保育與肥育豬隻豬肺炎型黴漿菌與豬鼻炎型黴漿菌感染狀況之調查

Investigation of infection status of Mycoplasma hyopneumoniae and Mycoplasma hyorhinis in nursery and finishing pigs

吳孟恬(Wu Meng-Tien)

指導教授 ： 邱明堂 ； 林昭男

國立屏東科技大學/獸醫學院/獸醫學系所/碩士(2021年)

https://doi.org/10.6346/NPUST202100130

摘要

豬黴漿菌性肺炎又稱豬地方性肺炎（swine enzootic pneumonia, SEP），常見乾咳與生長速率下降等臨床症狀，為保育與肥育期豬隻常見疾病，此病致病率高而致死率低，但在繼發細菌性病原感染後，容易使豬隻致死率上升，造成豬場經濟損失。SEP主要由豬肺炎型黴漿菌（Mycoplasma hyopneumoniae, MHP）引起，另有研究指出豬鼻炎型黴漿菌（Mycoplasma hyorhinis, MHR）可單獨感染豬隻，並引起與SEP相似之肉眼及組織病變。在台灣關於MHP及MHR在保育與肥育期之流行病學與檢出率相關研究較少，因此本研究目的為調查台灣保育與肥育豬隻的MHP及MHR檢出率、肺臟之病原定量比較及血清抗體力價之變化。208隻保育豬與189隻上市肥育豬樣本分別來自國立屏東科技大學動物疾病診斷中心與屠宰場，挑選有SEP肉眼病變之肺臟，以即時定量聚合酶連鎖反應檢測MHP、MHR及GAPDH基因，並進行相對定量分析。而確認為MHP及MHR陽性之肺臟樣本，會以原位雜合技術確認此兩種病原於肺臟組織的陽性訊號量。另選定四場有兩種MHP免疫計畫的豬場，將其分為VA與VB組，各場於3、8、12、16、20、24週齡分別採集兩組豬隻各10頭，每場共120管血液樣本，以酵素結合免疫吸附分析法檢測血清中MHP與MHR抗體力價，並分析抗體力價變化趨勢。保育豬的MHR qPCR陽性率（88.0%）顯著高於MHP qPCR陽性率（26.4%）（p<0.0001）；上市肥育豬的MHP 陽性率（94.7%）顯著高於MHR 陽性率（69.3%）（p<0.0001）；上市肥育豬的MHP陽性率顯著高於保育豬（p<0.0001），而保育豬的MHR陽性率顯著高於上市肥育豬（p<0.0001），保育豬MHR的相對定量值顯著高於MHP（p<0.0001），上市肥育豬則是MHP的相對定量值高於MHR（p<0.0001），顯示MHP與MHR易於不同飼養階段的豬隻檢出。原位雜合技術發現MHP與MHR陽性訊號出現的組織位置高度相似，而兩者的陽性細胞數並無顯著差異。MHP抗體檢測結果顯示，各場的VB組在施打疫苗後皆比VA組產生更高量的血清IgG量。24週齡的MHR血清抗體陽性率介於30-85%，顯示田間有高比例豬隻曾感染MHR，而豬場間的盛行率差異很大。本研究僅針對有SEP肉眼病變的肺臟檢測病原並另行檢測四間豬場的血清抗體力價，未來針對MHP與MHR的盛行率調查可更廣泛採樣，包含上呼吸道拭子與血清，個別檢測抗原與抗體，以獲得更完善的資料。

關鍵字

黴漿菌性肺炎 ； 豬肺炎型黴漿菌 ； 豬鼻炎型黴漿菌

並列摘要

Mycoplasmal pneumonia, also known as swine enzootic pneumonia (SEP), induces clinical signs such as dry cough and growth rate reduction in pigs, with high morbidity and low mortality and common in nursery and finishing pigs. Mortality will rise with secondary bacterial infections and such condition causes economic losses of the swine industry. SEP is mainly caused by Mycoplasma hyopneumoniae (MHP). However, Mycoplasma hyorhinis (MHR) also can induce gross and microscopic lesions of SEP. In Taiwan, there is currently limited information about the detection rate of MHP and MHR. Therefore, the aims of this study were to investigate the detection rate of MHP and MHR in nursery and finishing pigs in Taiwan, comparing quantity of MHP and MHR in lung, and dynamic of specific serum antibody titer. Two hundred and eight samples of nursery pigs and 189 samples of finishing pigs were collected at Animal Disease Diagnosis Center in National Pingtung University of Science and Technology and slaughterhouse, respectively. Real-time polymerase chain reaction was used to detect MHP, MHR and GAPDH genes, and the relative quantification had been analyzed. MHP and MHR in situ hybridization (ISH) had been employed to confirm quantity of the positive signal. Four pig farms that received two programs of MHP vaccination and divided into VA and VB groups were chosen, and 120 serum samples were collected from each farm. Serum samples from suckling to finishing pigs were collected and detected antibody titers by enzyme-linked immunosorbent assay (ELISA) and analyzed the dynamics of antibody titer. In nursery pigs, detection rate of MHR (88.0%) was significantly higher than MHP (26.4%) (p<0.0001). In finishing pigs, detection rate of MHP (94.7%) was significantly higher than MHR (69.3%) (p<0.0001). Relative quantification ratio of MHR was significantly higher than MHP in nursery pigs (p<0.0001) and was opposite in finishing pigs (p<0.0001). It suggested that MHP and MHR had been detected in different breeding age. ISH positive signal of MHP and MHR appeared at similar position, and there was no significant difference of positive cell number between MHP and MHR. VB groups had a higher IgG titer against MHP than VA group after vaccination in all 4 pig farms. Positive rate of MHR ELISA were ranged from 30% to 85% in 24 week-age pigs. It suggested that high proportion of pigs were infected MHR before slaughtering, but the prevalence varied greatly among different pig farms. This study just detected MHP and MHR in lungs with gross lesions of SEP and antibody of MHP and MHR in four pig farms. Therefore, swab sample of upper respiratory tract and serum could be collected for respective detection of pathogen and antibody in the future to obtain more comprehensive data about the prevalence of MHP and MHR.

並列關鍵字

Mycoplasmal pneumonia ； Mycoplasma hyopneumoniae ； Mycoplasma hyorhinis

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