铜缺乏对奶牛肝脏金属硫蛋白代谢的影响

为阐明金属硫蛋白在铜缺乏奶牛肝脏中的代谢特征 ,选择铜缺乏区有明显临床症状的奶牛 6头 ,采集肝脏样品后用差速离心法分离肝脏金属硫蛋白 ,以Sephadex G75进行层析纯化 ,测定各部分洗脱液中金属元素铜、锌、铁、镁的含量。将 6头健康奶牛的肝脏样品作为对照。试验结果表明 ,发病奶牛肝细胞浆Sephadex G75柱层析洗脱液中铜、铁含量峰值显著高于健康奶牛 ,且在后面部分层析液中出现小峰 ;发病奶牛肝细胞浆金属硫蛋白 (MT)层析液锌、镁含量曲线峰值宽阔且高于对照组 ,第 2峰形宽大且有前移现象。结论 :铜缺乏能够改变奶牛肝脏中金属硫蛋白的代谢     

中国牧草种子国际贸易格局研究及启示

为抓住机遇快速发展中国牧草种子产业,本研究首先从国际贸易商品结构及地理分布等角度分析了中国牧草种子贸易现状,其次,探讨了中国牧草种子贸易的特点,在此基础上总结出中国牧草种子贸易的未来趋势及启示。结果显示,中国牧草种子需求量将会进一步增加、牧草种子进口量短期内将会继续保持高位,但主要牧草品种终将依赖国内市场解决供应;而当前紧迫的任务则是推动进口草种制度规范化建设、积极推进中国牧草种子专业化生产及实施科技兴草战略。     

凝结芽胞杆菌的生物学功能及其在畜禽生产中的应用研究进展

凝结芽胞杆菌兼具乳酸菌和芽胞杆菌双重生物学功能,因具有良好的耐胃酸、耐胆盐、耐高温和耐储存等性能而受到广泛关注。就凝结芽胞杆菌的生物学功能及其在畜禽生产中的应用进行了综述,以期为凝结芽胞杆菌在畜禽生产中的应用研究提供参考。     

Cloned calves derived from somatic cell nuclear transfer embryos cultured in chemically defined medium or modified synthetic oviduct fluid

Somatic cell nuclear transfer (SCNT) is considered to be a critical tool for propagating valuable animals. To determine the productivity calves resulting from embryos derived with different culture media, enucleated oocytes matured in vitro were reconstructed with fetal fibroblasts, fused, and activated. The cloned embryos were cultured in modified synthetic oviduct fluid (mSOF) or a chemically defined medium (CDM) and developmental competence was monitored. After 7 days of culturing, the blastocysts were transferred into the uterine horn of estrus-synchronized recipients. SCNT embryos that were cultured in mSOF or CDM developed to the blastocysts stages at similar rates (26.6% vs. 22.5%, respectively). A total of 67 preimplantational stage embryos were transferred into 34 recipients and six cloned calves were born by caesarean section, or assisted or natural delivery. Survival of transferred blastocysts to live cloned calves in the mSOF and the CDM was 18.5% (to recipients), 9.6% (to blastocysts) and 42.9% (to recipients), 20.0% (to blastocysts), respectively. DNA analysis showed that all cloned calves were genetically identical to the donor cells. These results demonstrate that SCNT embryos cultured in CDM showed higher viability as judged by survival of the calves that came to term compared to blastocysts derived from mSOF cultures.     

蓝舌病病毒衣壳蛋白VP2、VP5、VP7酵母双杂交诱饵质粒的构建及鉴定

蓝舌病病毒(bluetongue virus,BTV)的结构主要由3层衣壳蛋白组成,其中VP2、VP5蛋白构成了BTV的外层衣壳,VP7蛋白构成了BTV的中间衣壳,最内层衣壳则由VP3蛋白构成。VP2、VP5及VP7蛋白在BTV侵染宿主细胞的过程中起着非常重要的作用。为了研究BTV与宿主细胞相互作用的分子机制,本研究将BTV的VP 2、VP 5、VP 7基因分别克隆到pGBKT7载体中,成功构建了pGBKT7-VP2、pGBKT7-VP5与pGBKT7-VP73个诱饵质粒,且通过自激活和毒性验证,证明所构建的3个质粒均无自激活作用,对酵母细胞无毒性作用。本研究为今后利用酵母双杂交筛选VP2、VP5、VP7蛋白中与宿主细胞相互作用的蛋白做好了铺垫,为深入研究BTV与宿主细胞的相互作用奠定了基础。     

槟榔江水牛OXCT1基因的分子特征及组织表达谱分析

本研究对槟榔江水牛3-酮酸辅酶A转移酶1（3-oxoacid CoA-transferase 1,OXCT1）基因的完整CDS区进行了PCR扩增,并对其功能生物信息学和多组织差异表达进行了分析。以普通牛OXCT1基因序列（GenBank登录号：XM_006076397）为参考序列,采用Primer Premier 5.0软件设计引物序列,以提取的槟榔江水牛基因组DNA为模板,PCR扩增获得槟榔江水牛OXCT1基因mRNA序列,扩增产物经测序后利用ORF Finder软件进行开放阅读框识别,获得水牛OXCT1基因CDS区全序列,并对其进行生物信息学分析。结果显示,槟榔江水牛OXCT1基因CDS序列全长1 563 bp,编码520个氨基酸,蛋白分子式为C₂₅₀₉H₄₀₄₁N₆₈₇O₇₄₆S₂₃,分子质量为56.50 ku,理论等电点（pI）为8.69,不稳定系数为27.49,平均疏水性（GRAVY）为-0.097,该蛋白属弱亲水性蛋白。OXCT1蛋白无信号肽和跨膜结构,属于线粒体膜蛋白;包含pcaJ_scoB_fam和AtoD 2个保守结构域,且具有5个功能活性位点。槟榔江水牛与普通牛、藏羚羊等5个物种的OXCT1氨基酸序列同源性≥ 97%。对槟榔江水牛13个组织进行表达谱分析表明,在泌乳期,OXCT1基因在乳腺中表达量最高,在肾脏、垂体、脂肪、大脑、皮肤和肌肉中不表达;在非泌乳期,OXCT1基因在除脂肪以外的其他12个组织中都有表达。OXCT1基因在槟榔江水牛泌乳期乳腺组织中表达量最高,推测其可能参与了水牛的乳脂合成调控事件。本研究结果可为深入了解乳脂合成代谢及其调控机制提供依据。     

