Horizontal transmission dynamics of White spot syndrome virus by cohabitation trials in juvenile Penaeus monodon and P. vannamei

White spot syndrome virus (WSSV), a rod-shaped double-stranded DNA virus, is an infectious agent causing fatal disease in shrimp farming around the globe. Within shrimp populations WSSV is transmitted very fast, however, the modes and dynamics of transmission of this virus are not well understood. In the current study the dynamics of disease transmission of WSSV were investigated in small, closed populations of Penaeus monodon and Penaeus vannamei. Pair cohabitation experiments using PCR as a readout for virus infection were used to estimate transmission parameters for WSSV in these two species. The mortality rate of contact-infected shrimp in P. monodon was higher than the rate in P. vannamei. The transmission rate parameters for WSSV were not different between the two species. The relative contribution of direct and indirect transmission rates of WSSV differed between the two species. For P. vannamei the direct contact transmission rate of WSSV was significantly lower than the indirect environmental transmission rate, but for P. monodon, the opposite was found. The reproduction ratio R₀ for WSSV for these two species of shrimp was estimated to be above one: 2.07 (95%CI 1.53, 2.79) for P. monodon and 1.51 (95%CI 1.12, 2.03) for P. vannamei. The difference in R₀ between the two species is due to a lower host mortality and hence a longer infectious period of WSSV in P. monodon.     

Erythrocyte Osmotic Fragility and Hematological Responses of Horses Administered Ascorbic Acid and Exposed to Road Transportation

The experiment was performed to evaluate the ameliorative effect of ascorbic acid (AA) on some hematological parameters and erythrocyte osmotic fragility (EOF) in horses transported by road. A total of 14 horses, consisting of seven experimental and seven control horses, were used for the experiment. Before the transportation, blood samples were obtained by jugular venipuncture from all the horses. Experimental horses were administered with AA (200 mg/kg dissolved in 20 mL of distilled water per os), whereas the control horses were given 20 mL of distilled water per os. Thereafter, the animals were transported for 6 hours and blood samples collected after transportation. Packed cell volume and hemoglobin concentration were higher (P < .05) in experimental than the control group, whereas total leukocytes reduced significantly (P < .05) in experimental in comparison with the control horses. Lymphocyte, neutrophil counts, neutrophil/lymphocyte ratio, and total protein decreased in experimental horses in comparison with control, but they were not significant (P > .05). Erythrocyte osmotic fragility was lower in experimental than the control at 0.3% NaCl concentration (P < .05). The result of the present study revealed that AA ameliorated changes in hematological parameters and EOF induced by road transport stress, partly because of its antioxidant properties.     

加减四君子汤对仔猪免疫机能及生产性能的影响

将72头（16.56±0.37）kg长大二元猪随机分为对照组、加减四君子汤组、抗生素组,每组4个重复,每个重复6头（公母各半）。对照组饲喂基础日粮,试验1组在基础日粮中添加中草药加减四君子汤,试验2组基础日粮中添加抗生素和高铜,于试验的第14天和第30天分别称重和采血,测定仔猪的生长性能、免疫指标和生理生化指标。结果显示,在试验第一阶段,中草药加减四君子汤组的平均日增重显著低于抗生素组（P〈0.05）,日粮粗蛋白质消化率极显著低于抗生素组（P〈0.01）,料肉比显著高于抗生素组（P〈0.05）,中草药加减四君子汤组的平均日增重、日粮粗蛋白质的消化率、料肉比与对照组相比差异不显著（P〉0.05）;而在试验第二阶段,中草药加减四君子汤组日增重和料肉比与抗生素组差异不显著（P〉0.05）,显著优于对照组（P〉0.05）;中草药加减四君子汤组粗蛋白质消化率显著低于抗生素组（P〈0.05）,与对照组相比差异不显著（P〉0.05）;中草药加减四君子汤组淋巴细胞ANAE阳性率在试验的两个阶段均显著高于抗生素组和对照组（P〈0.05）,对照组和抗生素组差异不显著;淋巴细胞转化率LTT（PHA）在第一阶段3个处理组之间差异不显著（P〉0.05）,在第二阶段中草药加减四君子汤极显著高于抗生素组和对照组（P〈0.01）,而对照组和抗生素组之间差异不显著（P〉0.05）;血清生化指标各处理组在整个试验期间差异均不显著（P〉0.05）。该结果表明,加减四君子汤具有明显的促生长作用,可提高断奶仔猪免疫力,增强机体抗病力,在猪饲料中添加一定剂量的加减四君子汤对动物健康无不良影响。     

山东省牛主要污染物产生量估算及环境效应研究

[目的]估算了山东省牛粪便的总量及其养分的负荷量和占当年排泄污染物的比例。[方法]根据2010年山东省和各地市牛存栏的行业和统计局两套数据和2012年行业数据,通过计算参数和估算的方法算出了牛粪产生总量。[结果]全省牛粪总共约在7000~9700万 t 之间,占当年所有畜禽粪便产生量的34.07%~37.37%之间,即三分之一以上。德州、济南两市单是牛粪便的土地承载量分别达到了29.7 t/hm2和27.4 t/hm2,接近了欧洲标准30 t/hm2的限量值。[结论]应该引起我们对全省牛业发展方式和发展战略的高度重视。     

