大西洋鲑感染杀鲑气单胞菌的行为响应及其生理机制研究

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	大西洋鲑感染杀鲑气单胞菌的行为响应及其生理机制研究
	衣萌萌
学位类型	博士
导师	刘鹰
	2015-05-22
学位授予单位	中国科学院大学
学位授予地点	北京
学位专业	海洋生态学
关键词	大西洋鲑（salmo Salar L.）杀鲑气单胞菌（aeromonas Salmonicida）游泳行为变色行为生理机制
摘要	大西洋鲑因具有个体大、肉质好、不饱和脂肪酸含量高等优点已被诸多国家引进养殖。但是，随着养殖规模的不断扩大，病害问题严重阻碍了大西洋鲑养殖业健康、可持续发展。目前关于杀鲑气单胞菌对养殖大西洋鲑鱼行为的影响未见报道。本研究探讨了大西洋鲑感染杀鲑气单胞菌后对其游泳和变色行为的影响及其生理机制，得到以下结论: （1）在现场调查实验中，发病组实验鱼的游泳能力低于健康实验鱼26.7%，虽然两组实验鱼的摆尾频率和游泳速度之间均存在显著的线性关系，但是发病组实验鱼线性回归方程的斜率显著低于对照组（P<0.05）。室内攻毒实验结果表明，临界游泳速度（U_crit）最低值出现在攻毒后第6 d的处理组，相对于对照组降低36.7%（P<0.05）；处理组实验鱼在实验过程中游动的持续时间逐步降低（P<0.05）；同对照组相比，处理组实验鱼摆尾频率与游泳速度之间线性回归方程的斜率出现先升高后降低的趋势（P<0.05）。（2）在对游泳行为影响的实验中，室内攻毒实验结果表明，与对照组相比，从攻毒的第4 d开始，处理组实验鱼的白细胞、淋巴细胞、单核细胞和粒细胞数量均发生显著变化；第6 d这种变化程度最高，白细胞总数，粒细胞数分别降低了2.8%和43.9%（P<0.05），淋巴细胞数及单核细胞数分别升高了63.3%和23.9%（P<0.05）；攻毒后血液免疫细胞数随着取样时间呈现显著的线性变化趋势（P<0.05）。重要的能源底物以及与能量代谢相关血液生化成分血糖、肝糖原、血清总蛋白、高密度脂蛋白、总胆固醇、血红蛋白含量分别比对照组低48.1%、56.5%、74.2%、63.2%、8.6%和49.2%，肌酸激酶在第2 d 升高97.3%，乳酸仅在攻毒后的第6 d显著积累（40.7%），而乳酸脱氢酶在攻毒后的第4和6 d均显著升高（分别升高77.6%和60.7%，P<0.05）。肌肉组织中细胞色素氧化酶亚基I（COX I）基因，异柠檬酸脱氢酶（IDH）基因，丙酮酸激酶（PK）基因，脂蛋白酯酶（LPL）基因，激素敏感性脂肪酶（HSL）基因和脂肪酸合成酶（FAS）基因的表达在攻毒后显著下降（P<0.05），而葡萄糖-6-磷酸脱氢酶（G6PD）基因和丙氨酸脱氢酶（GDH）基因的表达则显著升高（P<0.05）；攻毒后心脏组织中COX I基因，IDH基因，LPL基因和FAS基因的表达显著降低（P<0.05），而G6PD基因，PK基因，GDH基因和HSL基因的表达显著上调（P<0.05）；在肝脏组织中，杀鲑气单胞菌感染显著降低了GDH基因，HSL基因和FAS基因的表达（P<0.05），但是会显著提高COX I基因，IDH基因和G6PD基因的表达（P<0.05）。（3）与对照组相比，杀鲑气单胞菌感染后的实验鱼在白色背景下体色与背景色对比度低，变色速率高（P<0.05），表明大西洋鲑在感染杀鲑气单胞菌后对白色背景的响应变得更为敏感。而在黑色背景下的体色与背景色对比度高，但是变色速率快（P<0.05），表明大西洋鲑在病原感染后对黑色背景的响应程度低。（4）杀鲑气单胞菌感染导致肝脏和血清溶菌酶（LSZ）不同程度地升高（分别升高72.7%和61.9%，P<0.05）；肝脏碱性磷酸酶活性（AKP）在攻毒后显著升高89.4%（P<0.05），而血清中AKP活性在攻毒后第2 d显著升高100.5%后显著降低了48.3%~ 60.5%（P<0.05）；肝脏和血清中超氧化物歧化酶（SOD）活性在攻毒后有不同程度的升高（分别升高20.3%~24.0%，18.4%~33.1%，P<0.05）。杀鲑气单胞菌感染导致大西洋鲑肝脏和血清中能源底物含量不同程度的降低，其中肝脏可溶性蛋白含量降低了20.8%（P<0.05）；肝糖原含量降低78.3%~84.2%（P<0.05）；实验前期血糖含量降低38.1%和43.0%（P<0.05），但是在实验后期又恢复到正常水平；肝脏ATP含量升高33.1%~122.9%（P<0.05）。杀鲑气单胞菌感染后，同对照组相比处理组大西洋鲑血清中的皮质醇（7.2%~21.2%）、促黑激素（MSH）（25.8%~48.6%）和黑色素聚集激素（MCH）（24.1%~54.0%）出现不同程度的升高（P<0.05）。
其他摘要	Atlantic salmon have been introduced to many countries for cultivating because of the advantages of large individual, good flesh and high contents of unsaturated fatty acids. However, with the expansion of the fish farming, the frequently occurrence of diseases seriously hindered the healthy and sustainable development of Atlantic salmon farming industry. By now, the impact of Aeromonas salmonicida infection on behaviour of Atlantic salmon (Salmo salar L.) has not been reported. This study was conducted to investigate the effects of A. salmonicida infection on swimming and color change behaviour of Atlantic salmon and the physiological mechanism. The main conclusions were as follows: (1) The results of the survey experiment showed significant decrease of the critical swimming speed (U_crit) in the sick fish than in the healthy ones (about 26.7%, P<0.05). Although there were significant linear correlations between the tail beat frequency and swimming speed of the two groups, but the slope of linear correlation of the sick group was significant lower than the one of control group. The challenge experiments in laboratory showed that the pathogen injected group significantly impaired the U_crit compared with the control group, which were reduced by 36.7% at severe time, the 6^th day (P<0.05). The swimming time of the treatment group was reduced gradually. And compared with the control group, the slope of linear correlation of the treatment group was elevated first and then reduced. (2) The results challenge experiments in laboratory, the impact of A. salmonicida infection on behaviour and physiology of Atlantic salmon (Salmo salar L.), showed that the number of the total leukocytes, lymphocytes, monocytes and granµlocytes showed significant changes in challenged groups compared with the control groups from the 4^th day after infection. Furthermore, the biggest change occurred on the 6^th day after challenge, when the number of leukocytes and granµlocytes were significantly reduced by 2.8% and 