欧洲鳗拟指环虫病的治疗报告

1997年5月下旬，我市溪市镇六合围一水产养殖场，3口欧洲鳗地小发生厂似措环虫病，造成摄食迟钝并引起了少量死亡，经过及时诊断和处理，取得了很好的效果，现将有关消况介绍如下：1发病情况该养殖场靠近海边，水体盐度在10％—20％．4月底从福建购进规格7朝（200—300尾／kg）的欧洲鳗种72万尾，分放在1号、2号、3号地，每池面积4492m2，日常水位1．2－1．5m，放养后各方面比较正常。至5月21日起3口地援食明显减少，上台车逐日下降，24日1号地发现有几尾死鳗，至27日该池死亡数已近50尾。2诊断28日上午，每池各捞取3尾病鳗作检查，用手轻压…     

水库鲢鱼小鞘指环虫病鳃组织病理及其防治

在１９９１－１９９３年，笔者在清原县金家水库和后楼水库用敌敌畏进行了鲢小鞘指环虫病的防治试验，并对大水面防治鱼病的施药方法作了初步探索。试验结果表明，０．０８－０．２０ｐｐｍ的敌敌畏均能有效杀灭此虫。组织病理研究发现，病鱼鳃瓣缺损，粘液增多，鳃血管扩张充血，出血，呼吸上皮肿胀。上皮细胞增生，使鳃小片融合，鳃丝呈棍棒状；相邻几条鳃丝发生融合，形成一片上皮细胞板。病状严重时，鳃小片坏死、解体。     

鳗鲡拟指环虫的抗药性及防治对策

欧鳗体上寄生的拟指环虫对连年使用的甲苯咪唑已产生很强的抗药性，防治对策是：选用合适的消毒药物彻底清塘，采用新药“新灭蠕灵”杀灭拟指环虫；放养健康仔鳗，并用EZOⅢ型生物活性剂免疫促长。     

复方甲苯咪唑对拟指环虫的杀灭效果和对欧洲鳗的毒性

２６ ℃、２８ ℃、３０ ℃水温下复方甲苯咪唑对欧 洲鳗的毒性 试验表明： 随水温升 高、药浴时间延长、药物浓度提高, 甲 苯咪唑对欧洲鳗的毒性加 强, 复方 甲苯咪唑、甲苯咪唑、左旋咪唑对拟指环虫的杀灭率表明甲苯 咪唑对拟指环虫具强杀灭 能力, 左 旋咪唑对拟指环虫无杀灭能力, 可用甲苯咪唑替代复方甲苯咪唑。     

鳗鲡指环虫病及其防治

鳗鲡指环虫病最主要病害之一，病原是鲠鲡伪指环虫（Pseudodatylogyrusanguilae Yin＆Sproston，1948）和短沟伪指环虫（P_bizlKikuchi．1929）。1993年我国引进欧洲鳗试养，当时的问题就是死亡率高。主要是狂奔病引起的死亡，而具体表现为伪指环虫无法驱除。     

鳗鱼拟指环虫病的防治

拟指环虫病是整个鳗鱼养殖过程中最常见而又最麻烦的寄生性疾病，拟指环虫隶属于蠕虫类、吸虫纲、单殖亚纲、鳗拟指环虫(Pseudodactylogyrus anguilla)。据报告，它是已发现寄生在鱼类所有指环虫中最凶狠、顽固的种类。由镜检可见，其头前端有四叶，头背侧有黑色眼点，体呈浅灰色，体长达1．5毫米以上。其后端有七对小钩和一个大锚吸盘，绕缠于鳗鳃内吮吸鳗鱼的血及组织液。     

