基于代谢组解析大黄鱼对低温和饥饿胁迫的适应机制

Metabolomics-based analysis of adaptive mechanism of Larimichthys crocea to low temperature and starvation stresses

为探讨大黄鱼对低温和饥饿氧化损伤的响应机制,实验将体重为(21.38±2.46)g的大黄鱼在低温(8℃)或/和禁食条件下饲养。实验组可分为4个处理组:对照组(C组)、低温组(CC组)、饥饿组(F组)和饥饿+低温组(CF组),每组3个平行。低温和饥饿胁迫30 d后,计算成活率;采取肝脏样本,进行组织学观察,并利用化学荧光法和LC-MS非靶向代谢组学技术分析处理组间活性氧(ROS)和代谢产物的差异。结果显示,与C组相比,CC组、F组和CF组的成活率显著降低,而ROS含量显著升高,且肝细胞均出现不同程度的空泡和核萎缩现象,表明低温和饥饿胁迫对大黄鱼产生了氧化损伤。大黄鱼低温应激后,从CC vs.C和CF vs.F组中分别筛选出84种和154种差异代谢物,有5种重要的重叠代谢途径:甘油磷脂代谢、糖基磷脂酰肌醇(GPI)-锚生物合成和自噬等,表明细胞膜流动性和自噬在大黄鱼低温适应过程中发挥重要作用。大黄鱼饥饿应激后,从F vs.C和CF vs.CC组中分别筛选出184种和50种差异代谢物,有4种重要的重叠代谢途径:甘油磷脂代谢、糖基磷脂酰肌醇(GPI)-锚生物合成、ABC运输体和自噬等,表明能量代谢和自噬在大黄鱼饥饿过程中发挥重要作用。从CF vs.C组中筛选出差异代谢物126种,主要富集在糖基磷脂酰肌醇(GPI)-锚生物合成、甘油磷脂代谢、氧化磷酸化、淀粉和蔗糖代谢、FoxO信号通路、自噬和谷胱甘肽代谢等,表明细胞膜流动性、能量代谢、自噬和抗氧化系统在大黄鱼适应低温和饥饿联合胁迫过程中发挥重要作用。本研究结果为深入研究低温及其诱导的饥饿对大黄鱼生理功能的影响提供科学依据。

Large yellow croaker(Larimichthys crocea)is the most important warm-water marine commercial fish,which is widely distributed in the southeast coastal regions in China,such as Zhejiang,Fujian and Guangdong provinces.It is highly sensitive to cold and starvation,and massive death of this species can be observed during winters,leading to significant economic losses for farmers.This study aims to explore the response mechanism of L.crocea to oxidative damage caused by low temperature and starvation.Fish with an average weight of(21.38±2.46)g were exposed to low temperature(8℃)or/and under starvation stress.The fish were divided into four groups:control group(C group),cold group(CC group),fasting group(F group)and cold+fasting group(CF group),each with three replicates.The experiment lasted 30 d,survival rate was calculated,liver samples were obtained for histological observation,chemical fluorescence and LC-MS technology were used to analyze the dif-ference of reactive oxygen species(ROS)and metabolites in different treatment groups.The results showed that compared with C group,the survival rate of CC group,F group and CF group was significantly decreased,while the ROS content was significantly increased(P<0.05),and demonstrated vacuolation and nuclear atrophy,indicat-ing cold and starvation stresses induced oxidative damage.A total of 184 and 50 differential metabolites were obtained from CC vs.C and CF vs.F,respectively.There were five important co-metabolic pathways:glycero-phospholipid metabolism,glycosylphosphatidylinositol(GPI)-anchor biosynthesis,arginine biosynthesis,sphin-golipids metabolism and autophagy,indicating cell membrane fluidity and autophagy played an important role in cold adaptation.A total of 184 and 50 different metabolites were obtained from F vs.C and CF vs.CC,respect-ively.There were four important overlapping metabolic pathways:glycerophospholipid metabolism,glycosylphos-phatidylinositol(GPI)-anchor biosynthesis,ABC transporters and autophagy,indicating energy and material transport function,as well as autophagy played an important role in starvation stress of L.crocea.126 differential metabolites were obtained from CF vs.C,which were significantly enriched in glycosylphosphatidylinositol(GPI)-anchor biosynthesis,glycerophospholipid metabolism,oxidative phosphorylation,starch and sucrose metabolism,FoxO signal pathway,autophagy and glutathione metabolism,indicating cell membrane fluidity,energy metabol-ism,autophagy and antioxidant systems played an important role in cold and starvation adaptation.The results provide scientific basis for further study about the effects of low temperature and fasting on the physiological func-tions of L.crocea.