Engineering Research Center for Saline-alkaline Fisheries, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, China.
Sino-US Joint Laboratory of Aquatic Animal Physiology, East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Sciences, Shanghai, China.
Fish Physiol Biochem. 2020 Dec;46(6):1981-1990. doi: 10.1007/s10695-020-00850-4. Epub 2020 Jul 16.
Naked carp (Gymnocypris przewalskii), endemic to the saline-alkaline Lake Qinghai, have the capacity to tolerate combined hypoxia and high alkalinity. This study evaluated the effect of the interaction between carbonate alkalinity and hypoxia on ammonia excretion and blood gas variation in naked carp. Naked carp were subjected to normoxic, hypoxic and reoxygenation phases at two different carbonate alkalinity levels (CA0 = 0 mmol/L; CA32 = 32 mmol/L) for 4 days. The ammonia excretion rate (J) of the CA0 group rapidly decreased under hypoxia and recovered under normoxia for four consecutive days. The J under CA32 also decreased under hypoxia and recovered to its previous level in the first 2 days. However, the J under CA32 was lower than that under CA0. The blood pO, sO of CA0 and CA32 group was significantly reduced under hypoxia, after which both groups recovered. Blood pCO of the CA32 group was lower than CA0 throughout the experiment. There were no changes in haematocrit of the naked carp exposed to carbonate alkalinity and hypoxia. The alkaline water increased the pH of the blood and contributed to increased haemoglobin O affinity. Overall, the present findings reveal that naked carp is a tolerant species that can maintain main ionic homeostasis under severe alkalinity and hypoxia. The high alkaline water is beneficial for naked carp to adapt to hypoxic environment.
裸鲤（Gymnocypris przewalskii）是青海盐湖特有的物种，具有耐受缺氧和高碱性的能力。本研究评估了碳酸盐碱度与缺氧相互作用对裸鲤氨排泄和血气变化的影响。将裸鲤暴露于两种不同碳酸盐碱度水平（CA0 = 0 mmol/L；CA32 = 32 mmol/L）的正常氧、缺氧和再氧化阶段 4 天。CA0 组在缺氧下的氨排泄率（J）迅速下降，并在连续 4 天恢复正常氧水平。CA32 下的 J 也在缺氧下下降，但在第 2 天恢复到之前的水平。然而，CA32 下的 J 低于 CA0。CA0 和 CA32 组的血液 pO、sO 在缺氧下显著降低，之后两组均恢复。整个实验过程中，CA32 组的血液 pCO 均低于 CA0。暴露于碳酸盐碱度和缺氧的裸鲤的红细胞压积没有变化。碱性水增加了血液的 pH 值，增加了血红蛋白 O 的亲和力。总的来说，本研究结果表明，裸鲤是一种耐受物种，能够在严重的碱性和缺氧条件下维持主要离子的内稳态。高碱性水有利于裸鲤适应缺氧环境。
