Seroprevalence and molecular detection of porcine sapovirus in symptomatic suckling piglets in Guangdong Province,China

The seroprevalence and genetic identification of sapovirus (SaV) in symptomatic suckling piglets were investigated in Guangdong Province, China, between November 2011 and April 2013. Serum (n?=?960) and diarrheic fecal (n?=?101) samples collected from symptomatic suckling piglets in Guangdong Province were evaluated for antibodies against SaV using indirect enzyme-linked immunosorbent assay (iELISA). The overall seroprevalence of SaV in symptomatic suckling piglets was 61.9 % (594/960). Positive animals were found in all regions with seroprevalence ranging from 52 to 67.8 %, but the difference was not statistically significant (P?>?0.05). In addition, RNA of SaV was extracted from diarrheic fecal samples, and the partial polymerase gene was amplified by RT-PCR and then sequenced. Seven of 101 (6.9 %) samples were found to contain porcine SaV. Phylogenetic analysis showed that all the porcine SaV isolates belong to the porcine SaV genogroup III (GIII). This is the first report of SaV seroprevalence in symptomatic pigs in China.     

有机酸在断奶仔猪饲料中的应用研究进展

早期断奶仔猪常出现断奶应激,导致腹泻。有机酸具有多种生理功能,可显著降低断奶应激,减少腹泻,促进生长。因此通过把握有机酸的作用机理,针对仔猪腹泻的原因,了解影响有机酸作用效果的因素,有选择地在饲料中加以使用,可以达到减少断奶应激、促进仔猪生长的目的。     

仔猪的消化道生理与断奶应激

在现代养猪生产模式中,消化道发育尚不完善就实行强制断奶是仔猪生长过程中面临的一个重要生理阶段。由日粮、营养及内外环境等因素的改变而带来的应激对仔猪正常生理功能的发挥将造成极大的影响。本文立足于仔猪的胃肠道生理特点,结合以前的研究结果和最近的发现,综述了断奶对胃肠道生理、微生物区系和免疫系统的影响以及日粮组成对胃肠道健康的影响。     

The survey of porcine teschoviruses, porcine circovirus and porcine transmissible gastroenteritis virus infecting piglets in clinical specimens in China

A multiplex PCR assay was developed and evaluated for its ability to simultaneously detect three viral infections of swine. Specific primers were carefully selected from articles published for each of the following three viruses: porcine circovirus type II (PCV2), porcine teschovirus (PTV) and porcine transmissible gastroenteritis virus (TGEV). Each target produced a specific amplicon with a size of 353 bp (PCV2), 168 bp (PTV) and 499 bp (TGEV). The sensitivity of the multiplex PCR using purified plasmid constructs containing the specific viral target fragments was 6.60?×?10², 8.43?×?10² and 7.30?×?10² copies for PCV2, PTV and TGEV, respectively. Among 127 samples which were collected from Heilongjiang, Jilin, Henan and Guangxi provinces, the single infection of PCV2, PTV and TGEV was 99.21, 46.88 and 65.35 %, respectively, and co-infection of the three viruses was 26.77 %. In conclusion, the multiplex PCR has the potential to be useful for routine molecular diagnosis and epidemiology.     

Growth performance and health status in weanling piglets fed spray-dried porcine plasma under typical Northern European conditions

The effect of inclusion of spray-dried porcine plasma (SDPP) in diets for weanling piglets was studied. The objectives were to determine whether SDPP would have positive effects on post-weaning piglet performance and health under typical Northern European conditions. In experiment 1, 160 weanling piglets were assigned randomly to a control diet or a diet containing 3% SDPP, which was added at the expense of both fishmeal and dried skim milk. In experiment 2, 264 weanling piglets were assigned to a control diet containing whey protein, a diet without whey protein but with SDPP or a diet containing both whey protein and SDPP. In essence, SDPP was added to the test diets at the expense of either whey protein or fishmeal. Piglets were fed the diets for 3 weeks. In experiment 1, the piglets fed the SDPP diet had a 7% higher average daily gain (ADG) and a 4% lower feed conversion ratio (FCR) (p < 0.05) during the first 3 weeks after weaning than did those fed the control diet. There were no differences in leucocyte counts or γ-globulin. In experiment 2 there were no significant differences in ADG and FCR among the dietary treatments. It is concluded that low amounts of SDPP in weanling diets can have positive effects on growth performance under Northern European conditions.     

