徐州某规模猪场防疫措施的建立与实施——“五流”生物安全防控

非洲猪瘟在我国流行已有两年多的时间,尽管很多科研团队都在致力于非洲猪瘟疫苗的研发,但尚未有治疗措施和有效的疫苗来控制该病。因此现阶段“生物安全”是控制非洲猪瘟最为有效,也是唯一的方法。文章总结出目前规模化猪场常见的感染风险有“人员流动、物品流动、车辆流动、水源流动、猪群流动”(即“五流”),并提出严格控制“五流”的生物安全防控措施(即“五流”生物安全防控),以减少外界病原与猪只的接触,稀释病原浓度,降低病原载量,最大程度地降低规模化养猪场感染疾病的风险。为当前规模化猪场建立有效的生物安全措施提供参考。     

结构创新的楼房猪场是防非保供的一种可行模式

传统的养猪模式难以应对诸如非洲猪瘟这样的疫病,普通平层猪场叠加而成的楼房没有从本质上得到改进,而结构创新之后的楼房猪场在养猪的可靠性上大大增强,并可能发展为城市养猪新模式,为防非保猪、稳产保供提供一种解决方案。在此基础上升级的"料、养、宰、商一体化"造肉工厂模式,更是一种能把运猪变为运肉的可行解决方案。当这些模式得到应用和推广时,困扰行业的"猪周期"问题也将得到妥善解决。     

政策认知、执行力度与资源化利用满意度——基于河北省380家生猪养殖主体调研数据(上)

参与主体对于政策的评价是衡量政策实施效果的重要指标，探明政策参与主体满意度影响因素有助于了解主体自身需求，从而提高政策实施水平。文章基于对河北省380家生猪养殖主体调研数据，运用多元有序Logistic回归方法，分析生猪养殖主体自身政策认知以及相关政策执行力度对畜禽养殖主体废弃物资源化利用满意度的影响。结果表明：养殖主体资源化利用政策了解程度能够显著提升其资源化利用政策满意度；仅考虑养殖主体政策参与力度，随着参与力度增加，满意度亦会显著提升。但综合考虑其他因素，参与力度对于满意度提升效果则不再显著；养殖主体感知政策执行力度增加不利于政策满意度提升。此外，生猪养殖主体废弃物资源化利用政策了解程度增加，可以显著提升其报告资源化利用政策“满意”可能性。而单纯提高资源化利用政策执行力度并不能显著提高养殖主体资源化利用政策满意度。因此，要提高养殖主体政策满意度，应多渠道提升宣传力度，鼓励养殖主体积极参与，提高其参与意识，不断改善现有政策执行方式。     

Transmission of methicillin-resistant Staphylococcus aureus strains between different kinds of pig farms

The main objective of the present study was to investigate if different kinds of pig farms, like farrowing farms and rearing farms, play a role in the transmission of methicillin-resistant Staphylococcus aureus (MRSA) to Dutch finishing farms. Twelve farrowing farms, 11 finishing farms, 6 farrow-to finish farms, 1 rearing farm and 1 centre for artificial insemination were included. Screening of 310 pigs from these 31 farms showed 35 pigs (11%) to carry MRSA in their nares. On 7 of the 31 (23%) investigated farms colonized pigs were found, including 3 finishing farms, 3 farrowing farms and 1 farrow-to-finish farm. The use of standard antimicrobial medication of the pigs seemed to be a risk factor for MRSA carriage. Screening of the pigs on six farms supplying pigs for the MRSA positive farms revealed that the pigs on all but one farm were MRSA positive. Genotyping revealed that all MRSA strains were non-typeable by PFGE using the SmaI restriction enzyme and had multilocus sequence type (MLST) ST398. Different spa-types were found including t011, t108, t567, t899 and t1939, but the spa-types on epidemiologically related farms were identical indicating that MRSA are transmitted between farms through the purchase of colonized pigs. Two SCCmec types were found among the MRSA: type IV and type V. SCCmec type V was predominant. On two farms MRSA isolates with ST398, the same spa-type but with different SCCmec types (IV and V) were found, suggesting that different SCCmec elements have been inserted into MSSA with the same genotype. All MRSA strains were resistant to tetracycline, but additional resistances to erythromycin, lincomycin, kanamycin and gentamicin were also found. All MRSA isolates were negative for the exfoliative toxin genes (eta and etb), PVL toxin genes (lukF and lukS), toxic shock syndrome gene (tst-1), and the leukotoxin genes (lukE, lukD, lukM, lukF').     

