| Summary: | 碩士 === 國立屏東科技大學 === 熱帶農業研究所 === 90 === This study aims at investigating the effects of water temperature, ammonia-N and nitrite-N on the immune response of Taiwanese abalone, Haliotis diversicolor supertexta.
First examined was the immune factors of the abalone, including phenoloxidase activity (PO), superoxidase anion (O2-), total blood cells, phagocytosis, and clearance efficiency when the abalone was exposed to different water temperatures at 20, 24, 28 and 32℃ for 0, 24, 72 and 120 hours. The mortality rates were determined after the abalone was challenged with an injection of Vibrio parahaemolyticus. The results showed that the abalone had a higher disease resistance after being exposed to the water temperature at 20 and 24℃. However, the disease resistance significantly decreased at 28 and 32℃ (p＜0.05). The PO activity was significantly declined at 32℃, but increased at 20℃ when the exposure time was prolonged. After being exposed for 24 hours at 20 and 32℃, the total blood cell counts of the abalone significantly increased as compared with the initial counts taken at the beginning of the treatment. There was an inverse relationship found between the O2- concentration and the PO activity at 20℃. Both of the phagocytosis and the clearance efficiency were recovered after 120 hours and remained stable thereafter. At the lower water temperatures, the immune response of the abalone appeared to be better adaptable.
The immune response of the abalone was determined when it was exposed to ammonia-N solution at concentrations of 0.01 mg/l, 1.08 mg/l, 3.16 mg/l, 5.37 mg/l and 10.04 mg/l for 0, 24, 72 and 120 hours. After challenging with V. parahaemolyticus, the mortality rate of the abalone increased with the increase of the concentration of ammonia-N solution. The PO activity decreased when the abalone was exposed to the ammonia-N solution, except at the concentration of 1.08 mg/l, where the PO activity recovered after 120 hours. The O2- concentration significantly increased when the abalone was exposed to ammonia-N solution at all the concentrations above 3.16 mg/l, except at 10.04 mg/l. The O2- concentration decreased at 10.04 mg/l after 72 hours and remained at a stable condition. However, this concentration was still higher than the initial concentration determined at the beginning of the treatment. Both of the phagocytosis and the clearance efficiency decreased with the increase of the ammonia-N concentrations.
The immune response of the abalone was determined when it was exposed to nitrite-N solution at concentrations of 0.02 mg/l, 0.96 mg/l, 2.85 mg/l, 5.03 mg/l and 10.16 mg/l for 0, 24, 72 and 120 hours. After challenging with V. parahaemolyticus, the mortality rate of the abalone increased at the nitrite-N concentration of 10.16 mg/l. The PO activity at all of the concentrations of nitrite-N increased after 24 hours. However, the activity at the concentrations above 2.85 mg/l decreased with the increase of the exposure time. Despite the decrease, this activity was still higher than the initial activity measured at the beginning of the treatment. The O2- concentration increased with the increase of both of the exposure time and the nitrite-N concentration. The phagocytosis and the clearance efficiency decreased with the increase of the nitrite-N concentration. The phagocytosis and the clearance efficiency could be used as health indicators for the abalone under the stress of ammonia-N and nitrite-N.
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