>0.05);硒源添加浓度在0.4￣1.0 m g/kg时,纳米硒组仔猪生长性能、T-AO C显著(P<0.05)高于亚硒酸钠组,M D A和活性氧含量显著(P<0.05)低于亚硒酸钠组;硒源添加浓度在0.10￣0.40 m g/kg时,2种硒源对谷胱甘肽过氧化物酶(G SH-Px)活性的影响无显著差异(P>0.05);在0.50、1.0 m g/kg硒添加水平上,纳米硒组G SH-Px活性显著(P<0.05)高于亚硒酸钠组。上述结果提示:纳米硒的W einberg剂量-效应的最适剂量范围宽于亚硒酸钠。 相似文献
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Hyperglycaemic effect of xylazine 总被引：2，自引：0，他引：2
In cats, xylazine, an analogue of clonidine, produced hyperglycaemia when injected intravenously. The effect was obtained in unanaesthetized cats and in pentobarbitone sodium anaesthesia. The hyperglycaemia was not a central effect, nor due to adrenaline release from the adrenals, nor to a direct action of xylazine on the liver. It resulted from a fall in plasma insulin produced by an action of xylazine on the pancreas, inhibiting insulin secretion without affecting glucagon secretion. The increase in the glucagon/insulin ratio, by stimulating glucose production in the liver, was probably responsible for the xylazine-induced hyperglycaemia. 相似文献
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K Kallela 《Nordisk veterinaermedicin》1975,27(11):562-569
Pure red clover was selected for plant estrogen analyses from the fresh fodder crops of 1972 and 1973. The investigations were made on fresh red clover and on the same red clover after periods of storage of varying length. The red clover was stored in manilla bags in a silo among the ordinary silge fodder, use being of the "green solution method" (Farmos Oy). In the studies the estrogenic effect of the fodder was ascertained by means of bioassay, the criterion being the increase in murine uterine weight. The known plant estrogens were determined by thin layer chromatography and by liquid chromatography. The estrogenic effect of the red clover silage fodder of 1972 was greater in all the silage fodder samples than it was in the fresh red clover. The quantity of individual isoflavones and "transformed" estrogen too, was greater in many of the silage fodder samples than it was in the respective fresh red clover. The estrogenic effect of the silage fodder made from the red clover of 1973 varied considerably; in some samples it was greater but in most it was smaller than the estrogen effect of the fresh red clover. However, apart from a few exceptions, the quantity of individual isoflavones and of transformed estrogens was smaller than it was the fresh red clover. 相似文献
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Canine mammary tumours: protective effect of late ovariectomy and stimulating effect of progestins 总被引：1，自引：0，他引：1
W Misdorp 《The Veterinary quarterly》1988,10(1):26-33
Ovariectomy, even when performed at an advanced age, was found to be to some extent protective against mammary tumour development in dogs. Bitches treated with progestins had a slightly higher risk for mammary tumours (all types, benign and malignant) than controls. Progestin treatment did not increase the risk of mammary cancer. Benign tumours in (treated and untreated) dogs appeared earlier than malignant ones. Progestin treatment resulted in earlier appearance of both benign and malignant tumours than in controls. The ratio solitary/multiple mammary tumours was not significantly different between treated and untreated dogs. 相似文献