新生猪肌组织成纤维细胞的分离培养和鉴定

研究建立了猪肌组织成纤维细胞体外培养的模型,采用组织块培养方法获得了新生猪肌组织成纤维细胞并进行体外培养.观察细胞形态,通过绘制细胞的生长曲线来研究肌组织成纤维细胞的生长规律,利用RT-PCR和免疫细胞化学染色对所获得的细胞进行鉴定,再用双荧光素酶检测系统来检测细胞的转染效率.通过形态学观察、RT-PCR和免疫细胞化学染色结果表明,已成功培养了猪肌组织成纤维细胞,纯度达90%以上.     

BPI基因在梅山猪初生断奶以及成年阶段的组织表达谱分析

为探讨杀菌/通透性增强蛋白(BPI)基因在梅山猪从初生到成年各个时期不同组织中的表达规律,利用qPCR检测初生、断奶、性成熟、体成熟4个重要发育时期(即1、35、134、158日龄)梅山猪的心脏、肝脏、脾脏、肺脏、肾脏、胃、肌肉、胸腺、淋巴结、十二指肠、空肠和回肠12个组织中BPI基因的表达水平。结果表明:4个不同发育阶段BPI基因的组织表达谱在心脏、肝脏、脾脏、肌肉和胸腺中均表现出相对一致的规律,即BPI基因的表达量一直处于极低水平,而在肠道组织中从初生到成年各时期均高度表达;BPI基因在胃中的表达程度随着日龄增长而显著提高;在小肠组织中,35日龄断奶仔猪BPI基因的表达水平极显著高于其他3个日龄。综上,推断肠道中BPI基因的高度表达是仔猪从初生就具有的抵抗大肠杆菌等病原感染属固有免疫的一部分,而在胃中的表达很可能是其后天为了抵御不断侵染的大肠杆菌等病原的结果。     

A comparably high virulence strain of porcine reproductive and respiratory syndrome virus isolated in Taiwan

Porcine reproductive and respiratory syndrome virus (PRRSV) has been endemic in Taiwan since 1991. This study aimed to present a highly virulent PRRSV in Taiwan based on farm data collection and both in vitro and in vivo evaluations in virus challenge studies. This virulent PRRSV strain was first noticed on Farm TSYM due to continuously high nursery mortality rate and severe PRRSV-associated pneumonia. In phylogenetic surveillance, the PRRSV TSYM-strain remained in the predominant position for years, even with several other PRRSV strain invasions. In laboratory challenge trials, the TSYM-strain led to prolonged pyrexia, growth retardation, high mortality rates and high viremia titer that similar to the highly pathogenic PRRSV. The TSYM-strain isolate also triggered early interleukin-10 up-regulation and significantly higher infection rates under in vitro experiments. This study provides information of a comparably virulent strain in Taiwan and its appearance in both farm and laboratory levels.     

Effect of adding Lactobacillus plantarum or a formic acid containing-product to fermented liquid feed on gastrointestinal ecology and growth performance of piglets

