中草药对欧洲鳗病原菌的抑制作用研究

测试了中草药对5株欧洲鳗致病菌的单独、联合抑菌效果，并测试了中草药、化学治疗剂联合抑菌效果。黄连、地锦草、乌梅、黄芩对病原菌抑制效果显著，中草药联合无显著提高药效作用，其使用效果与其中抑菌效果最强药物的含量相关，中草药化学治疗剂联合对病原菌作用效果显著。     

中草药对鳖疖疮病病原菌抑菌作用的研究

由于高密度养殖，鳖的生活环境恶化，抗病力减弱，自身免疫力下降，鳖发病率越来越高。而使用化学药物防治，易使鳖的抗病力减弱，致病菌产生耐药性，从而使效果越来越差。同时化学药物在鳖体中残留蓄积可产生毒副作用，产生癌、畸、突变等，危及鳖和人体的健康，所以使用中草药防治鳖病，既是鳖病防治的需要，也是人们生活保健的需求。本文采用常见中草药金银花、野菊花、五倍子、千里光、辣蓼、车前草、大蒜、紫苏等８种中草药对鳖疖疮病病原菌进行抑菌试验，为生产中正确使用中草药防治鳖病及其它细菌性鱼病提供理论依据。１材料与方法１…     

欧洲鳗败血症的诊治

鳗鲡是水产大省福建的主要养殖对象 ,是福建省的四大出口支柱产业之一。我国于 2 0世纪90年代初开始大规模引进欧洲鳗 ,由于异地饲养及养殖池老化等原因 ,欧洲鳗疾病发生率逐年上升 ,其中以败血症感染率最高 ,危害最大。据统计 ,福建省的鳗鲡养殖场 ,1 998年欧洲鳗败血症的感染率在 5 0 %左右 ,死亡率 5 %～ 1 0 % ;1 999年的感染率在 70 %左右 ,死亡率 8%～ 1 5 % ;2 0 0 0年 4月至 7月的感染率达 80 %左右 ,死亡率 5 %～3 0 % ,仅福州长乐地区 2 0 0 0年因败血症而死亡的欧鳗就达 3 5 0万尾。由于对该病的流行病学不甚了解 ,欧洲鳗发病后…     

黄霉素对生长缓慢的欧洲鳗促生长效果的研究

本文讨论了在配合饲料中添加不同剂量黄霉素对生长缓慢的欧洲鳗（Ａｎｇｕｉｕａａｎｇｕｉｌｌａ）仔鳗的促生长效果。试验结论：添加黄霉素的配合饲料对欧洲鳗有显著促生长作用。其适宜添加量为１０－１５ｐｐｍ，以添加１５ｐｐｍ为最佳，该组的增重比为１２１（对照组为１００），饵料系数为１．４５，经济效益最好。     

对养殖欧洲鳗狂奔病的初步探讨

本文根据笔者的调查研究，介绍了欧洲鳗狂奔病的发生概况及发生狂奔病的群体症候、个体症状及超微病理变化，分析了发病原因，同时介绍了诊断方法及所采取的综合防治方法。     

中草药对欧洲鳗脱粘病的防治作用研究

选用具有较强抗菌、杀菌和调节动物机体免疫功能等作用的中草药组方作为欧鳗的中草药饲料添加剂,在基础饲料中分别添加了3个水平（1％、1．5％和2％）的中草药,以基础饲料为对照,进行脱粘病预防和治疗试验。结果表明：预防组和治疗组死亡率较对照组极显著降低（P〈0．01）。而各试验组间未出现显著差异,并且预防组明显低于治疗组（P〈0.05）,1％和2％药饵组间无显著差异（P〉0．05）,由此证实中草药增强了鱼体非特异性免疫能力,对欧鳗脱粘病有良好的预防和治疗作用。     

关于温室养殖欧洲鳗的几点看法

唐山龙冠特种水产养殖有限公司从1997年5月开始引进欧鳗,试养在温室密养车间的水泥池中,截止1998年8月已有部分欧鳗达到商品规格,养殖获得成功。笔者参与了整个养殖过程,现谈几点看法：一是要把好投苗关。做到充氧鳗鱼袋的水温与池内水温一致时再放苗。我公司1997年5...     

欧洲鳗白仔苗的培育技术

沙县地处闽西北山区,近年来,养鳗业发展迅速,现已兴建养鳗场１０家,每年投放欧洲鳗白仔苗５００万～６００万尾。由于欧洲鳗苗种产地及其生物学特性与日本鳗存在着一定的差异,且养殖技术与日本鳗不同。欧鳗白仔苗培育阶段成活率的高低、规格是否整齐、能否降低三类苗数量,直接影响到全年商品鳗生产的产量和效益。几年来,对四个鳗场进行定期取样镜检,现场技术指导,发现疾病及时用药治疗,取得了显著的成效。一般白仔苗成活率达到９５%以上。三类苗最低数量在９%,一般在１０%～１５%。一类苗最高数量达４８%。现将白仔苗的培育技术介绍如下:一…     

欧洲鳗主要疾病的防治

欧洲鳗主要疾病的防治在绝大部分情况下，欧洲鳗都携有不同程度的病毒、细菌和寄生虫病原体并维持它们与寄主之间的一种平衡状态。但一旦由于环境、寄主健康状况等因素发生变化，这一平衡就会被打破。欧洲鳗的养殖形式又大都是以封闭式的循环水养殖系统为主，引用水源的水...     

