南美白对虾桃拉综合症在我国的流行状况及其趋势（下）

3.TS的发病时间。TS可发生于南美白对虾的整个养殖期,但更多出现于虾苗放养后的10~40天期间,而且以蜕皮期更为严重,因为该时期幼虾身体虚弱,外壳柔软,易于感染。一般在虾的蜕皮前期的后期和蜕皮后期的初期症状最为典型。4郾TS对南美白对虾的危害性。虽然TS的累积死亡率差别较大     

罗非鱼相似症状疾病的防治对策

在罗非鱼的养殖中常常见到症状相似、疾病不同，且均对罗非鱼危害严重的暴发性流行病，2006年在漳州长泰暴发这样一种细菌性流行病。这种疾病以“突眼”为症状，死亡率高达15％～20％，损失惨重。针对这种“突眼”症状的疾病，特介绍如下的防治对策。     

解析观赏鱼疾病的发生原因及防治措施

一、观赏鱼疾病的发生原因 导致观赏鱼发病的原因很多，也很复杂，其致病的机理是：当外界不利因素对机体的胁迫超过了机体的负荷能力时，鱼类就开始表现出各种症状。不同的致病原因会引发出不同的症状与之对应。家庭饲养热带观赏鱼疾病发生的原因主要有：     

黄颡鱼“红头病”一种新的细菌性传染病

近年来，人工养殖的黄颡鱼发生了一种新的疾病，与目前已报道的黄颡鱼疾病在流行规律、症状和病理变化等方面都不完全一致。此病传染性强，死亡率高，防治困难。随着养殖规模的扩大，其造成的损失也日益增大，据不完全统计，其直接经济损失已达100万元左右。本文就该病的病原、流行规律、症状与病理变化、诊断及防治措施等作一初报。     

猪圆环病毒病流行特点、危害状况及防制策略

猪圆环病毒病是近年来倍受重视的一种在世界各地广泛存在的慢性疾病，是系列疾病的总称，其临床症状主要表现为进行性呼吸困难、消瘦和体表淋巴结肿大、腹泻、黄疸、贫血、死亡以及其他诸多临床症状；当与其他病原继发感染或并发感染时，症状表现更为复杂。病理特征为全身器官组织的炎性变化。该病已成为影响养猪业发展的传染病之一，引起世界许多国家兽医工作者的高度重视。与圆环病毒Ⅱ型感染有关的猪病主要有断奶后多系统衰竭综合征、猪皮炎和肾病综合征、母猪繁殖障碍、猪间质性肺炎、传染性先天性震颤、肠炎6种疾病。     

大口黑鲈病害及防控措施(上)

<正>一、大口黑鲈病害的类型与病程特征1.大口黑鲈病害的类型根据大口黑鲈病害发生的原因，可分为传染性疾病、侵袭性疾病和非寄生性疾病。(1)传染性疾病。传染性疾病常称为传染病，是由病毒、细菌、真菌等病原微生物引起、可在大口黑鲈之间、大口黑鲈与其他水生动物之间传播的一类疾病，     

鱼类内脏病的诊治

鱼类内脏疾病自1995年6月在我县发现以来，呈逐年上升趋势，至今笔者已诊治了36个病例，治愈22例，控制病情11例，无效3例，有效率达91．7％。现把对该病的诊治技术小结如下。一、基本情况（一）发病特点鱼类内脏疾病常与寄生虫病、赤皮病、烂鳃病、肠炎病等并发。若是急性突发，病鱼体表无明显症状，若是慢性死亡，症状为几种病症混杂一起，难以断定具体属于哪一类型疾病。采用消毒剂消毒水体，口服抗生素或有关鱼药厂生产的内服药，一般都难以奏效。发病鱼类症状一般是鱼体离群独游，有时在水体中失去平衡，鱼体表背部两侧鳞片脱落、充血…     

