套式PCR在中华绒螯蟹颤抖病病原螺原体检测中的应用

提取人工分离、培养的中华绒螯蟹颤抖病病原螺原体的基因组DNA,并进行梯度稀释作为PCR模板,根据GenBank已有螺原体16S rRNA基因序列设计出套式PCR外部引物,将螺原体特异性引物作为内部引物,利用套式PCR对梯度稀释的模板进行扩增,得到271 bp产物,对照已有的一步PCR检测法,检测灵敏度提高100倍,最小检测达15.5 fg数量级螺原体DNA,从而建立更为灵敏的中华绒螯蟹颤抖病病原螺原体的检测方法。     

吴中区中华绒螯蟹颤抖病发病现状调查与对策

<正>苏州市吴中区水产养殖业发达,是河蟹养殖老区,蟹农养殖经验丰富、技术水平较高,但是令广大养殖户担心的是河蟹颤抖病似有卷土重来之势。2018年8月至11月,吴中区临湖镇现代渔业示范园、东山镇俞家厍、车坊镇澄湖养殖场共16个蟹塘先后发生程度不一的河蟹颤抖病病例。我们对疑似颤抖病的病蟹进行细菌学检测,同时送样到江苏省渔业技术推广中心,采用中华绒螯蟹螺原体PCR检测方法(SC/T 7220-2015)检测是否存在螺原体。本文报道2018年吴中区河蟹颤抖病发病现状的调查结果和分析,并提出相应的防病对策。     

中华绒螯蟹1种球状病毒颗粒的电镜观察

中华绒螯蟹(Ｅｒｉｏｃｈｅｉｒｓｉｎｅｎｓｉｓ)养殖病害问题已成为制约养殖生产的主要因素,病害造成的损失逐年增长,损失也越来越严重。1996年以来,江苏、浙江、安徽等地相继发生养殖中华绒螯蟹患颤抖病成批死亡的病例,养殖单位采用多种抗菌药物治疗均无明显效果。病蟹...     

清苔灵对水草和中华绒螯蟹的影响

<正>通过用不同浓度的清苔灵对中华绒螯蟹浸浴3d,结果证明清苔灵浓度分别为0、0.15、0.2、0.3、0.45mg/L对中华绒螯蟹无不良影响;通过用0.15mg/L清苔灵对水草和河蟹养殖试验,证明清苔灵对水草和河蟹有显著的影响,2周后河蟹出现死亡,随时间的延长死亡逐步上升。1不同浓度清苔灵对河蟹的影响1.1试验方法1.1.1材料和方法市售中华绒螯蟹幼蟹,20g左右,健壮,活力好;清苔灵(扑草净有效含量     

中华绒螯蟹病原豚鼠气单胞菌的鉴定及其致病性分析

为明确江苏苏州某养殖场中华绒螯蟹(Eriocheir sinensis)死亡病因,本研究从病蟹肝胰腺组织中分离到优势生长菌,对分离菌进行致病性、形态与生理生化特征及gyrB基因同源性与系统发育分析.结果显示:分离菌为豚鼠气单胞菌(Aeromonas caviae),分离菌SHZ1对中华绒螯蟹半数致死量(LD50)为1....     

中华绒螯蟹"抖抖病"的防治技术

“抖抖病”是近几年河蟹养殖中发病最多、危害最大的一种疾病，也是给从业者造成经济损失的一个重要原因。为寻求有效防治药物，不少渔药厂家组织专业技术人员攻关，对病因作了分析、检测，并分别研制成了多种防治中华绒螯蟹“抖抖病”的特效药，从而为广大养蟹户提高经济效益带来了希望。２００２年常熟市渔业病害防治中心进行了中华绒螯蟹“抖抖病”防治技术研究试验，现将试验情况总结汇报如下：一、试验材料与方法１．材料：“止抖王”、“蟹抖停”１号、２号、“蟹宁”、“蟹病康”、“蟹菌净”等。２．试验方法：选择唐市、沙家浜、任…     

