【作者】 胡华锋；

【导师】 胡承孝； 介晓磊；

【作者基本信息】 华中农业大学 ， 植物营养学， 2011， 博士

【摘要】 硒是人和动物必需微量元素,兼具营养、毒性和解毒三重生物学功能,是生命的“保护剂”。我国72%土壤缺硒,生产的牧草、饲料不能满足动物硒营养的需求。饲料中添加矿物硒安全性差,用有机硒则成本高昂。因此,开发研究新的饲料硒源具有重要意义。紫花苜蓿(Medicaco sativa L.)是一种富硒能力较强的优质饲料资源,而植物体内富集的硒主要以有机硒形式存在；因此可以依据土壤学、植物营养学和动物营养与饲料学原理,通过向牧草施用矿物硒,使硒吸收、同化、富集到牧草体内,根据家畜营养需要,直接或作为富硒添加剂添加到饲料中,饲喂家畜,从而达到家畜安全生产、高效补硒的目的；也可组配富硒功能性饲料,生产符合国家《食品中硒限量卫生标准》(GB13105-91)的富硒畜产品；此研究对于牧草、饲料、动物营养及人类健康等具有重要的理论意义和应用价值。因此本文在总结国内外硒与植物、动物营养关系研究进展的基础上,通过植物试验和动物试验,以紫花苜蓿和蛋鸡为载体,系统研究了硒在土-草-饲-畜系统中的营养效应,并初步分析了有关的机制。主要研究结果如下：1.适量叶面施硒能显著(P<0.05)促进紫花苜蓿对硒吸收；提高紫花苜蓿体内全硒、无机硒和有机硒含量,并与施硒量呈正相关；且紫花苜蓿全硒、无机硒及有机硒存在显著(P<0.05)的正相关关系。叶面施硒能显著(P<0.05)提升紫花苜蓿有机硒转化率及硒肥利用率,紫花苜蓿有机硒转化率和硒肥利用率均随施硒量的增加呈先升后降趋势,施硒100 mg kg-1紫花苜蓿有机硒转化率最高；施硒50 mg kg-1紫花苜蓿硒肥利用率最高；2.基础日粮添加富硒牧草显著(P<0.05)影响蛋硒含量,蛋硒含量随添加富硒牧草硒含量的提高而升高,但蛋硒转化率却与添加富硒牧草硒水平呈负相关。基础日粮添加富硒牧草能显著(P<0.05)提高蛋鸡胸肌、心肌、脾、肝脏、肾脏及血液等组织器官的硒含量,且随添加富硒牧草硒水平升高而升高。添加富硒牧草显著(P<0.05)提高了蛋鸡粪硒含量,粪硒含量与添加富硒牧草硒含量呈显著(P<0.05)正相关。蛋鸡对生物硒的吸收能力随时间推移而在增强,蛋鸡对硒水平<2.319mg kg-1的日粮硒吸收能力更强。基础日粮添加富硒牧草能显著(P<0.05)影响蛋鸡饲料硒的吸收效率,吸收率随添加富硒牧草硒含量的增加而呈先升后降趋势。添加硒含量5.97mg kg-1富硒牧草组的饲料硒吸收率最高,极显著(P<0.01)高出基础日粮组722.46%。3.施硒量与牧草硒、饲料硒、粪便硒、鸡蛋硒和组织(胸肌、心肌、肝、脾、肾和血液等)硒含量之间存在极显著(P<0.01)的线性关系,它们的线性方程为：叶施硒肥牧草硒：y=0.0912x+0.7021(R2=0.9915),叶施硒肥饲料硒：y=0.0118x+0.2199(R2=0.9867),叶施硒肥粪便硒：y=0.0137x+0.6817(R2=0.9926),叶施硒肥鸡蛋硒：y=0.0023x+0.1993(R2=0.9904),叶施硒肥胸肌硒：y=0.0011x+0.0783(R2=0.9593),叶施硒肥心肌硒：y=0.0016x+0.2740(R2=0.9466),叶施硒肥肝脏硒：y=0.0045x+0.5966(R2=0.9673),叶施硒肥脾脏硒：y=0.0019x+0.7068(R2=0.9868),叶施硒肥肾脏硒：y=0.0038x+0.6957(R2=0.9803),叶施硒肥血液硒：y=0.0002x+0.0424(R2=0.9603)。4.适量基施硒肥能显著(P<0.05)提高紫花苜蓿对硒的吸收能力；显著(P<0.05)提升紫花苜蓿体内全硒、无机硒及有机硒含量,并与施硒量呈正相关；且紫花苜蓿全硒、无机硒及有机硒存在显著(P<0.05)的正相关关系。紫花苜蓿硒吸收能力随生育期呈先升后降的倒“V”型变化；初花期紫花苜蓿吸收硒的能力最强；紫花苜蓿硒含量随生育期而降低。紫花苜蓿叶全硒对牧草全硒的贡献率均>60%；硒肥显著(P<0.05)提升紫花苜蓿有机硒的转化率,施硒紫花苜蓿有机硒转化率基本上在40%-50%之间；当施硒量0.45 mg kg-1时,紫花苜蓿有机硒转化率>50%；而未施硒紫花苜蓿有机硒转化率<40%。紫花苜蓿有机硒转化率随生育期的发展呈下降趋势。但紫花苜蓿硒肥利用率却很低,整个生育期虽施硒0.45kg hm-2紫花苜蓿硒肥利用率最高,但不超过1.5%；硒肥利用率随生育期的进程呈先升后降,初花期硒肥利用率最高。5.施硒量与牧草硒含量之间存在极显著(P<0.01)的线性关系,它们的线性方程为：基施硒肥苗期牧草硒：y=1.9912x+0.1827(R2=0.9696),基施硒肥分枝期牧草硒：y=1.7394x+0.1724(R2=0.9670),基施硒肥孕蕾期牧草硒：y=1.5045x+0.1542(R2=0.9694),基施硒肥初花期牧草硒：y=1.2547x+0.1588(R2=0.9835),基施硒肥盛花期牧草硒：y=1.0044x+0.1500(R2=0.9904)。6.基施硒肥能提高紫花苜蓿土壤有效硒含量,土壤有效硒含量与施硒量呈正相关；施硒1.05kg hm-2能极显著(P<0.01)提高土壤有效硒含量；施硒量≥1.05kg hm-时,土壤有效硒含量随紫花苜蓿生育期呈现明显降低趋势,降幅为：24.75%-40.84%,且苗期、分枝期土壤有效硒含量显著(P<0.05)高于盛花期。7.叶面施硒能提高紫花苜蓿草产量,且产草量随施硒量的增加呈先升后降趋势；施硒100mg kg-1效果最好,草产量显著(P<0.05)高出未施硒紫花苜蓿1623 kg hm-2.适量叶面施硒还能显著(P<0.05)提高紫花苜蓿粗蛋白和粗脂肪的含量和累积量,施硒100mg kg-1效果最好,含量分别显著(P<0.05)高出未施硒紫花苜蓿13.84%和48.07%,累积量提高320.84kg hm-2和140.97kg hm-2,且紫花苜蓿粗蛋白和粗脂肪的含量和累积量均随施硒量增加呈先升后降。叶面施硒未显著(P<0.05)影响紫花苜蓿粗灰分和NDF的含量,其积累量均以施硒100 mg kg-1最高,并显著(P<0.05)高于未施硒紫花苜蓿；叶面施硒对紫花苜蓿ADF和HF含量和累积量均无显著(P<0.05)影响。适量叶面施硒能显著(P<0.05)促进紫花苜蓿对磷、钾、锌、铜、锰、硼和钼的吸收；对磷、钾、锌和铜而言,施硒1OO mg kg-1效果最好；对锰、硼和钼而言,施硒70 mg kg-1效果最好；叶面施硒未能显著(P<0.05)促进紫花苜蓿对钙和铁的吸收。且紫花苜蓿磷、钾、锌、铜、锰、硼、钼和铁积累量随施硒量增加呈先升后降趋势。叶面施硒显著(P<0.05)提高了紫花苜蓿锰的含量,而未显著(P<0.05)影响钙和铁的含量；适量叶面施硒能显著(P<0.05)提高磷、钾、钼、硼、锌和铜含量,过量则能显著(P<0.05)降低紫花苜蓿硼的含量。且紫花苜蓿磷、钾、锌、铜、锰、硼和钼含量随施硒量增加而呈先升后降。8.基施硒肥能显著(P<0.05)提高紫花苜蓿干物质累积量；且累积量随施硒量的增加呈先升后降趋势,施硒0.45kg hm-2紫花苜蓿干物质累积量最大；基施硒肥提高分枝期和孕蕾期干物质累积速率,降低初花期干物质累积速率；且紫花苜蓿干物质累积速率随生育期呈升-降-升-降的倒“W”型变化,峰值出现在分枝期和初花期。适量基施硒肥能显著(P<0.05)提高紫花苜蓿叶茎比；叶茎比随施硒量呈先升后降趋势,施硒0.45kg hm-2紫花苜蓿叶茎比最大；紫花苜蓿叶茎比随生育期呈现先升后降的倒“V”型变化,峰值出现在分枝期。基施硒肥未显著(P<0.05)影响紫花苜蓿植株含水率；紫花苜蓿植株含水率随生育期而下降；分枝期以前,紫花苜蓿植株含水率>80%,而分枝期以后降为70%左右。基施硒肥能促进紫花苜蓿生长,紫花苜蓿株高随施硒量增加呈先升后降趋势,施硒0.45kg hm-2紫花苜蓿植株最高；紫花苜蓿生长速率随生育期呈先升后降的倒“V”型变化,孕蕾期出现生长高峰；基施硒肥对紫花苜蓿生长速率的影响因生育期而异,苗期到孕蕾期呈现施硒肥提高生长速率,以施硒0.45kg hm-2生长速率最大；而孕蕾期到盛花期,呈现施硒肥降低紫花苜蓿的生长速率。9.适量基施硒肥能显著(P<0.05)提高紫花苜蓿粗蛋白含量,粗蛋白含量随施硒量增加呈先升后降,施硒0.45kg hm-2粗蛋白含量最高；紫花苜蓿粗蛋白含量随生育期呈升-降-升的“N”型变化；苗期到分枝期呈现上升趋势,分枝期到初花期呈下降趋势,而初花期到盛花期呈上升趋势；紫花苜蓿粗蛋白含量在分枝期达到最大；紫花苜蓿叶粗蛋白对牧草总粗蛋白的贡献率>65%；且叶粗蛋白贡献率随紫花苜蓿生育期呈降-升-降的倒“N”型变化；叶粗蛋白贡献率苗期最大,其次是初花期,分枝期最小。10.适量基施硒肥能显著(P<0.05)提高紫花苜蓿粗脂肪含量,粗脂肪含量随施硒量增加呈先升后降,施硒0.45kg hm-2粗脂肪含量最高；紫花苜蓿粗脂肪含量随生育期呈升-降的倒“V”型变化；施硒推迟了紫花苜蓿粗脂肪高峰值的生育期,施硒紫花苜蓿粗脂肪含量初花期达到峰值,而未施硒紫花苜蓿在孕蕾期达到峰值。