池塘溶氧昼夜变化对鳜葡萄糖代谢和血糖含量的影响

The effect of diel variation of dissolved oxygen content in a pond on the glucose metabolism and plasma glucose level of Siniperca chuatsi

中文关键词: 鳜  溶氧  昼夜变化  血糖  葡萄糖代谢

英文关键词: Siniperca chuatsi  Dissolved oxygen  Diel variation  Plasma glucose  Glucose metabolism

中文摘要:

      为探究池塘溶氧昼夜变化对鳜(Siniperca chuatsi)葡萄糖代谢和血糖含量的影响，本研究分别在17:00 (T1)、23:00 (T2)、次日07:00 (T3)、11:00 (T4)、17:00 (T5)共5个连续时间点采样并测定分析，比较了鳜池塘常氧组(>5 mg/L)与昼夜溶氧变化组葡萄糖代谢相关指标的时序差异。结果显示，1 d中，池塘溶氧经历常氧与低氧的周期性变化，T3时，池塘溶氧最低，平均为0.93 mg/L；T5时，池塘溶氧最高，平均为10.58 mg/L。T3和T4时，血浆中葡萄糖显著降低，乳酸含量显著升高；肝脏中肝糖原含量下降，乳酸含量显著升高，ATP含量显著降低；肝脏有氧代谢柠檬酸合酶(CS)活性显著降低，无氧代谢酶乳酸脱氢酶(LDH)活性显著升高；糖酵解酶中己糖激酶(HK)、磷酸果糖激酶(PFK)、丙酮酸激酶(PK)活性显著升高，糖原分解酶糖原磷酸化酶(GP)活性无显著变化；hk、pfk、pk、ldh-a和gp基因表达量显著上升，cs表达量显著下降，葡萄糖转运蛋白glut2表达量无显著变化。研究表明，鳜养殖池塘中，溶氧存在昼夜周期性交替变化，溶氧水平的下降会引起鳜葡萄糖代谢发生变化，由有氧代谢转变为无氧代谢而导致能量利用方式发生变化。

英文摘要:

      Diel variation of dissolved oxygen content in aquaculture is common. Generally, the dissolved oxygen content in the pond is the highest in the afternoon and the lowest in the early morning. Siniperca chuatsi usually feeds in the early morning because of its unique feeding habits, therefore the low dissolved oxygen level may affect its metabolism. In this study, S. chuatsi was subjected to different oxygen conditions, a control group (>5 mg/L) and an experimental group (dissolved oxygen changed with sunlight) for 24 h to determine glucose metabolism systemically. The following results were obtained: (1) Dissolved oxygen level in the experimental group that underwent periodic variation was the lowest at 07:00, with an average dissolved oxygen level of 0.93 mg/L; and the dissolved oxygen was the highest at 17:00, with an average dissolved oxygen level of 10.58 mg/L. (2) At T3 and T4, the plasma content of experimental group significantly decreased and lactic acid content increased significantly; liver glycogen and ATP content decreased, whereas lactic acid content increased significantly. (3) At T3 and T4, the activities of the key enzymes involved in glucose metabolism in liver varied; the activity of aerobic metabolism enzyme citrate synthase (CS) significantly decreased while that of anaerobic metabolism enzyme lactate dehydrogenase (LDH) increased significantly; the activity of glycolysis enzyme hexokinase (HK), phosphate fructose kinase (PFK), pyruvate kinase (PK) increased significantly and the activity of glycogenolytic enzyme glycogen phosphorylase (GP) exhibited no significant difference. (4) At T3 and T4, the expression of hk, pfk, pk, ldh-a, gp genes in the experimental group increased significantly, the expression of cs significantly decreased, and the expression of glucose transporter 2 (glut2) was not significant difference. Thus, when diel variation periodically changed dissolved oxygen level in the pond, lower dissolved oxygen level lead to change in glucose metabolism, from aerobic metabolism to anaerobic metabolism, and the energy utilization mode of S. chuatsi had changrd.