鳃指环虫引发鱼类暴发牲出血病的防治

自5月份以来，本地区鱼类暴发性出血病暴发，笔者在诊治过程中发现，患鱼类暴发性出血病的占检测总数的95%以上；而检测虫类90％左右是鳃指环虫类。     

鳗鲡疱疹病毒对欧洲鳗鲡的致病性研究

为了明确鳗鲡疱疹病毒(Anguillid herpesvirus, AngHV)的致病性,本实验采用一株从鳗鲡“脱黏败血综合征”病料中分离的AngHV(NA16108),研究了其对欧洲鳗鲡幼鳗的致病性。结果显示,注射AngHV的鳗鲡体表出现黏液脱落、鳍条出血、红头等症状;鳃部出现黏液增多、出血,肝脏褪色、肿大,脾脏和肾脏肿大等病变;进一步的组织病理学观察发现,鳗鲡的体表黏液及黏膜上皮细胞脱落,次级鳃瓣增生、呼吸细胞肿胀坏死,脾脏细胞坏死、黑色素细胞聚集,肾小管管壁上皮细胞坏死、管腔变窄等病理症状;这与鳗鲡“脱黏败血综合征”的发病特征一致。致死率分析显示,从第4天开始攻毒组鳗鲡开始出现死亡,第7天和第14天的累计死亡率分别达到26.7%和56.7%;荧光定量PCR检测显示,在攻毒鳗鲡肝脏、脾脏、肾脏、肠道、鳃和皮肤黏液中均可检测到AngHV;另外,用鳗鲡卵巢细胞系(eel ovary cell line, EO)从攻毒鳗鲡主要内脏器官中重新分离出AngHV,表明鳗鲡发生了AngHV的系统侵染。研究表明,AngHV是鳗鲡“脱黏败血综合征”的致病病原,这为深入开展该病的发病机制及防控研究奠定了基础。     

Effects of ambient ion concentrations on gill ATPases in fresh water eel,Anguilla anguilla

Branchial activities of Na⁺,K⁺-ATPase (ouabain sensitive), Mg²⁺ ATPase (ouabain insensitive) and kinetic analysis of high and low affinity Ca²⁺ ATPase were measured inAnguilla anguilla that had been acclimated to demineralized water (DW, Ca < 10 M), freshwater (FW, Ca = 2 mM), and Low calcium freshwater (L-Ca, Ca = 0.9 mM). Na⁺,K⁺-ATPase activity decreased while ouabain insensitive activity increased when ambient Ca²⁺ decreased. Two kinetic forms of Ca²⁺ ATPase could be resolved in each environmental condition. The stimulation coefficients of both sites or enzymes were not affected by ambient Ca²⁺ concentrations. The maximal velocity of both the high and the low affinity Ca²⁺ ATPase was increased when external Ca²⁺ was decreased during acclimation. The low affinity Ca²⁺ ATPase and the Mg²⁺ stimulated enzyme could be a non specific enzyme accepting either Ca²⁺ or Mg²⁺. Results are compared with previous results in the literature and in relation to the branchial morphology and ionic exchanges in fish.     

含嗜水气单胞菌气溶素的免疫刺激复合物的制备及其对欧洲鳗的免疫效果

将嗜水气单胞菌气溶素(AerA)基因定向连接到pET-32a(+)表达载体,转化大肠杆菌BL21（DE3）,SDS-PAGE分析表明,硫氧还蛋白-气溶素融合蛋白（Trx-AerA）表达量占重组菌总蛋白量的65.5%。将上述融合蛋白与商品化的QuilA混合,分别添加Mega-10、卵磷脂、胆固醇获得Trx-AerA ISCO Ms。其中同时添加Mega-10、卵磷脂、胆固醇组蛋白质回收率最高为10.46%,仅添加QuilA组蛋白回收率为1.82%,两者差异显著（P＜0.05）。分别采用Trx-AerA、Trx-AerA ISCOMs、Trx ISCOMs经腹腔注射免疫欧洲鳗,免疫30d后,每个实验组取5尾实验鱼采集血清,按1：200稀释通过ELSIA法检测抗体水平,同时采用菌数为2.0×106CFU的嗜水气单胞菌ZN1株进行攻击,测定免疫效力。结果显示：Trx-AerA免疫组相对保护率为0%（3/15）,Trx-AerA ISCOMs免疫组为83.3%（13/15）,Trx ISCOMs免疫组为50%（9/15）; 3个免疫组针对气溶素的特异性抗体水平OD450值分别为0.19,0.52,0.36,Trx-AerA ISCOMs免疫组、Trx-AerA免疫组显著高于Trx ISCOMs免疫组（P＜0.05）。结果表明影响嗜水气单胞菌免疫效力的除了气溶素的抗体水平外,ISCOMs等也能够增强非特异性免疫保护应答。     