且紫花苜蓿叶粗脂肪对牧草总粗脂肪的贡献率>50%。11.适量基施硒肥能显著(P<0.05)提高初花期和盛花期紫花苜蓿粗灰分含量,但未能显著(P<0.05)影响苗期、分枝期和孕蕾期粗灰分含量。紫花苜蓿粗灰分含量随施硒量增加呈先升后降,施硒0.45kg hm-2紫花苜蓿粗灰分含量最大。紫花苜蓿粗灰分含量随生育期呈升-降-升倒“N”型变化；苗期到分枝期紫花苜蓿粗灰分含量略有提升,分枝期到初花期处于下降期,初花期到盛花期又略有提升。且紫花苜蓿叶粗灰分对牧草总粗灰分的贡献率>55%。适量施硒能显著(P<0.05)提高分枝期叶粗灰分的贡献率,但对苗期、孕蕾期、初花期和盛花期影响不显著(P<0.05)。12.适量基施硒肥能显著(P<0.05)降低孕蕾期紫花苜蓿NDF含量,而未能显著(P<0.05)影响其它生育期NDF含量；施硒紫花苜蓿NDF含量随施硒量的增加呈先降后升趋势；施硒0.45kg hm-2紫花苜蓿NDF含量最低。紫花苜蓿叶NDF对牧草总NDF的贡献率因生育期而异,苗期和分枝期叶NDF贡献率均>50%,孕蕾期、初花期和盛花期在40%-50%。适量施硒能显著(P<0.05)降低紫花苜蓿ADF含量,ADF含量均随施硒增加呈先降后升趋势,施硒0.45 kg hm-2紫花苜蓿ADF含量最低；紫花苜蓿ADF含量随生育期呈升-降-升“N”型变化；苗期到孕蕾期ADF含量处于上升期,孕蕾期到初花期处于下降期,而初花期到盛花期又处于上升期。紫花苜蓿叶ADF对牧草总ADF的贡献率与生育期有关；苗期仅施硒0.45 kg hm-2紫花苜蓿叶ADF贡献率>50%,分枝期施硒0.25 kg hm-2、0.35 kg hm-2、0.45 kg hm-2紫花苜蓿叶ADF贡献率>50%；孕蕾期、初花期和盛花期叶ADF贡献率<50%；叶ADF对牧草总ADF的贡献率随生育期呈先升后降趋势,峰值出现在分枝期。适量施硒能显著(P<0.05)提高分枝期和盛花期紫花苜蓿HF含量,但未显著(P<0.05)影响其它生育期HF含量；且施硒紫花苜蓿间HF含量差异不显著(P<0.05)；紫花苜蓿叶HF对牧草总HF的贡献率与生育期有关,苗期、分枝期和初花期,叶HF贡献率均>50%；孕蕾期仅施硒量≥0.75kg hm-2紫花苜蓿叶HF贡献率>50%；盛花期施硒紫花苜蓿叶HF贡献率>50%,而未施硒紫花苜蓿叶HF的贡献率<50%。13.适量施硒能显著(P<0.05)提高紫花苜蓿磷和钾含量；磷和钾含量均随施硒增加呈先升后降趋势,施硒0.45kg hm-2紫花苜蓿磷和钾含量最大。紫花苜蓿叶磷和叶钾对牧草总磷和总钾的贡献率与生育期有关；苗期和分枝期,叶磷对牧草总磷的贡献率>60%,而孕蕾期、初花期和盛花期>50%。紫花苜蓿叶磷的贡献率总体上随生育期呈下降趋势。苗期、孕蕾期、初花期和盛花期叶钾对牧草总钾的贡献率>50%,而分枝期>60%。叶钾贡献率总体上随生育期的推移而呈现先升后降趋势,峰值出现在分枝期。14.基础日粮适量添加富硒牧草能显著(P<0.05)提高蛋鸡产蛋率,日产蛋量和降低料蛋比,且产蛋率和日产蛋量随添加富硒牧草硒含量提升呈先升降趋势,料蛋比呈先降后升趋势。15.基础日粮添加富硒苜蓿(SA)能显著(P<0.05)提高产蛋率,日产蛋量(P<0.05),降低料蛋比(P<0.05)；添加酵母硒(SY)也能显著(P<0.05)提高产蛋率；而添加普通苜蓿(CA)、亚硒酸钠(SS)和酵母硒(SY)组对日产蛋量和料蛋比均没显著影响(P<0.05)。添加富硒苜蓿(SA)在上述生产方面,略优于酵母硒(SY),而显著(P<0.05)优于普通苜蓿(CA)和亚硒酸钠(SS)。16.基础日粮添加亚硒酸钠(SS)、酵母硒(SY)或富硒苜蓿(SA)均能极显著(P<0.01)提高蛋鸡蛋硒的含量；添加植物硒-富硒苜蓿(SA)蛋鸡蛋硒极显著(P<0.01)高于添加亚硒酸钠(SS),但极显著(P<0.01)低于酵母硒(SY)。蛋硒含量随试验期的延长而增加。亚硒酸钠(SS)、酵母硒(SY)或富硒苜蓿(SA)三种硒源蛋硒转化率大小顺序为：酵母硒(SY)>富硒苜蓿(SA)>亚硒酸钠(SS)。且三种硒源的蛋硒转化率均极显著(P<0.01)低于基础日粮组。亚硒酸钠(SS)、酵母硒(SY)或富硒苜蓿(SA)三种硒源均极显著(P<0.01)提高蛋鸡胸肌、心肌、肝、脾和肾组织硒含量；添加酵母硒(SY)蛋鸡胸肌、心肌、肝、脾和肾硒含量均显著(P<0.05)高于添加亚硒酸钠(SS)和富硒苜蓿(SA)；而添加富硒苜蓿(SA)蛋鸡胸肌硒含量极显著(P<0.01)高于添加亚硒酸钠(SS)；心肌和肾硒含量极显著(P<0.01)低于添加亚硒酸钠(SS)；脾和肝硒含量与添加亚硒酸钠(SS)差异不显著(P>0.05)；说明富硒苜蓿(SA)作为硒源安全性远高于酵母硒(SY)。添加亚硒酸钠(SS)的组胸肌硒含量未能显著(P>0.05)高于添加普通苜蓿(CA),而添加普通苜蓿(CA)胸肌硒含量显著高于(P<0.05)基础日粮。17.基础日粮添加亚硒酸钠(SS)、酵母硒(SY)或富硒苜蓿(SA)均能极显著提高蛋鸡血硒含量(P<0.01),添加酵母硒(SY)或富硒苜蓿(SA)较亚硒酸钠(SS)能极显著(P<0.01)提高蛋鸡血硒含量。硒源能显著(P<0.05)影响蛋鸡的粪硒含量；添加亚硒酸钠(SS)、酵母硒(SY)或富硒苜蓿(SA)组蛋鸡粪硒含量均极显著高于(P<0.01)添加普通苜蓿(CA)组和基础日粮组。添加富硒苜蓿(SA)组蛋鸡粪硒含量未显著(P<0.05)高于添加酵母硒(SY)组,却显著(P<0.05)低于添加亚硒酸钠(SS)组,在饲料全硒相同的情况下,鸡对酵母硒(SY)的吸收能力,略高于富硒苜蓿(SA)；而鸡对酵母硒(SY)和富硒苜蓿(SA)的吸收能力均显著(P<0.05)高于亚硒酸钠(SS)。蛋鸡对有机硒的吸收能力随试验期的延伸仍在加强；试验21天后,蛋鸡对无机硒的吸收能力趋于稳定。亚硒酸钠(SS)、酵母硒(SY)和富硒苜蓿(SA)三种硒源均可极显著提高蛋鸡饲料硒的吸收率(P<0.01),酵母硒(SY)组效果略优于富硒苜蓿(SA)组,而富硒苜蓿(SA)组显著(P<0.05)优于亚硒酸钠(SS)组。18.综上所述,紫花苜蓿作为河南省种植面积最大的牧草,对硒比较敏感,而河南大部分地区属低硒区域。因此,施用硒肥是该区域提高紫花苜蓿草产量及硒含量、改善品质的必要农业措施,而叶面施硒效果要远远优于基施。关于畜禽补硒的硒源,如单从蛋鸡对硒富集能力来讲,其三种硒源的能力大小顺序为：酵母硒(SY)>富硒苜蓿(SA)>亚硒酸钠(SS)；但从蛋鸡的生产能力和安全性讲,富硒苜蓿(SA)要优于酵母硒(SY)。因此,富硒苜蓿(SA)可以作为一种优质的硒源添加剂应用于畜禽生产中。我们可根据施硒量与牧草硒含量之间的线性方程,依据动物硒营养需要,生产不同硒水平牧草,低水平硒含量牧草可直接饲喂,而高水平硒含量牧草可作硒源添加剂；结合本论文试验结果,认为日粮中添加施硒量为30 mg kg-1～100 mg kg-1生产的富硒苜蓿(SA)可用作蛋鸡生产的常规添加剂,既显著(P<0.05)提高了蛋鸡生产性能,又显著(P<0.05)增加了蛋硒和组织硒含量,可取得良好的经济效益；而添加施硒量≥100 mg kg-1生产的富硒苜蓿,既能获得牧草的高产,又能开发生产人类补硒的功能性蛋品和肉品,这不仅会获得较好的经济效益,而且会带来更好的社会效益。更多还原

【Abstract】 Selenium (Se) is the necessary microelement of human beings and animals. It is the protestant of life, which has triple biology function of nutrition, toxicity and detoxification.72% of the soil is Se deficiency in China, and the pastures and feed produced in it cannot meet the demands of Se by animals. The feed added mineral Se is poor safety, but the organic Se is costly. Therefore, the development and research of new Se source for feed become more and more important. Alfalfa (Mediacom sativa L.) is a kind of high quality feed resource that has strong ability to enrich Se, and The Enriched Se in plants mainly exists in the form of organic Se. Based on the soil science, plant nutrition, animal nutrition and feed