日粮因素导致奶牛乳脂率下降的生物学机制

乳脂是受日粮因素影响最大的一种乳成分，且多数情况下容易发生乳脂率下降。最近十几年来对日粮因素导致奶牛乳脂率下降的机理研究表明，造成乳脂率下降的原因是由于日粮因素改变了瘤胃微生物的发酵参数，尤其是瘤胃pH值，使瘤胃微生物对日粮中的多不饱和脂肪酸(PUFA)的生物氢化作用不完全，造成微生物生物氢化作用的中间产物共轭亚油酸(CLA)和反式十八碳烯酸(TFA)在瘤胃中蓄积。它们可以抑制动物体内脂肪酸的从头合成途径，乳脂中短链脂肪酸的比例减少，而CLA和TEA的比例相对升高，导致奶牛的乳脂率降低。因此，奶牛日粮中保证足够数量的有效纤维以维持瘤胃正常发酵，可有效限制作为CLA和TEA丰富来源的多不饱和脂肪酸的数量，对维持正常的乳脂率非常重要。     

新疆北疆地区临床型乳房炎病原细菌的分离鉴定

旨在调查新疆北疆地区奶牛乳房炎高发季节细菌性乳房炎病原菌种类,为该病的药物防治及免疫学防治提供科学依据。选择新疆北疆14个规模化牛场共采集623份临床型乳房炎奶样进行了细菌分离鉴定,结果显示,分离得到468株细菌,其中兼性厌氧革兰氏阴性杆菌占25．2％;链球菌占22．6％;葡萄球菌和微球菌52．2％。     

奶牛金黄色葡萄球菌乳腺炎小鼠模型的建立

目的利用从临床乳腺炎奶牛乳样中分离纯化的金黄色葡萄球菌（S.aureus）感染小鼠乳腺,建立奶牛金黄色葡萄球菌乳腺炎小鼠模型。方法将产后8～10 d的ICR远交系母鼠随机分为3组,包括无菌生理盐水对照组,低剂量攻菌组（含金黄色葡萄球菌2×102CFU）和高剂量攻菌组（含金黄色葡萄球菌5×106CFU）。以小鼠第4对乳腺为攻菌部位,用非损伤方法经乳头管注入生理盐水或金黄色葡萄球菌。攻菌24h后采集乳汁进行白细胞计数;从眼球采血,进行血常规检测和流式细胞计数;之后处死母鼠,取乳腺组织进行匀浆细菌计数,并做乳腺组织切片。结果高剂量攻菌组不论是体温、组织学观察,还是乳汁白细胞计数、乳腺匀浆细菌计数、血常规指标和流式细胞计数,都和对照组有显著或极显著差异（P〈0.05）;而低剂量攻菌组与对照组相比,除血液CD4＋/CD8＋比值差异显著外（P〈0.05）,其余指标差异均不显著。结论金黄色葡萄球菌浓度为5×106CFU、攻菌时间24 h时,成功建立了远交系小鼠金黄色葡萄球菌乳腺炎模型,而2×102CFU细菌浓度则不适于远交系小鼠乳腺炎模型的建立。     

基于激光三维成像自动判定奶牛体况技术研究

当前奶牛体况判断多是人工进行,较为落后,耗费大量的人力以及时间,导致判断误差较大,结果不可靠。为此,提出基于激光三维成像自动判定奶牛体况技术。首先对摄像机进行标定,再利用标定后的摄像机激光三维扫描奶牛体况,得到奶牛三维非刚性坐标。奶牛大部分体况可转换成两点之间的距离或三点之间夹角的测量;在此基础上,对奶牛体型性状指标进行判断,以达到自动判定奶牛体况的目的。实验结果表明,采用所提方法对奶牛体型性状指标进行判断,操作简单易行,判断误差较低,结果较为可靠。     

奶牛的E-玫瑰花环试验

应用E-玫瑰花环试验检测奶(犊)牛的细胞免疫状况，12头小犊牛的E-玫瑰花环率平均为25％，9头大牛的E-玫瑰花环率平均为35．8％：白细胞分类计数结果为12头小犊牛淋巴细胞百分比为74．1％，9头大牛的为70．2％，所检出的各项指标均在正常范围内，随着时间的推移，成年奶牛的细胞免疫功能强于小犊牛．     

"Protein-only" or "virino" in prion diseases?

