Vaccination of Plasmid DNA Encoding Somatostatin Gene Fused with GP5 Gene of Porcine Reproductive and Respiratory Syndrome Virus Induces Anti-GP5 Antibodies and Promotes Growth Performance in Immunized Pigs

Somatostatin （SS） is a hormone that inhibits the secretion of growth hormone. Immunization against SS can promote the growth of animals. This paper described the effects of DNA immunization on the growth and antibody response in mice and pigs immunized with a plasmid DNA encoding SS fused with GP5 of porcine reproductive and respiratory syndrome virus （PRRSV）. A fragment of 180 bp encoding partial SS gene was amplified by PCR from the genomic DNA of peripheral blood mononuclear cells of pigs, and cloned as a fusion gene with PRRSV GP5 in plasmid pISGRTK3. Three times of immunization with the resulting plasmid pISG-SS/GP5 induced anti-GP5 antibodies in BALB/c mice and pigs, as demonstrated by GP5-specific ELISA and immunoblotting. Compared with pigs immunized with empty vector pISGRTK3, the growth performance of pigs immunized with pISG-SS/GP5 was increased by 11.1% on the 13th week after the last vaccination. The results indicated the plasmid DNA encoding SS and PRRSV GP5 fusion gene elicited anti-GP5 antibodies and improved the growth performance of immunized pigs.     

北京黑猪对注射猪生长激素(PST)的效应

已知用生长激素(PST)处理美国的肥育猪可提高饲料报酬、生长速度和胴体的瘦肉率。由于中国猪比美国猪更肥一些,饲料报酬较低和生长较慢,因而设想用生长激素处理中国猪可能更有效。本试验在肥育期28天内用 PST 处理北京黑猪(由中国地方猪,约克夏和巴克夏杂交育成),在每天饲喂4次的个体饲养组(n=12,6头公猪和6头母猪)中,每天注射2毫克和4毫克 PST 的猪,其饲养报酬分别提高22.3%和30.6%(P<0.01),主要是提高了生长速度(分别比对照组快24.4%和30.2%)(P<0.01),而对饲料摄入量没有影响。每天注射 PST 2毫克(28天),群饲猪(6头/圈,4圈/处理组)得到了类似的结果:饲料报酬提高22.7%(P<0.01);生长速度提高25%(P<0.01)。屠宰分析的结果表明,每天注射2和4毫克 PST 的猪,最后肋膘厚率平均降低19.2%(P<0.01)。剥离分析半片胴体的结果表明,PST 处理猪的疫肉总量和瘦肉率分别提高21.4%和13%(P<0.01),而总脂肪量和脂肪率则分别降低16.7%(P<0.05)和22%(P<0.01)。胴体的化学分析获得类似结果。PST 处理猪的背最长肌的 ...     

Effect of dietary addition of seaweed and licorice on the immune performance of pigs

In pig production, dietary additive antibiotics are usually used for growth stimulation and disease prevention, although there is public concern about the increased incidence of resistant antibiotics and food safety. It is possible that such antibiotics might be replaced by naturally derived products such as seaweed and licorice. In this study, we evaluated the effect of dietary addition of seaweed and licorice on enhancing the immune function in swine. The animals of each group (eight animals per group) were sensitized at day 42 and 49, and the immunoglobulin production and the expression of cytokines were detected by the ELISA and real‐time PCR. As the results, saliva IgA production of the seaweed‐treated group increased around five times compared to that of control (day 56). Delayed hypersensitivity reaction and IgG production of the seaweed‐treated group increased around 1.8–2.0 times. In addition, enhanced saliva IgA production was detected at day 50 (around two times) and day 51 (around five times) by the licorice treatment, and lower expression level of tumor necrosis factor‐α messenger RNA at day 51 (around 1/25) was observed in the licorice treatment. We conclude that the replacement of antibiotics by naturally derived dietary additives might be feasible for immune system enhancement.     

融合表达猪圆环病毒2型ORF1和ORF2基因真核质粒的构建及对小鼠的免疫原性

用PCR法扩增出猪圆环病毒2型的Rep蛋白基因（933bp）和Cap蛋白基因（705bp）,将其定向克隆于真核表达载体pcDNA3.1（＋）的多克隆位点上,构建真核表达质粒pcDNA-ORF1-ORF2。将构建好的重组质粒pcD-NA-ORF1-ORF2按100μg/只腿部肌肉注射BALB/c小白鼠,同时设pcDNA-ORF1、pcDNA-ORF2、pcDNA3.1-（＋）、PCV2全毒疫苗和PBS为对照,共免疫2次,间隔2周。分别于首免后第0、7、14、21、28、42天用MTT法检测小鼠脾淋巴细胞的增殖效应,用ELISA法检测小鼠的抗体水平;并于首免后第0、7、14、21、28天测定脾淋巴细胞中各细胞亚群的比例,对该核酸疫苗的免疫原性进行初步评价。结果显示,重组质粒能诱导鼠体产生较强的细胞免疫和体液免疫,并从免疫后第7天起所测各组数据均显著高于（P〈0.05）或极显著高于（P〈0.01）其他试验组。结果表明,将ORF1和ORF2基因共同用于PCV2核酸疫苗的研发具有很好的前景,为研究新型猪圆环病毒疫苗奠定了基础。     

