【作者】 刘大志；

【导师】 肖调义； 肖克宇；

【作者基本信息】 湖南农业大学 ， 水产养殖， 2007， 硕士

【摘要】 近年来，湖南省一些大鲵养殖场中人工养殖的大鲵不断发生大规模的疾病，给大鲵养殖业造成了巨大的经济损失。为了尽快查清引起大鲵发病的原因，进而寻找防治疾病的方法，笔者经过近3年的时间首次对湖南省润孚公司、张家界大鲵保护中心等地的大鲵的疾病进行了流行病学调查。对患病大鲵经解剖取样、送武中科院汉病毒所检测，排除了此病是由病毒引起的可能性；经显微镜观察，排除由寄生虫引起死亡的可能性。经调查研究发现：患病大鲵的体表、肌肉、肝脏、胰脏、肾脏、肠道、胃、肺等器官组织出现不同程度的充血、出血，腹部膨大，有大量腹水，并发生溶血，故将此病暂定名为大鲵细菌性败血症(Bacterial septicermia)。本文主要对这种细菌性败血症进行了病原特性与病理变化的初步研究。于2004年～2006年12月间先后对湖南润孚生物工程公司人工养殖10尾典型症状的患病大鲵的6个不同组织器官进行了病原检测，共分离纯化出600余株细菌。通过人工感染大鲵、革兰氏染色、生化鉴定比较、敏感药物测定等试验，最后选定具有代表性的9株为供试菌株。选取其中一株进行大鲵回归实验与16SrDNA扩增与测序，结果确认引起该病的病原菌为嗜水气单胞菌。药敏试验结果表明，9株菌株均对9株菌株对环丙沙星、头孢曲松、头孢他啶、头孢孟多、头孢哌酮、庆大霉素、头孢西丁药物相对比较敏感，而对克林霉素、头孢唑林、甲硝唑、SMZ具有耐药性。对病鲵血液进行40余项血液病理学指标检测分析，其结果表明：只有9项测定值处于健康水平参考值范围内，其余30项测定值均远远低于健康水平参考值。取病鲵的肝脏、胰脏、肠道、胃、肺、肾等器官组织用福尔马林液固定，石蜡切片，H．E．染色，在光学显微镜下进行观察。结果表明：肝脏的肝小叶结构不清，毛细血管和小叶间胆管被破坏，巨噬细胞增多，肝细胞肿胀、变性、坏死，散乱分布，看不到明显的中央静脉，没有明显的肝细胞索，肝组织中的毛细胆管和小叶胆管破裂，胆管中的物质渗入到肝组织中；胰脏腺细胞变性，有的细胞坏死、解体，腺泡细胞间充斥大量脂肪细胞；胃内壁固有层被破坏，胃上皮细胞解体；小肠绒毛膜柱状上皮细胞纹状缘消失，肠系膜、卵系膜充气积水；肺组织无完整支气管，含大量淋巴细胞；肾小管多数处于变性、坏死；肾小管内发生淤血，有红细胞浸润，肾小体坏死、解体。更多还原

【Abstract】 In recent years, Andrias davidianus Blanchard in fishponds was affected by diseases, leadingto economical loss for fishing farmers. In order to investigated the reason and find efficientprotection strategy, the epidemiology ofAndrias davidianus Blanchard was conducted in HunanRunfu Bio-Products Co.,Ltd and Andrias davidianus Blanchard Protection Center in Zhangjiajiefor three years. The affected Andrias davidianus Blanchard was anatomized and viruses in thesampleswere determined in Wuhan Institute of Virology, Chinese Academy of Sciences. Theresult showed that the disease neither was affected by viruses nor parasites. However, pathologicalsymptoms such as hyperemia, hemorrhage; swelling abdomen, refractory ascites and hemolysiswere observed in the body, muscle, liver, pancreas, kidney, intestine, stomach and lung ofAndrias davidianus Blanchard with infection The disease was identified as bacterial septicermiabased on above symptoms.Ten affected Andrias davidianus Blanchards in fishponds were taken fromHunan Runfu Bio-Products Co.,Ltd from 2004 to 2006. Six organs from ten ofAndrias davidianus Blanchards were chosen for pathological investigation and 600bacteria were isolated. Nine out of 600 bacteria in the affected Andrias davidianusBlanchards was used for determining medical resistance by gram staining, biologicalidentification and medical sensitivity. All of nine bacteria were sensitive tociprofloxacin, ceftriaxone sodium, ceftazidime, cefamandole Nafate, cefoperazoneSodium, gentamycin sulfate, and cefoxitin sodium, while they were resistant toclindamycin, cefazolin, metronidazole and sulfamethoxazole. One bacteria strain inAndrias davidianus Blanchards was selected for 16S rDNA PCR amplification andsequencing in a regression experiment. The result revealed that the disease wasresulted from aeromonas hydrophila.The blood of the affected Andrias davidianus Blanchards was used fordetermining 40 pathological parameters. It was fond that 9 parameters were includedin the reference range of health and others lowered the healthy references. The tissuesof liver, pancreas, intestine, stomach, lung and kidney in Andrias davidianus Btanchardwith infection was fixed in formlin solution, formed paraffin slices, stained in H.E.andthen observed trader optical microscope. The lobular structure of liver was not clear.The capillary vessel and the bile duct within lobules were destroyed. The increasedmacrophages, cell swelling, denaturalization and necrosis of liver were found in thepresent study. But central vein and cytopigment were not observed in liver. The capillaceous and lobular bile duct in liver were broken. The substances from bile ductinfiltrated into liver tissues. The grand cell of pancreas was denatured and some ofthem were necrotic. Moreover, plenty of fatty cells filled up within glandular alveolus.The intrinsic layer in inner cell wall of stomach was destroyed and stomachicepidermis cells were disaggregated. Microvillis of nonciliated columnar cells of theintestines disappeared. Mesentery and ovarian capsules were inflated and accumulatedwith water. In lung tissues, there was no integrated bronchus, while plenty oflymphoid cells. The symptom of acute tubular necrosis and denaturation were found.Some gores were founded in renal tubules. Hematid was soaked in renal tubules too.Renal corpuscle was necrotic and disintegrated.更多还原