用配制海水进行中华绒螯蟹人工繁殖的试验

本文报道了用人工配制的海水繁殖中华绒螯蟹的试验。介绍了人工配制海水的总盐度、各种主要化学成分含量、水温、溶氧量、饵料等，对中华绒螯蟹交配、产卵、孵化、骚状幼体的发育的影响。据试验，总盐度在10‰到17‰对中华绒螯蟹的促产是比较适宜的。其中钙的含量在144mg／L至335mg／L之间时，都有可能将潘状幼体育成大眼幼体，而且在此幅度内随着含量的提高育成率也有提高的趋势。镁的含量以461mg／L到935mg／L之间比较适宜。钾的适宜含量约在200mg／L到400mg／L之间。铁的适宜含量是0．02mg／L到0．05mg／L。铜的需要量似乎极微，即使缺无也无明显影响。水温变化对蟹卵的孵化及骚状幼体的发育有影响。中华绒螯蟹产卵时的适宜温度在14℃以上，蟹卵在21．1～26．9℃条件下，约需13—27天孵化，潘状幼体的发育的适温似乎比孵化时的适温要稍稍高些。中华绒螯蟹骚状幼体对缺氧的忍受度远较鱼类低，当溶氧量在2mg／L时引起骚状幼体大量死亡，下降至1．4mg／L可引起立即死亡。骚状幼体正常发育所需的溶氧量在4mg／L以上．盐水丰年虫的无节幼体是培育中华绒螯蟹的骚状幼体理想的饵料。     

中华绒螯蟹新疆越冬成活率试验

河蟹在南方越冬早已获得成功,但在北方却鲜有报道,此次试验不仅满足了春季部分消费者对河蟹的需求,而且填补了春季无本地蟹上市的空白。本文主要研究了2010年11月1日-2011年2月28日期间中华绒螯蟹成蟹在北方越冬时的成活率,结果如下:一、材料与方法1.试验材料本试验所用中华绒螯蟹均来自新疆     

恩诺沙星与中华绒螯蟹血浆蛋白结合率的研究

为探索养殖过程中恩诺沙星(Enrofloxacin,ENR)施用于中华绒螯蟹(Eriocheir sinensis)中的药效情况,文章通过静置平衡透析法分析研究了恩诺沙星与中华绒螯蟹血浆的蛋白结合率.试验测得的中华绒螯蟹血浆蛋白浓度为63.95±0.29 mg·mL-1,蛋白分子量主要集中在66.2-97.1 kDa之间,恩诺沙星与中华绒螯蟹血浆蛋白的结合率在47.39%-82.58%之间.分析结果认为,恩诺沙星与中华绒螯蟹血浆50%以上的蛋白结合率,在中华绒螯蟹养殖生产过程中需要慎重考虑恩诺沙星的有效药物浓度及其与其它药物的竞争作用,以能充分发挥恩诺沙星的作用.     

中华绒螯蟹“颤抖病”病毒提纯方法的比较

以患“颤抖病”中华绒螯蟹组织浓缩液为材料,比较了差速离心结合PEG盐析法(方法1)、葡聚糖柱层析法(方法2)和蔗糖密度梯度超速离心法(方法3)三种方法分离提纯病毒的效果,对提纯病毒进行紫外吸收测定及电镜检查等。结果表明:方法3是用于分子生物学等深入研究该病的比较理想的提纯方法;而方法1所得病毒浓缩液虽纯度不及方法3,但基本可以满足一般研究的要求,且对仪器及技术的要求相对较低;方法2则介乎方法1与方法3之间。故可根据具体需求和实验室条件选择适合的中华绒螯蟹“颤抖病”病毒提纯方法。     