Movements of the European eel (Anguilla anguilla) in a chalk stream

Abstract – The movements of wild European eels (Anguilla anguilla L.) were monitored continuously over a 2‐year period in a tributary of the River Itchen, Hampshire, UK, using a passive integrated transponder (PIT) antenna system. The time of these movements was then related to a number of monitored and calculated environmental parameters. No eel movements were recorded in the winter months when mean stream temperature was below 10 °C. The numbers of movements peaked in May, when mean water temperatures and day length were increasing. The movement of eels was significantly (P < 0.001, R² = 0.45, N = 72) correlated with the time of sunset, with the majority (72%) recorded during the hours of darkness. The results of this investigation have implications for the design/timing of surveys of yellow eel populations and their habitat associations and suggest that successfully determining the microhabitat preferences of active resident eels will require remote monitoring throughout the 24‐h period.     

Management issues relating to the European eel, Anguilla anguilla

In many European countries there is growing concern over reduced recruitment and catches of the European eel, Anguilla anguilla (L.). Evidence of the decline, together with possible reasons for the changes as detailed by various authors, are reviewed. It is suggested that the problems need to be addressed now and on various levels. Proposals for management actions, as outlined by the Environment Agency for England and Wales, are summarized by way of example.     

Recovery from transportation by road of farmed European eel (Anguilla anguilla)

The objective of this study was to assess the effects of transportation of marketable eel (0.15 kg) in the Netherlands with respect to welfare. Eels (Anguilla anguilla) were obtained from a commercial farm and acclimatized for 7 weeks at the laboratory. Fish were transported according to regular commercial procedures. The animals were placed in water‐filled transport tanks on the trailer. Fish density increased from 72 kg m^?3 (husbandry) to 206 kg m^?3 (fasting) and was further increased to 270–290 kg m^?3 during transport. Fish transport lasted 3 h after which the eels were returned to laboratory recirculation systems to measure parameters indicative of stress load, i.e. mortality, plasma cortisol, lactate and non‐esterified fatty acids (NEFA) as well as gill morphology. Samples were taken at 0, 6, 24, 48 and 72 h after transport in transported fish and non‐transported counterparts (controls). Transportation affected water quality within known tolerable limits. No mortality during or after transport was observed. After 6 h, plasma cortisol levels had returned to baseline. However, energy metabolism had increased suggesting that transportation of eels resulted in an increased energy demand that lasted for at least 72 h in the fasted animals. Thus, it is conceivable that exposure to adverse conditions, prior to stunning/killing, in a slaughterhouse may result in allostatic overload in eel.     

Errors in ocular index measurements in European eel Anguilla anguilla (L.)

Abstract –  Knowledge of maturation state of eels ( Anguilla anguilla , L.) based on ocular index (OI) serves management and research functions, such as estimating how much silver eel actually could escape from a particular basin or determining more precisely the developmental biology of a particular eels. OI implies the measurements of five variables (total length and eyes diameters) in a formula which can be sensitive to measurement error. To investigate this issue, we carried out a comparative study using 13 European eels harvested in Camargue (Rhône Delta, France) and three replicated measurements by three different observers. The estimated amplitude of OI imprecision at a 95% confidence level was 1.8 whatever eel and observer. Such error may lead to classification problems particularly when OI values are close to the threshold values used to discriminate between yellow and silver stages. This study not only raised the problem of the OI imprecision but also brought up the need to develop standardised protocol for identifying silver eels. To reach this goal, two different ways are proposed in conclusion.     