断奶仔猪腹泻的防治措施

仔猪腹泻在断奶仔猪中的发病率和病死率较高。本文分析了该病的常见发病原因，并根据具体情况提出了综合防治措施。     

猪沙波病毒抗体间接ELISA检测方法的建立及初步应用

以原核表达重组蛋白作为抗原建立了猪沙波病毒(SaV)抗体的间接ELISA检测方法。使用矩阵滴定法确定抗原包被浓度为6.4μg/mL,血清稀释倍数为1∶50。试验选用1%BSA作为封闭液,血清和二抗的最佳作用时间分别为60 min和40 min。选择无致癌的TMB为底物,确定TMB最佳反应时间为10 min。通过对20份猪阴性血清样品的检测,计算阳性判定值为0.203。通过交叉试验、批内和批间重复性试验证明,本研究建立的SaV间接ELISA检测方法具有特异性高,重复性好的特点,可用于猪沙波病毒抗体的检测。     

猪IL-2、IL-4、IL-10和IFN-γ的TaqMan实时定量RT-PCR检测体系的建立

为了解猪体内细胞免疫应答机制,本研究建立猪细胞因子IL-2、IL-4、IL-10和IFN-γ的TaqMan实时定量RT-PCR检测体系.以五指山小型猪cDNA为模板,扩增IL-2、IL-4、IL-10和IFN-γ的基因保守区,构建相应的重组质粒,并将其作为标准品构建标准曲线.结果显示,各标准曲线的相关系数r值均大于0.990,扩增效率为90%～105%;该检测方法的敏感性较高,IL-4检测下限为1 copies/μL,IL-2、IL-10及IFN-γ检测下限达为102copies/μL;重复性较好,批内重复试验与批间重复试验变异系数均小于5%.本研究为病毒感染后猪体内免疫应答等研究提供方法.     

断奶日龄对仔猪生产性能和消化酶活性的影响

选取遗传基础相似、体重相当来自9窝母猪的48头杜长大仔猪为研究对象。随机平均分为2组,分别于23日龄和28日龄断奶,各组分别在断奶当天,断奶后3 d、7 d、14 d宰杀取样。测定各组在断奶后2周内的生产性能以及空肠内容物和胰腺消化酶的活性。结果表明:28日龄断奶的仔猪平均日增重、日平均采食量均显著高于23日龄断奶的仔猪。断奶后仔猪空肠消化酶均有所下降,其中28日龄断奶的仔猪所受影响相对较小。     

High genetic diversity in RdRp gene of Brazilian porcine sapovirus strains

Sapovirus is one genus within Caliciviridae family that causes diarrhea in humans and animals. Sapovirus (SaV) has been classified into seven genogroups (GI to GVII). The GIII, GVI, and GVII, which prototype is Cowden, JJ681, and K7/JP strains, respectively, infect pigs. The objective of this study was to characterize wild-type Brazilian SaV strains from piglet stool samples and determine SaV infection frequency, age distribution and association with diarrheic disease. Stool samples from 113 piglets up to 28-days-old were collected from 34 pig farms located in the States of Minas Gerais (MG), Mato Grosso do Sul (MS), Paraná (PR), Santa Catarina (SC), and Rio Grande do Sul (RS), during 2004 and 2005. The specimens were evaluated for enteric calicivirus by RT-PCR assay with primers p289/290, designed to detect the polymerase gene of SaV and norovirus. Thirty four (30.1%) samples were positive for SaV and five amplicons were sequenced. Phylogenetic analyses placed BRA29-MS/04 and BRA52-PR/05 sequences into the GIII of SaV genus. BRA04-SC/04, BRA21-RS/04, and BRA37-MG/05 demonstrated low identity with the Cowden strain but were closely related (up to 86.3%) to the Japanese and Dutch SaV strains, grouping together in a new cluster (GVIII?) in the phylogenetic tree. SaV infection was detected more frequently (p=0.0001) in animals between 22 and 28 days of age, in equal frequencies in piglets with and without diarrhea (p=0.59), and in the five Brazilian States. In this study, such as other unclassified worldwide SaVs, the Brazilian strains showed high genetic variability. Furthermore, the distribution and frequency of SaV infection provides evidence that the virus is circulating in Brazilian pig herds.     

