Tropical Aquaculture Research and Development Center, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Sanya, China.
Key Laboratory of Efficient Utilization and Processing of Marine Fishery Resources of Hainan Province, Sanya Tropical Fisheries Research Institute, Sanya, China.
PLoS One. 2023 Oct 5;18(10):e0289606. doi: 10.1371/journal.pone.0289606. eCollection 2023.
Heat is a powerful stressor for fish living in natural and artificial environments. Understanding the effects of heat stress on the physiological processes of fish is essential for better aquaculture and fisheries management. In this experiment, a heating rod was used to increase the temperature at 2°C/h to study the changes of energy allocation (CEA) and energy metabolity-related enzyme activities, including pepsin, trypsin, amylase, lipase, acid phosphatase, lactate dehydrogenase, alanine aminotransferase, glutamic oxalic aminotransferase and energy reserve (Ea), energy expenditure (ETS), in juvenile yellowfin tuna cells under acute temperature stress. The results showed that the Ea of juvenile yellowfin tuna muscles in response to high temperature (34°C) was significantly lower than that of the control (28°C), and it also increased ETS. At 6 h, CEA decreased slightly in the high-temperature group, but, the difference in CEA between 24 h and 0 h decreased. After heat stress for 6 h, the activities of acid phosphatase (ACP), lactate dehydrogenase (LDH), alanine aminotransferase (ALT) and glutamic oxalacetic transaminase (AST) increased, indicating that the metabolic rate was accelerated. After heat stress for 24 h, the activity of ALT decreased, indicating that with time elapsed, the activities of some protein metabolizing enzymes increased, and some decreased. In this study, digestive enzymes, trypsin and lipase increased gradually. After heat stress, Ea and Ec change significantly. Yellowfin tuna muscles use lipids in response to sharp temperature increases at high temperatures, red muscles respond to temperature changes by increasing energy in the early stages, but not nearly as much, and white muscles reduce lipids.
热是生活在自然和人工环境中的鱼类的一个强大压力源。了解热应激对鱼类生理过程的影响对于更好的水产养殖和渔业管理至关重要。在这项实验中，使用加热棒将温度以 2°C/h 的速度升高，以研究能量分配 (CEA) 和与能量代谢相关的酶活性的变化，包括胃蛋白酶、胰蛋白酶、淀粉酶、脂肪酶、酸性磷酸酶、乳酸脱氢酶、丙氨酸氨基转移酶、谷氨酸草酰基氨基转移酶和能量储备 (Ea)、能量支出 (ETS)，在急性温度应激下，黄鳍金枪鱼幼鱼细胞。结果表明，黄鳍金枪鱼幼鱼肌肉对高温（34°C）的 Ea 明显低于对照（28°C），并增加了 ETS。在 6 小时时，高温组的 CEA 略有下降，但 24 小时和 0 小时之间的 CEA 差异减小。热应激 6 小时后，酸性磷酸酶（ACP）、乳酸脱氢酶（LDH）、丙氨酸氨基转移酶（ALT）和谷氨酸草酰基氨基转移酶（AST）的活性增加，表明代谢率加快。热应激 24 小时后，ALT 活性下降，表明随着时间的推移，一些蛋白质代谢酶的活性增加，而一些则减少。在这项研究中，消化酶胰蛋白酶和脂肪酶逐渐增加。热应激后，Ea 和 Ec 变化明显。黄鳍金枪鱼肌肉在高温下急剧升高时使用脂肪，红肌在早期通过增加能量来应对温度变化，但不如白肌多，白肌减少脂肪。