烘丝工艺参数对烟丝加工质量的影响

【目的】优化烟丝干燥的最佳工艺参数,为提高烘丝加工质量提供科学依据。【方法】采用均匀设计法,通过直观分析和多元回归分析考察切丝含水率、HT蒸汽压力、筒壁温度、热风温度和排潮开度等因素对烟丝物理指标和感官质量的影响。【结果】切丝含水率、HT蒸汽压力、筒壁温度、排潮开度和热风温度对烟丝填充值、整丝率、碎丝率等物理指标均有一定影响;除切丝含水率外,其他4个工艺参数对烟丝感官质量也有明显影响。通过多元回归分析得到烘丝加工的最佳工艺参数组合：在切丝含水率19.0%、HT蒸汽压力0.32 MPa、筒壁温度137℃、热风温度105℃、排潮开度自动调节的条件下,烟丝填充值、整丝率和感官质量得分较优化前分别提高0.18 cm^3/g、2.3%和1.3分,碎丝率下降0.7%。【结论】切丝含水率、HT蒸汽压力、筒壁温度、热风温度和排潮开度对烟丝物理指标和感官质量的影响各不相同,在烟丝实际烘干加工过程中,适当调整各工艺参数,可有效提高烟丝加工质量。     

半导体工业废水污染特征因子初探

指出了集成电路和印制电路板是半导体工业的主要组成部分,而在生产过程中会大量使用氢氟酸,使得虽经过处理后的生产废水中氟离子浓度仍较高,达到7 mg/L左右;通过将半导体企业排放废水与生活污水、地下水及地表水中氟离子浓度进行比较,提出了以氟离子浓度作为半导体工业废水的污染特征因子,并结合不同雨污混接类型污染特征因子,依据物料和水量守恒得出不同混接类型的近似混接水量比例计算公式,以期为后续的雨污混接溯源和雨污改造工程提供借鉴。     

开花麻竹叶绿素荧光参数测定

叶绿素荧光是研究光合作用的有效探针。为了探讨开花对麻竹光合作用的影响,应用PAM-100分别测定了开花与未开化麻竹的叶绿素荧光参数。结果表明,随着光强的升高[0~2 000μmol/（m^2·s）],在开始阶段[0~200μmol/（m^2·s）]麻竹叶片的NPQ、Y（NPQ）、Y（ND）、ETR（Ⅱ）和ETR（Ⅰ）均迅速升高,Y（Ⅱ）和Y（Ⅰ）却迅速下降,之后变化缓慢并趋于平稳,而Y（NA）和Y（NO）几乎一直维持平稳;其中未开花麻竹的NPQ、Y（Ⅰ）和ETR（Ⅰ）均高于开花麻竹,Y（Ⅱ）、Fv/Fm和ETR（Ⅱ）无明显差异。在本实验培养光照下[230μmol/（m2·s）],未开花麻竹的NPQ、Y（Ⅰ）和ETR（Ⅰ）也均高于开花麻竹。由此表明,开花引起麻竹PSⅠ的Y（Ⅰ）和ETR（Ⅰ）以及PSⅡ的NPQ降低,这意味着开花麻竹的光保护能力下降,使得PSⅠ受体侧电子积累,导致光合效率下降。     

主要作业参数对单船中层拖网性能的显著性分析

以网口高度和网具阻力作为单船中层拖网性能的表现,在拖速3.0~5.5kn的范围内,选择上、下手纲,重锤,沉力,浮力,上、下叉纲7个作业参数作为影响其性能的因子,共进行了27次不同因子相互组合的模型系列试验。结果显示:显著性因子个数随拖速增加而增加,但到一定拖速后显著性个数不变;在不同拖速条件下,上手纲和下手纲变化对网具性能的影响均不大;重锤和浮力在不同的试验条件下,均是网具性能的主要影响因子。     

牙鲆"鲆优2号"不同养殖地点生长和存活性状的基因型与环境互作分析

为比较牙鲆"鲆优2号"在不同养殖地区的生长和存活性能,实验利用连续多代对生长性状和抗迟缓爱德华氏菌病性状遗传参数评估和基因组选择的结果筛选出的亲本,建立28个"鲆优2号"家系,在河北(Site 1)和山东(Site 2)进行对比养殖试验,利用混合线性动物模型对生长和存活性状进行了基因型与环境互作分析。Site 1和Site 2的平均日增重分别为1.5和1.2 g/d,养殖成活率分别为81.4%和82.2%,"鲆优2号"在两个养殖地点的生长和抗病性能均表现优异。不同养殖环境间收获体质量和存活性状的遗传相关分别为0.57(<0.7)和0.82(>0.7),说明不同养殖环境间收获体质量存在显著的基因型与环境互作效应,但是不同养殖环境间存活性状的基因型与环境互作效应不显著。研究表明,牙鲆"鲆优2号"新品种在不同养殖地点的生长和存活性能均表现良好,为保证良好的推广效果,需要对牙鲆的制种方案进一步优化,针对不同的养殖地区进行"鲆优2号"苗种生产,或培育具有普适性的"鲆优2号"苗种,保证在不同养殖环境下的快速生长和高存活率优势。