theory, through applying the mineral Se to pastures, the Se can be absorbed, assimilated and enriched into pastures. And according to nutrition needs of livestock, Directly or adding the Se-rich pastures into feed to feed livestock, Thus it can reach the purpose of livestock safety production and supplying Se efficiently; and matching also Se-rich functional feed, to produce Se-rich animal by-products that meet the national《Tolerance limit of Se in foods》(GB13105-91). This research has important theoretical significance and application value to pasture, feed & animal nutrition and human health. So this paper was based on summarizing the domestic and international research progress of the relations of Se and plants, animal nutrition, then through the plant and animal experiments, it studies the nutrition effect of Se in the system of soil-pasture-feed-animal systematically, and preliminarily analyses the internal mechanism. The main research results are as follows:1. For alfalfa, spraying Se fertilizer on alfalfa leaves properly could significantly (P＜0.05) improve the absorption of Se, and improve the content of total Se, inorganic Se and organic Se. it was positively correlated with the application rate of Se; and it was also positive correlation among total Se, inorganic Se and organic Se of alfalfa;Se fertilizer application enhanced the conversion rate of organic Se and the utilization ratio of Se fertilizer significantly (P<0.05), and the conversion rate of organic Se and the utilization ratio of Se fertilizer increased first and then decreased with the addition of Se fertilizer,the conversion rate of organic Se of alfalfa was highest by spraying 100 mg Se kg-1, the utilization ratio of Se fertilizer of alfalfa was highest by spraying 50 mg Se kg-1,2.Addition of Se-rich forge in the basal diet could significantly (P<0.05)affect Se content of eggs, the Se content of eggs increased with the addition of forge Se content. However, the conversion rate of egg-Se ratio was negatively correlated with the forge Se content. The Se content of layer breast muscle, heart, spleen, liver and kidneys and other organs could be significantly (P<0.05) increased with the addition of Se-rich forge in the basal diet, being gradually increased followed by the addition of Se-rich forge. Addition of Se-rich forge in the basal diet could significantly (P<0.05) increase the Se content of layer blood, and the Se content of layer blood increased followed by the addition of the Se level of Se-rich forge. The Se absorption capacity of layer was gradually enhanced with time passing. Se absorption increased obviously as Se<2.319 mg kg-1 was added in the basal diet. Addition of Se-rich forge in the basal diet could significantly (P<0.05) affect Se uptake efficiency, which increased first and then decreased with the addition of the Se level of Se-rich forge. Se uptake efficiency was highest as 5.97mg kg-1 Se-rich forge was added in the basal diet, very significantly higher 722.46% than control group (P<0.01).3. it was very significantly (P<0.01)linear connection between Se rate and the content of pasture, feedstuff, dung,egg, tissue (Breast muscle, Cardiac muscle,Spleen, Liver, Kidney,blood).their linear equation as follows:The linear equation between foliar Se rate and Se content of pasture was y=0.0912x+0.7021(R2=0.9915);The linear equation between foliar Se rate and Se content of feedstuff was y=0.0118x+0.2199(R2=0.9867); The linear equation between foliar Se rate and Se content of dung was y=0.0137x+0.6817(R2=0.9926);The linear equation between foliar Se rate and Se content of egg was y=0.0023x+0.1993(R2=0.9904);The linear equation between foliar Se rate and Se content of Breast muscle was y=0.0011x+0.0783(R2=0.9593);The linear equation between foliar Se rate and Se content of Cardiac muscle was y=0.0016x+0.2740(R2=0.9466);The