养殖对虾常见病害及应对措施

由白斑综合症病毒（WSSV）感染引起的，发病前期虾须、尾扇发红，身体消瘦，摄食尚可，体表无其他异常。病虾漫游于水面，不久便下沉死亡，这时用显微镜检测病虾头胸甲中央部位，发现有雪花形、放射状白色斑纹。到了发病后期，大多数病虾残胃或空胄，头胸甲向外张开（鳃丝肿帐所致）且极易剥离，肝胰脏肿胀，外观模糊，手捻易碎，有红色组织液流出，甲壳与附肢上出现明显的白色斑纹，游泳缓慢无力，不久便死亡。     

日本对虾拟阿脑虫病的防治

２００１年我们在进行日本对虾越冬实验中发现了部分试验箱的越冬虾感染了蟹栖拟阿脑虫病，现将其防治措施介绍如下：蟹栖拟阿脑虫（Paranophryscarcini）为原生动物的一种，属于鞭纤目，嗜污科（Philasteridae），虫体呈葵花籽形，前端较尖，后端钝圆，虫体大小平均４６．９微米×１４．０微米，最宽在身体后１／３处，全身披有均匀的纤毛，身体后端正中有一条较长的尾毛。一、发病情况及病因分析患病虾外观没有特殊症状，有些虾的鳃部变黑，但镜检发现为粘附的污物及有机碎屑。病虾被感染后摄食降低，并且运动能力减弱，但并未马上死亡，…     

农业部渔业局推荐新药──对虾克毒王

对虾暴发性病毒病的防治新药──对虾克毒王，经过１９９５年在福建、广东、山东、天津、辽宁等地共５０００多亩大面积养虾生产推广试验表明，只要按照《中国对虾养成技术规范》操作，以“对虾克毒王”药物做成药饵，在虾发病之前或发病初期投喂，可以增强其抗病能力，抑制病毒的传播感染，使病虾康复，延长生长时间，减少死虾量，对病毒病的发生可以起到较好的防治作用，受到了虾农的普遍欢迎。对虾克毒王由中国水产科学研究院和首都医科大学合办的北京海康达生物技术开发公司与农业部全国水产技术推广总站合作开发。１９９４年８月经首都…     

对虾白斑综合征病毒在螯虾动物模型的感染特性

应用克氏原螯虾作为动物模型研究对虾白斑综合征病毒（ＷＳＳＶ）的感染增殖特性，涉及感染温度，感染途径，继发感染，半数致死量（ＬＤ５０），免疫保护及保存期等，结果显示，２２－２５℃时，接种ＷＳＳＶ的螯虾一般于２－７d内死亡，温度升高对病毒增殖影响不显著，３０－３２℃时，平均死亡时间２－６d，温度降低对病毒增殖影响较显著，１５－１９℃时，接种螯虾平均２－１０d内死亡，８－１０℃时，平均死亡时间３－６d，感染途径分别用腹节肌肉，腹节皮下洲射及口服，均能使螯虾感染发病，而浸泡方式不能使螯虾发病，细菌分离和细菌定量结果表明，寄考于螯虾心脏，肝胰腺内的阴沟肠杆菌在感染后期大量增殖，菌量分别是正常螯虾的２５和３０倍，形成继发感染，用螯虾心脏，肝胰腺内的阴肠杆菌在感染后期大量增殖，菌量分别是政党螯虾的２５和３０倍，形成继发梁。用螯虾测定ＷＳＳＶ的ＬＤ５０为１０^-6.5.mL^-1种毒液，将病毒５６℃，３０min灭活后免疫螯虾，不能使螯虾形成免疫保护，ＷＳＳＶ匀浆液－３０℃冻存１年后失活，而－３０℃冻存于螯虾体内ＷＳＳＶ保存１年后仍有活力。     

克氏原螯虾养殖中种质改良技术

克氏原螯虾近年来养殖势头迅猛，成为渔民增收的又一个新的经济增长点。但由于我国地域辽阔，各地的自然条件方面差距较大，导致了各地的克氏原螯虾在养殖过程中出现了体形、外观、肉质、生长速度等方面的差异。克氏原螯虾亲虾繁育后代后逐大部分不会死亡，继续蜕壳、生长、繁育后代，且群体繁育力比较强。经过多年的养殖，     

