郭欽明2006-08-312018-07-062006-08-312018-07-061998-07-31http://ntur.lib.ntu.edu.tw//handle/246246/29805Tilapia is one of economically important culture species in Taiwan, and its culture industry has contributed significantly to the national economic development. Since tilapias, a tropical species which are known less tolerant to the cold, are suitable for culture in the warm season of the year, mass mortality has often occurred in the winter when the cold front prevails, and consequently resulted in catastrophic loss in the industry. The objectives of this research are aimed to comprehend the physiological responses, energy metabolism mechanisms , expression and biological functions of cold-shock proteins in order to develop reliable technology for improved cold tolerance of commercial important cultured species, tilapia. The achievements will certainly contribute tremendously to sustained growth of aquaculture industry in this country. Diversification in temperature tolerance and adaptation mechanisms in teleosts have been evolved from species differences in temperature niche. The temperature compensation mechanisms, species- specific under a defined temperature environment, enable fish by its capacity adaptation to maintain physiological homeostasis, but in adverse environment, a strategy of resistance adaptation is unanimously followed for survival and propagation. The behavioral responses and energy consumption for temporal thermal acclimation and the metabolic process, among others, for a long-term adaptation are reliable indicators to the state of thermal compensation towards physiological homeostasis. Alternation in key enzyme activities and metabolic pathway have been the general paradigm of thermal acclimation and adaptation at the subcellular levels. Hyperglycemic responses of tilapias were clearly demonstrated at 15 °C. The blood glucose content was markedly elevated from 42.89 mg/dl to 88.09 mg/dl in 2 hr. Similarly, the cold toerant grass carps at 12 °C showed the increase in the blood glucose from 62.44 mg/dl to 93.35 mg/dl in 6 hr, and the responses were much pronounced in tilapias than grass carps. In contrary, the blood glucose increased from 42.89 mg/dl to 57.26 mg/dl in 1 hr for the tilapias at 10 °C, which believed a low lethal limit of this species, evidences suggested that tilapias have shown a sign of physiological exhausion resulting from the degration of regulatory capabilities under this particular temperature. Hyperglycemia is therefore concluded to be a general stress response in fish, and the difference in the hyperglycemic response reflects a speciesspecific difference in the thermal tolerance. A significant elevation of blood lactate was only detected in the tilapias at 10 °C, but not in other treatments. This suggests that lactate is produced through anaerobic metabolic pathway to meet a burst demand in the energy source under the extreme thermal condition. Finally, the oxygen consumption is a reliable indicator for physiological conditions of fish, and the trend of changes in the oxygen consumption was found highly correlated with the temperatures and the duration of sustained stimulation.吳郭魚為台灣重要養殖魚種之一，其 產業對台灣漁業發展上是相當重要的。惟 因吳郭魚為熱帶魚種，適於高溫養殖，每 在冬季寒流來襲之際，因其耐寒性欠佳而 大量凍斃，產業損失甚為慘重，有鑑於此， 就吳郭魚對低溫之生理反應與能量代謝的 調節進行全盤性研究，探討本省主要養殖 經濟魚種吳郭魚與耐寒性強之草魚在低溫 適應下能量代謝型態及途徑之異同﹐確定 吳郭魚耐寒性不足之生理因素，就此，應 用生物技術以改進吳郭魚耐寒性，為本研 究之主要目標。 魚類在不同棲息環境下生存繁衍，經 由適應演化發展出對水溫變動的調節機 能，出現耐溫性不同的魚種，因而，每一 魚種對於水溫環境變動，具有與生俱來的 適應潛力，以維持生理狀態的恆定性。魚 類遭遇到低溫壓迫時，就低溫衝擊之幅 度，魚類立即產生行為反應及生理上的反 應與調節，以抒解低溫對生理機能產生的 影響。本研究中吳郭魚之耐寒性欠佳，在 15 ℃低溫之急速刺激下，血糖量的增加非 常明顯，僅僅在2 hr 內即由42.89 mg/dl 遽 增至88.09mg/dl，增加幅度達2 倍之多。 吳郭魚暴露於10 ℃水溫中，血糖量僅由 42.89 mg/dl，在1 小時內增加到57.26 mg/dl，雖然血糖量增加幅度不甚顯著，主 要原因在於吳郭魚對10 ℃之刺激反應，生 理已失去調節能力, 呈現衰減的結果。至於 耐寒性草魚，在12℃低溫下，血糖量亦有 增加之現象，但其增加幅度相當有限，在6 hr 內由62.44 mg/dl 增加到93.35 mg/dl。由 此可見，血糖量的增加是共同性的次級壓 迫反應。不同耐寒性魚種對相近低溫之刺 激，所產生之反應程度確有明顯之差異。 血乳酸量的明顯變化僅出現於10 ℃ 水溫下、乃源自於掙扎所造成的結果。至 於氧氣消耗量之下降、是與水溫之高低及 剌激持續時間呈相關性。application/pdf69610 bytesapplication/pdfzh-TW國立臺灣大學漁業科學研究所Cold temperature adaptationEnergy metabolismCold shock protein耐寒性血糖量能量代謝酵素吳郭魚草魚[SDGs]SDG8journal articlehttp://ntur.lib.ntu.edu.tw/bitstream/246246/29805/1/872311B002026B28.pdf