- 學位論文
樹皮萃取物對體外培養臺灣水鹿(Rusa unicolor swinhoii)腸胃道線蟲之影響
In vitro effect of the bark extracts on gastrointestinal nematodes of the Formosan Sambar Deer (Rusa unicolor swinhoii)
摘要
許多鹿科動物都有啃食樹皮行為，而啃食的狀況與原因會隨地點不同而改變。臺灣水鹿在玉山國家公園塔塔加遊憩區的啃食行為主要發生於夏季且有偏好樹種。本研究為檢驗塔塔加地區水鹿啃食樹皮行為是否為驅除腸胃道寄生蟲。本研究於2020年9月至2022年9月在塔塔加地區每月採集水鹿排遺並且檢測腸胃道線蟲感染狀況，並檢驗華山松及鐵杉之樹皮萃取物，是否會降低水鹿排遺中的腸胃道線蟲蟲卵的孵化率及幼蟲的存活率。結果顯示水鹿在塔塔加地區腸胃道線蟲感染強度最高發生於6-8月，並且感染強度與降雨量、溫度、濕度和啃食狀況呈顯著正相關(p<0.05)。在樹皮萃取物方面，華山松及鐵杉樹皮萃取液都顯著降低了腸胃道線蟲蟲卵孵化率及幼蟲存活率(p<0.05)。本研究發現塔塔加地區水鹿啃食樹皮的季節性與寄生蟲感染強度有關係，且樹皮有明確的抑制線蟲蟲卵孵化及存活率的效果，這些結果都支持自我醫療假說。綜合本研究與前人研究的結果，本研究提出「自我醫療與營養補充整合假說」，亦即水鹿是因為腸胃道寄生蟲影響身體狀況和鈣質吸收，因此啃食樹皮以排除體內寄生蟲並補充鈣質。
並列摘要
Bark stripping is a common behavior in cervids, and the state and reason for this behavior vary depending on the location. Bark stripping of Formosan sambar deer mainly occurs during the summer and display a preference for specific tree species in the Tatajia of Yushan National Park. This study aims to examine whether bark stripping of sambar deer is a mean to exclude gastrointestinal parasites in the Tatajia. We collected sambar deer fecel samples from September 2020 to September 2022 in the Tatajia, analyzed gastrointestinal nematode infections. Additionally, extracts from Masters Pine and Taiwan Hemlock bark tested to determine whether they could decrease the hatching rate of gastrointestinal nematode eggs and the survival rate of larvae. The results showed that the highest intensity of gastrointestinal nematode infection in sambar deer occurred from June to August in the Tatajia area. The infection intensity exhibited a significant positive correlation with rainfall, temperature, humidity, and bark stripping behavior(p<0.05). In terms of bark extracts, Masters Pine and Taiwan Hemlock bark extracts significantly decrease the hatching rate of gastrointestinal nematode eggs and the survival rate of larvae.Our results show a correlation between the seasonality of bark stripping behavior and the intensity of parasitic infection. Moreover, the bark extracts exhibited inhibitory effects on the hatching and survival rates of nematode, supporting the self-medication hypothesis. Based on the results of this study and previous research, we propose the "Integrated Hypothesis of Self-Medication and Nutritional Supplementation" for sambar deer. This hypothesis suggests that sambar deer engage in bark stripping behavior to exclude gastrointestinal parasites and supplement calcium due to the impact of parasitic infections on their physical condition and calcium absorption.