我国天然低硒饲料对畜禽生产、健康与疾病的影响

 应用我国天然缺硒饲料，在实验室条件下进行了猪、鸡和鸭的缺硒模型试验研究。结果表明：饲料缺硒可导致生产中畜禽发生一系列表现在不同部位、不同程度的病理变化和临床症状。用缺硒饲料喂仔猪8周、雏鸡2周后，血液及组织中含硒量与GSH-Px活性显著降到较低值，并趋于稳定，这与动物开始出现缺硒症状的结果一致。鸡试验证明，缺硒日粮中补加100mg/kg维生素E或补加0.05ppm以上的硒，可防止鸡发生渗出性素质病。但仅补维生素E不能防止鸡胰脏的缺硒病变，还需同时补硒。对鸡胰脏中Cu、Zn、Mn等含量的测定结果表明，缺硒使胰脏变性，导致Cu、 Zn、Mn代谢障碍及含量下降（P＜0.05）。试验还证明，增加日粮中蛋白质水平可加剧缺硒状况对畜禽的危害程度，说明对饲料条件较好，生长较快的畜禽品种，特别是幼畜、幼禽，应适当提高硒的需要量。

EFFECT OF PRACTICAL DIETARY SE-DEFICIENCY ON PRODUCTION HEALTH AND DISEASES OF LIVESTOCK AND POULTRY

Natural Feeds deficient in Se were used to study Se deficient models of pigs, chicks and ducks under experimental conditions. It showed that feed Se deficiency caused a se. ries of, marked pathological changes and necrosis in different parts of animals, which was a main reason of causing Se deficiency of livestock and poultry in practice. Quantitative analyses indicated the principles in which dietary Se levels influenced diseases and death of animals, distributions of Se in various tissues and blood of the boty, GSHPx activity and other mineral concentrations (such as Cu, Zn and Mn). It was proved that the piglets fed Se-deficient diets for 8 weeks and the chicks for 2 weeks had a markedly lower Se content and GSH-Px activity in blood and tissues with a stable tendency, which were in agreement with the results obtained when animals produced Se deficient diseases in the early days. Chick experiments also confirmed that supplementations of Se-deficient diets with Vit. E of 100 mg/kg or Se of more than 0.05ppm prevented chicks from exudative diathesis. But supplementing Vit. E alone couldn't prevent chicks from pancreas necrosis resulting from Se deficiency, which showed important roles of Se in protecting pancreas. Besides, the results of Cu, Zn and Mn et. al contents in chick pancreas indicated that severe Se deficiency resulted in a significant decrease of the above mineral concentrations (P<0.05), suggesting the effects of Se deficiency on pancreas necrosis and Cu, Zn and Mn metabolisms. Animal experiments also confirmed that a higher level of dietary protein could increase the harmful effects of Se deficiency on animals by raising growth of animals, indicating that it is necessary to increase Se requirements for these species of animals with better feed conditions and fast growth, especially younger livestock and poultry.