| 摘要: |
| 以体长（1.932±0.204）cm、体质量（1.386±0.055）g的棘胸蛙蝌蚪为实验动物，在水温（24±0.2）℃、DO（7.30±0.01）mg/L、pH 7.30±0.01条件下，采用静水停食法开展了氨氮对蝌蚪的急性攻毒实验，并以此为基础，测定了不同氨氮质量浓度胁迫下棘胸蛙蝌蚪的排氨率、耗氧率、氧氮比及窒息点。结果表明：（1）蝌蚪对氨氮急性攻毒具明显的运动避毒行为，濒死个体的背部皮肤和肝脏均具明显的色变症状；（2）氨氮对蝌蚪的急性致死率具明显的剂量-时间效应，24h、48h、72h、96h LC50依次为177.5、151.7、148.6和146.8mg/L，毒性时段蓄积程度系数呈持续下降趋势，24-48h、48-72h、72-96h的时段MAC值分别为84.04%、10.1%和5.86%；（3）蝌蚪夜均、昼均、日均及时段排氨率随氨氮质量浓度增加均呈阶梯式下降趋势，其中时段排氨率与对照组均无显著差异的为9.80mg/L实验组，夜均、昼均、日均及时段排氨率与对照组均无显著差异的仅为2.45mg/L实验组（P>0.05）；（4）氨氮对蝌蚪呼吸耗氧具低毒兴奋效应，其夜均、昼均和日均耗氧率随氨氮质量浓度增加均呈先升后降趋势，峰值氨氮质量浓度范围均为4.90-7.35mg/L（P<0.05），与对照组均无显著差异的仅为14.70mg/L实验组（P>0.05），窒息点含氧量随氨氮质量浓度增加呈先降后升趋势，谷底出现于4.90mg/L实验组（P<0.05），与对照组无显著差异的仅为9.80mg/L实验组（P>0.05）；（5）实验期间，蝌蚪氧氮比（O：N）波动于18.87-25.34之间，昼均和日均氧氮比（O：N）随氨氮质量浓度增加均依次呈"上升-稳定-下降-再稳定"之趋势，两者的峰值氨氮质量浓度范围分别为4.90-14.70mg/L和4.90-9.80mg/L，夜均氧氮比（O：N）呈先升后降趋势，峰值出现于7.35mg/L实验组（P<0.05）。 |
| 关键词: 棘胸蛙蝌蚪 氨氮 急性毒性 排氨率 耗氧率 氧氮比(O:N) 窒息点 |
| DOI：10.11693/hyhz20180500109 |
| 分类号:S966.3 |
| 基金项目:余姚市与浙江海洋学院市院合作项目：棘胸蛙集约化高效养殖关键技术集成与综合示范，2013—2016。 |
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| ACUTE EFFECT OF AMMONIA TOXICITY ATTACK ON MORTALITY, AMMONIA EXCRETION RATE, OXYGEN CONSUMPTION AND SUFFOCATION POINT ON PAA SPINOSA TADPOLES IN AQUATIC ECONOMY |
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NIU Chun-Ge1, YANG Cheng2, SHEN Tu-Yan1,3, ZHENG Xiao-Jing1, WANG Zhi-Zheng1
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1.Zhejiang Ocean University, Zhoushan 316022, China;2.Ningbo Marine and Fisheries Research Institute, Ningbo 315000, China;3.Yuyao Aquatic Technology extension Center, Yuyao 315040, China
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| Abstract: |
| The Paa spinosa tadpoles with a length of 1.932±0.204cm and body weight of 1.386±0.055g were used as experimental animals. Under the condition of water temperature of 24±0.2℃, DO 7.30±0.01mg/L and pH 7.30±0.01, the acute effect of ammonia toxicity attack on tadpoles was carried out with the method of static water without feeding and the basis of this condition to determine the ammonia excretion rate, oxygen consumption, the proportion of oxygen and nitrogen and suffocation point of Paa spinosa tadpoles under different ammonia concentration exposure. The results shows that (1) tadpoles had obvious exercise avoidance behavior for against acute attack of ammonia, so the back skin and liver of the dying individual have obvious symptom of chromosis; (2) tadpoles have significant dose-time effect of ammonia nitrogen on acute mortality, 24h, 48h, 72h and 96h LC50 were 177.5, 151.7, 148.6 and 146.8mg/L in succession. The cumulative degree coefficient of toxic time showed a downward trend, and the value of MAC in the time frame 24-48h, 48-72h and 72-96h were 84.04%, 10.1% and 5.86% respectively. (3) The rate of ammonia excretion of the tadpoles decreased step by step with the increase of ammonia concentration in average night. There was no significant difference in ammonia excretion rate between 9.80mg/L experimental group and control group and there was no significant difference in night average, day average, daily average and period ammonia excretion rate between 2.45mg/L experimental group and control group (P>0.05). (4) The effect of ammonia nitrogen on respiration and oxygen consumption of tadpoles was low. The rate of oxygen consumption at night, day and day increased first and then decreased with the increase of ammonia concentration. The range of the peak concentration of ammonia nitrogen was 4.90-7.35mg/L (P<0.05), but there was no significant difference between the 14.70mg/L group and the control group (P>0.05). The oxygen content in the asphyxiating point decreased first and then increased with the increase of the concentration of ammonia nitrogen. The bottom of the valley appeared in the 4.90mg/L experimental group (P<0.05), but there was no significant difference between the 9.80mg/L experimental group (P>0.05) and the control group (P>0.05). (5) During the experiment, the oxygen nitrogen ratio of tadpoles fluctuated between 18.87-25.34, and the average daily oxygen nitrogen ratio (O:N) increased with the increase of ammonia concentration. The peak NH3-N concentration ranges were 4.90-14.70mg/L and 4.90-9.80mg/L, respectively. The average oxygen and nitrogen increased first and then decreased in the 7.35mg/L experimental group (P<0.05). |
| Key words: Paa spinosa tadpoles ammonia acute toxicity ammonia excretion rate oxygen consumption rate oxygen to nitrogen ratio:(O:N) asphyxiation point |