linear equation between foliar Se rate and Se content of Liver was y=0.0045x+0.5966(R2=0.9673);The linear equation between foliar Se rate and Se content of Spleen was y=0.0019x+0.7068(R2=0.9868);The linear equation between foliar Se rate and Se content of Kidney was y=0.0038x+0.6957(R2=0.9803);The linear equation between foliar Se rate and Se content of blood was y=0.0002x+0.0424(R2=0.9603).4. For alfalfa, applying the moderate Se base fertilizer could significantly (P<0.05) improve the absorption of Se, and increase the content of total Se, inorganic Se and organic Se, and it was positively correlated with the application rate of Se; and it was also positive correlation among total Se, inorganic Se and organic Se of alfalfa;The absorption of Se showed the inverted "V" type of rise-fall, the highest peak was in the initial bloom stage, but the content of Se in alfalfa decreased as the development of alfalfa growth stage. The contribution rate of alfalfa leaf Se for the total forage Se was more than 60%. Se fertilizer application significantly increased (P<0.05) the conversion of alfalfa organic Se, the organic Se conversion of alfalfa fertilized with Se was 40%～50% on the whole;and the conversion of alfalfa organic Se was above 50% when applying 0.45kg Se hm"2 or more, however the organic Se conversion of alfalfa fertilized without Se was no more then 40%.the conversion of alfalfa organic Se showed the declining trend as the development of the alfalfa growth stage.However, the application rate of Se fertilizer was very low, the utilization rate of Se fertilizer reached highest peak when applying 0.45kg Se hm-2, but it was also less than 1.5%; and the utilization rate of Se fertilizer increased first and then decreased during the whole growth period, the highest utilization rate of Se fertilizer was in the initial bloom stage.5 it was very significantly (P<0.01)linear connection between Se rate and the content of pasture,their linear equation as follows:The linear equation between base Se rate and Se content of pasture in the seeding stage was y=1.9912x+0.1827(R2=0.9696); The linear equation between base Se rate and Se content of pasture in the branching stage was y=1.7394x+0.1724(R2=0.9670); The linear equation between base Se rate and Se content of pasture in the bud stage was y=1.5045x+0.1542(R2=0.9694); The linear equation between base Se rate and Se content of pasture in the initial bloom stage was y=1.2547x+0.1588(R2=0.9835); The linear equation between base Se rate and Se content of pasture in the flowering stage was y=1.0044x+0.1500(R2=0.9904).6. The content of available Se in soil was improved by applying Se base fertilizer, and there was a positive correlation between the content of available Se in soil and the base application level of Se fertilizer, and the available Se content in soil was increased high significantly at the applying of 1.05 kg hm-2, and the available Se content in soil showed the trend to decrease with the growing-time of alfalfa above the applying of 1.05 kg hm"2, and the decreasing amplitude from 24.75% to 40.84%, and the content of available Se in soil in the seeding and the branch stage was significantly higher than that of bloom stage.7. Spraying Se fertilizer on alfalfa leaves could improve the yield, and the yield of alfalfa increased first and then decreased with the addition of Se fertilizer, the best amount of Se was 100 mg kg-1, the alfalfa field significantly (P<0.05) improved by 1623 kg hm-2 compared with the alfalfa without Spraying Se fertilizer. Spraying Se fertilizer on alfalfa leaves correctly could also significantly (P<0.05) improve the content and accumulation of crude protein and crude fat, and the best amount of Se was 100 mg kg-1, compared with that of the control treatment, the content improved by 13.84% and 48.07% and the field