欧洲鳗li血液指标的研究

以114尾欧洲鳗li(Anguilla anguilla)为材料，测定了血液中红细胞数，白细胞数，血红蛋白值，比积，白细胞分类计数值及各型血型细胞大小等正常值，按统计学原理进行分析，并对总体正常值范围进行估计，另对欧洲鳗li的血液指标与其他鱼类的血液指标进行了比较。     

Plasma lipoproteins in European eels (Anguilla anguilla): effects of estradiol

A dose-response effect was observed on the plasma concentration of vitellogenin (ALPP, alkali-labile protein P) over a 33 day time-course with repetitive estradiol-17 treatment of European eel (Anguilla anguilla). The plasma estradiol-17 concentration in the treated groups was not proportional to the doses injected. In the groups treated with a medium (0.5 mg kg BW^-1) or high dose (5 mg kg BW^-1) of estradiol there was a significant increase in the plasma total cholesterol concentration during the 33 day time course. The most marked dose-response effect of estradiol was that of plasma total lipids. The distribution of cholesterol between the different lipoprotein classes was dose-related: high density lipoproteins (HDL) predominated in the controls and in the low and medium dose groups, while low density lipoproteins (LDL) predominated over HDL in the group given the high estradiol dose. Plasma HDL concentration was markedly decreased in the high dose treated group; this finding is interesting since HDL plays an important role in the uptake of cholesterol from the extrahepatic tissue.     

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.     

Increased abundance of European eel (Anguilla anguilla) in acidified Norwegian rivers after liming

The prevalence and abundance (density 100 m^?2) of European eel (Anguilla anguilla) were studied by means of electrofishing in 13 acidified rivers in Norway that had been limed to restore acceptable water quality for Atlantic salmon (Salmo salar). Status of Atlantic salmon in these rivers varied prior to liming, from being entirely lost in six highly acidified rivers and in different stages of decline in seven less acidified rivers. Four of the rivers are heavily affected by hydropower development. The abundance and prevalence of European eel increased significantly during the study period. The best model for predicting eel abundance was that with four explanatory variables: time after liming, time after liming squared, status of salmon stocks and hydropower regulation. The eel density was expected to increase by a factor of almost 5 after 10 years of liming. The model also predicts that a river with a formerly reduced Atlantic salmon stock has a 2.8 times higher density of eel than rivers with formerly lost salmon stocks. Before liming, European eel were on average recorded at 15 and 41% of the sampling stations in rivers with formerly lost and reduced Atlantic salmon populations, respectively, increasing to 49 and 68% in individual rivers, respectively, after 10 years of liming. The recovery of European eel in these formerly acidified rivers by means of liming took place during the same period as their abundance declined in other parts of their distribution area in Norway and elsewhere in Europe.     

中草药添加剂对日本鳗鲡生长和非特异性免疫效应的研究

在基础饲料中分别添加0.5 g/kg、1.0 g/kg和1.5 g/kg的自制中草药免疫添加剂,配制成3种试验饲料,以基础饲料为对照组饲料,每处理设3个平行样,对体重为30~40 g的日本鳗鲡(Anguilla japonica)进行为期60 d的饲养试验,每20 d取样一次,以相对增重率、成活率和血清中的溶菌酶(LZM)、一氧化氮合酶(NOS)、碱性磷酸酶(AKP)和超氧化物歧化酶(SOD)活性为指标,探讨了中草药免疫添加剂对日本鳗鲡生长和非特异性免疫效应的影响。结果显示:饲料中添加中草药免疫添加剂可以显著提高日本鳗鲡的增重率,降低饲料系数(P<0.05)。试验组日本鳗鲡血清中的LZM、NOS、AKP和SOD等活性均高于对照组。因此,中草药免疫添加剂具有显著促生长和增强机体免疫能力的作用,建议在实际生产中的添加量为1.0 g/kg较为合适。     

