高温应激对鳜幼鱼血清生化指标及肝脏sod基因和热休克蛋白基因表达的影响

Effects of high-temperature stress on serum biochemical indexes,liver sod gene and heat shock protein gene expression of juvenile Siniperca chuatsi

  • 摘要: 【目的】探究高温环境下鳜(Siniperca chuatsi)幼鱼血清生化指标、免疫指标、肝脏抗氧化相关基因表达的变化规律,明确其对高温的效应及耐受限度,为鳜在高温环境下的科学养殖提供参考依据。【方法】以21℃为对照组,设25、29和33℃等3个高温组,对鳜幼鱼进行96 h的高温应激试验,通过血清生化指标试剂盒测定血清生化及免疫指标,并采用实时荧光定量PCR检测鳜幼鱼肝脏抗氧化相关基因的表达情况。【结果】在高温应激下鳜幼鱼血清的葡萄糖(Glu)浓度、甘油三酯(TG)浓度、总胆固醇(TC)浓度、谷丙转氨酶(ALT)活性和谷草转氨酶(AST)活性均有不同程度变化,且同一生化指标在同一时间不同应激温度下的差异明显。随着应激时间的延长,鳜幼鱼血清Glu浓度整体上呈先降低后升高的变化趋势; TG和TC浓度整体上呈下降趋势,应激96 h后各高温处理组的血清TG和TC浓度均低于对照组; 33℃处理组的血清TP浓度也呈先降低后升高的变化趋势,但各高温处理组与对照组间的差异均不显著(P>0.05,下同); 25℃处理组的血清ALT活性在应激48 h时显著升高(P<0.05,下同),29℃处理组的血清AST活性则在应激24 h时显著升高;各高温处理组的血清溶菌酶(LZM)活性基本上高于对照组,应激48 h后各高温处理组的血清免疫球蛋白M(IgM)浓度整体上低于对照组。鳜幼鱼肝脏sod基因相对表达量随应激温度的升高整体上呈上升趋势,hsp90α基因相对表达量随应激时间的延长或应激温度的升高基本上呈先升高后降低的变化趋势,hsp70α基因相对表达量则整体上呈下降趋势。【结论】高温环境致使鳜幼鱼产生强烈的应激反应,为避免因应激而导致氧化损伤,鳜幼鱼通过提高sod基因表达、增加能量利用及减少IgM合成和分泌进行自我调节,但应激后期由于应激时间过长或应激强度超过其调节能力,致使鳜出现组织损伤。由于高温应激对鳜幼鱼生理代谢产生显著影响,并降低其非特异性免疫能力,因此在鳜养殖生产中应加强高温季节的养殖管理,避免水温快速变化带来不利影响,并做好鳜的病害防控工作。

     

    Abstract: 【Objective】 To explore the changes in serum biochemical indicators, immune indicators, and liver antioxidant related gene expression of juvenile Siniperca chuatsi under high-temperature environment, clarify their effects on high temperature and tolerance limits, and provide reference for scientific cultivation of S. chuatsi under high-temperature environment.【Method】 Using 21℃ as the control group, three high-temperature groups of 25, 29 and 33℃ were set up to carry out a 96 h high-temperature stress test on juvenile S. chuatsi. The serum biochemical and immune indexes were determined by serum biochemical indicator kit, and the expressions of antioxidant related genes in liver of juvenile S. chuatsi were detected by real-time fluorescent quantitative PCR.【Result】 Under high-temperature stress, the serum glucose(Glu) concentration, triglyceride(TG) concentration, total cholesterol(TC) concentration, alanine aminotransferase(ALT) activity, and aspartate aminotransferase(AST) activity of juvenile S. chuatsi changed in varying degrees, and the same biochemical index had great differences at different stress temperatures at the same time. With the prolongation of stress time, the serum Glu concentration of juvenile S. chuatsi showed a trend of decreasing first and then increasing;the concentrations of TG and TC showed a downward trend on the whole, and the concentrations of TG and TC in the serum of each high-temperature treatment group were lower than those of the control group after 96 h of stress;the serum TP concentration in the 33℃ treatment group also showed a trend of decreasing first and then increasing, but there was no significant difference between the high-temperature treatment groups and the control group(P>0.05, the same below). The serum ALT activity in the 25℃ treatment group significantly increased at 48 h of stress(P<0.05, the same below), while the serum AST activity in the 29℃ treatment group significantly increased at 24 h of stress;the activity of serum lysozyme(LZM) in each high-temperature treatment group was basically higher than that in the control group, and the serum immunoglobulin M(IgM) concentration in each high-temperature treatment group was generally lower than that in the control group after 48 h of stress. The relative expression of sod gene in the liver of juvenile S. chuatsi generally increased with the increase of stress temperature, the relative expression of hsp90α gene basically increased first and then decreased with the prolongation of stress time or the increase of stress temperature, the relative expression of hsp70α gene showed a downward trend overall.【Conclusion】 High-temperature environment causes a strong stress response in juvenile S. chuatsi. In order to avoid oxidative damage caused by stress, juvenile S. chuatsi self-regulate by increasing the expression of sod gene, increasing energy utilization, and reducing the synthesis and secretion of IgM. However, in the late stage of stress, due to prolonged stress or stress intensity exceeding its regulatory capacity, the S. chuatsi undergoes tissue damage. Since high-temperature stress has a significant impact on the physiological metabolism of juvenile S. chuatsi and reduces their non-specific immunity, it is necessary to strengthen the cultivation management of S. chuatsi during the high-temperature season, avoid adverse effects caused by rapid changes in water temperature, and prevent S. chuatsi from diseases.

     

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