43.9% (P<0.05), and the number of lymphocytes and monocytes were significantly increased by 63.3% and 23.9% (P<0.05), compared with the control groups respectively. The number of immunocyte in the blood showed a significant linear trend over sampling time (P<0.05). As the important energy substrate and biochemical composition of the blood associated with energy metabolism, the serum glucose, hepatic glycogen, total protein, high density lipoprotein, total cholesterol and haemoglobin levels of challenged fish were reduced by 48.1%、56.5%、74.2%、63.2%、8.6% and 49.2% compared with the control ones, respectively (P<0.05). Compared with the control group, the creatine kinase activity (CK) of the challenged group increased by 97.3% on the 2^nd day, and the lactate accumulated (40.7%) only on the 6^th day. Accordingly, the lactic dehydrogenase activity of the challenged group increased by 77.6% and 60.7% on the 4^th and 6^th day compared with the control group respectively (P<0.05). The results showed that the expression levels of cytochrome oxidase subunit I (COX I), isocitrate dehydrogenase (IDH), pyruvate kinase (PK), lipoprotein lipase (LPL), hormone sensitive lipase (HSL) and fatty acid synthetase (FAS) in the muscle significantly decreased from the 2^nd or 4^th day after infection (P<0.05), while the expression levels of glucose-6-phosphate dehydrogenase (G6PD) and glutamate dehydrogenase (GDH) significantly increased (P<0.05). The expression levels of COX I, IDH, LPL and FAS in the heart significantly decreased from the 2^nd or 4^th day after challenge (P<0.05), while the G6PD, PK, GDH and HSL significantly increased from the 2^nd or 4^th in the pathogen injected group (P<0.05). In the liver, the expression levels of GDH, HSL and FAS decreased significantly from the 2^ndday (P<0.05), while COX I, IDH and G6PD significantly increased from the 2^nd or 4^th in the pathogen injected group (P<0.05). (3) In the white background, constrast of the fish infected by A. salmonicida was decreased significantly compared with the control group, and discoloration rate was significanty improved (P<0.05). The results indicated that Atlantic salmon after A. salmonicida infection became more sensitive to white background. While in the black background, A. salmonicida infection resulted in higher constrast and discoloration rate of challenged fish (P<0.05), showing a low responsiveness of Atlantic salmon in the black background after pathogen infection. (4) A. salmonicida infection resulted in lysozyme (LSZ) activity of the liver and serum increased by varying degrees (72.7% and 61.9% respectively, P<0.05). Alkaline phosphatase (AKP) activity of the liver increased by 89.4% after challenged by A. salmonicida (P<0.05), while AKP activity of the serum increased first by 100.5% significantly on the 2^nd day after challenge and then reduced from 48.3% to 60.5% (P<0.05). Superoxide dismutase (SOD) activity of the liver and serum increased in varying degrees (from 20.3% to 24.0%, and 18.4% to 33.1% respectively, P<0.05). A. salmonicida infection resulted in the energy substrates of the liver and serum decreased by varying degrees. Soluble protein content of the liver decreased by 20.8% (P<0.05), and glycogen content decreased from 78.3% to 84.2% (P<0.05). Glucose levels of the serum decreased by 38.2% and 43.0% (P <0.05) on the 1^st and 2^nd day, but returned to normal levels in the latter. ATP content of the liver increased from 33.1% to 122.9% (P<0.05) during the experiment. Compared with the control group, the serum cortisol (7.2% ~ 21.2%), melanocyte stimµlating hormone (MSH) (25.8% ~ 48.6%) and melanin-concentrating hormone (MCH) (24.1% ~ 54.0%) levels of the treatment group elevated in varying degrees after challenges by A. salmonicida (P<0.05).
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/22785
专题	海洋生物技术研发中心
作者单位	中国科学院海洋研究所
第一作者单位	中国科学院海洋研究所
推荐引用方式 GB/T 7714	衣萌萌. 大西洋鲑感染杀鲑气单胞菌的行为响应及其生理机制研究[D]. 北京. 中国科学院大学,2015.

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