影响西藏卤虫无节幼体在淡水中存活时间的几个因素分析

ANALYZING SURVIVAL FACTORS OF NAUPLII IN FRESHWATER ON ARTEMIA IN TIBET AUTONOMOUS REGION, CHINA

  • 摘要: 为对水产养殖育苗实践中活体饵料西藏卤虫(Antemia tibetiana)的应用提供参考, 研究不同钠盐对孵化率、无节幼体在淡水中存活时间的影响, 分析NaCl浓度、孵化液pH和淡水水温等因素对西藏卤虫无节幼体在淡水中存活时间, 记录各组无节幼体在淡水中50%和100%死亡所需时间。结果表明, 不同钠盐显著影响西藏卤虫的孵化率, Na2SO4组显著高于NaCl组(P<0.05), Na2CO3组显著低于NaCl组(P<0.01), 其他各组之间差异不显著(P>0.05)。以NaCl组孵化出的无节幼体在淡水中存活时间最长, 50%存活时间达13h, Na2SO4组孵化的无节幼体存活时间显著低于NaCl组(P<0.05), 而Na2CO3和NaNO3组存活时间极显著低于NaCl组(P<0.01), 在Na2CO3中孵化的无节幼体死亡速度最快。孵化率高的实验组存活时间不是最长, 显示孵化率与存活率之间并无关联性。随着孵化液NaCl浓度升高, 无节幼体在淡水中存活时间逐渐延长, 至35‰时达到最高, 但当孵化液NaCl浓度达40‰时, 存活时间开始下降。随着孵化液pH从6.5—8.0逐渐升高, 存活时间逐渐延长, 至pH8.0时达到最高, 孵化液pH继续升高, 存活时间逐渐缩短, 到pH10.0时, 50%存活时间只有3.54h, 死亡速度最快, pH8.0组与其他实验组相比较差异显著(P<0.05)。在5℃淡水中无节幼体50%死亡时间为18.54h, 显著长于15℃水温组, 当水温≥20℃时, 所有组别50%存活时间短于水温15℃组, 差异显著(P<0.05)。孵化时钠盐的种类、NaCl浓度、孵化液pH和淡水水温对西藏卤虫无节幼体在淡水中存活时间有显著影响。

     

    Abstract: Artemia is an important living bait in Tibet Autonomous Region, China, which has been widely used in aquaculture and breeding practice. The survival time of nauplii in freshwater affects the utilization rate of feeding. This study explored the effects of different sodium salts on hatching rates and survival time of nauplii in freshwater. The nauplii survival time of Artemia in Tibet in freshwater under different NaCl contents, incubation pH and freshwater temperatures were analyzed, and the 50% and 100% of nauplii mortalities in freshwater were recorded to provide reference for breeding practice. The results indicated that different sodium salts significantly affected the hatching rate of Artemia in Tibet with the highest hatching rate in Na2SO4 group was significantly higher than that in NaCl group (P<0.05), the lowest hatching rate in Na2CO3 was significantly lower than that in NaCl group (P<0.01), and no significant difference among other groups (P>0.05). The survival time of nauplii hatched in the NaCl group was the longest with a 50% survival time of 13 hours, while the survival time of nauplii hatched in the Na2SO4 group was shorter than that in NaCl group (P<0.05). The lowest survival time of nauplii was the Na2CO3 group, and both Na2CO3 and NaNO3 groups had lower hatching rate than that in NaCl. The mortality of nauplii hatched in Na2CO3 was the fastest among all groups. These results indicated no correlation between hatching rate and survival rate. As the hatching salinity increases, the survival time of nauplii in freshwater gradually prolonged and reached the longest at the salinity of 35‰, but when the hatching salinity reached 40‰, the survival time began to decrease. As pH increases from 6.5 to 8.0, the survival time of nauplii increased and reached the longest at pH=8.0, and then the survival time gradually decreased when incubation pH continued to increase. 50% survival time of naupliiwas only 3.54h at pH 10.0 with the highest mortality. The 50% survival time of nauplii incubated in pH8.0 was prolonged compared with other groups (P<0.05). The 50% death time of nauplii in freshwater at 5℃ was 18.54h, which was significantly longer than that in the 15℃ group. When the water temperature was ≥20℃, the 50% survival time in all groups decreased significantly than that in the 15℃ group (P<0.05). These results indicated that sodium salt, salinity, incubation pH, and freshwater temperature have significant effects on the nauplii survival time in freshwater of Artemia in Tibet Autonornous Region.

     

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