常见病害防治方法

病名：固着类纤毛虫病病原：最常见的为聚缩虫、单缩虫、微孢子虫、吸管虫、累枝虫和钟形虫等。症状：虾类（南美白对虾、罗氏沼虾、青虾等）被固着类纤毛虫附着时，虾体外观呈黑色，体表有灰黑色绒毛。当大量虫体寄生在虾体、鳃、附肢时，轻者病虾活动能力下降，不摄食、不蜕壳，生长缓慢，影响鳃的呼吸，重则与细菌性疾病并发，引起虾的死亡；成虾感染寄生虫后体表粗糙，     

虾白斑病的防治

虾白斑病的防治本病由细菌引起．健康的虾往往因吃了带病虾附肢后而感染；也有放养虾密度过大，投饵过量造成池底有机质污染引起的．在发病初期，病虾甲壳上可见白斑，分布以头胸部为主，其次腹部也有，有时病虾输卵管末端也有白斑存在。后期由白斑转为黑斑，病虾离群独游...     

国外简讯

国外简讯日本发现新的车虾病毒病１９９３年春天至秋天，西日本各地的对虾养殖场发生了新的车虾病毒病，造成车虾大批死亡。该病的特点是发病快，从出现死虾到大批死亡仅几天时间；死亡率高（８０％以上）；受害范围广，从稚虾到成虾都会受到感染。病虾身体变红或褪色，外...     

白斑综合征病毒和桃拉综合征病毒对凡纳滨对虾的混合感染

2003年10月青岛胶州市对虾养殖场养殖的凡纳滨对虾出现大规模死亡，死亡率在90％以上，典型症状为肝胰腺发红、通过镜检排除寄生虫和细菌感染后，利用免疫荧光抗体技术(IFAT)和PCR方法从病虾鳃中检出白斑综合征病毒(WSSV)，同时利用RT—PCR方法住同一批病虾鳃中检出桃拉综合征病毒(TSV)。结合发病症状，可以认定两种病毒的混合感染造成了凡纳滨对虾的大规模死亡。     

对虾人工养殖技术讲座 第六讲 对虾养殖病害防治

1对虾育苗期常见病害和防治对虾育苗过程常见病及防治方法如下：（1）越冬亲虾褐斑病此病因虾体外伤引起，病原体是一种能破坏甲壳的细菌。得病对虾初期患处呈白色，以后为褐色，外观呈划痕状、点片状或不规则块状。严重时呈黑色。虾体各部位都可发生，以第二、三腹节的背面为多数，也最容易感染。感染后的对虾食欲减弱，甲壳变软，蜕壳困难，患处下方卵巢不能正常发育，萎缩变红，还可能引起其他病原体感染，病情加剧。治疗方法：用福尔马林25X10‘或孔雀绿0．4X106泼洒在池内各处，一天后进行换水，每天换水1／5，直到药液消失，为一个疗…     

Recent information on tick-borne diseases (II)

Tick-borne encephalitis (central european encephalitis) and Lyme disease (erythema chronicum migrans) are diseases mainly transmitted by ticks of the ixodus ricinus species. The tick-borne encephalitis, a virus infection, can produce severe encephalitic symptoms. There is no specific treatment but the infection can be prevented by active or passive immunization. Lyme disease is caused by a spirochete (borrelia burgdorferi). Due to the variety of often uncharacteristic symptoms this infection is not easily recognized. However, early diagnosis and antibiotic treatment are necessary to prevent chronic damage to skin, joints, heart or nervous system.     

Recent information on tick-borne diseases (I)

Tick-borne encephalitis (central European encephalitis) and Lyme disease (erythema chronicum migrans) are diseases mainly transmitted by ticks of the Ixodes ricinus species. The tick-borne encephalitis, a virus infection, can produce severe encephalitic symptoms. There is no specific treatment but the infection can be prevented by active or passive immunization. Lyme disease is caused by a spirochete (Borrelia burgdorferi). Due to the variety of often uncharacteristic symptoms this infection is not easily recognized. However, early diagnosis and antibiotic treatment are necessary to prevent chronic damage to skin, joints, heart or nervous system.     