棘胸蛙烂皮病奇异变形杆菌的分离、鉴定及对药物敏感性研究

从患烂皮病的棘胸蛙(Rana spinosa)中分离到一株致病菌,通过形态学、生理生化试验等方法鉴定该致病菌株为奇异变形杆菌(Proteus mirabilis)。同时,通过抑菌圈法研究了该菌株对11种抗生素、11种中草药、4种消毒剂的敏感性。结果显示:该菌株对头孢曲松、阿莫西林、链霉素、诺氟沙星、庆大霉素、卡那霉素、氯霉素等抗生素敏感,对四环素、红霉素不敏感;未观察到黄芪、茵陈对该菌的抑制作用,忍冬藤抑菌效果最好,其次依次为紫花地丁、金银花与甘草、鱼腥草、大青叶与柴胡、陈皮、黄连;致病菌株对消毒剂的敏感性依次为:高锰酸钾﹥三氯异氰脲酸﹥硫酸铜﹥氧化钙。     

Chemical Prevention and Treatment of Winter Saprolegniosis (“Winter Kill”) in Channel Catfish Ictalurus puncfatus1

The efficacies of formalin, potassium permanganate, sodium chloride, and copper sulfate as prophylactic treatments for saprolegniosis (“winter kill”) in channel caffish Icralums puncratus were evaluated. Formalin and copper sulfate were also evaluated as postinfective treatments for the disease. Each of the five experiments was conducted with 5–to 7-g channel catfish placed in static water aquaria maintained in refrigerated tanks. Water temperature was reduced from 25 to 10 C within 36 h and maintained at 10 ± 0.5 C for 28 d. Fish were exposed to cultured Saprolegnia sp. at 20 C, and morbidity and mortality data were recorded for 28 d. Saprolegnia sp.-associated mortalities occurred 7–10 d after exposure. Formalin (25 mg/L) was effective as both a prophylactic and postinfective treatment for saprolegniosis. Copper sulfate was effective in preventing saprolegniosis at a concentration of 0.1 mg/L, but was ineffective as a postinfective treatment. Sodium chloride at 5,000 mg/L was effective in preventing saprolegniosis, but was not practical for use in the commercial catfish industry. Potassium permanganate (up to 0.5 mg/L) was not effective in preventing or treating saprolegniosis in channel caffish. Based on the results of this study, it may be possible to prevent saprolegniosis in channel catfish using formalin or copper sulfate during winter when fish are immunosuppressed by rapid decreases in water temperature or to treat infected fish with formalin. However, the routine use of chemicals to control this disease should not be recommended until studies on their efficacy under typical caffish culture conditions and the effect of long-term use of chemicals on fish and on the environment are completed.     

Kinetic analysis of oxytetracycline residues in Chinese mitten crab,Eriocheir sinensis,muscle following intramuscular administration

Crab culture is a very important economic industry in China. An epidemic of tremor disease of Chinese mitten crabs, Eriocheir sinensis, has become a serious problem in recent years. A spiroplasm has been proved to be the causative agent of this disease. Oxytetracycline (OTC) is used widely in aquaculture and was confirmed to be very effective against this pathogen. In this study, the distribution and depletion patterns of OTC in crab muscle were evaluated following single intramuscular doses of 2, 8 and 40 mg kg^?1 body weight. OTC was detected with a validated HPLC method. Concentration–time profiles were well described by a three‐compartment model with first‐order absorption after a single dose of 8 and 40 mg kg^?1. For comparison, a non‐compartment model was employed. A withdrawal time of 48.29 and 55.92 days was suggested prior to consumption after receiving 8 and 40 mg kg^?1. A recommended therapeutic dose of OTC in theory was calculated to be 36.37 mg kg^?1. OTC was distributed well throughout the body. The elimination of OTC in muscle was slower compared with fish and other crustaceans. A dose of 40 mg kg^?1 is suggested for practical use.     

