活性氧自由基对动物健康及饲料质量的影响

本文简单介绍了活性氧(ROS)的定义和劬物体内活性氧的来源,并进一步从机理上探讨了ROS造成的饲料脂质过氧化的原因及其危害,重点阐述了ROS对畜禽健康、生产性能和肉质的影响,同时也指出了机体自身产生的适量的ROS的一些生理意义。     

Cryopreservation of gander semen

1. The effect of dimethylacetamide (DMA) and dimethyl sulphoxide (DMSO) on the cryopreservation of gander semen were investigated. An improved survival rate of spermatozoa after freeze-thawing was obtained when semen was frozen by a fast-freezing procedure on dry ice with 9% DMA as the cryoprotectant. 2. Gander semen, which was frozen during mid season, was tested for fertilising ability in different times of the season. The percentage of fertility during d 3 to d 9 after 2 consecutive inseminations was 68% to 95%, depending on the date of artificial insemination.     

绿壳蛋鸡与兴义矮脚鸡杂交性能的研究分析

摘要：把试验鸡群分为4组：A组为绿壳蛋鸡;B组为兴义矮脚鸡：C组为绿壳蛋鸡（♂）×兴义矮脚鸡（♀）;D组为兴义矮脚鸡（♂）×绿壳蛋鸡（♀）。本试验拟对绿壳蛋鸡、兴义矮脚鸡亲本及其正反交后代的生长性能,0、2、4、6、8、10、12周龄料肉比,以及产蛋性能进行观察与比较。探索两者间的杂交性能,达到改善绿壳蛋鸡早期生长性能和产蛋性能的目的。试验结果表明：4组鸡的体重、胸宽、胸深、体斜长、胸角的差异极显著（P〈0．01）,胫长、胫围、胸骨长差异显著（P〈0．05）。D组的饲料报酬略高于C组（D组早期增重较C组快）。A组饲料报酬最低,B组次之。4组鸡的受精率、孵化率差异极显著（P〈0．01）,蛋重、蛋形指数差异显著（P〈0．05）。利用绿壳蛋鸡和兴义矮脚鸡杂交出来的后代在生长性能和产蛋性能方面都有较好优势,可以充分利用它们各自的优势。进行更深层次研究,满足市场对禽肉及蛋的需求。     

A Droplet Digital PCR Method for Detection of Newcastle Disease Virus

This experiment was conducted to establish a droplet digital PCR (ddPCR) method for the detection of Newcastle disease virus (NDV). A ddPCR method was developed, which the primers and probes were designed based on the conservative regions of F gene of NDV. The concentration of primer and probe, the annealing temperature in ddPCR reaction were optimized. The sensitivity, specificity and reproducibility of ddPCR method were evaluated. In results, the optimal primer concentration and the probe concentration were 900 and 250 nmol·L^-1, the optimum annealing temperature was 55℃. The detection limit of ddPCR method was 1.8 copies·μL^-1 with a good linear response, it had no cross reaction with other six viruses (include IBV), the coefficient of variation of sample repetition was 2.4%. All the results showed that NDV ddPCR was sensitive and specific, it was suitable for quantitative detection of clinical samples infected with NDV.     

Population changes in Phytophthora infestans in Taiwan associated with the appearance of resistance to metalaxyl

In recent years, late blight, caused by Phytophthora infestans (Mont) De Bary, has increased in severity in many parts of the world, and this has been associated with migrations which have introduced new, arguably more aggressive, populations of the pathogen. In Taiwan, late blight has been endemic on outdoor tomato crops grown in the highlands since the early 1900s, but recent epidemics have been more damaging. To ascertain the present status of the Taiwanese population of P infestans, 139 isolates of the pathogen collected and maintained by the Asian Vegetable Research and Development Center (AVRDC) were characterized using mating type, metalaxyl sensitivity, allozyme genotype, mitochondrial haplotype and RFLP fingerprinting. Up to 1997, all isolates were found to belong to the old clonal lineage of P infestans (US-1 and variants), but in isolates from 1998 a new genotype appeared, and by 2000 this had apparently completely displaced the old population. This new genotype was an A1 mating type and has the dilocus allozyme genotype 100/100/111, 100/100 for the loci coding for glucose-6-phosphate isomerase and peptidase, respectively. These characters, together with RG57 fingerprinting, indicated that these isolates belonged to the US-11 clonal lineage, a minority (11%) being a previously unreported variant of US-11. Whereas metalaxyl-resistant isolates were not detected in the old population, 96% of the new genotypes proved resistant, with the remainder being intermediate in sensitivity. It may be inferred from this sudden, marked change in the characteristics of the Taiwanese P infestans that a new population of the pathogen was introduced around 1997-98 and that this may well have already been metalaxyl-resistant when it arrived, although a role for in situ selection cannot be excluded.     