猪伪狂犬病毒和猪细小病毒双重PCR方法的建立及初步应用

目的本研究旨在建立一种适用于临床样品和动物源性生物制品中猪伪狂犬病毒和猪细小病毒同时检测的双重PCR技术。方法针对猪伪狂犬病毒(PRV)的gE基因和猪细小病毒(PPV)的VP2基因的保守区域分别设计引物。结果经条件优化后,所建立的双重PCR方法能特异性地检测出样品中的PRV(581bp)和PPV(202bp)。结论本方法具有良好的特异性、敏感性和稳定性,适用于临床样品中对PRV和PPV的同时检测,也可用于猪源性生物制品的检测。     

猪流行性腹泻病毒M蛋白单克隆抗体的制备及鉴定

为制备猪流行性腹泻病毒(PEDV)抗M蛋白单克隆抗体(MAb),本研究以截短表达的His-M重组蛋白免疫BALB/c小鼠;以截短表达的GST-M重组蛋白作为包被抗原,采用常规的淋巴细胞杂交瘤技术制备杂交瘤细胞,通过间接ELISA进行筛选,得到一株稳定分泌抗M蛋白MAb.MAb亚类鉴定为IgG2b型,轻链为к链,杂交瘤细胞培养上清和诱导的小鼠腹水抗体效价分别为1:3000和1:2×105.Western blot试验表明该MAb能够识别重组及天然的PEDV M蛋白.间接免疫荧光试验表明该MAb能够与PEDV感染的Vero E6细胞产生特异性免疫荧光.     

猪瘟病毒、猪繁殖与呼吸障碍综合征病毒和乙型脑炎病毒多重RT-PCR检测方法的建立

根据猪瘟病毒(CSFV)的E2基因保守序列、猪繁殖与呼吸障碍综合征病毒(PRRSV)的ORF7基因及部分ORF6和3-UTR基因序列和猪乙型脑炎病毒(JEV)的E基因保守序列,设计了3对引物,扩增大小分别为288 bp、430 bp和1 015 bp目的片段.以纯培养病毒抽提RNA,制备cDNA模板,利用3对引物,通过条件的优化,建立了同时检测这3种病毒的多重RT-PCR.CSFV、PRRSV和JEV的RNA最小检出量分别为0.270 ng、0.049 ng、0.067 ng,其它的RNA病毒如TGEV以及DNA病毒如PPV、PrV、PCV-2检测结果为阴性.以β-actin为对照,利用本方法检测了174份临床样品(血清、肺脏和胎儿),其结果为:PRRSV、CSFV和JEV的阳性率分别为30.4%、4.6%和1.7%;CSFV和PRRSV混合感染阳性率为1.7%.同时对临床样品中CSFV、JEV和PRRSV阳性PCR产物进行测序分析,发现CSFV、PRRSV和JEV的PCR产物序列和NCBI数据库中目标基因的同源性分别为92%、90%和89%,这证实了多重PCR的阳性结果为上述3种病毒.结果证明,所建立的多重RT-PCR可用于临床检测.     

瘦素与肥胖并发症关系的研究进展

目的研究瘦素 (LEP) 对猪原代脂肪细胞脂滴相关基因FITM2、PLIN1和PLIN2 mRNA表达的影响。方法采用不同质量浓度的LEP (0、50、100和150 ng/mL) 处理15日龄三元杂交猪 (DLY) 皮下原代脂肪细胞48 h,试剂盒测定细胞中甘油三酯 (TAG)含量,qPCR检测脂滴相关基因mRNA表达水平。结果与0 ng/mL LEP相比,100 ng/mL LEP可显著增加猪原代脂肪细胞TAG含量以及FITM2和PLIN2 mRNA表达水平 (P<0.05),显著下调PLIN1 mRNA表达水平 (P<0.05);与50和100 ng/mL LEP相比,150 ng/mL LEP可显著降低脂肪细胞TAG含量 (P<0.05),显著上调PLIN1和PLIN2 mRNA表达水平 (P<0.05)。结论LEP可促进猪原代脂肪细胞FITM2和PLIN2 mRNA表达,可促进或抑制PLIN1 mRNA表达,但LEP对脂滴相关基因表达的促进或抑制存在质量浓度差异性。     

基于抗体筛查的美国猪群流行性腹泻病毒真流行率分布推断

养殖家畜的冠状病毒,如猪流行性腹泻病毒(porcine epidemic diarrhea virus,PEDV),其基因序列与蝙蝠体内冠状病毒基因序列高度相似,可引起猪肠道感染并导致仔猪大量死亡,对动物健康危害极大.本研究基于对美国猪群PEDV流行毒株表观流行率的数据挖掘作为先验信息,以2019年美国生猪入境中国西南...