Salmonella Vaccination in Pigs: A Review

The control of Salmonella enterica in pig production is necessary for both public and animal health. The persistent and frequently asymptomatic nature of porcine Salmonella infection and the organism's abilities to colonize other animal species and to survive in the environment mean that effective control generally requires multiple measures. Vaccination is one such measure, and the present review considers its role and its future, drawing on studies in pigs from the 1950s to the present day. Once established in the body as an intracellular infectious agent, Salmonella can evade humoral immunity, which goes some way to explaining the often disappointing performance of inactivated Salmonella vaccines. More recent approaches, using mucosal presentation of antigens, live vaccines and adjuvants to enhance cell‐mediated immunity, have met with more success. Vaccination strategies that involve stimulating both passive immunity from the dam plus active immunity in offspring appear to be most efficacious, although either approach alone can yield significant control of Salmonella. Problems that remain include relatively poor control of Salmonella serovars that are dissimilar to the vaccine antigen mix, and difficulties in measuring and predicting the performance of candidate vaccines in ways that are highly relevant to their likely use in commercial production.     

猪的肢蹄病(续完)

上期回顾:上期简单分别介绍了分娩舍、保育舍和生长肥育舍相关猪肢蹄病的发病情况。     

A Review of Pseudorabies (Aujeszky''s Disease) in Pigs

The main features in terms of etiology, clinical signs, pathogenesis, pathology, diagnosis, epizootiology and control and prevention that are known about pseudorabies are briefly reviewed. Areas still lacking in information which may provide more effective and reliable means of dealing with pseudorabies are mentioned and recommendations using available tools and knowledge to deal with the problem of pseudorabies are given.     

丙硫苯咪唑在猪体内的药代动力学研究

本文建立了用反相高效液相色谱法测定丙硫苯咪唑及其代谢物丙硫苯咪唑亚砜、丙硫苯咪唑砜的血药浓度的方法,并测定了6头健康猪口服丙硫苯咪唑(25mg/kg)后亚砜和砜的血药浓度及有关药代动力学参数。结果:给药后20min采血,6头猪血中,丙硫苯咪唑原形药均未检出,而以丙硫苯咪唑亚砜和丙硫苯咪唑砜的形式出现。以NaVa pack C18 4μm 0.39×15cm为固定相,紫外检测器波长为290nm,甲苯咪唑为内标物,测定丙硫苯咪唑亚砜和砜.本法测得血清中亚砜的最低含量为23.56ng/mL,砜为16.54ng/mL。亚砜平均回收率为93.73±6.75％,砜为90.044±5.33％,不同浓度水平测定结果的日内和日间变动系数均在10％以下。丙硫苯咪唑亚砜和砜的药代动力学符合有吸收因素二室模型,健康猪口服丙硫苯咪唑后,亚砜半衰期(t1/B)为12.6466±1.8491h;血浆清除率(CL_B)为0.1364±0.0921L/(kg·h);血药浓度达峰时间(Tmax)为10h,峰浓度(Cmax)为11.919±1.382μg/mL血清;药时曲线下面积(AUC)为1156.69±742.52μg/(mL·h)。     

Tail Biting in Pigs

One of the costly and welfare-reducing problems in modern pig production is tail biting. Tail biting is an abnormal behaviour, characterized by one pig's dental manipulation of another pig's tail. Tail biting can be classified into two groups: the pre-injury stage, before any wound on the tail is present, and the injury stage, where the tail is wounded and bleeding. Tail biting in the injury stage will reduce welfare of the bitten pig and the possible spread of infection is a health as well as welfare problem. The pigs that become tail biters may also suffer, because they are frustrated due to living in a stressful environment. This frustration may result in an excessive motivation for biting the tails of pen mates. This review aims to summarize recent research and theories in relation to tail biting.     

Hyperostosis in Newborn Pigs

Hyperostosis “thick legs” is reported in a case involving 7 of a litter of 11 purebred Landrace piglets. The 12 limbs involved showed variable degrees of thickening and immobility; tension and fixation of the skin. Necropsy revealed extensive fibrous connective tissue, enlargement and edema of associated lymph nodes and hypoplasia of muscle groups. Radiographs revealed osteodystrophia along the shafts of long bones. The case is compared to previous reports of infantile cortical hyperostosis in children and “thick legs” in pigs.     

