盐度和温度对中国鲎幼鲎耗氧率和排氨率的影响

Effects of Salinity and Temperature on Oxygen Consumption and Ammonia Excretion Rates of Juvenile Tachypleus tridentatus

关键词:  中国鲎  盐度  温度  耗氧率  排氨率  氧氮比

Key words:  Tachypleus tridentatus  salinity  temperature  oxygen consumption rate  ammonia excretion rate  O/N

摘要:

为研究盐度和温度对中国鲎（Tachypleus tridentatus）幼鲎呼吸代谢的影响，采用单因子试验测定盐度和温度对两阶段幼鲎（1龄和2龄）耗氧率和排氨率的影响。结果显示，在盐度5-40、温度25-37℃时，中国鲎1龄幼鲎的耗氧率为19.50-29.70 μg/（g·h），2龄幼鲎为35.37-56.12 μg/（g·h）；随着盐度的升高，1龄和2龄幼鲎的耗氧率和排氨率均呈先降低后升高的趋势，1龄幼鲎耗氧率和排氨率最低值出现在盐度35和盐度30试验组，2龄幼鲎最低值则均出现在盐度20试验组，盐度与耗氧率、排氨率之间的关系符合二次回归方程；温度为25-33℃时，幼鲎的耗氧率和排氨率随温度的升高而显著升高（P<0.05），两阶段幼鲎耗氧率和排氨率的最高值均出现在33℃试验组，当温度继续升高到37℃时，幼鲎的耗氧率和排氨率均出现明显下降趋势(P<0.05），温度与幼鲎耗氧率、排氨率之间的关系也符合二次回归方程；不同盐度下幼鲎的O/N大体上呈先增大后减少的趋势，1龄幼鲎O/N最大值出现在盐度30试验组，2龄幼鲎最大值出现在盐度20试验组，不同温度下1龄和2龄幼鲎的O/N的变化趋势正好相反。以上研究表明，中国鲎幼鲎的耗氧率整体处于较低水平，且其代谢主要由蛋白分解供能；盐度和温度对幼鲎的代谢均有显著影响，高盐或低盐情况下幼鲎的代谢率显著高于适宜盐度条件，温度高于33℃时幼鲎的代谢率不升反降。

Abstract:

In order to explore the effects of salinity and temperature on the respiratory metabolism of juvenile Tachypleus tridentatus, a single factor experiment was used to measure salinity and temperature on the oxygen consumption rate and ammonia excretion rate of the two-stage juvenile T.tridentatus (1st and 2nd instars). The results showed that the oxygen consumption rate of the 1st and 2nd instar juvenile T.tridentatus were 19.50-29.70 μg/(g·h) and 35.37-56.12 μg/(g·h) respectively, under the conditions of salinity 5-40 and temperature 25-37℃. With the increase of salinity, the oxygen consumption and ammonia excretion rates of the 1st and 2nd instar juvenile T.tridentatus tended to decrease first and then increase. The lowest values of oxygen consumption rate and ammonia excretion rate of the 1st instar juvenile T.tridentatus were found in the salinity 35 and 30 test groups, and that of the 2nd instar juvenile T.tridentatus were found all in salinity 20 test group. The relationship between salinity and oxygen consumption rate or ammonia excretion rate conformed to the quadratic regression equation. When the temperature was 25-33℃, the oxygen consumption rate and ammonia excretion rate of juvenile T.tridentatus increased significantly with the increase of temperature (P<0.05). The highest values of oxygen consumption rate and ammonia excretion rate of two stages of juvenile T.tridentatus both appeared in the 33℃ test group. When the temperature continued to rise to 37℃, the oxygen consumption rate and ammonia excretion rate of juvenile T.tridentatus decreased significantly (P<0.05).The relationship between temperature and oxygen consumption rate and ammonia excretion rate of juvenile T.tridentatus also conformed to the quadratic regression equation. In general, the O/N value of the juvenile T.tridentatus increased first and then decreased under different salinity levels. The maximum O/N value of the 1st instar juvenile T.tridentatus was found in the salinity of 30 test group, and that of the 2nd instar juvenile T.tridentatus was in the salinity of 20 test group.Under different temperatures, the change trend of O/N value of the 1st and 2nd instar juvenile T.tridentatus was opposite.The above studies indicated that the oxygen consumption rate of juvenile T.tridentatus was at a low level, and its metabolism was mainly powered by protein decomposition.Salinity and temperature had significant effects on the metabolism of juvenile T.tridentatus.The metabolic rate of juvenile T.tridentatus under high or low salinity was significantly higher than that under suitable salinity condition. When the temperature was higher than 33℃, the metabolic rate decreased rather than increased.