鱼类对溶解气体过饱和水体的敏感性分析

大坝泄洪可携带大量空气进入水中,导致下游河道出现溶解气体过饱和,给水生生物特别是鱼类的生存造成威胁。通过自行设计的室内试验装置,研究了影响溶解气体过饱和度的因素及不同鱼类对气体溶解过饱和的敏感性。鱼类暴露在溶解气体过饱和环境中易出现突眼、充血和气泡等气泡病症状。鲢、鳙和鳊在溶解气体含量高的水体中容易患气泡病,草鱼和鲫稍次,基本可以忽略溶解气体过饱和对黄颡鱼和鲶的影响。     

Ecosystem services of geoduck farming in South Puget Sound,USA: a modeling analysis

Provisioning and regulatory ecosystem services of Pacific geoduck clam (Panopea generosa) culture were simulated for an intertidal shellfish farm in Eld Inlet, South Puget Sound, Washington, USA. An individual geoduck clam growth model was developed, based on a well-established framework for modeling bivalve growth and environmental effects (AquaShell?). Geoduck growth performance was then validated and calibrated for the commercial farm. The individual model was incorporated into the Farm Aquaculture Resource Management (FARM) model to simulate the production cycle, economic performance, and environmental effects of intertidal geoduck culture. Both the individual and farm-scale models were implemented using object-oriented programming. The FARM model was then used to evaluate the test farm with respect to its role in reducing eutrophication symptoms, by applying the Assessment of Estuarine Trophic Status (ASSETS) model. Farm production of 17.3 t of clams per 5-year culture cycle is well reproduced by the model (14.4 t). At the current culture density of 21 ind m^?2, geoduck farming at the Eld Inlet farm (area: 2684 m²) provides an annual ecosystem service corresponding to 45 Population-Equivalents (PEQ, i.e. loading from humans or equivalent loading from agriculture or industry) in top-down control of eutrophication symptoms. This represents a potential nutrient-credit trading value of over USD 1850 per year, which would add 1.48% to the annual profit (USD 124,900) from the clam sales (i.e. the provisioning service). A scaling exercise applied to the whole of Puget Sound estimated that cultured geoducks provide a significant ecosystem service, of the order of 11,462 PEQ per year (about USD 470,600) in removing primary symptoms of eutrophication, at the level of the whole water body. The modeling tools applied in this study can be used to address both the positive and negative externalities/impacts of shellfish aquaculture practices in the ecosystem and thus the trade-offs of the activity.     

Atlantic herring as a dietary component for culture of Atlantic salmon

Chopped herring was readily eaten by Atlantic salmon. Fry, parr and smolts grew well on a herring-rich diet but after long periods fry and smolts developed symptoms of nutritional deficiency which were quickly cured by omitting herring from the diet. Parr, fed herring and liver separately on alternate days, did not show ill effects. The symptoms are believed due to a high content of thiaminase in herring. Mixing herring with other thiamine-rich foods did not prevent the harmful effects in salmon, pre-sumably owing to inactivation of the thiamine in the food mixture. It is suggested that the beneficial effects of a herring diet can be retained and the harmful effects prevented by feeding herring and some other thiaminase-free food separately during alternate periods.     

Diagnosis and treatment of Mycoplasma bovis mastitis (MbM) in dairy cows

The diagnosis of Mycoplasma bovis mastitis (MbM) usually comes too late. Consequently the capital early symptoms are described for a probable diagnosis in order to enable prophylactic measures and to prevent ineffective expensive treatments and loss of time. Following a definite diagnosis of MbM by culture, a repeated application of the CMT milk test combined with bacteriological culture detects infected cows and they should be culled. All cows of exceptional breeding value can be treated by repeated intramammary infusions of specific antimycoplasma antibiotics with a fair chance of healing, by preference during the dryudder period.     