60-year prion and scrapie research has led to a dilemma in understanding the unknown aetiology of the infectious neurodegenerative disorders with intriguing features. Current progress and dilemma in prion research are briefly but critically reviewed. Instead of providing a comprehensive coverage of the research history, attentions in this view are drawn toward both the major breakthrough in the advancement of protein-only hypothesis, and the puzzle why this hypothesis has not been fully accepted. In order to resolve the prion enigma in neuroscience, it is suggested that both technical and concept barriers remain to be crossed. Since prion research is a multi-interdisciplinary subject, this view is intended to both facilitate a better understanding of prion phenomenon by more scientists in natural science, and invite scientists outside the fields of molecular genetics and protein science for collaboration.     

"Protein-only" or "virino" in prion diseases?

60-year prion and scrapie research has led to a dilemma in understanding the unknown aetiology of the infectious neurodegenerative disorders with intriguing features. Current progress and dilemma in prion research are briefly but critically reviewed. Instead of providing a comprehensive coverage of the research history, attentions in this view are drawn toward both the major breakthrough in the advancement of protein-only hypothesis, and the puzzle why this hypothesis has not been fully accepted. In order to resolve the prion enigma in neuroscience, it is suggested that both technical and concept barriers remain to be crossed. Since prion research is a multi-interdisciplinary subject, this view is intended to both facilitate a better understanding of prion phenomenon by more scientists in natural science, and invite scientists outside the fields of molecular genetics and protein science for collaboration.     

Characterization of ovarian follicular fluids of sheep,pigs and cows using proton nuclear magnetic resonance spectroscopy

Summary Proton NMR spectra were produced for Graafian follicular fluids obtained by aspiration from sheep, pig and cow ovaries. The following low molecular mass, non-protein-bound metabolites were detected at concentrations exceeding 0.1 mM: acetate, alanine, creatinine/creatine, glycine, D-3-hydroxybutyrate, lactate, valine. Glucose was difficult to quantify and N-acetyl sugars gave a broad resonance at 2.06 ppm, presumably representing side-chains of glycoproteins. Ethanol was detected at up to millimolar concentrations in some specimens, though the physiological significance of this finding was not clear. The concentrations of all metabolites were comparable to those of plasma. These results have therefore shown that NMR spectroscopy is useful for gaining a broad and semiquantitative impression of the more abundant metabolites in the fluids of preovulatory Graafian follicles.     

炭基微生物菌剂促进牛粪好氧堆肥腐熟过程研究

为评估炭基微生物菌剂促进牛粪好氧堆肥的腐熟效果,以牛粪为原料加入自制炭基微生物菌剂进行为期34 d的堆肥试验,并以纯牛粪为空白对照,研究堆肥过程中理化指标和微生物群落的变化。结果表明,添加炭基微生物菌剂后,1 d内可使堆温达到53 ℃,堆体最高温度为71.7 ℃,较对照组最高温度高出4.6 ℃,且高温期延长3 d。至堆肥结束时,处理组和对照组的含水率、E₄/E₆,GI分别为29%和33%,1.5和1.9,145.5%和127.6%。通过相关性分析得出,累计温度、含水率、pH值等理化指标相关性数值增大为67%,与细菌门水平间相关性数值增加了56%。添加0.1%(w/w)的炭基微生物菌剂可加快腐熟过程,提高微生物多样性,加快微生物群落的演替和对物料的分解代谢,促进腐熟进程,为炭基微生物菌剂在好氧堆肥中的应用提供了理论依据。     

玉米秸秆厌氧生物发酵制氢的特性研究

以玉米秸秆作为发酵底物,牛粪堆肥作为菌种来源,进行了30 L规模生物发酵制氢的特性研究.主要对底物发酵过程产氢途径进行分析,由液相末端发酵产物确定发酵类型.通过检测实验过程中发酵液的成分,分析了产氢的影响因素,并提出了持续稳定产氢的适宜方法.实验结果显示,玉米秸秆厌氧发酵制氢为丁酸型发酵,产氢反应过程中产氢量与微生物的生长特性紧密相关.