猪流行性腹泻病毒或猪德尔塔冠状病毒攻毒对保育猪的生长性能和组织沉积的影响

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猪流行性腹泻病毒或猪德尔塔冠状病毒攻毒对保育猪的生长性能和组织沉积的影响

S. M. Curry, K. A. Gibson, E. R. Burrough,K. J. Schwartz, K. J. Yoon and N. K. Gabler

　　猪流行性腹泻病毒（PEDV）和猪德尔塔冠状病毒（PDCoV）都是可引起腹泻、脱水甚至死亡等临床症状的冠状病毒家族的成员。目前有很多专注于这些病毒的分离、基因组测序、致病性和毒力方面的研究，但接种PEDV和PDCoV后猪只长期的生长性能和组织沉积方面的信息就相当的少。因此本试验的目的就是为了探明接种PEDV或PDCoV后42天内猪只的生长性能和组织增长情况。挑选75头断奶两周左右且未感染PEDV和PDCoV的Choice Genetics大白纯系阉公猪和小母猪（体重=10.81 ± 0.81 kg）。考虑体重和性别因素将猪只随机分为三个处理组，每个处理8个栏。各处理设置如下：1）对照组（n = 8）；2）PEDV接种组（n = 8）；3）PDCoV接种组（n = 8）。在接种后第2、5、7和14天时将猪只进行安乐死后收集组织，并进行后续处理分析。在接种后第2、5、7天，以及其后的每周都要记录栏采食量和栏重直到接种后第42天。每栏指定一头猪，采用双能X射线吸收计量法（DXA）对猪只的初始和最终的体组成进行测量，6周试验期间的组织增长率也要被测量。通过对猪只的粪便样品进行实时定量PCR分析后得出PEDV感染的峰值是在接种后第三天，而PDCoV感染的峰值为接种后的第4天。整个试验期间对照组试验猪保持未感染PEDV和PDCoV。总的来说，对照组和PDCoV接种组猪只在平均日增重、日均采食量和料肉比方面并无差别（P > 0.05）。PEDV接种组猪只在42天整个试验期内日均采食量相较对照组和PDCoV接种组分别下降了19%和27%。相较对照组和PDCoV接种组，PEDV并没有显著降低整个试验期的日增重和料肉比；然而，相较对照组来说，PEDV接种组日增重和日均采食量最大幅度的下降（P < 0.05）发生在接种后14天内。由于流行性腹泻，猪只整个机体组织的增长受到影响，与对照组猪只相比，其脂肪、瘦肉、蛋白和骨矿物质沉积都分别下降了24%、20%、21%和42%（P < 0.05）。综上所述，保育猪的生长性能极大的受到了PEDV的影响。奇怪的是，PDCoV并没有对保育猪的生长性能产生负面影响。该试验为进一步探明猪肠道冠状病毒对生长猪的纵向影响提供了线索。

Nursery pig growth performance and tissue accretion modulation due to porcine epidemic diarrhea virus or porcine deltacoronavirus challenge

S. M. Curry, K. A. Gibson, E. R. Burrough,K. J. Schwartz, K. J. Yoon and N. K. Gabler

Porcine epidemic diarrhea virus (PEDV) and porcine deltacoronavirus (PDCoV) are both members of the family Coronaviridae which induce clinical signs of diarrhea, dehydration, and in some circumstances, mortality. Most research has been focused on isolation, genome sequencing, pathogenicity, and virulence of these viruses, but there is little information on long-term growth performance and tissue accretion of pigs inoculated with PEDV or PDCoV. Therefore, our objective was to determine the effect of PEDV or PDCoV infection on growth performance and tissue accretion over 42 d following inoculation. A total of 75 Choice Genetics Large White Pureline barrows and gilts (BW = 10.81 ± 0.81 kg) at approximately 2 wk post-wean and na&#239;ve for PEDV and PDCoV were selected. Pigs were allotted based on BW andsex, stratified across 3 treatments with 8 pens per treatment. Treatments were:1) Control (n = 8); 2) PEDV inoculated (n = 8); and 3) PDCoV inoculated (n =8).On day post inoculation (dpi) 2, 5, 7, and 14 pigs were euthanized for tissue collection and analyses from these tissues are discussed elsewhere. Pen feed intake and BW were recorded on dpi 2, 5, 7, and weekly thereafter until dpi 42. On 1 designated pig per pen, initial and final body composition was determined using dual-energy X-ray absorptiometry (DXA) and tissue accretion rates were calculated over 6 wk test period. Peak PEDV infection was noted at 3dpi compared with 4 dpi for PDCoV pigs as determined by fecal swab quantitative real-time PCR (RT-PCR). Control pigs remained negative for PEDV and PDCoV throughout the experiment. Overall, Control and PDCoV pigs did not differ in ADG, ADFI or G:F (P > 0.05). Compared to Control and PDCoV pigs, the overall 42 d ADFI was reduced in the challenged PEDV pigs (P < 0.05) by 19 and 27%, respectively. PEDV did not significantly reduce the overall ADG or G:F compared with Control and PDCoV pigs; however, the biggest reduction in ADG and ADFI for PEDV pigs was within 14 dpi compared to the Control pigs (P < 0.05). Whole body tissue accretion was altered due to PED, with fat, lean, protein, and bonemineral accretion reductions by 24, 20, 21, and 42%, respectively (P < 0.05) compared with Control pigs. Overall, nursery pig performance was greatly impacted by PEDV challenge. Surprisingly, the PDCoV challenge did not negatively influence nursery pig performance. This study provides further insight into the longitudinal impact swine enteric coronaviruses have on growing pigs.

来源：猪营养国际论坛CSIS    翻译：李光燃