基于MaxEnt模型的检疫性害虫小蔗螟在中国的潜在分布预测

小蔗螟是重要的检疫性害虫,许多国家将其列入检疫性害虫名录,主要危害甘蔗、玉米等作物。本研究基于小蔗螟分布记录,结合环境数据,采用MaxEnt软件对其在中国潜在分布区进行预测。结果表明：小蔗螟在我国的高度和中度适生区主要分布在海南、云南、广东、广西及福建等。影响小蔗螟分布的最主要环境变量是最暖季平均降雨量和温度变化方差。阐明小蔗螟在我国潜在地理分布及限制其分布的环境变量,可为我国的检疫工作提供理论依据。     

检测南方水稻黑条矮缩病毒胶体金免疫试纸条的建立

由白背飞虱Sogatella furcifera(Horváth)传播的南方水稻黑条矮缩病毒(Southern rice blackstreaked dwarf virus,SRBSDV)是目前我国南方水稻上危害最严重的病毒,为开发简便、快速、准确的SRBSDV病毒检测技术和检测试剂,以感染SRBSDV的植物粗提液为免疫原,利用杂交瘤技术制备了2株抗SRBSDV的单抗(14A8和15G6),并利用制备的单抗建立了可快速、特异、灵敏地检测SRBSDV的胶体金免疫试纸条。结果表明,2株制备单抗的抗体类型及亚类均为Ig G1、kappa链,单抗腹水的间接ELISA效价均达到10~(-7);Western blot分析表明,2株单抗均与SRBSDV的外壳蛋白亚基有特异反应,而不与水稻黑条矮缩病毒(Rice black-streaked dwarf virus,RBSDV)反应。以制备14A8和15G6单抗分别为捕获抗体和胶体金标记抗体,开发成能在5 min内准确、特异地检测水稻植物和白背飞虱传毒介体体内SRBSDV的胶体金免疫试纸条;灵敏度分析表明,该检测试纸条的检测水稻病叶的灵敏度达到1∶6 400倍(g/m L),检测单头携毒白背飞虱的灵敏度达到1∶51 200倍(单头/μL)。田间样品检测结果表明,该试纸条的检测结果与RT-PCR的符合率达到100%。建立的SRBSDV胶体金免疫试纸条可对南方水稻黑条矮缩病毒进行快速、特异、灵敏的诊断和检测。     

辛硫磷混剂毒性联合作用

本研究以Ｈａｒｒｉｓ法对辛硫磷与甲基对硫磷、灭多威以及３种拟除虫菊酯以等毒剂量混配时对大鼠急性经口毒性联合作用的性质进行了评价。结果表明,辛硫磷与甲基对硫磷混配为拮抗作用;与灭多威混本为相加作用;辛硫磷与溴氰菊酯或高效氯氰菊酯混配时毒性分别增加４￣６倍多,呈协同作用;与氰戊菊酯混配虽属相加作用但毒性有较大增加,为预期毒性的１．５倍。本研究表明辛硫磷与有机磷或氨基甲酸酯混配可出现相加或拮抗作用,而与     

浙闽樱桃地理分布模拟及气候限制因子分析

预测不同气候情景下篦子三尖杉(Cephalotaxus oliveri Mast.)的地理分布格局,为其资源保护、合理利用与开发提供指导,也为其起源与地理演化研究奠定基础。

基于100个分布点信息与19个气候因子,采用BIOCLIM模型构建当前(1970—2000年)以及未来(CO₂浓度倍增) 篦子三尖杉的地理分布趋势,并采用主成分分析法分析影响其地理分布的主要气候因素。

篦子三尖杉在中亚热带地区以低海拔分布为主。BIOCLIM模型结果显示：在当前气候条件下,篦子三尖杉最佳适生区集中在湖南、湖北、贵州和重庆;未来气候变化情境(CCM3)下,其潜在分布面积将减小,并有向西迁移的趋势;该模型受试者工作特征曲线下的面积为0.911±0.023,预测精度较高。主成分分析结果表明：温度季节性、气温年较差和昼夜温差与年温差比值是限制篦子三尖杉地理分布的主要因素,且温度因子的作用大于水分因子。

随着全球气候变暖,篦子三尖杉的适生区有破碎化及丧失的风险,应重视对该物种的动态监测及迁地保护。

     

基于去趋势分析的中国温带旱柳开花始期对气候变暖的响应

为了更准确地揭示植物在物候水平上对气温变化的响应与适应机制,在去气温和物候时间序列趋势的基础上,建立日尺度的气温?物候回归模型,分析中国温带地区40个站点1986-2011年旱柳开花始期对气温变化的响应与适应机理。结果表明：中国温带地区77.5%的站点旱柳开花始期呈提前趋势,相应的敏感时段春季气温则呈上升趋势（0.8±0.5℃·10a-1）。其中,75%的站点物候期或气温时间序列存在显著变化趋势。进行去趋势处理后,17.5%的站点相关性发生变化,去趋势前其相关性较低,去趋势后,表现为显著负相关;模拟的均方根误差（RMSE）从去趋势前的5.5d降至去趋势后的4.9d,说明去趋势方法能提高气温-物候响应关系诊断的精确度。基于去时间序列线性趋势的气温－物候回归模型,得到92.5%的站点旱柳开花期与敏感时段春季气温呈显著负相关关系,即随着气温的升高,旱柳开花期呈提前趋势,其线性响应速率为-2.5±2.1d·℃-1。