玉米发芽过程中酶系最适条件的确定

[目的]系统研究玉米在发芽过程中的3种酶活力的变化,确定玉米最佳发芽条件。[方法]以玉米为原料,通过正交试验,研究发芽温度、发芽时间和含水率对玉米发芽过程中酶活力的影响,在确定最佳发芽条件下比较各种酶活力的变化趋势。[结果]正交试验表明,玉米最佳发芽条件为:发芽温度25℃,发芽时间6 d,含水率46.1%。玉米α-淀粉酶活力主要在发芽阶段形成,发芽促进了α-淀粉酶活力的快速增长直至达最高值;-β淀粉酶活力随发芽进行缓慢增加至最大值;纤维素酶活力也随着发芽进行缓慢增加至最大值。[结论]-α淀粉酶、-β淀粉酶和纤维素酶酶活力都呈现随着时间的变化先增大后减小的趋势,最大值均出现在第5天前后。     

木薯后期衰老对淀粉积累的影响

对新选056、南洋红、GR891、辐选01、华南124和新选048六个木薯品种生育后期抗衰老生理和淀粉积累特性进行研究。结果表明:不同木薯品种生育后期抗衰老生理与淀粉积累特性有明显差异,木薯后期茎叶生长状况对块根淀粉积累有明显影响,后期茎叶过早衰老或生长过旺对块根淀粉积累都不利。对抗衰老能力最强的是华南124,其次是辐选01和新选048,抗衰老能力最弱的是南洋红。其中新选056、南洋红、GR891、辐选01、华南124和新选048生育后期叶片过氧化物酶活性分别为383.93△OD470/gFw.min,279.33△OD470/gFw.min,405.20△OD470/gFw.min,445.97△OD470/gFw.min,364.43△OD470/gFw.min和202.20△OD470/gFw.min;丙二醛含量分别为0.0178μmol/gFW,0.0189μmol/gFW,0.0237μmol/gFW,0.0153μmol/gFW,0.0128μmol/gFW和0.0140μmol/gFW;可溶性糖含量分别为0.74%,0.70%,1.02%,0.84%,1.12%和1.30%;自由水/束缚水比值分别为3.07,4.77,6.85,3.64,2.57和3.11;块根淀粉含量分别为29.6%,25.8%,32.8%,32.7%,25.6%和28.9%。     

血液和组织标本中脂肪酸组成的毛细管柱气相色谱分析

用氯仿甲醇抽提、三氟化硼－乙醚甲醇酯化，然后利用毛细管柱和程序升温的方法进行气相色谱分析，建立了血浆和红细胞膜总脂以及组织磷脂和中性脂脂肪酸组成的毛细管柱气相色谱分析法。图谱表明各峰间分离效果良好、峰形尖锐、干扰少。各种脂肪酸的最小检测限均可达１０－（－１１）ｇ／ｓ，ＦＩＤ对各脂肪酸的响应均呈线性。实验重复性好，回收率达定量分析要求．     

冬闲田种植扁穗雀麦及饲养黑山羊技术研究

扁穗雀麦是多年生禾本科饲料作物，具有特别耐寒、返青早、生长快、产草量高、营养价值好、抗病力强的特点，是冬季及早春生长利用较好的饲草作物。在水稻冬闲田种植，以10月上、中旬播种，播量为2．5－3．0kg/667m^2较好，鲜草产量达2334．5kg/667m^2以上。利用其饲喂黑山羊，对黑山羊的日增重及经济效益均能获得较好的效果，是冬季及早春季节山羊充肥的理想草料。     

四川省攀西地区山羊泰勒虫病血清学检测

为了解四川省攀西地区山羊泰勒虫病流行情况,用双抗原夹心ELISA方法,对采自凉山彝族自治州和攀枝花市10个县/市的640份山羊血清样品进行检测。结果显示:攀西地区10个县/市羊泰勒虫血清抗体阳性率介于52.78%～100%,平均阳性率为73.44%(470/640);春季阳性率最高,秋季最低;经卡方检验,不同地区和季节的羊泰勒虫血清抗体阳性率差异均显著(χ~2=54.392,P 0.01和χ~2=38.157,P 0.01)。结果表明,攀西地区羊泰勒虫病流行较为严重,且流行呈现明显的地区和季节性特征。本研究为该地区羊泰勒虫病防控提供了流行病学参考数据。     

广西边境地区高致病性禽流感风险分析

为评估广西边境地区高致病性禽流感防控形势,根据文献报道的高致病性禽流感风险评估模型,对生态环境、候鸟迁徙及数量、饲养模式、运输和贸易、屠宰和废物处理、本地和周边地区的疫情形势、预防和控制措施等7大准则层22项指标综合计算发现,边境县(市、区)高致病性禽流感发生风险概率0.5,为中度风险以上,其中靖西、东兴、防城和港口发生风险概率0.6,为高风险。高风险因素主要为:市场被污染、越南疫情严重、水禽占比高,饲养管理和生物安全水平低、位于候鸟迁徙线上、市场管理水平低、市场卫生条件差、屠宰管理不到位、边境地区兽医机构效能不高。为防止广西边境地区高致病性禽流感的发生,必须要提高生物安全措施、做好免疫接种、加强监测和流行病学调查工作、提高兽医机构效能。     