健康养殖专栏

怎样区分罗非鱼细菌病与营养性疾病在罗非鱼养殖过程中，常常会出现突眼、白内障、腹水等症状，这些病症在细菌病和营养性缺乏症中都会出现，很容易引起混淆。下面我们将讨论区分罗非鱼细菌病和营养性缺乏症的方法。细菌性疾病发生的原因是在罗非鱼放养过程中操作不慎或放养密度高，罗非鱼之间的相互摩擦损伤而造成体表受伤，并由水中致病菌感染而引发的疾病。而营养缺乏症产生的原因是饲料中缺乏某些维生素和微量元素，由于表皮溃疡后被水中的条件致病菌──嗜水气单胞菌继发感染。一、诊断1．细菌病常伴有内脏结节样病灶和肛门发炎充血的…     

2004年上海及周边地区南美白对虾病害流行态势剖析(下)

二、2004年南美白对虾病害流行态势剖析1.南美白对虾病害流行的原因2004年上海及周边地区南美白对虾病害暴发流行的病原较为复杂,有可能是原来所发现的病毒,也可能是变异株和新的病原体,还可能是多种病原的混合感染。虽然我们从症状和发病时间上的初步调查结果与TS的流行基本相     

惑染强毒新城疫的诊断与防治

随着养鸡业的蓬勃发展，各种疾病也随之发生，但目前影响养鸡业发展的疾病仍以新城疫最为严重，自2003年元月份以来，山东，安徽，江苏等部分地区流行一种产蛋率下降。呼吸症状严重，死亡率高，拉黄白绿稀粪为主要特征的疾病，经过流行病学的分析，结合临床诊断与剖检变化综合防治，最后确诊为强毒新城疫感染。     

Rapid detection and identification of viral and bacterial fish pathogens using a DNA array-based multiplex assay

Fish diseases can be caused by a variety of diverse organisms, including bacteria, fungi, viruses and protozoa, and pose a universal threat to the ornamental fish industry and aquaculture. The lack of rapid, accurate and reliable means by which fish pathogens can be detected and identified has been one of the main limitations in fish pathogen diagnosis and fish disease management and has consequently stimulated the search for alternative diagnostic techniques. Here, we describe a method based on multiplex and broad-range PCR amplification combined with DNA array hybridization for the simultaneous detection and identification of all cyprinid herpesviruses (CyHV-1, CyHV-2 and CyHV-3) and some of the most important fish pathogenic Flavobacterium species, including F. branchiophilum, F. columnare and F. psychrophilum. For virus identification, the DNA polymerase and helicase genes were targeted. For bacterial identification, the ribosomal RNA gene was used. The developed methodology permitted 100% specificity for the identification of the target species. Detection sensitivity was equivalent to 10 viral genomes or less than a picogram of bacterial DNA. The utility and power of the array for sensitive pathogen detection and identification in complex samples such as infected tissue is demonstrated in this study.     

中草药防治寄生性鱼病的概述

通过查阅近年来国内有关中草药防治寄生性鱼病的文献,系统的介绍了常见的寄生性鱼病,并就其中草药防治的研究与应用进行分析。结果显示寄生虫数量达到或超过其危害阈值时,均会构成鱼类病害,危害较大的有斜管虫、双穴吸虫、头槽绦虫、锚头鳋等,控制病原体数量于危害域值之下是鱼病防治的基本策略之一。中草药对寄生性鱼病具有一定的防治作用,加强中草药对寄生性鱼病的研究意义重大。     

Bacteriocins and their applications for the treatment of bacterial diseases in aquaculture: a review

Aquaculture is one of the fastest growing food producing sectors in the world. The increase in the world population requires faster growth in aquaculture for better food availability and to overcome malnutrition. But this worldwide growth of aquaculture is overwhelmed by catastrophic fish diseases and spoilage during cultivation and preservation problems caused by pathogenic bacteria. Various remedies are available for food preservation and also from the bacterial diseases in the fish production. Due to the emergence of antibiotic resistance and adverse effects, an alternative to antibiotic is the need of the hour. The proteins such as bacteriocins, i.e. ribosomally synthesized antimicrobial peptides (AMPs) and possess antagonistic against closely related and other bacteria. These proteins are produced by most lineages of bacteria which are playing key roles in recognition and possess a cognate immunity system for self‐protection as well as host protection from infections. These proteins are potent immunomodulators with broad spectrum inhibition properties which are further used as novel therapeutic agents. In this review, we have tried to summarize the bacteriocins on the basis of their classifications, structural and functional attributes, mode of actions, bacteriocins isolated from fish and gut microbiota and presence of beneficiary bacteria in the fish gut. Further, this study highlighted where further research is a prerequisite to increase our basic understanding and search for novel bacteriocins to elucidate the proteins/peptides having antimicrobial properties for disease control in aquaculture as an alternative to antibiotics.     