increased by 320.84 kg hm-2 and 140.97 kg hm-2 respectively;and the content and accumulation of crude protein and crude fat of alfalfa both increased first and then decreased with the addition of Se fertilizer,However, it had no significant effect on the content of crude ash and NDF, and the field reached highest value when Se was 100 mg kg-1, and it was significantly (P<0.05) higher than that of control. Moreover, spraying Se fertilizer on alfalfa leaves had no significant (P<0.05) effect on the content and accumulation of ADF and HF.Spraying Se fertilizer on alfalfa leaves appropriately could promote the absorption of phosphorus, potassium, zinc, copper, manganese, boron and molybdenum. For phosphorus, potassium and zinc, the best amount of Se was 100 mg kg-1, and the best amount of Se was 70 mg kg-1 for copper, manganese, boron. However, spraying Se fertilizer on alfalfa leaves could not significantly (P<0.05) promote the absorption of calcium and iron. The communication of phosphorus, potassium, zinc, copper, manganese, boron, molybdenum and iron increased first and then decreased with the addition of Se. Spraying Se fertilizer on alfalfa leaves increased the manganese content of alfalfa significantly (P<0.05), but the effect on the calcium and iron content was not significant (P<0.05). Applying the moderate Se base fertilizer could increase phosphorus, potassium, molybdenum, boron, zinc and copper content significantly (P<0.05), while the boron content decreased significantly (P<0.05) if the Se fertilizer was excessive. Phosphorus, potassium, zinc, copper, manganese, boron and molybdenum content of alfalfa increased first and then decreased with the addition of Se.8. The dry matter of alfalfa was increased significantly (P<0.05) by the application of Se base fertilizer, and it showed a increased first and then decreased trend as the amount of Se base fertilizer increased, the dry matter of alfalfa was highest in the treatment of Se base application 0.45 kg hm-2.and the dry matter accumulation rate in branch period and pregnant bolls was also raised, and that at the primary flowing stage was decreased. Dry matter accumulation rate of alfalfa showed the "W" pattern of rise-fall-rise-fall during the whole growth stage, and the peak values were in the branch period and primary flowing stage.The stem-leaf ratio of alfalfa was significantly (P<0.05) increased by applying the proper Se base fertilizer, and it showed a increased first and then decreased trend as the amount of Se base fertilizer increased, and the stem-leaf ratio was highest in the treatment of Se base application 0.45 kg hm-2. The stem-leaf ratio of alfalfa showed inverted "V" pattern of rising first and falling then during the whole growth stage and the peak value was in the branch period. The plant moisture content of alfalfa was not affected significantly (P<0.05) by the application of Se base fertilizer. The plant moisture content of alfalfa showed the decreased trend during the whole growth stage. Before the branch period, the plant moisture content of alfalfa were more than 80%, and after that, it decreased to about 70%. Applying Se base fertilizer could promote the growth of alfalfa, and the height of plant showed a increased first and then decreased trend as the level of Se fertilizer base application increased, and the plant was tallest when the base application level of Se was 0.45 kg hm-2. The growth rate of alfalfa showed inverted "V" pattern of rising first and falling then during the whole growth stage and the growing peak occurred in the pregnant bolls. Applying base Se fertilizer had different effects on the growth rate of alfalfa at different stages. Se fertilizer base application could promote the growth rate from seedling stage to pregnant bolls, and the highest growth rate occurred in the treatment of Se 