碱式氯化铜对断奶仔猪的促生长效应研究

本试验研究了碱式氯化铜(TBCC)对断奶仔猪的促生长效应。试验采用完全随机区组设计,将180头30d断奶的杜×长×大仔猪依体重、性别、窝别随机分为5个处理组,分别饲喂添加需要量水平铜的玉米-豆粕-干乳清粉型饲粮、在未添加外源铜的玉米-豆粕-干乳清粉型饲粮基础上分别添加150、200、250mg/kg铜(源于TBCC)和250mg/kg铜(源于硫酸铜)的饲粮。试验期35d。结果表明,各处理组间猪的日采食量、日增重和耗料/增重比无显著差异(P>0.10),但在表观数字上,以150mg/kg碱式氯化铜源组为最优,250mg/kg的硫酸铜源组次之,200、250mg/kg的碱式氯化铜源组及对照组较差。     

去皮膨化豆粕在断奶仔猪日粮中的应用

试验采用2×3因子设计,在以普通豆粕为主的日粮Ⅰ和以去皮膨化豆粕为主的日粮Ⅱ中分别添加进口鱼粉0%、2.5%和5%,试验共6个处理组,各处理组日粮营养水平相同。将150头31日龄的断奶PIC仔猪(平均体重为6.09￣6.31kg)按体重相近的原则随机分为6个处理组,每处理组5个重复,每个重复5头仔猪,考察去皮膨化豆粕对仔猪生产性能和养分消化率的影响。结果表明,与普通豆粕相比,去皮膨化豆粕能改善仔猪的采食量(P=0.061),提高日增重5.1%,降低腹泻指数31.6%,改善对营养物质的消化率。鱼粉也影响仔猪的生产性能、营养物质消化率和腹泻指数,但与豆粕类型间存在显著的互作效应(P<0.05),普通豆粕日粮中添加鱼粉,仔猪的生产性能、营养物质消化率和腹泻程度均有改善,添加5%鱼粉组效果最好;而去皮膨化豆粕中添加鱼粉除能降低仔猪料肉比外,对仔猪采食量、日增重、营养物质消化率及腹泻指数均无改善作用。试验表明,利用去皮膨化豆粕配制断奶仔猪日粮完全可以不添加鱼粉,但结合生长性能和经济效益考虑,以去皮膨化豆粕日粮中添加2.5%进口鱼粉最好。     

禽流感病毒RT-PCR及多重RT-PCR检测技术的建立

研究建立了禽流感病毒（AIV）A型、H5、N1、H9、N2亚型特异性RT-PCR及HS／N1、H9／N2、A／H5／Nl多重RT-PCR检测技术，用于检测或同时检测和鉴别A型及H5N1、H9N2亚型AIV。所建立的RT-PCR和多重RT-PCR从核酸提取、基因扩增到产物分析在3～4h内即可完成，经对36株AIV及相关病毒分离物检测，与病毒分离鉴定的结果完全一致，且与相关病毒或其他亚型无交叉反应。采用多重RT-PCR检测80份棉拭子样品，并与病毒分离鉴定方法比较，二者H5N1、H9N2亚型的鉴定结果完全吻合。结果表明，该方法具有快速、敏感、特异等优点，为临诊样品中AIV型及H5N1、H9N2亚型鉴定和诊断的有效方法。     

利用触发相机在中国湖南省壶瓶山国家级自然保护区追踪华南虎

2001—2003年的20个月里,我们在中国湖南省壶瓶山国家级自然保护区内设置了一些触发相机,以确定该地区是否存在华南虎（Pantheratigrisamoyensis）。共设置r3种触发相机,包括TrailMaster（美国）的主动式和被动式相机以及WildlifeTwo（中国深圳）的被动式相机。首先在保护区西部沿着小路和动物足迹放置了一些相机。之后又从2002年开始在保护区东部追加放置了一些相机,这是因为有村民报告在这一区域发生了家畜丢失,发现猫科动物足迹以及听到吼叫声。在2002年5月到2003年12月的20个月期间,共8307个拍摄日,获得6180张照片,其中有1437张包括野生动物（平均每100个拍摄日17张野生动物照片）。合计拍摄到33种野生动物。,野猪（Susscrofa）、红腹锦鸡（Chrysolophuspictu．s）和毛冠鹿（Elaphoduscephalophus）是被拍摄最频繁的物种。既没有拍到虎和其他大型猫科动物,也没有拍到水鹿（Cervusunicolor）这种虎重要的猎物。最频繁被拍摄到的猫科动物是豹猫（Prionailurusbengalensis）。村民偶尔报告的掠走山羊的事件可能是豹（Pantherapardta）造成的,但是不能确定。利用触发相机调查超过1000d没有拍摄到虎,这一充分的证据足以支持该调查区没有虎的结论（d=0．05）。20个月超过8300个拍摄日没有在壶瓶山拍摄到虎,显示该地区没有虎。值得注意的结果是拍到红腹锦鸡、黄喉貂（Martesflavigula）、毛冠鹿和黑熊（Ursusthibetanus）的频率很高。这些物种是中国或国际受保护物种,包括被列为国内受保护物种,或同时列为国际受保护物种,又或者像毛冠鹿这种几乎是未知的物种。壶瓶山国家级自然保护区附近有3个保护区。我们讨论建议将这4个保护区合并为一个更大的保护地域来保护虎及其猎物。并且在此简要地评论了我们使用的3种触发相机的性能。     

