电晕休眠对珍珠龙胆石斑鱼无水保活生理响应的影响

EFFECTS OF ELECTROCUTION DORMANCY ON THE PHYSIOLOGICAL RESPONSES OF PEARL GROUPER (EPINEPHELUS FUSCOGUTTATUS × E. LANCEOLATUS) UNDER HYPOOSMOTIC TRANSPORT CONDITIONS

  • 摘要: 为探讨鱼类电晕休眠低温无水保活新技术, 研究采用单因素实验与响应面法优化珍珠龙胆石斑鱼的电晕诱导休眠工艺参数, 探讨电晕休眠无水保活及复苏后鱼体的生化响应、氧化应激指标及能量代谢的变化规律。结果表明, 珍珠龙胆石斑鱼在电压为126 V、电击时间为5s、温度为18℃的条件下, 在15℃下的无水存活时间最长, 可达到(15.92±0.3)h。鱼体电晕休眠后, 随着无水保活时间的延长, 血清葡萄糖(GLU)含量和乳酸脱氢酶(LDH)活性显著增加(P<0.05); 脑组织中氧化应激指标谷胱甘肽S转移酶(GST)活性和热休克蛋白70 (HSP70)的含量显著提升(P<0.05), 相比于对照组, 分别增加了54.33%和22.46%。在此过程中, 低温无水保活胁迫下脂质过氧化物MDA和ROS的产生受到明显抑制, 说明鱼体通过提高GST的活性和HSP70的含量可以缓解保活过程中的氧化应激反应, 激活了鱼体在应激过程中抗氧化防御机制。此外, 电晕休眠处理, 鱼体的糖原含量显著提高(P<0.05), 以抵御无水保活过程中能量的消耗, 维持鱼体的能量代谢平衡。进行复苏后, 鱼体可以维持至与对照组相当的较低代谢水平。电晕休眠技术有效延长了珍珠龙胆石斑鱼的存活时间, 通过提高抗氧化能力增强了其对环境胁迫的耐受性, 为水产运输提供了一种高效、低成本且环境友好的解决方案, 为鱼类的活体运输提供新模式。

     

    Abstract: With the continuous development of global aquaculture, fish transportation has become a crucial issue for the efficient growth of the industry. As a high-value aquatic species, the Pearl grouper (Epinephelus fuscoguttatus × E. lanceolatus) often experiences severe stress during transportation due to factors such as environmental changes, high density, and prolonged transportation time, which leads to a decline in immune function and even mortality. Traditional aquaculture transportation relies on water to meet the physiological needs of fish, but the consumption of nutrients and oxygen in the water often becomes a bottleneck that limits long-duration transport. The dry preservation technology, as an innovative transportation method, significantly reduces the use of water, lowers transportation costs, and extends transportation time and distance. However, traditional live transportation technologies rely on chemical anesthesia and hypothermic dormancy, which have raised concerns regarding drug residues and extended durations. Therefore, the corona sleep technology, a green, safe, and efficient new physical induction method, has gradually become a research hotspot. Currently, research on the application of corona sleep technology in Pearl grouper mainly focuses on its combination with low-temperature water-based preservation techniques. However, studies on combining it with dry preservation techniques are not yet reported. This study takes the Pearl grouper as the experimental subject and uses pulsed direct current electric shocks to induce dormancy, aiming to explore the joint application of corona sleep technology and dry preservation techniques. Through single-factor experiments combined with response surface optimization, the optimal corona sleep parameters for Pearl grouper were determined: voltage 126 V, shock time 5s, shock temperature 18°C, frequency 30 Hz, current 1 A, and duty cycle 25%. Under these conditions, the corona treatment induced dormancy, and the dormant grouper survived for (15.92±0.34)h in dry preservation at 15°C. Under the optimal corona treatment conditions, the biochemical responses, oxidative stress indicators, and energy metabolism changes of the grouper during dry preservation were analyzed. The results showed that with the extension of preservation time, the levels of cortisol (COR) and glucose (GLU) in the serum significantly increased (P<0.05). The COR level reached its maximum value at 14h, increasing by 50.39% compared to the control group. Blood glucose content significantly increased between 3 and 14h of dry preservation (P<0.05), indicating that the fish maintained blood glucose levels through gluconeogenesis. The activity of lactate dehydrogenase (LDH) continued to increase, suggesting that corona-induced dormancy triggered severe physiological stress, leading to elevated stress indicators. In addition, the levels of glutathione S-transferase (GST) and heat shock protein 70 (HSP70) in the liver and brain tissues significantly increased (P<0.05), helping to alleviate the oxidative damage caused by the corona treatment and suppress the production of lipid peroxidation product malondialdehyde (MDA) and reactive oxygen species (ROS) during the low-temperature dry preservation process. This indicates that the fish’s antioxidant system was effectively activated, reducing the damage caused by environmental stress. Glycogen in the liver significantly decreased between 3h and 14h, while lactate in the muscles gradually increased, which was consistent with the rise in lactate dehydrogenase (LDH) activity, suggesting enhanced anaerobic metabolism. As the dry preservation time increased, glycogen was depleted and lactate accumulated. After rehydration, lactate levels significantly decreased, indicating that the fish had resumed aerobic metabolism. This suggests that the corona-induced dormancy technology can regulate energy metabolism pathways and alleviate energy consumption under low-oxygen conditions. In conclusion, the corona-induced dormancy technology can effectively extend the survival time of pearl gentian grouper in a dry environment. Moreover, it alleviates stress damage during dry preservation by activating antioxidant defense mechanisms and energy metabolism pathways. This study provides a novel and eco-friendly technological solution for live transportation of pearl gentian grouper and other marine fish species, laying a theoretical foundation and practical guidance for the future development of aquaculture and transportation technologies.

     

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