0.45 kg hm-2, while it could decrease the growth rate from pregnant bolls to bloom stage.9. The crude protein content of alfalfa, which increased first and turned down later with the increasing Se fertilizer base application, was improved significantly (P<0.05) by applying the moderate base Se fertilizer. The treatment of base applying Se 0.45 kg hm-2 had the highest crude protein content. The crude protein content of alfalfa showed the "N" type change of rise-fall-rise during the whole growth stage, which appeared rising trend from seedling period to branching stage, declined from branching stage to initial florescence and increased from primary flowing stage to bloom stage. The crude protein content of alfalfa was the highest value in the branching stage.The contribution rate to total crude protein content of pasture came from alfalfa leaves were all above 65%, which were more than stalk. And the contribution rate of alfalfa leaves crude protein showed the inverted "N" type of fall-rise-fall during the whole growth stage, which reached the highest value in seedling period, secondly in primary flowing stage and the smallest in the branching stage.10. Applying the moderate Se base fertilizer significantly increased (P<0.05) the content of crude fat, which increased first and then decreased with the addition of Se fertilizer. The treatment of base applying Se 0.45 kg hm"2 had the highest crude fat content. The crude fat content of alfalfa showed the inverted "V" type of rise-fall in the growth period. The growth period of the highest peak of content of crude fat of alfalfa was delayed by Applying Se base fertilizer; The content of crude fat reached highest peak in initial bloom stage for the alfalfa fertilized with Se, while the alfalfa fertilized without Se appeared in bud stage. And the contribution rate of alfalfa leaves crude fat for the total forage crude fat was more than 50%, higher than stem.11. The effects of Se application as base fertilizer on crude ash content were different during different growth period. Applying the moderate Se base fertilizer increased (P<0.05) the content of crude ash in initial bloom stage and florescence stage, but it did not affect that in seeding stage, branching stage and pregnant bolls stage significantly (P<0.05). The content of alfalfa crude ash increased first and then decreased with the addition of Se fertilizer, and the highest peak occurred in the treatment of base applying Se 0.45 kg hm-2. The content of alfalfa crude ash showed the inverted "N" type of rise-fall-rise during the whole growth period. From the seeding stage to branching stage the content of alfalfa crude ash increased slightly and decreased from branching to initial bloom stage then increased slightly after initial bloom stage. And the contribution rate of alfalfa leaf for total forage crude ash reached 55% or more, higher than that of stem. Applying the moderate Se base fertilizer significantly increased (P<0.05) the contribution rate of leaf crude ash in branching stage, but it had no significant effects on that in seedling stage, pregnant bolls stage, initial bloom stage and florescence stage.12. The effects of Se application as base fertilizer on the NDF, ADF and HF content of alfalfa were different during different growth period. Applying the moderate Se base fertilizer significantly decreased (P<0.05) the NDF content in pregnant bolls stage, but it had no significant (P<0.05) effect on that in the other growth stage. The content of NDF of alfalfa fertilized with Se decreased first and then increased with the addition of Se fertilizer, and the smallest content occurred in the treatment of base applying Se 0.45 kg hm-2.The leaf NDF for the contribution rate of total forage was related with the growth stage, during the seeding and branching stage, the contribution rate were