Physicochemical properties of β and α'α subunits isolated from soybean β-conglycinin

Soy protein has shown great potential for use in biobased adhesives. β-Conglycinin is a major component of soy protein; it accounts for 30% of the total storage protein in soybean seeds. β-Conglycinin was isolated and purified, and its subunits' (β, α'α) physicochemical and adhesive properties were characterized. Crude β-conglycinin was isolated from soy flour and then purified by the ammonium sulfate precipitation method. The α'α and β subunits were isolated from the purified β-conglycinin by anion exchange chromatography. Yields of α'α subunits and β subunits from 140 g of soy flour were 1.86 g (1.3%) and 0.95 g (0.67%), respectively. The minimum solubility for α'α subunits, β subunits, and β-conglycinin occurred in pH ranges of 4.1-5.4, 3.5-7.0, and 4.8-5.3, respectively. Transmission electron microscopy showed that the β subunits existed as spherical hydrophobic clusters, whereas α'α subunits existed as uniformly discrete particles at pH 5.0. Differential scanning calorimetry showed that β subunits had higher thermal stability than α'α subunits. The pH had a lesser effect on adhesion strength of the β subunits than on that of the α'α subunits. The adhesives made from β subunits also showed greater water resistance than those from α'α subunits and β-conglycinin. Soy protein rich in β subunits is likely a good candidate for developing water-resistant adhesives.     

Isolation and characterization of a novel H9N2 influenza virus in Korean native chicken farm

An outbreak of avian influenza, caused by an H9N2 low-pathogenic avian influenza virus (AIV), occurred in a chicken farm and caused severe economic losses due to mortality and diarrhea. AIV was isolated and identified in a sample from an affected native Korean chicken. Genetic analysis of the isolate revealed a high sequence similarity to genes of novel reassortant H9N2 viruses isolated from slaughterhouses and live bird markets in Korea in 2008 and 2009. Animal challenge studies demonstrated that the replication kinetics and pathogenicity of the isolate were considerably altered due to adaptation in chickens. Vaccine protection studies indicated that commercial vaccine was not able to prevent virus shedding and clinical disease when chickens were challenged with the isolate. These results suggest that the novel H9N2 virus possesses the capacity to replicate efficiently in the respiratory system against vaccination and to cause severe disease in domestic chickens. The results also highlight the importance of appropriate updating of vaccine strains, based on continuous surveillance data, to prevent the possibility of a new H9N2 epidemic in Korea.     

Reviewing model application to support animal health decision making

Animal health is of societal importance as it affects human welfare, and anthropogenic interests shape decision making to assure animal health. Scientific advice to support decision making is manifold. Modelling, as one piece of the scientific toolbox, is appreciated for its ability to describe and structure data, to give insight in complex processes and to predict future outcome. In this paper we study the application of scientific modelling to support practical animal health decisions. We reviewed the 35 animal health related scientific opinions adopted by the Animal Health and Animal Welfare Panel of the European Food Safety Authority (EFSA). Thirteen of these documents were based on the application of models. The review took two viewpoints, the decision maker's need and the modeller's approach. In the reviewed material three types of modelling questions were addressed by four specific model types. The correspondence between tasks and models underpinned the importance of the modelling question in triggering the modelling approach. End point quantifications were the dominating request from decision makers, implying that prediction of risk is a major need. However, due to knowledge gaps corresponding modelling studies often shed away from providing exact numbers. Instead, comparative scenario analyses were performed, furthering the understanding of the decision problem and effects of alternative management options. In conclusion, the most adequate scientific support for decision making - including available modelling capacity - might be expected if the required advice is clearly stated.     

Epidemiological simulation modeling and spatial analysis for foot-and-mouth disease control strategies: a comprehensive review

Foot-and-mouth disease (FMD) is one of the most serious transboundary, contagious viral diseases of cloven-hoofed livestock, because it can spread rapidly with high morbidity rates when introduced into disease-free herds or areas. Epidemiological simulation modeling can be developed to study the hypothetical spread of FMD and to evaluate potential disease control strategies that can be implemented to decrease the impact of an outbreak or to eradicate the virus from an area. Spatial analysis, a study of the distributions of events in space, can be applied to an area to investigate the spread of animal disease. Hypothetical FMD outbreaks can be spatially analyzed to evaluate the effect of the event under different control strategies. The main objective of this paper is to review FMD-related articles on FMD epidemiology, epidemiological simulation modeling and spatial analysis with the focus on disease control. This review will contribute to the development of models used to simulate FMD outbreaks under various control strategies, and to the application of spatial analysis to assess the outcome of FMD spread and its control.