喀斯特山区草地施肥对放牧乌蒙半细毛羊抗氧化系统功能的影响

摘要

To identify the effect of different nitrogen fertilizer on grassland,fertilization and grazing treatments were applied to perennial grassland grazed by Wumeng semi-fine wool sheep in Weining County.The results showed that copper content in grasses was relatively low,but was higher than the minimum requirement for sheep.Application of nitrogen significantly increase nitrogen content (P＜0.01) in herbage but there were no differences among different forms of nitrogen.Ammonium sulfate significantly increased the sulfur and zinc content (P＜0.01) of herbage,but significantly decreased the selenium content (P＜0.01).At the end of grazing experiment,copper,iron and selenium concentration in the blood of sheep grazing grassland treated with ammonium sulfate was significantly lower (P＜0.01) than in sheep grazing ammonium nitrate treated grassland;blood zinc and sulfur were also significantly higher (P＜0.01).Sheep grazing ammonium sulfate treated pasture had significantly lower (P＜0.01) blood hemoglobin and hematocrit capacity than sheep grazing pasture treated with ammonium nitrate and the control (no fertilizer);antioxidant enzymes including serum ceruloplasmin,serum superoxide dismutase and serum glutathione peroxidase were significantly lower (P＜0.01) than in sheep grazing the pasture treated with ammonium nitrate and the control.Malondialdehyde (MDA) content was also higher (P＜0.01).There were no differences in other blood mineral element concentrations,blood indexes and serum biochemical values.It was concluded that fertilizer selection should be based on soil mineral content;grassland with low copper content is not suitable for ammonium sulfate fertilizer.Ammonium sulfate fertilizer significantly affected the antioxidant system function.%为选择草地施肥的肥料种类,减少施肥对乌蒙半细毛羊产业的影响,在威宁县凉水沟种羊场多年生人工草地开展施肥和放牧试验.结果表明:凉水沟种羊场人工草地牧草铜含量相对较低,但仍高于乌蒙半细毛羊营养需要标准;施肥极显著增加牧草氮含量(P＜0.01),各施肥处理之间没有明显差异.硫酸铵施肥显著增加牧草硫和锌含量(P＜0.01),显著降低了牧草硒的含量(P＜0.01).放牧试验结束时,施硫酸铵草地的乌蒙半细毛羊血液中铜、铁和硒的含量极显著低于施硝酸铵草地和对照组(P＜0.01),动物血液锌和硫含量极显著高于硝酸铵施肥牧场和对照组(P＜0.01).硫酸铵施肥牧场的乌蒙半细毛羊血红蛋白、红细胞压积容量极显著低于硝酸铵施肥牧场和对照牧场(P＜0.01),血清铜蓝蛋白含量、血清超氧化物歧化酶活力、血清谷胱甘肽过氧化物酶活力和血清过氧化氢酶等抗氧化酶的活力极显著低于硝酸铵施肥牧场和对照牧场(P＜0.01),丙二醛的含量显著高于硝酸铵施肥牧场和对照牧场(P＜0.01).血液其他矿质元素和血液指标及血清生化值在2个施肥处理和对照之间均差异不显著.因此得出结论,草地施肥的种类需要根据土壤矿物质分布和含量情况确定,铜含量低的牧场不适合硫酸铵施肥,硫酸铵施肥明显影响了乌蒙半细毛羊机体抗氧化系统功能.