动植物蛋白源替代鱼粉研究进展

With the fast development of aquaculture, fish meal needs increased in recent years, however the quantity of fish catching decreases gradually. Fishmeal is a limited feed resource, and serious concem exists on the future availability of this feedstuff for incorporation in fish diets. Undoubtedly, fish meal is well recognized as the best dietary protein source for most marine carnivorous fishes which required high dietary protein levels compared to omnivorous or herbivorous fish. Fishmeal is known for their high content of essential amino acids and fatty acids, low carbohydrates, high digestibility, low levels of anti-nutritional factors (for fresh fish meal) and is a very good source of minerals and is highly palatable. Thus fish meal is in high demand as the protein source for many formulated diets. However, production of fish meal consumes approximately 35 % of the total global fish catch, and the increasing price and potentially unstable supply in the market could be limiting factors for marine fish culture. There have been strong efforts to define and develop cost-effective protein sources that can, at least partly, substitute for expensive high-quality fish meals in least-cost feed formulations. The search for fish meal substitutes and altemative dietary protein sources is an international research priority that could be of considerable economic advantages. Therefore it is urgent task to find animal and plant protein sources in place of fish meal. Among these, plant feedstuffs have received most attention in recent years, but due to their amino acid unbalances, .presence of anti-nutritional factors and low palatability, a high level of replacement of fish meal with plant feedstuffs in omnivorous fish is generally not well accepted. This paper reviews the research status for other protein sources replacing fish meal based on available information in the literature. Animal and plant protein sources nutrient values are evaluated from the aspect of digestibility, antinutrients, physiological status and suitable supplementation.     

A method to estimate the abundance of fish based on dual-frequency identification sonar (DIDSON) imaging

In this paper, a new method based on the dual-frequency identification sonar imaging is presented to estimate the abundance of fish. The proposed method can detect, track and count fish individually. Fish targets can be acquired with a depth-first search algorithm once its edge is detected based on the Sobel Operator from a complicated image. Multiple fish targets can be tracked using the nearest neighbor algorithm combined with the Extended Kalman Filtering. In order to validate the effectiveness of the proposed method, an experiment was conducted in Qingcaosha reservoir in Shanghai. The manual detection method based on sonar images was used as a reference method. The results showed that the fish were identified with less than 5% error compared with the manual detection results. The statistical error of fish numbers between the automated method and the reference method was approximately 10%.     

Can accidental introductions of non‐native species be prevented by fish stocking audits?

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Cryptobia (Trypanoplasma) salmositica and salmonid cryptobiosis