above 50%, but it was 40%-50% during pregnant bolls stage, initial bloom stage and flowering stage. Applying the moderate Se base fertilizer significantly decreased (P<0.05) the ADF content of alfalfa, which showed decrease first and then increase. The ADF content of alfalfa reached the lowest peak in the treatment of applying Se 0.45 kg hm-2. The ADF content showed the "N" type of rise-fall-rise during the whole growth period. The ADF content was increased from the seeding to pregnant bolls stage, but decreased from the bud to initial bloom stage, and then increased after the initial bloom stage. The contribution rate of alfalfa leaf for total forage ADF was related with in the growth stage. In the seeding stage, the contribution rate was above 50% only applying Se 0.45 kg hm-2. Applying Se 0.25 kg hm-2, 0.35 kg hm-2 and 0.45 kg hm-2, the contribution rate was all above 50%. While it all below 50% after branching stage. Above all, the contribution rate of alfalfa leaf for total forage ADF was increased first and then decreased, and the highest peak appeared in the branching stage. Applying the moderate Se base fertilizer could significantly (P<0.05) increase the HF content in the branching and flowering stage, but it had no significant (P<0.05) effect that during other growth stage. Se fertilizer rate could not significantly (P<0.05) affect the alfalfa HF content; The contribution rate of alfalfa leaf for the total forage HF was related with the growth stage. In the seeding, branching and initial bloom stage, the contribution rate was above 50%. In pregnant bolls stage, the contribution rate was above 50% only applying 0.75 kg Se hm-2 or more. In the florescence stage, the contribution rate of the leaf HF of alfalfa fertilized with Se for the total forage HF was above 50%, but the blank was below 50%.13. Applying the moderate Se base fertilizer could significantly (P<0.05) increase the P and K contents. The P and K contents were increased first and then decreased, and it reached highest peak with the Se fertilizer application of 0.45 kg hm-2. The contribution rate of alfalfa leaf P and K for the total forage P and K was related with the growth stage. In the seeding and branching stage, the contribution rate of alfalfa leaf P for the total forage P was more than 60%, and it was above 50% after the branching stage. The contribution rate of alfalfa leaf P showed the decreased trend by and large as the development of the alfalfa growth stage. In the seeding stage, bud stage, initial bloom stage and flowering stage, the contribution rate of alfalfa leaf K for the total forage K was more than 50%, but it was above 60% in the branching stage, The contribution rate of alfalfa leaf K increased first and then decreased by and large as the development of the alfalfa growth stage.and the highest peak appeared in the branching stage.14. Addition of Se-rich forge in the basal diet could significantly (P<0.05) increase the egg laying rate of layer, daily egg yield and decrease feed-egg ratio. With the addition of the forge Se content increased, the egg layinrate of layer and daily egg yield increased first then decreased, but feed-egg ratio is inverse.15. Addition of Se-rich alfalfa(SA) in the basal diet could significantly(P<0.05) increase laying rate, daily egg yield(P<0.05)and decreased feed-egg ratio(P<0.05); Addition of Se-rich yeast(SY) could also significantly(P<0.05) increase laying rate. There was no significantly(P<0.05)effect with addition of common alfalfa (CA), sodium Se (SS) or Se yeast(SY). Addition of Se-rich alfalfa (SA) was superior to SY, but it was significantly superior to CA and SS.16. Addition of SS、SY and SA in the basal diet could very significantly (P<0.01) increase the Se content of layer eggs; The Se content of layer eggs supplemented with SA was very significantly (P<0.01) higher