猪瘟病毒cF114株E2基因在家蚕杆状病毒表达系统中的融合表达

为进一步利用家蚕杆状病毒表达系统研制猪瘟病毒(CSFV)新型的亚单位疫苗,将猪瘟病毒cF114株囊膜糖蛋白E2基因克隆至带有GST标签的分泌表达杆状病毒转移载体pAcSecG2T的EcoRⅠ和BamHⅡ位点之间,获得了带有杆状病毒囊膜蛋白gp67信号肽-GST-E2元件的重组杆状病毒转移载体pAcSecG2T-E2,与线性化家蚕杆状病毒Bm-BacPAK6 DNA共转染家蚕BmN细胞,筛选重组病毒(Bm-BacPAK6-E2),PCR证实所分离的重组病毒含有目的片段E2基因。SDS-PAGE图谱显示,感染重组病毒后,在细胞培养液上清和家蚕幼虫、蛹的血淋巴中均可检测到一条分子量为63 kD左右的特异性条带;感染Bm-BacPAK6-E2家蚕蛹的血淋巴可检测到GST活性,接种病毒148 h后重组蛋白的表达水平达到17.11μg/mL。     

化学发光直接竞争免疫分析法检测猪尿中莱克多巴胺残留

本试验研究建立了猪尿中莱克多巴胺（Ractopamine, RAC）残留的直接竞争化学发光免疫检测方法。合成了莱克多巴胺和辣根过氧化物酶的偶联物（RAC-HRP）,方法的检测限为0.09 ng/mL,空白猪尿中添加浓度为0.5、10和100 ng/mL RAC时,检测范围为0.3～157.0 ng/mL;回收率为76.3%～87.6%,批内变异系数为10.0%～12.2%,批间变异系数为14.2%～15.2%。     

古巴非洲猪瘟根除的经验与借鉴

1971年非洲猪瘟首次传入古巴并于当年根除,1980年再次传入并在一年内又被根除。古巴能快速根除非洲猪瘟,主要与防控专业委员会的及时成立,协作机制的快速建立;全面扑杀措施的快速实施,健康猪产品的合理利用;民间团队的积极参与以及政府财政的大力支持密切相关。古巴的根除经验,可为我国非洲猪瘟的防控提供参考。     

云南某农村猪戊型肝炎病毒分子流行病学调查

目的了解昆明市某猪场戊型肝炎病毒感染情况,进一步探究病毒基因型及分子进化情况,为戊型肝炎防控提供参考。方法从该猪场随机采集39份新鲜粪便,用逆转录巢式聚合酶链反应对HEV ORF2部分基因片段扩增、克隆及测序;应用生物信息学软件进行同源性分析并构建系统进化树。结果PCR检测结果发现：该猪场核酸阳性率达35.9% (14/39)。同源性分析结果表明：14株流行毒株核苷酸序列与GenBank中HEV I~IV 型参考株的同源性分别为77.4%~83.9%、81.0%~83.2%、78.8%~86.9%和90.5%~98.5%,全部流行株均属基因IV型。进化分析结果表明：YN-KM-9与该猪场其他流行毒株同源性较远,应属不同基因亚型。结论该猪群HEV IV感染率较高,对公共卫生安全构成潜在威胁。     

The effect of depopulation and restocking on reproductive and growth performances on Japanese commercial swine farms

This study compared the reproductive and growth performances of pigs before and after depopulation and restocking after a foot-and-mouth disease outbreak in Japan. Data for the time period before and after depopulation and restocking were obtained from three farrow-to-finish farms. As a result of depopulation and restocking, hygiene levels were improved, and common infectious diseases, such as porcine reproductive and respiratory syndrome and Aujeszky’s disease, remained undetected on the farms. Compared with before depopulation, reproductive and growth performances improved after depopulation; the number of total pigs born was higher, the postweaning mortality rate was lower, and the age at slaughter was lower (P<0.05). In summary, depopulation and restocking improved the reproductive and growth performances of pigs.     