不同日粮类型和粗蛋白质水平对四川山地乌骨鸡生产性能和屠宰性能的影响

试验旨在研究不同日粮类型和粗蛋白质水平对四川山地乌骨鸡生产性能和屠宰性能的影响。采用2×2因子设计,设2种日粮类型(玉米—豆粕型和玉米—豆粕—酵母蛋白型)和2个粗蛋白质水平(16.5%和14.5%)。选用23周龄的四川山地乌骨鸡480只,设4个处理,每个处理4个重复,每个重复30只鸡。预试期14 d,正试期120 d。结果表明,日粮类型对四川山地乌骨鸡的生产性能无显著影响(P>0.05),日粮16.5%粗蛋白质水平组平均蛋重显著高于14.5%粗蛋白质水平组(P<0.05)。日粮类型与粗蛋白质水平互作可显著影响平均蛋重(P<0.05),但对产蛋率、日产蛋量、日采食量和料蛋比均无显著影响(P>0.05)。日粮类型、粗蛋白质水平及日粮类型与粗蛋白质水平互作对四川山地乌骨鸡的屠宰性能均无显著影响(P>0.05),其中玉米—豆粕—酵母蛋白型(粗蛋白质16.5%)日粮组屠宰率、全净膛率、半净膛率、胸肌率和腿肌率最佳。结果提示,四川山地乌骨鸡的平均蛋重受日粮粗蛋白质水平影响较大;饲喂粗蛋白质水平为16.5%的玉米—豆粕—酵母蛋白型日粮可获得较好的生产性能和屠宰性能。     

Expression kinetics of chicken β2-microglobulin and Class I MHC in vitro and in vivo during Marek’s disease viral infections

Marek’s disease virus (MDV) is a highly cell-associated herpesvirus that causes a disease in chickens characterized by tumor formation and immunosuppression. The changes of major histocompatibility complex (MHC) expression in different MDV-infected cells are not completely understood. In this study, we investigated the expression of the Class I MHC and β2-microglobulin (β2m) genes in response to MDV infection at different time points by real-time PCR. In both in vitro and in vivo, the expression levels of Class I MHC and β2m genes were upregulated during early MDV infections in comparison to control cells; We also found that the expression of Class I MHC gene was downregulated in BudR (5-bromo-2′-deoxyuridine)-treated MSB1 cells at 48 h and MDV-infected chicken embryo fibroblast cells (CEF) at 120 and 168 h post infection (hpi); Furthermore, compared to control groups, Class I MHC and β2m expression levels were downregulated in peripheral blood lymphocytes (PBLC) from MDV-infected chickens at 14 and 28 days post infection (dpi); Interestingly, both Class I MHC and β2m gene expression levels increased again in PBLC from MDV RB1B-infected chickens at 35 dpi, in which MDV was in the latent or transformed infection stages. In addition, Class I MHC expression was clearly decreased in MDV-infected CEF at 120 hpi although β2m expression was significantly increased. These changes in Class I MHC and β2m gene expression might provide more insights into host-virus interaction.     

晾晒时间对初花期紫花苜蓿青贮发酵品质的影响

本试验旨在研究不同晾晒时间对3个品种紫花苜蓿（Medicago sativa）初花期青贮发酵品质的影响。在刈割后经2、4和6 h晾晒的紫花苜蓿青贮原料中加入青贮添加剂进行裹包青贮180 d,然后通过现场感官评定和实验室分析评价紫花苜蓿青贮的发酵品质。结果表明,晾晒4~6 h可以提高3个品种的紫花苜蓿的青贮发酵品质;晾晒6 h与2 h相比丁酸、氨态氮含量显著降低（P<0.01）,可溶性糖的含量极显著增加（P<0.01）;粗蛋白含量在晾晒4 h时能很好地保存（P<0.01）;加入添加剂可显著降低青贮饲料中的中性洗涤纤维和酸性洗涤纤维含量（P<0.01）。3个品种的紫花苜蓿均在晾晒4~6 h时青贮效果最好。     

鸡黄病毒灭活疫苗的研制及免疫效果研究

鸡黄病毒FQ—C1株经SPF鸡胚连续传40代后,检测其尿囊液毒的ELD50达到1×10^-4.33／0．1mL。将该病毒第40代SPF鸡胚液毒灭活后制备成油乳剂灭活疫苗。SPF雏鸡和蛋鸡安全性试验表明,该疫苗的安全性好,无不良影响。以该疫苗一次单剂量（1mI／只）免疫开产蛋鸡,28d后攻以鸡黄病毒强毒测定疫苗的保护效果,结果显示疫苗免疫组较未免疫组蛋鸡的产蛋率高出75．8％,产蛋保护率达93．2％以上。试验表明,本研究制备的鸡黄病毒灭活疫苗安全性好,且具有良好的免疫原性,免疫后可有效抵抗鸡黄病毒所致的产蛋骤降。