维生素E对鹅反季节繁殖卵泡发育的调节作用及研究现状     

李思明  唐艳强  肖海红  郭小泽  陈彦良  刘文舒  欧阳玲花 《动物营养学报》2017,29(12):4245-4248

鹅的繁殖具有典型的季节特征,最终导致全年不均衡生产,使市场供需不足,价格波动较大。维生素E对家禽保持正常繁殖机能发挥重要作用。但关于维生素E对鹅产蛋基因、卵泡发育调控、生殖器官以及反季节繁殖卵泡发育过程中细胞凋亡基因Dicer和产蛋性能候选基因(CGLP)等表达影响的相关研究鲜见报道。本文就维生素E对调节种鹅反季节繁殖卵泡发育的研究现状及其展望作一综述。  相似文献   

Pathogenic Analysis of Two Strains of Porcine Reproductive and Respiratory Syndrome Virus     

LI Zhi  SUI Xiu-kun  WU Jing  XIN Ting  LI Ming  GAO Xin-tao  JIANG Yi-tong  HOU Shao-hua 《中国畜牧兽医》2017,44(5):1477-1483

Samples of sick pigs suspected of porcine reproductive and respiratory syndrome (PRRS) infection were collected from Hebei and Fujian provinces in China in 2016. Studies were carried out to investigate the variation characteristics of the isolated virus strains.The virus isolates were propagated in Marc-145 cells and caused syncytial cytopathic effect. RT-PCR and indirect fluorescent assay (IFA) results showed that the isolates were HP-PRRSV and hence designated as PRRSV CZ16A and NP16A, respectively. In order to study the pathogenicity of CZ16A and NP16A, the isolated strains were purified by plaque-isolation, and then inoculated to 60-days-old healthy pigs, which were negative in both of PRRSV infection and antibody. Clinical observation, histopathological changes and viremia detection were carried out to evaluate the pathogenicity of these two strains of PRRSV. Results showed that both isolates could replicate in pigs and cause a high body temperature, but these two strains of PRRSV isolates could not cause morbidity or mortality in experimental animals.Autopsy results also showed that NP16A could cause consolidation of the lung, lymph node enlargement in tested animals, suggesting that its virulence was a little stronger than CZ16A.  相似文献   

Long-term base cation mass balances for Swedish forests and the concept of sustainability     

Harald Sverdrup  Kaj Rosen 《Forest Ecology and Management》1998,110(1-3):221-236

Data from the Swedish Forest Inventory was used to calculate mass balances for base cations Ca, Mg and K for Swedish forests. Using lysimeter and forest survey soil analyses to estimate present base cation leaching from the root zone reveals that weathering plus base cation deposition is not sufficient to support both, the present base cation leaching rate and the present rate of uptake caused by stem growth. Calculations suggest that 96% of the productive forested area may have higher rates of removal than supply for one or more base cation. Under a best-case scenario, assuming less pollution, the present growth rate and 100% efficiency in uptake of available nutrients, the area with more removal than supply would still be at least 30% of the total area. Forest soils are being depleted at a rate where the exchangeable reservoirs have high risk of being severely depleted in the next few decades in central and southern Sweden. During 1983–1985 the depletion rate is calculated to be, on the average, 0.33 keq ha⁻¹ year⁻¹. The weathering rate and present base cation deposition can sustain growth at a level where (80–85)×10⁶m³ stemwood year⁻¹ can be harvested. Any harvested growth beyond this volume must be sustained by artificial means.

For whole-tree harvesting without base cation return, the calculations indicate that it would significantly increase the base saturation depletion rate to an average of 0.62 keq ha⁻¹ year⁻¹, and risk depletion of the soil in less than one-to-two rotation periods almost anywhere in Sweden.

The calculations stress the importance that sustainable forest management must include the management of nutrient fluxes and reservoirs.  相似文献   

植物群落镶嵌性分析与推论     

王俊杰  张继强 《甘肃林业科技》2014,(2):1-7

为了解释植被中植物群落的镶嵌性和群落与地形的对应性,在分析种子发芽出苗特性的基础引入植物种子引发概念,提出种子发芽策略概念,在分析总结植物生长发育繁衍特点的基础提出植物繁衍策略概念,综合提出条件竞争优势概念,以解释植物群落的镶嵌性  相似文献   

机插水稻的生育特性与栽培技术   总被引：1，自引：0，他引：1  

胡友发  熊多根  彭玲  刘芬  刘方义 《现代农业科学》2009,(1):55-56,58

阐述水稻机插优点及生育特性，并介绍了水稻机插大田栽培管理技术，以期指导大田生产。  相似文献   

克鲁兹王莲繁殖器官的解剖结构和开花结实习性的初步研究     

李爱华 《湖北林业科技》2013,(1):14-17,91

2006年笔者对克鲁兹王莲繁殖器官的解剖结构和开花结实习性进行了仔细观察。掌握了王莲的开花结实习性后,可用人工杂交的方法选育出王莲的杂交新品种。王莲属和同科的芡实属具有较密切的亲缘关系,能否用属间杂交的方法选育出王莲与芡实的杂交新品种,是一项值得试探的研究课题。  相似文献   

