豬隻運輸過程中緊迫源與唾液腎上腺皮質醇之關聯性

隨著家畜飼養方式集約化與規模化，家畜活體運輸的移動路徑越來越長，運輸期間動物是否感到緊迫、痛苦逐漸引起社會大眾的關心。因此，動物運輸在近年來已成為動物福利探討的重要議題之一。本試驗旨在以高屏地區商用肉豬為對象，調查運輸過程中豬隻唾液腎上腺皮質醇含量與緊迫源的關聯。每趟運輸隨機採集1至3隻豬隻，於牧場繫留欄位內、牧場車體上和肉品市場車體上之唾液樣本，以酵素聯結免疫吸附分析法（ELISA）檢測腎上腺皮質醇（Cortisol）含量，記錄運輸過程中各項緊迫源變化，再以簡單迴歸、多元複迴歸與非線性迴分別歸探討兩者間之關連，並在調查前針對唾液採集裝置對皮質醇的回收率、唾液腎上腺皮質醇的日夜節律以及豬隻的緊迫試驗進行基礎測驗，確保調查之準確性。基礎測驗結果顯示：本試驗所使用的唾液採集裝置 Cortisol-Salivette®有良好的皮質醇回收率；唾液皮質醇的日夜節律高峰在09:00、11:00 以及 15:00；緊迫試驗中，豬隻唾液皮質醇可以即時地反映豬隻緊迫程度。運輸調查結果發現：電擊棒使用頻率、豬隻承載密度和豬隻驅趕前後的皮質醇變化無顯著關聯（P=0.9184, 0.5294）。豬隻承載密度和豬隻運輸前後皮質醇變化亦無顯著關聯（P=0.2456）。驅趕與運輸時間和豬隻在驅趕及運輸前後的皮質醇變化無顯著關聯（P=0.6760, 0.5520），但當運輸時間界於 35 至 70 分鐘時，運輸時間與皮質醇變化有顯著關聯（R*2=0.5699, P=0.0187）。而豬隻驅趕前後的皮質醇變化與豬隻運輸前後的皮質醇變化有顯著的關聯（R*2=0.3947, P=0.0161）。總時間與豬隻在整趟運輸前後的皮質醇變化則存在幾乎顯著的非線性關聯（P=0.0871）。本研究以調查台灣運輸現況為主軸，調查結果顯示，在現行豬隻運輸過程與操作中，電棒使用頻率與豬隻承載密度等被視為影響動物福利的緊迫源，與豬隻皮質醇變化沒有顯著關聯性。而運輸時間（介於35至70分鐘）與皮質醇變化的顯著關聯顯示豬隻在此時間範圍內，運輸時間越長，皮質醇含量越低，說明豬隻有適應運輸緊迫的能力；豬隻驅趕前後皮質醇變化與運輸前後皮質醇變化之間的顯著關聯，則顯示部分豬隻對於驅趕緊迫並不敏感。總上所述，雖無法明確得知影響豬隻驅趕和運輸的主要緊迫源為何，但可確定豬隻驅趕前後與運輸前後的腎上腺皮質醇含量變化，兩者之間有關連。肉豬場應於豬隻在進入車體前給予良好照護，以提升豬隻運輸時之動物福利。

關鍵字

豬隻動物福利；動物運輸；緊迫；腎上腺皮質醇

並列摘要

With the scale-intensive production of animal husbandry, whether animals feel stressed during transportation has gradually aroused the concern of the public. Thus, animal transportation has become an important issue in animal welfare discussion in recent years. The study aimed to investigate the transportation of commercial pigs in Southern Taiwan. The saliva samples were taken from several pigs randomly before loading, after loading and arrival at the meat market in each transportation. The cortisol level was tested via ELISA. The relationships between cortisol level and various stressors were analyzed via simple linear regression, multiple regression and nonlinear regression. Basal experiments were done before investigation, including recovery rate of saliva collection device, circadian rhythm of salivary cortisol in swine and response of salivary cortisol to stress in swine, in order to ensure the accuracy of investigation. The results of basal experiments showed the saliva collection device in this study has acceptable recovery rate; peaks of circadian rhythm of salivary cortisol are at 09:00, 11:00 and 15:00; salivary cortisol in swine can instantly reflect the degree of stress. The results of investigation of transportation showed no significant correlation between cortisol change after loading and stressors, for example, the use of electric sticks (P=0.9184), loading density (P=0.5294) and loading time (P=0.6760). Same results were found between loading density and cortisol change after transport (P=0.2456). Similarly, no significant correlation was found between cortisol change after transport and transport time (P=0.5520). However, there was a significant correlation between time and cortisol change after transport when the duration is between 35 to 70 minutes (R2=0.5699, P=0.0187). Also, a significant correlation was found between cortisol change after loading and after transport (R2=0.3947, P=0.0161). There is an almost significant nonlinear correlation between total time and cortisol changes (P=0.0871). This study focused on the current status of swine transportation in Taiwan. Interestingly, during the process and the handling of transportation, the use of electric sticks and loading density, the stressors that assumed to compromise animal welfare, have no significant correlation with cortisol changes in pigs. Whether the pigs are able to adapt in the situation of transportation requires further studies. Correlation between cortisol change after loading and after transport showed part of pigs are not sensitive to loading stress. In conclusion, it’s sure that cortisol change after transport is related to cortisol change after loading although the main stressors that exactly affect loading and transport are unclear. Good animal care should be provided when loading pigs into vehicle, in order to improve animal welfare during transportation.