基于祖源分析的猪遗传成分鉴定

解析不同品牌猪肉的遗传成分对商业品牌的保护,防伪溯源及中国地方猪种的改良和开发具有重要参考价值。从市场上选取4种不同来源的猪肌肉组织通过全基因组重测序,并结合已发表的59头猪的数据,对其祖先成分进行分析,推测它们祖先可能的来源及其各祖先成分的含量。利用线粒体基因组数据判断4头猪的母系来源,揭示可能的母系来源。59头参考个体包含12个品种,分别是杜洛克猪、长白猪、大白猪、皮特兰猪、二花脸猪、金华猪、姜曲海猪、梅山猪、巴马香猪、陆川猪、五指山猪和香猪。将12个品种划分为商品猪、中国东部猪和中国南方猪。研究中,利用ADMIXTURE和RFMix软件分别对4头测试个体进行祖先成分的评估。设定4头测试个体的祖先群体为3类时,发现其中一头含有54.8%的商品猪成分和45.2%的中国南方猪成分,另一头含有81.3%的商品猪成分,而剩下的两头含有的商品猪成分占到97.0%以上。设定祖先群体为12类时,发现其中一头含有64.8%的杜洛克猪成分和35.2%的陆川猪成分;另一头含有的祖先成分比较复杂,长白猪的含量为22.5%,大白猪的含量为27.6%,五指山猪的含量为8.6%,二花脸猪的含量为5.5%,梅山猪、姜曲海猪和巴马香猪的含量均在1.2%左右;而剩余两头猪的祖先成分主要是杜洛克猪、长白猪、大白猪和皮特兰猪。另外,线粒体的祖源判断提示其中一头猪的母系来源可能是陆川猪或相近地方品种的母猪。通过常用的祖源分析方法对4头猪进行祖先血统成分的估计,发现4头猪的遗传成分各不相同,并能清晰地知道不同个体中祖先成分及占比。该研究结果证明通过祖源分析的方法可以估算每个测试个体的遗传成分来源。使用祖源成分作为遗传特征,可为品牌猪肉的鉴定和品牌保护提供重要的遗传学参考,也可以为中国地方猪品种的保护、开发提供指导和参考。     

猪的几种人畜共患病的血清学调查

弓形虫病、衣原体病和布氏杆菌病虽病源各不相同,但都属于人畜共患病,具有重要的公共卫生意义. 　　……     

圩猪及其二元杂交品种猪氟烷基因的基因频率分析

试验采用PCR-RFLP分子标记技术检测了圩猪(62头)、长白(64头)、杜洛克(61头)、英系大约克(60头)以及长圩零世代(65头)、一世代(121头)、二世代(243头)共676头猪的Hal基因基因型的分布情况.结果表明,在检测的各猪种中,Hal基因显性纯合子频率分别为:1.013,0.71,0.80,0.62,0.91,0.88,0.82; 杂合子频率分别为:0,0.29,0.20,0.37,0.09,0.12,0.18.由此说明,虽然氟烷敏感基因频率和基因型频率在长圩3个世代猪种中分布均较低,但Haln基因频率和HalnHaln"基因型频率在长圩3个世代中仍呈上升趋势.应进一步采用标记辅助选择方法降低Haln基因频率,直至完全剔除Haln基因.     

猪胚胎附植部分因子研究进展

产仔数性状是养猪业中一个重要的经济性状,而胚胎附植对猪产仔数的高低有重要的影响。胚胎附植的调控涉及到多个生物学过程,在其中发挥作用的物质（附植因子）很多。作者针对孕酮、孕酮受体、雌二醇、雌激素受体α（ESR1）和促红细胞生成素产生肝细胞受体配体（Eph-ephrin）系统这几种附植因子的相关研究进行了归纳总结,重点阐述了这些因子在母胎对话过程中的时空表达、功能、突变、调控等方面的研究进展。其中,孕酮及其受体在猪胚胎附植活动中全程发挥着重要作用,黄体分泌的孕酮与母猪子宫内膜腔上皮、腺上皮、基质和肌细胞中的孕酮受体结合发挥作用,使这些组织细胞分泌多种附植因子,这些附植因子进一步参与胚胎附植过程。雌二醇是雌激素中含量最多、活性最强的一种激素,主要由卵巢颗粒细胞分泌,雌激素受体α是子宫内雌二醇的主要受体,二者结合可使母猪发情;此外,附植中处于游离状态的胚泡也分泌雌二醇,其是一个让母猪子宫内膜得以识别的信号,允许胚泡附植。Eph-ephrin系统作用广泛,其在人、小鼠和猪的胚胎附植过程中发挥着重要作用。系统中的EphA1、ephrin A1、EphA4等基因在猪的胚胎附植期表达量显著高于空怀猪,它们在子宫内膜附植点的表达量显著高于附植点间的部位,且ephrin A1的抑制表达会降低子宫内膜上皮细胞的迁移和黏附能力。这些附植因子都在猪胚胎附植活动中发挥着重要作用,对它们的深入研究将有利于明确猪胚胎附植调控机理,进一步揭示猪高繁机理。