左旋咪唑对中华绒螯蟹非特异性免疫功能及抗病力的影响

为测定在饲料中添加左旋咪唑(LMS)对中华绒螯蟹(Eriocheir sinensis)的免疫调节作用,以0(对照)、100、200和300 mg·kg~(-1)干饲料的剂量将LMS添加于基础饲料中制成颗粒饲料,投喂中华绒螯蟹7 d,然后投喂不含LMS的对照组饲料。在投喂含LMS的饲料之前(0周)和投喂后2、4、6、8周,采样测定中华绒螯蟹的血细胞总量(THC)、不同血细胞数量(DHC)、吞噬活性、呼吸爆发(超氧阴离子的释放)、酚氧化酶(PO)活性和溶菌酶(LSZ)活性;并在投喂含LMS的饲料后的第4周,按1.2×10~7cfu·kg~(-1)体重的剂量,体腔注射接种中华绒螯蟹致病性嗜水气单胞菌(Aeromonas hyrophila)CL99920菌株,记录接种10d后中华绒螯蟹的累积死亡率。结果显示,各LMS处理组的血细胞总量(THC)、透明细胞(HC)数量、吞噬百分率、呼吸爆发、PO活性和LSZ活性均显著地高于对照组(P<0.05);颗粒细胞(GC)数量、血细胞吞噬指数与对照组无显著差异(P>0.05);LMS处理组的蟹对嗜水气单胞菌的抵抗力明显增强。研究表明,饲喂适量的LMS可增强中华绒螯蟹的免疫力和抗病力;在本试验条件下,200 mg·kg~(-1)干饲料的剂量为最适添加剂量。     

中华倒刺鲃溃烂病组织病理学及药敏试验

对嘉陵江船体网箱养殖的中华倒刺鲃(Spinibarbus sinensis)在春末夏初流行的溃烂病进行了组织病理学和药物敏感试验。结果表明,病灶部位的红细胞溶血,淋巴细胞增生,肌原纤维和肌细胞溶解,肌细胞膜消失,血管充血、出血;病鱼的肾小管上皮细胞与基底膜分离,肾小管管壁细胞之间产生缝隙,肾脏中的血管破裂,红细胞溶血;病鱼的肝小叶中央细胞大量坏死,部分外周细胞也出现了坏死;病鱼的胰脏和脾脏没有发生明显病变。21种抗菌类药物和5种组合药物的药敏试验结果表明,病原菌对硫酸庆大霉素、硫酸妥布霉素、硫酸链霉素、硫酸阿米卡星、头孢曲松钠、氧氟沙星葡萄糖、氨苄西林钠7种药物敏感,对溴氯海因、食盐、强氯精、高锰酸钾、甲基蓝、甲醛6种药物表现耐药性。     

Effects of dietary folic acid on growth,antioxidant capacity,non‐specific immune response and disease resistance of juvenile Chinese mitten crab Eriocheir sinensis (Milne‐Edwards, 1853)

An 8‐week study was conducted to determine folic acid requirement and its effect on antioxidant capacity and immunity in juvenile Chinese mitten crab Eriocheir sinensis (Milne‐Edwards, 1853), followed by a challenge assay with the pathogen Aeromonas hydrophila for 2 weeks. Folic acid was added to a basal diet at seven levels (0, 0.5, 1.0, 2.0, 4.0, 8.0, 16.0 mg folic acid kg^?1 diet), and a diet free of folic acid and vitamin B₁₂ was also included as a control. Crabs were fed twice daily in 32 tanks with 7.76–8.17 mg oxygen L^?1, 25.0–31.0 °C and 7.5–8.3 pH. Growth and feed efficiency were significantly greater in crabs fed ≥2.0 mg folic acid kg^?1, but not significantly different between crabs fed diets >2.0 mg folic acid. The superoxide dismutase activity and glutathione S‐transferase activity were highest in crabs fed ≥2.0 mg folic acid kg^?1, followed by those fed 0.5 and 1.0 mg folic acid kg^?1, and the control diet. The malondialdehyde content was highest in crabs fed the control diet, followed by those fed 0 mg folic acid kg^?1, and the lowest value occurred in those fed ≥0.5 mg folic acid kg^?1. Phenoloxidase activity and total haemocytes were significantly higher in crabs fed ≥2.0 mg folic acid kg^?1 than other diets. Crabs fed 2.0 mg folic acid kg^?1 had the highest lysozyme, acid phosphatase and alkaline phosphatase activities but the lowest cumulative mortality. The optimum dietary folic acid requirement by E. sinensis was estimated at 2.29–2.90 mg kg^?1 diet.