A study was carried out to investigate whether adding a starter culture or a formic acid containing-product to fermented liquid feed of suboptimal microbial quality could improve the characteristics of the mixture and the gastrointestinal ecology and growth performance of piglets. Four experimental diets were prepared: Feed and water were mixed in the ratio 1:2.5 (w/w) in four closed tanks. Diet 1) Three times daily, 50% of the mixture stored in the tank was removed and then replaced with an equal amount of fresh feed and water, (FLF), positive control; Diet 2) Three times daily, 95% of the mixture stored in the tank was removed and then replaced with an equal amount of fresh feed and water. Escherichia coli K12 (1 × 10⁶/g) was added every morning (COLI); Diet 3) as the COLI treatment and added Lactobacillus plantarum VTT E-78076 (1 × 10⁶/g) every morning (+PLANTARUM); and Diet 4) as the COLI treatment and added 0.26 g AIV/KemiSile 2 plus/100 g mixture three times daily (+ACID). One hundred and sixty weaners were used. On day 14, one littermate from each pen was killed and the gastrointestinal tract removed. The remaining piglets were used to measure the effect of the experimental diets on growth performance during the first six weeks post-weaning. The +ACID diet had lower numbers of lactic acid bacteria and Enterobacteriaceae, higher numbers of yeasts, and lower concentration of lactic acid and acetic acid than the COLI and +PLANTARUM diets. Feeding the +PLANTARUM and the +ACID diets increased daily weight gain during the six weeks post-weaning (P ≤ 0.02) compared to feeding the COLI diet. The +ACID group showed the highest numerical daily feed intake in all periods. The gain/feed during the six weeks post-weaning tended to be lowest in the COLI group (P < 0.10). The counts of lactic acid bacteria able to grow at 20 °C were lowest in the stomach (P ≤ 0.003) and distal small intestine (P ≤ 0.06) of the +ACID group. The counts of yeasts able to grow at 37 °C in the stomach were highest in the +ACID (P ≤ 0.01) and FLF groups (P ≤ 0.09). The number of yeasts able to grow at 20 °C in the stomach and distal small intestine was highest in the FLF fed piglets, followed by the +ACID group. This study showed that addition of L. plantarum VTT E-78076 or AIV/KemiSile 2 plus to fermented liquid feed of suboptimal microbial quality improved growth performance without affecting the gastrointestinal ecology of piglets substantially.     

Phenotypic and genotypic traits of Staphylococcus aureus strains isolated from pig carcasses

A total of 142 S. aureus strains isolated from pig carcasses from abattoirs A (n = 98) and B (n = 44) were characterized by phenotypic and genotypic traits. Phenotypically, 96% showed yellow-pigmented colonies, 63% β/δ hemolysis, 85% were egg yolk-positive and 99% were positive for clumping factor/protein A. Only 25% of the strains were resistant to the antimicrobials tested (abattoir A: 19%; abattoir B: 39%), especially to penicillin and ampicillin. None of the strains harbored the mecA gene, which is conserved in methicillin-resistant S. aureus. The biofilm associated genes icaA, icaD and bap were present in 100%, 100% and 0% of the strains. Genes for staphylococcal enterotoxin (SE) were detected in 51% (abattoir A) and 14% of the strains (abattoir B). Among strains harboring SE genes (n = 56), 63%, 31%, 4% and 2% tested positive for seg/sei, seg, sei and sec, respectively. The amplification of the 3′ end of the coagulase gene (coa) yielded amplicons of 400, 436, 602, 682 or 776 bp. Coa restriction profile (CRP) analysis using HaeIII resulted in seven patterns (a–d, e1–e3). CRP (c) was detected most frequently at both abattoirs, whereas CRP (a) was restricted to abattoir A and CRP (e3) to abattoir B. In the slaughter process (abattoir B), (i) two CRPs (b and d) were only found before dehairing/singeing, and (ii) four CRPs (c, e1–e3) were identified throughout the process. The genotyping revealed a remarkable homogeneity in S. aureus strains from the two different abattoirs and the slaughter process stages. These results may be explained by the distribution of a limited number of S. aureus genotypes in the pig population. Moreover, as the predominant CRPs (c, e1–e3) persisted throughout the slaughter process in abattoir B, it may be hypothesized that these types are characterized by colonization advantages.     

南昌白猪血清转铁蛋白血液结合素及淀粉酶的遗传多态性研究

应用改进的淀粉凝胶电泳法研究了培育品种南昌白猪进贤系、南昌系、安义系及其杂交亲本品种星子黑猪、大约克猪的转铁蛋白（Ｔｆ）、血液结合素（Ｈｐｘ）和淀粉酶（Ａｍ）３种血清蛋白的多态性,测定并分析了各自的基因型及基因频率的特点,结果表明：南昌白猪３个系的遗传结构与大约克猪甚为相似,而与星子黑猪的差异明显。