The Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao 266003, China.
The Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao 266003, China.
Comp Biochem Physiol C Toxicol Pharmacol. 2019 Jul;221:73-81. doi: 10.1016/j.cbpc.2019.04.001. Epub 2019 Apr 4.
Pacific white shrimp, Litopenaeus vannamei (9.38 ± 0.17 cm, 10.08 ± 0.35 g), with different ammonia-N tolerances were exposed to NH (1.61 mg/L) for 192 h, and the levels of key enzymes and biochemical substances involved in energy metabolism were compared to assess the role of the regulation of energy metabolism on the shrimp's adaptation to ammonia-N stress. Higher ammonia-N tolerance in the shrimp (Tolerance group) was achieved through nutritional fortification, whereas shrimp that were not nutritionally fortified comprised the Control group. The mortality rates in the Control and Tolerance groups at the end of the period of ammonia-N stress exposure were 64.44% and 40.00%, respectively. Within 1 h of exposure to ammonia-N stress, the glucose concentration in both groups declined rapidly, and no significant difference was detected between the two groups. In general, the triglyceride and cholesterol concentrations in the Control group were higher than those in the Tolerance group, and accumulations and/or fluctuations in these metabolites to varying degrees were observed. The Tolerance group presented higher phosphofructokinase (PFK) and pyruvate kinase (PK) activity compared with the Control group from 1 to 48 h of exposure to ammonia-N stress, whereas the opposite result was observed from 96 to 192 h. Similarly, during exposure to ammonia-N stress, the Tolerance group showed higher and lower lactate dehydrogenase (LDH) activity than the Control group from 1 to 24 h and from 48 to 92 h, respectively. In addition, compared with the Control group, the shrimp in the Tolerance group exhibited higher succinate dehydrogenase (SDH) activity, especially from 48 to 192 h of exposure to ammonia-N stress. The results of this study suggest that anaerobic carbohydrate (in the early stage) and aerobic metabolism (in the late stage) plays an important role in the shrimp's response to ammonia-N stress. In addition, maintenance of the normal operation of lipid metabolism is equally important for improving the tolerance of L. vannamei to ammonia-N stress.
太平洋白对虾（9.38±0.17cm，10.08±0.35g），具有不同的氨氮耐受能力，分别暴露于 NH（1.61mg/L）192h，比较参与能量代谢的关键酶和生化物质的水平，以评估能量代谢的调节在虾适应氨氮胁迫中的作用。通过营养强化，虾的耐氨氮能力（耐受组）得到提高，而未进行营养强化的虾组成对照组。在氨氮胁迫暴露结束时，对照组和耐受组的死亡率分别为 64.44%和 40.00%。暴露于氨氮胁迫 1h 内，两组虾的葡萄糖浓度迅速下降，两组间无显著差异。一般来说，对照组的甘油三酯和胆固醇浓度高于耐受组，并且这些代谢物在不同程度上积累和/或波动。与对照组相比，耐受组在暴露于氨氮胁迫的 1-48h 内，磷酸果糖激酶（PFK）和丙酮酸激酶（PK）活性更高，而在 96-192h 时则相反。同样，在暴露于氨氮胁迫期间，耐受组的乳酸脱氢酶（LDH）活性在 1-24h 和 48-92h 时均高于对照组，而在 96-192h 时则低于对照组。此外，与对照组相比，耐受组的虾在暴露于氨氮胁迫的 48-192h 时，琥珀酸脱氢酶（SDH）活性更高，尤其是在暴露于氨氮胁迫的 48-192h 时。本研究结果表明，在虾应对氨氮胁迫的过程中，无氧碳水化合物（早期）和有氧代谢（晚期）起着重要作用。此外，维持脂代谢的正常运转对提高南美白对虾对氨氮胁迫的耐受性同样重要。