than that supplemented with SS, but it was very significantly (P<0.01) lower than that supplemented with SY. The Se content of layer eggs increased with test time passing. The order of conversion ratio about the three Se source was:SY>SA>SS, they were very significantly lower than control. SS, SY and SA all could increase the Se content of the layers breast muscle, myocardial, liver, spleen and kidney. The Se content of layers’breast muscle, myocardial, liver, spleen and kidney supplemented with SY were significantly (P<0.05) higher than that supplemented with SS and SA, but the Se content of layers’breast muscle supplemented with SA was very significantly (P<0.01) higher than that supplemented with SS. The Se content of myocardial and renal were very significantly (P<0.01) lower than that supplemented with SS. The Se content of spleen and liver had no significant (P>0.05) difference with that supplemented with SS. In conclusion, as a source of Se, SA is much safer than SY. The Se content of breast muscle had no significant difference between basal diet supplemented with SS and CA, but that supplemented with CA was significantly (P<0.05) higher than that of control.17. Addition of SS, SY and SA in the basal diet could increase the Se content of layer blood very significantly (P<0.01), compared with SA, addition of SS and SY in the basal diet could increase the Se content of layer blood very significantly (P<0.01). Se source could significantly affect the Se content of layer manure, it was very significantly (P<0.01) higher than control. The Se content of layer manure that basal diet was added with SA was not significantly higher than that added with SY, but it was significantly lower than that added with SA. In the condition of that were same amount of Se, the SY absorption capacity was higher than SA. But the SY and SA absorption capacity was significantly higher than SS. The organic Se absorption capacity of layers improved with test time passing, and it tended to stable 21 days later. SS, SY and SA all could increase the Se absorption rate of layers very significantly (P<0.01). The group added with SY was slightly superior to that added with SA, and the group added with SA was significantly superior to that added with SS.18. Above all, alfalfa, as the largest planting area of forage in Henan province, is sensitive to Se, while most areas of there are very poor in Se element. Therefore, it is the necessary agriculture measures to increase the alfalfa yield and Se content and improve the quality by applying Se fertilizer. And The effect of spaying Se fertilizer on alfalfa leaves is far prior to apply Se as base fertilizer.For Se source, for example, just considering the ability of Se concentration of layer, the ability of three Se source is yeast Se (SY)> Se-rich alfalfa (SA)> sodium Se (SS). Speaking of the production capacity and safety of layer, Se-rich alfalfa (SA) is prior to yeast Se (SY). Therefore, Se-rich alfalfa (SA) can serve as a kind of high quality Se source additives used in livestock production. We can use the linear equation between Se rate and the Se content of pasture, according to Se nutrition need of livestock, and produce the different Se content pasture,the low Se content pasture may directly feed, and the high Se content pasture may act as Se source additives;Compared with the results of the paper, we think that adding the 30 mg kg-1～100 mg kg-1 of SA in diet can be used the regular additives, which increased the productivity of layer and increased the content of egg Se and organization Se greatly. It will get a good economic benefit. While adding SA more than 100 mg kg-1, we can obtain high forage yield and develop and produce a human egg and patch of Se functionality, which will not only make a good economic benefit, but also bring a better social benefits.更多还原