低温胁迫对七带石斑鱼幼鱼血清生化指标的影响

摘要

Serum biochemical parameters were investigated in juvenile Epinephelus septemfasciatus (300 ± 20 g) subjected to low-temperature stress. The experimental fish at a temperature of 12.4 ℃ were directly shifted to a lower temperature seawater (8.0 ℃) for 0, 1, 2, 5, 10 days. The results showed that, the activity of serum AKP showed an irregular variation trend as a result of low temperature stress, and was significantly higher than that in cold water at 2 days. Enzyme activity of GGT showed a parabolic trend with the maximum efficiency in cold water for 2 days, and minimum for lOdays. Glutamate-oxaloacetate (GOT) and glutamyl-transpeptidase (GPT) were increased with the increasing stress duration, and the activities of GOT and GPT at low temperature were significantly higher than those in control group. Enzyme activities of LDH showed insignificant change during the experimental duration. The concentration of serum total protein (TP) showed a descending trend. There was a slight change in concentration of GLU during the prophase of experiment, while the concentration of GLU exposed to low temperature stress at 10 days was 3.9 times high than that in the control group. The concentration of serum TG decreased at earlier stage and mounted at the end of experiment, and no significant difference in TG concentration was found between the initial and end of experiment. CREA concentration showed a similar trend with the TP concentration, declined to 22% of original concentration (48.57±34.96 mmol/L). During the whole experimental duration, no significant difference was found in serum ionic density. In conclusion, juvenile fish with similar size in this experiment can withstand sudden low-temperature change stress and the stress has cumulate effects on juvenile Epinephelus septemfasciatus, indicating that during winter the time offish kept at 8 ℃ should not exceed 10 days in practice.%研究了体质量为(300±20)g的七带石斑鱼幼鱼从12.4℃海水直接转入到8.0℃的海水中,低温胁迫不同持续时间(0、1、2、5、10 d)血清生化指标的变化.结果表明,低温导致AKP活性呈不规则变动,2d时其活性显著高于同期对照.GGT活性先升后降,2d时酶活性最高,10d酶活性最低.GOT和GPT活性随低温胁迫时间延长呈增加态势,10d时与同期对照组之间活性差异显著.LDH活性在胁迫前及实验时期差异均不显著.TP含量随低温胁迫时间延长而下降.GLU胁迫前期变化未达显著性差异,但10d时含量与对照组差异显著.TG含量先降后升,胁迫前与实验结束时所测得的含量无显著性差异.CREA含量的变化趋势与TP相似,也随胁迫时间而降低,10 d时只有胁迫前(48.57+34.96) mmol/L含量的22％.低温胁迫对血清离子浓度变化未产生大的影响,实验前、至低温胁迫10d的测试结果均未达到显著性差异的水平.研究认为,实验幼鱼能适应跳跃式降温胁迫;低温胁迫对七带石斑鱼幼鱼的胁迫有累积效应.在实际生产越冬期间8.0℃低温时间不宜超过10d.