碱度胁迫对青海湖裸鲤血清生理生化指标的影响

Effects of alkalinity stress on serum physiological indexes of Gymnocypris przewalskii

【目的】探究碱度对青海湖裸鲤(Gymnocypris przewalskii)相关生理生化指标的影响,对制定青海湖裸鲤应对碱环境的策略提供理论参考。【方法】以青海湖裸鲤血清为研究对象,进行慢性碱度胁迫,碱度先逐渐上升至最高点后逐渐降低(未胁迫为对照),测定分析取各胁迫点血清中激素、渗透、能量、氧化及免疫等指标的变化。【结果】青海湖裸鲤血清的皮质醇(COR)、钙(Ca^(2+))、血糖(GLU)、渗透压(OS)、Na^(+)/K^(+)-ATPase(NKA)、碳酸酐酶Ⅱ(CAⅡ)、碳酸酐酶Ⅳ(CAⅣ)、总蛋白(TP)、白蛋白(ALB)、球蛋白(GLOB)、甘油三酯(TG)、丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GPX)和丙二醛(MDA)变化趋势相同,均为随碱度升高先升高后下降,随碱度降低则先下降后升高。COR与CAIV、总胆固醇(TC)、ALT、GPX和MDA呈极显著正相关(P<0.01),与TP、GLOB、高密度脂蛋白(HDL-C)、低密度脂蛋白(LDL-C)、TG和CAT呈显著正相关(P<0.05,下同)。胰岛素样生长因子Ⅰ(IGF-Ⅰ)、超氧化物歧化酶(SOD)、钠(Na^(+))、碱性磷酸酶(AKP)和酸性磷酸酶(ACP)有相同变化趋势,无论碱度升高还是下降,均呈先下降后升高变化趋势。三碘甲状腺原氨酸(T3)、TC、HDL-C和LDL-C与碱度呈负相关,肌酐(CREA)和总胆红素(TBIL)与碱度呈正相关。IGF-Ⅰ与T3呈显著正相关。甲状腺激素(T4)含量和乳酸脱氢酶(LDH)活力随碱度升高先升高后下降再恢复,之后随碱度降低先下降后升高。生长激素(GH)和氯(Cl-)随碱度升高先升高后下降再升高,之后随碱度降低逐渐升高。催乳素(PRL)含量随碱度升高先稍微下降后恢复再降低,之后随碱度降低先迅速升高后恢复。钾(K^(+))浓度随碱度升高而下降,随碱度降低先升高后下降。尿酸(UA)含量随碱度升高先下降后恢复,随碱度降低逐渐下降。尿素(UREA)含量随碱度升高先升高后恢复再升高,随碱度降低继续升高后恢复。【结论】在碱度胁迫时,青海湖裸鲤COR起主导作用,T3和IGF-Ⅰ协同,T4调控GH辅助,从而维持鱼类的体液稳态;TP、ALB、GLOB和TG含量的升高、SOD活力先下降后恢复及AKP活力先下降后恢复再升高等反应可能是青海湖裸鲤应对碱环境的一个重要策略。

【Objective】The study was to figureout the effect of alkalinity on relevant physiological and biochemical parameters of Gymnocypris przewalskii,provide reference for developing the strategies of G.przewalskii to cope with the alkaline environment.【Method】Using the serum of G.przewalskii as the research object,chronic alkalinity stress was carried out.The alkalinity gradually increased to the highest level and then decreased(without stress as the control).The changes in hormones,permeability,energy,oxidation,and immune indicators in the serum of each stress point were measured and analyzed.【Result】Cortisol(COR),calcium(Ca^(2+)),blood glucose(GLU),osmolality(OS),Na^(+)/K^(+)-ATPase(NKA),carbonic anhydraseⅡ(CAⅡ),carbonic anhydraseⅣ(CAⅣ),total protein(TP),albumin(ALB),globulin(GLOB),triglycerides(TG),alanine aminotransferase(ALT),aspartate aminotransferase(AST),catalase(CAT),glutathione peroxidase(GPX)and malondialdehyde(MDA)levels showed the same changetrend,all of which increased and then decreased with increasing alkalinity.And the trend decreased and then increased with decreasing alkalinity.COR showed extremely significant positive correlation with CAIV,TC,ALT,GPX,and MDA(P<0.01),and significant positive correlation with TP,GLOB,high-density lipoprotein(HDL-C),low-density lipoprotein(LDL-C),TG,and CAT(P<0.05,the same below).Insulin-like growth factorⅠ(IGF-Ⅰ),superoxide dismutase(SOD),sodium(Na^(+)),alkaline phosphatase(AKP)and acid phosphatase(ACP)showed the same trend of decreasing followed by increasing regardless of alkalinity increase or decrease.Triiodothyronine(T3),total cholesterol(TC),HDL-C and LDL-C levels were negatively correlated with alkalinity,while creatinine(CREA)and total bilirubin(TBIL)levels were positively correlated with alkalinity.IGF-C was significantly positively correlated with T3.Thyroid hormone(T4)content and lactate dehydrogenase(LDH)activities increased,then decreased and then recovered with increasing alkalinity.Their activities decreased and then increased with decreasing alkalinity.Growth hormone(GH)and Cl-content increased,then decreased,then increased with increasing alkalinity.They gradually increased with decreasing alkalinity.Prolactin(PRL)levels decreased slightly,recovered and then decreased again with increasing alkalinity,it increased rapidly and then recovered with decreasing alkalinity.Potassium(K^(+))concentration decreased with increasing alkalinity.K^(+) concentration increased and then decreased with decreasing alkalinity.Uric acid(UA)content decreased and then recovered with increasing alkalinity,its content gradually decreased with decreasing alkalinity.Urea(UREA)content increased,and then recovered,and continued to increase with increasing alkalinity,it continued to increase and then recovered with decreasing alkalinity.【Conclusion】During alkalinity stress,COR plays a dominant role in G.przewalskii,with T3 and IGF-Ⅰacting in concert and T4 regulating GH auxiliary,thereby maintaining humoral homeostasis in fish;the increase of TP,ALB,GLOB and TG contents,the decrease and later recovery of SOD activity,and the decrease and later recovery and later increase of AKP activity may be an important strategy for G.przewalskii to cope with the alkaline environment.