碩士 / 國立臺灣大學 / 漁業科學研究所 / 89 / Larvae whose organs are under developing uptake plenty of Ca2+ from water for development. However, the environment fish inhabited varies in Ca2+ concentration from 0.002 mM (softwater) to 10 mM (seawater). The purpose of the present study is to compare the strategies of the larvae of different species, goldfish (Carassius auratus), zebrafish (Danio rerio) and ayu (Plecoglossus altivelis), in calcium balance mechanism. Pre-hatched embryos were incubated in low-, mid- and high-Ca2+ artificial freshwater to determine their Ca2+ balance capabilities, which were examined via the measurement of whole body Ca2+ content and Ca2+ influx. Moreover, larvae acclimated to mid-Ca2+ medium were directly transferred to low-Ca2+ medium to determine their sensitivities to low-Ca2+ environments. In addition, the Ca2+ uptake kinetics were deteremined in zebrafish and goldfish incubated in high- or low-Ca2+ artificial freshwater. The results showed that Ca2+ content of both zebrafish and ayu acclimated to low-Ca2+ media were significantly lower than those acclimated to mid- or high-Ca2+ media after long term acclimation. However, Ca2+ content of goldfish in low-, mid- and high-Ca2+ groups showed no significant difference. In the aspect of the Ca2+ influx rate, low-Ca2+ group was significantly higher than mid- and high-Ca2+ groups in goldfish after long term acclimation. In contrast, the Ca2+ influx rate in low-Ca2+ group was significantly lower than that in mid- and high-Ca2+ groups in zebrafish and ayu. During low-Ca2+ challenges, goldfish, zebrafish and ayu reduced their Ca2+ influx with different degrees, i.e., 72-88%, 49-72% and 35-65%, respectively. These data indicates that goldfish are more resistant to low-Ca2+ environments among the three species.
3-day-old goldfish larvae acclimated to low-Ca2+ environment resulted in a 13% increase in Jmax and an 84% decrease in Km when compared to that acclimated to high-Ca2+ group. Similar changes were also found in zebrafish larvae (8% increase in Jmax and a 67% decrease in Km). From the present study, it is concluded that Ca2+ uptake efficiency in fish larvae varies among the three species. Goldfish possesses a more effective Ca2+ regulatory capacity than do zebrafish and ayu. The differences in the strategies for Ca2+ balance may be associated with the differences in the development patterns and the inhabiting environments.
| Identifer | oai:union.ndltd.org:TW/089NTU00451011 |
| Date | January 2001 |
| Creators | Yi-Yen Chen, 陳怡燕 |
| Contributors | Pung-Pung Hwang, 黃鵬鵬 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 47 |
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