【作者】 刘勇；

【导师】 李广丽； 田昌绪； 周大颜；

【作者基本信息】 广东海洋大学 ， 农业硕士（专业学位）， 2024， 硕士

【摘要】 1.本论文首先研究了持续高温胁迫后胡子鲇的生长性能和组织结构损伤情况。结果显示:(1)经过34℃高温处理的实验组在30天与对照组(28℃)相比无显著差异,但在高温处理持续到60天和90天时,实验组得体重和体长均显著低于对照组。(2)在经历90天高温处理后,胡子鲇的肝脏和鳃组织出现了明显的组织学损伤。肝脏组织表现出充血、空泡变性、细胞核碎裂和溶解,以及严重的空泡化;而鳃组织则显示鳃丝缩短、结缔组织增生和上皮细胞融合现象。此外,Tunel荧光染色法观察显示,高温组的肝脏和鳃组织中Tunel阳性细胞数量显著增加。2.进一步研究高温胁迫对胡子鲇的肝脏和鳃组织抗氧化酶以及血清生理指标的影响。结果显示:(1)持续的高温胁迫下,胡子鲇肝脏的抗氧化酶活性呈现出不同的变化模式。具体而言,超氧化物歧化酶(SOD)活性在经过30天和60天的高温处理后并未显著变化,但到了第90天时,其活性显著提高(p<0.05)。过氧化氢酶(CAT)活性在整个高温胁迫期间均未观察到显著变化。谷胱甘肽过氧化物酶(GPx)活性在持续高温处理中均显著增加(p<0.05)。丙二醛(MDA)含量,在60天和90天的高温处理后显著减少(p<0.05)。(2)鳃组织中SOD和GPX活性在60天和90天的高温处理后均显著增加(p<0.05)。CAT活性在整个高温处理期间未观察到显著差异。MDA含量在高温处理90天时显著下降(p<0.05)。(3)在血清生化指标方面,经过90天的高温处理,胡子鲇的碱性磷酸酶(ALP)浓度显著增加(p<0.05)。与此同时,谷草转氨酶(AST)和谷丙转氨酶(ALT)的浓度在90天时均显著降低(p<0.05)。3.最后,对高温处理90天的肝脏和鳃组织进行了转录组分析。结果显示:(1)肝脏组织中筛选出1,330个差异基因,其中835个基因上调,495个基因下调。KEGG和GO富集分析显示差异基因主要与代谢、免疫和信号传导等通路相关。其中与免疫代谢相关的基因,如hsp90aa1、odc1、acod1、hspa5、cyp51a1、il1rl2、myd88、msmo、dhcr24和oplah的表达水平发生显著变化。(2)鳃组织中筛选出675个差异表达基因,其中407个基因上调,268个基因下调。其中nfkb2、slc25a25b、col11a1、slc25a38、ice1、ido2、psipl、camk2g、sh3bgr和sod3a表达水平发生显著变化,这些基因代谢、炎症免疫和细胞凋亡相关。综上所述,持续高温胁迫会抑制胡子鲇的生长,导致抗氧化酶(SOD、CAT、GPx)活性升高,并出现组织细胞凋亡现象。持续高温胁迫改变机体内免疫酶ALP、ALT、AST的活性,影响正常免疫功能。肝脏和鳃组织的转录组学分析显示,持续高温胁迫影响代谢、免疫和炎症相关基因的表达。本研究阐明了长期高温条件下胡子鲇的生长和生理变化,为深入理解其对高温环境的响应机制提供了参考。更多还原

【Abstract】 1.The study xamined the effects of sustained exposure to high temperatures on the growth and tissue damage in C.fuscus.Results indicated that C.fuscus exposed to 34°C for 30,60,and 90 days exhibited reduced body weight and length compared to those kept at 28°C,with significant differences observed after 60 and 90 days(p<0.05/p<0.01).Histological analysis after 90 days revealed notable damage in the liver and gill tissues,characterized by congestion,vacuolar degeneration,nuclear fragmentation,and severe vacuolization in the liver,and shortened gill filaments,connective tissue proliferation,and epithelial cell fusion in the gills.Tunel fluorescent staining also showed a higher number of Tunel-positive cells in the liver and gill tissues of the high-temperature group.2.The impact of high temperature stress on antioxidant enzymes in liver and gill tissues,as well as serum physiological indices of C.fuscus was examined.(1)The results indicated varying patterns of changes in antioxidant enzyme activities in the liver of C.fuscus over the continuous high temperature stress period.Specifically,superoxide dismutase(SOD)activity remained stable after 30 and 60 days but significantly increased(p<0.05)by the 90th day.Catalase(CAT)activity showed no significant fluctuations.Glutathione peroxidase(GPx)activity rose significantly(p<0.05)at 30,60,and 90 days of high temperature treatment.Malondialdehyde(MDA)content notably decreased(p<0.05)after 60 and 90 days of hyperthermia treatment.(2)SOD and GPX activities in gill tissues significantly increased(p<0.05)after both 60and 90 days of high temperature treatment with no significant differences in CAT activity observed.MDA content decreased significantly(p<0.05)at 90 days of high temperature treatment.(3)Regarding serum biochemical indices,alkaline phosphatase(ALP)concentration in C.fuscus significantly(p<0.05)rose after 90 days of high temperature exposure.Additionally,the concentrations of both alanine transaminase(AST)and alanine transaminase(ALT)were notably reduced(p<0.05)at 90 days.3.Finally,transcriptome analysis was conducted on liver and gill tissues exposed to high temperature for a duration of 90 days.The results indicated the identification of1,330 differentially expressed genes in the liver tissue,with 835 upregulated and 495downregulated genes.Enrichment analyses highlighted pathways related to metabolism,immunity,and signal transduction.Particularly,genes linked to immune metabolism,such as hsp90aa1,odc1,acod1,hspa5,cyp51a1,il1rl2,myd88,msmo,dhcr24,and oplah,exhibited notable changes in expression levels.In the gill tissue,675 DEGs were found,with 407 upregulated and 268 downregulated genes.Noteworthy alterations were observed in genes like nfkb2,slc25a25b,col11a1,slc25a38,ice1,ido2,psipl,camk2g,sh3bgr,and sod3a,which are associated with metabolism,inflammatory immunity,and apoptosis.In summary,sustained exposure to high temperatures hinders the growth of C.fuscus,resulting in an increase in antioxidant enzymes(SOD,CAT,GPx)and the initiation of tissue apoptosis.Moreover,sustained high-temperature stress disrupts the activity of immune enzymes ALP,ALT,AST,impacting immune function.Transcriptomic analysis of liver and gill tissues reveals alterations in gene expression related to metabolism,immunity,and inflammation under sustained high-temperature stress.This research sheds light on the growth and physiological adaptations of C.fuscus to elevated temperatures,offering insights into their response mechanisms in high-temperature environments.更多还原