Detection and genetic diversity of porcine rotavirus A,B and C in eastern Australian piggeries

Rotaviruses (RV) have a high prevalence in piggeries worldwide and are one of the major pathogens causing severe diarrhoea in young pigs. RV species A, B, and C have been linked to piglet diarrhoea in Australian pig herds, but their genetic diversity has not been studied in detail. Based on sequencing of the structural viral protein 7 (VP7) RVA G genotypes G3, G4 and G5, and RVC types G1, G3, G5, and G6 have been identified in Australian piggeries in previous studies. Although occurrence of RVB was reported in Australia in 1988, no further genetic analysis has been conducted. To improve health management decisions in Australian pig herds, more information on RV prevalence and genetic diversity is needed. Here, 243 enteric samples collected from 20 pig farms within Eastern Australia were analysed for the presence of RV in different age groups using a novel PCR-based multiplex assay (Pork MultiPath™ enteric panel). RVA, RVB, and RVC were detected in 10, 14, and 14 farms, respectively. Further sequencing of VP7 in selected RV-positive samples revealed G genotypes G2, G5, G9 (RVA), G6, G8, G14, G16, G20 (RVB), and G1, G3, G5, G6 (RVC) present. RVA was only detected in young (<10 weeks old) pigs whereas RVB and RVC were also detected in older animals (>11 weeks old). Interestingly, RVB and RVC G-type occurrence differed between age groups. In conclusion, this study provides new insights on the prevalence and diversity of different RV species in pig herds of Eastern Australia whilst demonstrating the ability of the Pork MultiPath™ technology to accurately differentiate between these RV species.     

Preparation of Adjuvant Diluent for Live Vaccine against Classical Swine Fever and Evaluation of its Immune Effects

The aim of this study was to develop a novel oil-in-water (O/W) emulsion as adjuvant diluents (AD) for live vaccine against classical swine fever (CSF) that could effectively enhance the immune effect of vaccine.The AD was prepared by high-pressure homogenization technique.Formulations and preparation parameters were optimized with response surface design.Its stability, particle size, polydispersity (PDI) and Zeta potential were characterized.The humoral immune response and cellular immune response of the AD were evaluated with BALB/c mice by intramuscular injection.The particle size of the AD prepared by optimized formulation and parameters was 100.4 nm, PDI was 0.147, and Zeta potential was —28.7 mV.The experiment results showed that the AD had good stability.The AD was inoculated combined with live vaccine against CSF into BALB/c mice by intramuscular injection.The results showed that the live vaccine against CSF specific immune responses could be evoked in mice by co-inoculation with AD and vaccine.The cellular immune response levels in co-inoculated groups were significantly higher than control group (P<0.05), with obvious phenomena of higher levels of IFN-γ, IL-6 and IL-4 in serum.The result revealed that cellular immune capability significantly improved with the AD.The results strongly revealed that cellular immune capability significantly improved by introducing AD for effective immune-adjuvant for live vaccine against CSF.     

非洲猪瘟疫情下猪育种面临的困境与对策

自2018年8月以来暴发的非洲猪瘟疫情给我国猪育种和生猪生产带来了极大的困扰，育种体系遭受重创。文章综述了非洲猪瘟对我国育种体系的影响、育种工作面临的困境与挑战以及非洲猪瘟形势下猪育种的对策。     

非洲猪瘟疫情背景下兽医公共卫生学课程的教学策略

兽医公共卫生学是利用一切与人类和动物健康问题有关的理论知识、实践活动和物资资源,为人类健康事业服务的一门综合性应用学科,在动物性食品安全、动物疫病及人兽共患病方面发挥着重要的防线作用。针对当前我国发生的非洲猪瘟疫情,在阐述兽医公共卫生学重要性的基础上,分析了兽医公共卫生学课程的教学策略,以期打破对兽医专业认识的局限性,强化理解兽医公共卫生的意义,提升兽医公共卫生学的课程价值,并为优化教学内容、提高教学质量提供指导。     

猪弓形虫病诊断与防治

猪弓形虫病是由刚地弓形虫感染引发的一种血液原虫病,该种疾病属于人畜共患病和典型的免疫性疾病,可以在多种牲畜群体中寄生。猪群一旦受到弓形虫感染,病情会快速传播,蔓延防控不及时,还会造成整个猪群全部发病,死亡率有时高达60%以上,是危害生猪养殖产业的常发病和高发病。因此,需要加强流行病学调查,在疾病进入流行高发期前,采取针对性措施防控,提高防控效果,降低发病率,保障养殖安全。该文探讨猪弓形虫病的流行病学、临床症状、病理变化、诊断方法和防治措施。