摘要
将点篮子鱼(Siganus guttatus)幼鱼由25℃转移至14℃、15℃、16 ℃、17℃和18℃条件下处理96h,测定在不同温度下、不同时间点点篮子鱼幼鱼肝脏抗氧化酶活性和丙二醛(MDA)含量变化,探讨了温度骤降对点篮子鱼幼鱼肝脏抗氧化酶活性的影响.结果显示:随着温度的降低和处理时间的延长,除14℃组外,其余各组超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GPX)活性均呈现先升后降的趋势;14℃组,SOD和GPX活性在3h时达到最高值,随着处理时间的延长,酶活性持续下降,在96 h时达到最低;14℃组CAT活性在处理后持续降低,在12h时达到最低,之后逐渐升高并在96 h时显著高于对照组.所有处理组中MDA含量随着处理时间的延长呈现出先升高后降低的趋势,最终各组MDA含量均显著高于对照组(P＜0.05).实验表明,温度骤降能激活点篮子鱼幼鱼肝脏中抗氧化酶活性,消除低温应激产生的活性氧自由基(ROS),但肝脏内MDA含量显著增加,表明点篮子鱼仍处于氧化应激状态.在14℃时,抗氧化酶活性变化趋势与25℃及其余温度处理组间均存在明显差异,表明此实验条件下鱼体不能适应14℃的温度.
Abstract
As fishes can not maintain their body temperatures,any alteration in water temperature affects their physiological and behavioral activities.Studies have shown that the survival of fish is closely related with water temperature,pressure,light and other factors.Changes in water temperature can cause a variety of physiological stress responses in fish.This can induce fish to accelerate metabolism and increase energy demand,accompanied by excessive production of reactive oxygen species.Excessive accumulation of free radicals can damage proteins,nucleic acids,sterols and other substances and result in cell membrane lipid peroxidation,which can weaken immune defense capability of fish and decrease resistance to disease,thereby affecting the normal growth of fish.Effects of low-temperature on the activities of antioxidant enzymes (SOD,CAT and GPX) and the MDA contents in the liver of juvenile rabbit fish (Siganus guttatus) (4.029 ± 0.669) g were investigated.Rabbit fish were acclimated for a month in aquaculture water with temperature (25 ±+ 1) ℃,salinity 10.Rabbit fish were fed with artificial feeds three times a day and residual baits were cleared after 40 minutes of feeding.After acclimation,the low-temperature stress experiment was conducted.The temperature of aquaculture water was maintained at 13 ℃,14 ℃,15 ℃,16 ℃,17 ℃ and 18 ℃ as six treatment groups,and control group of 25 ℃,and each group consisted of three parallels.We sampled the liver at 0,3,6,12,24,48,72 and 96 hours during the experiment,and examined the activities of antioxidant enzymes and the MDA contents.Results showed that as the temperature of aquaculture water decreased,the survival rate of rabbit fish.After the low-temperature treat,13 ℃ group rabbit fish all died within 10 min; 14 ℃ group rabbit fish had a large number of deaths at the start of the experiment,and then the survival rate dropped rapidly to 15％ at 3 h,and was only 2.5％ at 96 h; 15 ℃ group rabbit fish showed death at the beginning,with the extension of low-temperature stress,the survival rate at 96 h decreased to 65.0％ ; 16 ℃ group with a small amount of juvenile death at the beginning,and the survival rate was 97.5％ during the whole experiment; 17 ℃,18 ℃ and 25 ℃ groups rabbit fish showed no death,and the survival rate was 100％.Results also showed that low-temperature exercised a great effect on the activities of antioxidant enzymes.The activities of SOD,CAT and GPX in each group first increased and then gradually decreased except 14 ℃ group.When the temperature dropped to 14 ℃,there were significant differences in CAT activities and trends between 14 ℃ and 25 ℃ control groups,while not in SOD and GPX activities.There was no significant difference of SOD activities between the low-temperature treatment groups and 25 ℃ control group at 96 h (P ＞ 0.05),while SOD activity of 14 ℃ group was significantly lower than that of the rest of low-temperature treatment groups (P ＜ 0.05) ; CAT and GPX activities were significantly lower than that of 25 ℃ control group at 96 h (P ＜0.05).In addition,MDA contents in 14 ℃,15 ℃,16 ℃ and 17 ℃ treatment groups first increased and then decreased.MDA contents of 18 ℃ treatment group changed instablely with time,and had no significantly difference with 25 ℃ control group (P ＞ 0.05).The MDA contents of all treatment groups significantly increased at 3 h (P ＜ 0.05) and were significantly higher than that of 25 ℃ control group at 96 h (P ＜ 0.05),the contents of MDA showed an substantial increase trend as the temperature decreased.In conclusion,the plunge of water temperature may activate antioxidant enzymes activities in the liver of juvenile rabbit fish,and eliminate reactive oxygen species (ROS) induced by low-temperature stress.We found that there was a certain complementarity between CAT and GPX,which was in line with previous studies.The significant increase in MDA contents in the liver of juvenile rabbit fish indicated that the juvenile fish was in an oxidative stress state.The significant differences of the trends of antioxidant enzymes activities between 14 ℃ group and 25 ℃ control group indicated that juvenile rabbit fish can not adapt to the low temperature of 14 ℃ in such experimental conditions.
基金项目
中央级公益性科研院所基本科研业务费专项资金项目(2012T03)
农业科技成果转化资金项目(2013GB23260595)
上海市科技兴农推广项目(沪农科推字2014第3-2号)
国家科技期刊平台
NSTL
维普
万方数据