Salmonid cryptobiosis is caused by Cryptobia (Trypanoplasma) salmositica. The haemoflagellate has been reported from all species of Pacific Oncorhynchus spp. on the west coast of North America. It is normally transmitted by the freshwater leech, Piscicola salmositica, in streams and rivers, and sculpins, Cottus spp., are considered important reservoir hosts. The pathogen can also survive on the body surface of fish because it has a contractile vacuole to osmoregulate when the fish is in fresh water. This allows for direct transmission between fish, especially in aquaculture facilities. The parasite divides rapidly by binary fission in the blood to cause disease, the severity of which is directly related to parasitaemia. Cryptobia salmositica has a mitochondrium and it normally undergoes aerobic respiration; however, if its mitochondrium is damaged it will switch to glycolysis. Its glycolytic enzymes and catalase are contained in glycosomes. Cysteine protease is a metabolic enzyme, and its neutralization inhibits oxygen consumption and multiplication of the parasite. An important virulent factor in cryptobiosis is a secretory metalloprotease. The protective mechanism involves production of complement fixing antibodies, phagocytosis by macrophages, and cell-mediated cytotoxicity. Recovered fish are protected, probably for life as the immunity is non-sterile. Clinical signs of the disease include anaemia, anorexia, splenomegaly, general oedema and abdominal distension with ascites. The metabolism and swimming performance of infected fish are significantly reduced and the bioenergetic cost of the disease is very considerable. Fish are susceptible to hypoxia and their immune system is depressed during acute cryptobiosis. Severity of the disease and mortality rates vary significantly between species and stocks of salmon. Protective strategies include selective breeding of Cryptobia-resistant fish. This is innate resistance to infection and it is controlled by a dominant Mendelian locus. In these fish the parasite is lysed via the alternative pathway of complement activation. In Cryptobia-tolerant fish (infected with the pathogen but which do not suffer from disease) the metalloprotease secreted by the parasite is neutralized by alpha2 macroglobulin. Hence, the production of a transgenic Cryptobia-tolerant salmon is an option. This strategy has the advantage in that human intervention (e.g. vaccination, chemotherapy) is not required once the transgenic fish is produced. Acquired immunity is another option; a single dose of the attenuated live vaccine protects fish for at least 2 years. The protective mechanism in vaccinated fish is similar to that in recovered fish. The trypanocidal drug, isometamidium chloride, is an effective therapeutic and prophylactic agent. It accumulates in the mitochondrium of the parasite and significantly disrupts aerobic respiration by causing lesions in the organelle. Efficacy of the drug is significantly increased after its conjugation to antibodies. This immuno-chemotherapeutic strategy has the advantage in that it will lower the drug dosage and hence side-effects of chemotherapy. It will probably reduce the accumulation of the drug in fish, an important consideration in food fish.     

Wild fish are not a significant reservoir for Neoparamoeba pemaquidensis (Page, 1987)

Amoebic gill disease (AGD), caused by the protozoan Neoparamoeba pemaquidensis (Page, 1987) is the most important disease affecting salmon farms in Tasmania. Reservoirs for this protozoan parasite are largely unknown. This study investigated wild fish as a potential reservoir of N. pemaquidensis . A total of 325 wild fish, comprising 12 different fish species, were caught from and around salmon farms and examined for the presence of AGD. None of the wild fish were infected with AGD. In a laboratory trial, seahorse, Hippocampus abdominalis , greenback flounder, Rhombosolea tapirina, and Atlantic salmon, Salmo salar, were challenged with N. pemaquidensis . Neoparamoeba pemaquidensis was detected on the gills on 10 of 15 (66.7%) flounder, nine of 24 (37.5%) seahorses, and six of six (100%) Atlantic salmon. However, paramoebae positive flounder and seahorse lacked the characteristic AGD gill pathology. It is concluded that AGD does not appear in wild fish and wild fish do not seem to be a reservoir of the pathogen.     

A meta-analytic review of monoterpene for fish anaesthesia

The use of anaesthetic agents has been increasing to address the welfare needs of different fish species in scientific and aquaculture practices. MS-222 is the most used synthetic anaesthetic but some limitations and side effects have been reported. Natural substances have been used as potential substitutes with clove oil playing an important role due to its eugenol content. Yet, other monoterpenes have shown anaesthetic properties in different fish species. As such, a quantitative assessment has been conducted to explicitly relate and summarise the use of monoterpenes with described anaesthetic properties in fish. A combined PubMed, Web of Science, Scopus, PubMed Central and Europe PMC electronic database search was performed, from January 2002 to August 2022, following the PRISMA guidelines. Out of 1555 articles retrieved from the literature search, 30 English reports met the criteria for inclusion in the meta-analysis through a generic inverse-variance method (random-effects model) and according to the fish age. The findings show a total of 10 different monoterpenes with high homogeneity and effectiveness in inducing anaesthesia and recovery according to the fish anaesthetic criteria. Further subgroup analysis showed these effects were independent of fish age. Meta-regression of the included studies revealed an inverse linear association between anaesthesia induction and recovery time and water bath temperature while no further correlation was found with other confounding factors (body weight, water pH and dissolved oxygen levels). Although further studies will be required, this meta-analysis provides robust evidence that different monoterpenes serve as an attractive and effective alternative for fish anaesthesia although water bath temperature also played an important role in anaesthesia outcome.