干旱胁迫对不同种源沙棘产量因子影响分析   总被引：2，自引：1，他引：1  

金争平  温秀凤  张吉科  顾玉凯  金书源 《国际沙棘研究与开发》2008,6(2):33-38

为了探讨、揭示干旱胁迫对沙棘生育与产量形成因子间的关系。本文采用田间调查与室内实验分析相结合。结果表明沙棘单株生育与产量关系受干旱胁迫影响最大,造成植株生长势衰弱与减产。沙棘产量的形成,决定于植株生长势、水分利用效率、根系贮水能力、果枝数、座果率。  相似文献   

新疆高致病性猪蓝耳病病毒分离与鉴定   总被引：1，自引：0，他引：1  

简子健  盛卓君  苏贵成  马素贞  王晓萍  胡峻  王薇  马晓艳  冉多良 《新疆农业科学》2008,45(6):1172

从新疆发病仔猪的肺脏和淋巴结内体内分离到1株PRRSV病毒.该病毒能直接在Marc-145细胞上生长,继代培养72 h后产生细胞病变(CPE).经特异性荧光抗体和ELISA检测均为阳性,RT-PCR方法能扩增出该病毒的400 bp的特异性片段.从该病的流行病学、临床症状、病理学、病原的生物学特征来看,该分离株为猪繁殖与呼吸综合症病毒的变异株.这一结果提示PRRSV毒株变异是引起新疆地区猪场母猪、仔猪大量发病死亡的重要原因,必须引起各级兽医部门和猪场的高度重视.  相似文献   

广西PRRSV、PCV、CSF的混合感染及PRRSV分子病原学研究   总被引：1，自引：0，他引：1  

谢丽基  谢芝勋  庞耀珊  刘加波  邓显文  谢志勤  董建宝 《西南农业学报》2008,21(5)

为了弄清2007年发生于广西一些县市猪场的高致病性猪繁殖与呼吸综合征和其他疾病的混合感染情况,从广西7个县市发生高致病性猪繁殖与呼吸综合征的猪场采集病料,进行猪繁殖与呼吸综合征病毒(PRRSV)、猪圆环病毒(PCV)及猪瘟病毒(CSF)检测,并对检测的PRRSV进行分子病原学分析。结果显示,经PCR检测,86份样品中有60份为PRRSV阳性,36份为PCV阳性,2份为CSF阳性,说明发生于广西猪群的PRRSV与PCV共感染情况比较严重。通过PRRSVORF5基因序列比较分析发现,来自广西7个县市不同猪场的PRRSV高度同源,核苷酸序列同源性为98.5%~99.8%,推导编码的氨基酸序列同源性为98.0%~100.0%;与VR2332和LV株的核苷酸序列同源性分别为88.7%~89.7%和62.2%~63.1%,氨基酸序列同源性分别为88.6%~89.6%和60.5%~61.3%,表明7个县市不同毒株的ORF5基因区域变异不大,均属美洲型。  相似文献   

黑线姬鼠不同体重种群繁殖力变化     

杨再学  郑元利  郭永旺  金星  刘晋 《勤云标准版测试》2008,(9)

对贵州省余庆县1987～2007年2563只黑线姬鼠体重统计分析,结果表明:黑线姬鼠体重最低5.36g,最高53.41g,平均体重为26.31±8.14g,其个体体重主要分布在15.01～35.00g之间.占总鼠数的79.01%,是活动能力较强的个体.黑线姬鼠怀孕鼠最低体重为17.61g,睾丸下降鼠最低体重为16.50g,体重达16.0g以上时开始繁殖,随着体重的增加,种群繁殖力不断增加,体重达24.0g以上时,种群繁殖力迅速增加,怀孕率、睾丸下降率分别达31.82%、67.02%,接近雌鼠总怀孕率30.06%和雄鼠总睾丸下降率52.67%,繁殖指数达0.7138,亦接近总繁殖指数0.7599.黑线姬鼠不同年龄组种群繁殖力存在显著差异,随着种群年龄的增长,雌鼠怀孕率、胎仔数、雄鼠睾丸下降率、繁殖指数不断增加,成年Ⅰ组、成年Ⅱ组、老年组是黑线姬鼠种群的繁殖群体,因此,它们在种群中所占比例的多少与种群数量消长关系密切,可以作为预测黑线姬鼠种群数量的重要依据.  相似文献