低温胁迫对暗纹东方鲀肠道氧化应激、细胞凋亡及肠道微生物组成的影响

Effects of low temperature stress on the oxidative stress,apoptosis and intestinal microbial composition in intestine of Takifugu fasciatus

为了探究低温胁迫对暗纹东方鲀肠道氧化应激、细胞凋亡及肠道微生物组成的影响,实验测定了3个处理温度(25、19和13℃),4个取样时间点(0、6、24和96 h)下氧化应激、细胞凋亡与肠道微生物相关指标。结果显示,与对照组相比,随着温度降低肠道绒毛发生坏死、增生和杯细胞肿大。总超氧化物歧化酶(T-SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)的活性以及丙二醛(MDA)含量显著增加。肠道微生物组成多样性降低。肠道微生物丰度发生改变,如黄色杆菌属、副球菌属、乳球菌属和双歧杆菌属的丰度随温度降低而上升,梭菌属、气单胞菌属和嗜热芽孢杆菌属的丰度随温度上升而下降。细胞凋亡相关基因(caspase-3、caspase-7、caspase-9、p53、Bax和Bcl-2)的表达随温度降低升高。此外,实验发现副球菌属和嗜热芽孢杆菌属丰度的改变与肠道氧化应激、细胞凋亡均具有Pearson相关性,其可作为潜在微生物用来反映暗纹东方鲀是否处于氧化应激和细胞凋亡状态。本研究结果可为暗纹东方鲀健康养殖提供基础资料。

In order to explore the effects of low temperature stress on intestinal oxidative stress,apoptosis and intestinal microbial composition of Takifugu fasciatus,experiments were conducted to measure oxidative stress,apoptosis and intestinal microbe-related indicators at 3 treatment temperatures(25,19 and 13°C)and 4 sampling time periods(0,6,24 and 96 h).Compared with the control group,the results showed that as the temperature decreased,intestinal villi underwent necrosis,hyperplasia and enlargement of goblet cells,the enzymatic activities of total superoxide dismutase(T-SOD),catalase(CAT),glutathione peroxidase(GSH-Px)and the content of malondialdehyde(MDA)increased significantly,while the diversity of gut microbial composition decreased.Changes in gut microbial abundance,such as Xanthobacter,Paracocuus,Lactococcus,and Bididobacter increased with decreasing temperature,Clostridium,Aeromonas and Geobacillus decreased with increasing temperature,and the expression of apoptosis-related genes(caspase3,caspase7,caspase9,p53,Bax,Bcl-2)increased with the decrease of temperature.In addition,we found that the alterations in the abundance of Paracocuus and Geobacillus had Pearson correlations with intestinal oxidative stress and apoptosis,which may be potential microbes to reflect whether the T.fasciatus is in a state of oxidative stress and apoptosis.The results of this study provide reference for the healthy breeding of T.fasciatus.