中草药与复方对鲁氏耶尔森菌的体外抑菌作用

采用试管二倍稀释法测定了16种中草药单方及5种复方制剂对鲁氏耶尔森菌（Yersinia ruckeri）的最小抑菌浓度（MIC）。结果表明,黄芩（Radix Scutellariae）和诃子（Fructus Chebulae）对鲁氏耶尔森菌的抑菌作用最强,MIC均为0.028g·mL^-1,可作为防治水产养殖动物耶尔森菌病害的主要备选中草药;大黄（Radix et Rhizoma Rhei）的抑菌作用较强,其MIC值为0.227g·mL^-1,也可作为候选药物;青蒿（Herba Artemisiae）、金樱子（Fructus Rosae Laevigatae）、连翘（Fructus Forsythiae）、茵陈（Herba Artemisiae Scopariae）、五倍子（Galla Chinensis）及金银花（Flos Lonicerae）的抑菌作用较弱,其MIC值均为0.455g·mL^-1。5种复方制剂中,大黄、黄柏（Cortex Phel-lodendri）和黄芩3种中草药以5：3：2的比例配伍对鲁氏耶尔森菌具有最佳抑菌作用,其MIC值为0.057g·mL^-1,抑菌效果弱于黄芩,但远强于大黄单独使用,可为该细菌性疾病的防治提供复方配伍参考。     

47种中草药体外抑杀嗜水气单胞菌的药效研究

用琼脂扩散法(打孔法)测定了石榴皮等47种中草药对嗜水气单胞菌的抑制作用,并用二倍稀释法测定28种有抑菌作用的中草药对嗜水气单胞菌的最小抑菌质量浓度和最小杀菌质量浓度。结果显示石榴皮的抑菌和杀菌效果最好,其抑菌圈直径超过20mm,最小抑菌质量浓度和最小杀菌质量浓度均为7.81mg/mL;赤芍次之。虎杖等26种中草药有一定的抑菌和杀菌效果;陈皮等19种中草药无抑菌作用。石榴皮对嗜水气单胞菌的体外抑制效果最好。     

澳洲鳗适宜养殖温度的研究

通过测定不同水温下的采食率，间接确定澳洲鳗（Anguilla austrulis)的适宜养殖温度，并观察高温下的死亡状况和极限生存温度，发现澳洲鳗的适宜养殖温度接近于24℃，略高于欧洲鳗，略低于日本鳗，在18℃和35℃水温下，澳洲鳗仍有较强的采食率，致死上限温度为37℃，鱼苗比隔年老鳗有更好的耐热能力。     

Geosmin depuration from European eel (Anguilla anguilla) is not affected by the water renewal rate of depuration tanks

This study established that geosmin depuration from European eel is not affected by the water renewal rate of depuration tanks. A general fish bioaccumulation model extended with terms that account for effects of tank water renewal rate and system losses of chemicals, predicted strong effects of the water renewal rate of depuration tanks on geosmin depuration from European eel. Model predictions were validated in a depuration experiment with geosmin‐loaded European eel (n = 95) with a mean (SD) individual weight of 134.4 (5.0) g and a mean (SD) lipid content of 33.7 (2.8) % (w/w). Fish were depurated for 24, 48 or 72 h at three different tank water renewal rates (0.3, 3.3 and 33 day^?1). Treatments were installed by three different mean (SD) water flow rates (13.8 (1.3), 143.5 (9.2) and 1511 (80) L kg fish^?1 day^?1) over 30‐L tanks. Eels eliminated geosmin from their bodies, but unlike the model predicted, this was independent of the water renewal rate of the depuration tanks. Although being eliminated from the fish, geosmin hardly appeared and certainly did not accumulate in the water of the depuration tanks as the model predicted. This observation may be explained by geosmin being eliminated from eel as metabolite rather than the parent compound. Geosmin elimination from eel seems not to occur according to the generally accepted passive diffusion mechanism for excretion of lipophilic chemicals, and geosmin biotransformation by the eel seems indicated. Clearly geosmin depuration from European eel cannot be enhanced by increasing water renewal rates of depuration tanks.     

First isolation of Flavobacterium psychrophilum associated with reports of moribund wild European eel (Anguilla anguilla) in Scotland

In late April 2015, the River Dee Trust informed Marine Scotland Science, Fish Health Inspectorate (FHI), that there had been observations of dead and moribund European eels on the River Dee. Later in May, the Spey Fishery Board also reported a number of moribund European eels in a rotary screw smolt trap on the River Spey. In total, 10 cases involving moribund eels were investigated in 2015 and one case in 2016. In addition, a health screen was conducted to investigate the potential presence of Flavobacterium psychrophilum in healthy eels and Atlantic salmon from the River Dee in 2015. Externally, the diseased eels demonstrated white patches in different locations of the body. In all cases, F. psychrophilum was detected by bacterial isolation and/or molecular methods. Three isolates were further characterized by whole‐genome sequencing (WGS) as belonging to sequence type 15 (ST15). Histological examination of diseased European eels revealed lesions at the level of the integument. The pathogen screen for F. psychrophilum in wild healthy fish tested negative by PCR. Further investigation is required to understand the pathogenicity of this bacterium on the health of eels and the potential impact on the wild salmonid population.