Cutaneous myxidiosis in European eel,Anguilla anguilla (Linnaeus, 1758): histopathology,histochemistry and laminin immunohistochemistry

Histopathology, histochemistry and immunohistochemistry of the integument of European eel, Anguilla anguilla (Linnaeus, 1758), infected by Myxidium sp. are reported. Skin samples from affected and unaffected eels were dissected, formalin fixed, paraffin embedded, sectioned and stained with H&E, Periodic acid–Schiff's staining method, Alcian Blue 8 GX pH 2.5/Periodic acid–Schiff's and McCallum‐Goodpasture's Gram stain. Moreover, immunohistochemistry was performed using a primary polyclonal laminin antibody. Histologically, cysts (diameter 2–3 mm) were observed mainly under the scale pockets, encircled by a thin collagen layer, lined by elongated, flattened fibroblasts and containing bipolar, PAS‐ and Gram‐positive spores with opposite polar capsules. The epidermis stretched by the underlying cyst appeared dysplastic, thinned with a significant reduction in mucous cells number. Only inconsistent and aspecific inflammatory reaction was noted around the cysts at the dermis/epidermis interface. Intense laminin‐like protein immunolabel was documented in the plasmodial ectoplasm and related to host anergia. This was the first report of laminin immunolabel in a member of the Myxozoa. Epidermal dysplasia represents likely an aspecific response against the underlying tensile force exerted by the developing parasite cyst, while fibroblast and collagen encapsulation denote a parasite‐driven host response protecting, rather than harming, the encircled parasite.     

溴氰菊酯在欧洲鳗鲡体内药代动力学研究

在试验水温(25±1)℃时,按100μg·L-1的剂量给欧洲鳗鲡药浴溴氰菊酯36h后,采用气相色谱法测定血浆和肌肉中的药物浓度,研究了溴氰菊酯在欧洲鳗鲡体内的代谢及消除规律.采用DAS自动化药动学分析程序对数据进行分析.结果表明:欧洲鳗鲡血浆和肌肉中溴氰菊酯经时过程均符合一级吸收一室开放模型,血浆中主要药动学参数为:T1/2k为148.296h,Cmax为18.446μg·L-1,Tmax为14.7h.肌肉中主要药动学参数为:T1/2k为386.912h,Cmax为44.291μg·kg-1,Tmax为49.6h.肌肉作为可食性组织,且消除较慢,因此选取肌肉组织作为残留检测的靶组织,以10μg·kg-1为最高残留限量,在本试验条件下,建议休药期不低于9d.     

Spatial organisation of European eel (Anguilla anguilla L.) in a small catchment

Abstract –  Modelling-governing patterns of European eel ( Anguilla anguilla L.) distribution of four eel size classes (<150, 150–300, 300–450 and >450 mm) in the Frémur basin (northwest France) was done using artificial neural network (ANN) techniques and ecological profiles. Our results demonstrate the high predictive power of the ANN models. Some macro- and microscale factors, such as distance from the sea, depth and flow velocity, have the most significant influence on the models. Influence of distance from the sea appears to be very different from the spatial organisation usually described in river systems. In fact, the general tendencies of total eel densities according to the distance from the sea showed that densities increase weakly upstream. Another outcome was the variations in habitat preference according to the eel size, even if this species is spread over practically every type of microhabitat. Small eels were mainly found in shallow habitats with strong abundance of aquatic vegetation, whereas large eels tend to be found in intermediate to high depth with small to intermediate abundance of aquatic vegetation. Finally, we hypothesise that European eels change behaviour and microhabitat characteristic preference around a size of 300 mm.