Neonatal isoerythrolysis in newborn foals]

Aetiology, pathogenesis, clinical symptoms, diagnosis, prophylaxis and therapy of neonatal isoerythrolysis in foals are presented. Neonatal isoerythrolysis is caused by isoimmunisation of a brood mare to the Aa and Qa erythrocyte antigens of the foal. The disease can develop, when the mare does not possess Aa resp. Qa blood group antigens, is sensitized to the Aa or Qa erythrocyte antigens--i.e. through pregnancy, parturition, blood resp. plasma transfusions, etc.--and the foal suckles colostral antibodies to its own blood cells. Aa and Qa antibodies can cause haemagglutination and haemolysis in the foal, with a consequent decline in erythrocytes, PCV and haemoglobin resulting in several clinical symptoms. In most instances the first signs of the disease are noticed by day 2 and 3, ranging from 8 to 96 hours of life. Diagnosis is based upon clinical examination and determination of erythrocyte count, PCV and haemoglobin concentration and can be further confirmed by immunological tests. Several tests can be used to prevent the occurrence of neonatal isoerythrolysis in the newborn foal. Prior to parturition, brood mares can be typed for blood groups and tested for antibodies to Aa and Qa in order to identify mares at risk for causing neonatal isoerythrolysis in the foal. After birth, compatibility of the mare's colostrum and the foal's erythrocytes can be checked by the "jaundice foal agglutination" test. Some instructions for prophylaxis of neonatal isoerythrolysis and for the treatment by red blood cell resp. whole blood transfusions are given.     

Equine viral arteritis

Equine viral arteritis (EVA) caused by the equine arteritis virus, member of the genus arterivirus within the family of Togaviridae was recently isolated from the seminal plasma of two stallions indicating that the virus infection is also prevalent in the Federal Republic of Germany despite the apparent lack of acute clinical symptoms in the horse population. These findings are further supported by data from serological screenings. Out of 739 horse sera, 28 (3.8%) were found to have EVA virus-specific antibodies with titers greater than or equal to 4. It is important to note that the percentage of sero-positive horses was found to be increased from 1.8% in 1987-1988 to 6.8% in 1989. A voluntary prophylactic programme based on virological and serological tests is proposed to prevent further spread of the EVA virus infection. The pathogenesis, clinical symptoms and diagnosis of EVA are also reviewed.     

Yersinia ruckeri—A threat not only to rainbow trout

Yersinia ruckeri (Y. ruckeri) can cause mortalities that are contributing to substantial economic losses in the rainbow trout (Oncorhynchus mykiss) aquaculture sector. Because of its most characteristic clinical signs, the disease in rainbow trout caused by this pathogen is called enteric redmouth disease. Although it is considered to affect mainly salmonids, there are reports in the available literature of isolating this bacterium from other fish species, both clinically healthy and diseased. The aim of this study was to analyse the available data concerning yersiniosis in non‐salmonid fish. The analysed data indicate that Y. ruckeri is a threat not only to rainbow trout. Some of the affected species have high commercial importance and mortalities may contribute to high economic losses. The disease symptoms may not be specific and can be different from those characteristic for enteric redmouth in trout, which may lead to misdiagnosis. Collected information indicates that infection with Y. ruckeri should be taken into account in the diagnostic procedures not only in salmonids.     

急性病毒性鲫鳃出血病的病理变化

病毒性鲫(Carassius auratus)鳃出血病的突发流行可导致鱼高致死率,使中国部分养鱼场近些年受到重创。为了充分认识这种鱼病的发生发展过程,我们结合PCR、光学显微镜和透射电镜,对病鱼头肾等组织的病变及病毒分布情况进行了分析。注射自然发病鱼的组织滤液(病毒悬液),能使正常鲫感染,且出现与自然发病鲫相同的症状及高致死率;病原有典型疱疹病毒的形态特征(故称为鲫疱疹病毒,Ca HV)。经PCR扩增对已知鲤科疱疹病毒主要衣壳蛋白(MCP)基因进行检测,可确定Ca HV存在于被感染鱼的肝、脾、肾和头肾组织中。对组织病理变化及不同时序进行比较,结果表明Ca HV感染会引起鲫这些组织不同程度病变,而鳃和头肾的病理变化有显著时序相关性。在头肾细胞中还观察到大量Ca HV颗粒,预示鲫头肾是Ca HV侵染和复制的主要靶器官。