豬流行性腹瀉病毒或豬德爾塔冠狀病毒攻毒對保育豬的生長性能和組織沉積的影響

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豬流行性腹瀉病毒或豬德爾塔冠狀病毒攻毒對保育豬的生長性能和組織沉積的影響

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

　　豬流行性腹瀉病毒（PEDV）和豬德爾塔冠狀病毒（PDCoV）都是可引起腹瀉、脫水甚至死亡等臨床癥狀的冠狀病毒家族的成員。目前有很多專注于這些病毒的分離、基因組測序、致病性和毒力方面的研究，但接種PEDV和PDCoV后豬只長期的生長性能和組織沉積方面的信息就相當的少。因此本試驗的目的就是為了探明接種PEDV或PDCoV后42天內豬只的生長性能和組織增長情況。挑選75頭斷奶兩周左右且未感染PEDV和PDCoV的Choice Genetics大白純系閹公豬和小母豬（體重=10.81 ± 0.81 kg）。考慮體重和性別因素將豬只隨機分為三個處理組，每個處理8個欄。各處理設置如下：1）對照組（n = 8）；2）PEDV接種組（n = 8）；3）PDCoV接種組（n = 8）。在接種后第2、5、7和14天時將豬只進行安樂死后收集組織，并進行后續處理分析。在接種后第2、5、7天，以及其后的每周都要記錄欄采食量和欄重直到接種后第42天。每欄指定一頭豬，采用雙能X射線吸收計量法（DXA）對豬只的初始和最終的體組成進行測量，6周試驗期間的組織增長率也要被測量。通過對豬只的糞便樣品進行實時定量PCR分析后得出PEDV感染的峰值是在接種后第三天，而PDCoV感染的峰值為接種后的第4天。整個試驗期間對照組試驗豬保持未感染PEDV和PDCoV。總的來說，對照組和PDCoV接種組豬只在平均日增重、日均采食量和料肉比方面并無差別（P > 0.05）。PEDV接種組豬只在42天整個試驗期內日均采食量相較對照組和PDCoV接種組分別下降了19%和27%。相較對照組和PDCoV接種組，PEDV并沒有顯著降低整個試驗期的日增重和料肉比；然而，相較對照組來說，PEDV接種組日增重和日均采食量最大幅度的下降（P < 0.05）發生在接種后14天內。由于流行性腹瀉，豬只整個機體組織的增長受到影響，與對照組豬只相比，其脂肪、瘦肉、蛋白和骨礦物質沉積都分別下降了24%、20%、21%和42%（P < 0.05）。綜上所述，保育豬的生長性能極大的受到了PEDV的影響。奇怪的是，PDCoV并沒有對保育豬的生長性能產生負面影響。該試驗為進一步探明豬腸道冠狀病毒對生長豬的縱向影響提供了線索。

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.

來源：豬營養國際論壇CSIS    翻譯：李光燃