喹胺醇诱导仔猪氧化损伤的潜在性作用

12头断奶仔猪随机分为2组,分别单剂量口服或静脉注射喹胺醇,检测了给药后48 h内血抗氧化酶活力、MDA含量和血药浓度,旨在评估喹胺醇诱导氧化损伤的潜在性作用。结果,猪单次口服200 mg/kg喹胺醇后,血CAT活力在2～48 h间显著高于给药前（P〈0.05）,GSH含量与CAT活力变化呈相反趋势（P〈0.05）,SOD、GSH-Px、GSH-ST活力、MDA含量未见明显变化;单次注射3.0 mg/kg喹胺醇后,SOD活力在5～30 min内显著低于给药前（P〈0.05）,MDA含量与之呈相反变化,CAT、GSH-Px、GSH-ST活力、GSH含量给药前后均无显著性差异;血药浓度与抗氧化酶活力均呈负相关性,与MDA含量呈正相关性。结果表明,断奶仔猪单剂量口服或注射喹胺醇后,有导致抗氧化机能短暂紊乱的可能,但不会诱发氧应激性损伤。     

鸡IBV、NDV和AIV多重RT-PCR检测方法的初步建立

根据鸡传染性支气管炎病毒M基因、禽流感病毒NP基因和新城疫病毒F基因各设计1对引物,初步建立了针对鸡传染性支气管炎(IB)、新城疫(ND)和禽流感(AI)的多重RT-PCR鉴别诊断方法,并对其特异性和敏感性进行了检测。结果表明,所设计的3对引物可对同一样品中的IBV、NDV和AIV进行特异性扩增,所扩增的目的片断的长度分别为333bp(IBV)、438bp(NDV)和196bp(AIV);建立的多重RT-PCR检测方法能够检测出1ng/μLAIV、1ng/μLNDV和10ng/μLIBV的cDNA,说明该检测方法特异性强,敏感性较高。本研究所建立的多重RT-PCR方法可用于上述3种鸡病毒性呼吸道疾病的快速鉴别诊断,在临床诊断和流行病学调查方面具有较好的应用前景。     

Effects of supplemental L-tryptophan on serotonin, cortisol, intestinal integrity, and behavior in weanling piglets

Stress occurs in intensive pig farming when piglets are weaned and mixed. In this study, we investigated whether this stress might be reduced with elevated dietary levels of Trp. The effects of supplemental dietary Trp (5 g/kg of feed, as-fed basis) were tested on the neuroendocrine system, intestinal integrity, behavior, and growth performance in nursery pigs, both before and after mixing. Mixing occurred 5 d after weaning and diet introduction. On d 4, 5, and 6, Trp-fed pigs vs. control pigs showed approximately a 2-fold elevation in plasma Trp concentrations (68 +/- 7 vs. 32 +/- 2 micromol/L; P < 0.001), a 38% increase in hypothalamic serotonin turnover as measured by 5-hydroxyindoleacetic acid:5-hydroxytryptamine (P < 0.001), and an 11 to 18% increase (P < 0.05) in the intestinal villus height:crypt depth. Before (d 4) and at (d 5) mixing, saliva but not plasma cortisol concentrations were reduced (P < 0.02) by approximately 2-fold in Trp-fed pigs vs. control pigs. Intestinal paracellular (horseradish peroxidase) and transcellular (fluorescein isothiocyanate) transport of macromolecules were not affected by dietary treatment, but mixing induced a 2-fold reduction (P < 0.05) in transcellular transport. Behavioral responses (lying and standing) at mixing were not affected by dietary treatment, except on d 10 after diet introduction when Trp supplementation induced more lying and less standing (P < 0.02). Average daily gain and ADFI were not different among dietary groups (P > 0.10). In conclusion, supplemental dietary Trp (5 g/kg) to piglets increased hypothalamic serotonergic activity, reduced the salivary cortisol response to mixing, improved intestinal morphology, and reduced physical activity 10 d after diet introduction. Consequently, diets containing high Trp levels improved neuroendocrine components of stress and increased gastrointestinal robustness but did not affect behavioral reactivity in nursery pigs during weaning and mixing.