Transmission of some fish pathogenic viruses by the heron, Ardea cinerea

Abstract. Various possibilities of transmitting fish pathogenic VHS, SVC and IPN viruses by the heron, Ardea cinerea , were investigated. Shedding of IPN virus in the faeces could be demonstrated for a period of 7 days when about 1 g of IPN virus-infected trout fry was fed to the birds once only, whereas feeding larger quantities of infected fish on 5 consecutive days resulted in virus excretion for a further 5 days only. Infectious IPN virus could not be isolated from samples of blood and virus specific neutralizing antibodies could not be demonstrated in serum samples. A waterborne infection of trout fry was established by adding very small (0·2 g) quantities of faeces from herons fed IPN virus-contaminated fish to 20 1 water. Infectious SVC and VHS virus was also re-isolated from samples of food which were regurgitated by the herons at different times up to 120 min after feeding of contaminated fish. It was concluded that herons are able to act as mechanical vectors for IPN, VHS and SVC viruses and therefore, may be a potential source of infection and spread of the diseases.     

鱼类细胞培养技术研究进展

鱼类细胞培养技术是一种重要且有潜力的生物学研究技术手段和方法。随着生物技术的发展,越来越多的鱼类细胞系(株)被建立。鱼类细胞培养的具体方法因细胞种类而异,但是总体上有共同之处。作者针对鱼类细胞培养的发展现状、应用与特点、方法技术进行综述,并为鱼类细胞培养的发展前景作出展望。     

Salmonid fish viruses and cell interactions at early steps of the infective cycle

A flow cytometric virus-binding assay that directly visualizes the binding and entry of infectious pancreatic necrosis virus (IPNV), infectious haematopoietic necrosis virus (IHNV) and virus haemorrhagic septicaemia virus (VHSV) to several cell lines was established. The highest efficiency of binding was shown by the BF-2 cell line and this was used to study, at the attachment level, the interactions of these cells with salmonid fish viruses in coinfections, and to further determine if the earliest stage of the viral growth cycle could explain the previously described loss of infectivity of IHNV when IPNV is present. Our results demonstrated that IPNV binds to around 88% of cells either in single or dual infections, whereas IHNV attachment always decreased in the presence of any of the other viruses. VHSV binding was not affected by IPNV, but coinfection with IHNV reduced the percentage of virus-binding cells, which suggests competition for viral receptors or co-receptors. Internalization of the adsorbed IHNV was not decreased by coinfection with IPNV, so the hypothetical competence could be restricted to the binding step. Treatment of the cells with antiviral agents, such as amantadine or chloroquine, did not affect the binding of IPNV and VHSV, but reduced IHNV binding by more than 30%. Tributylamine affected viral binding of the three viruses to different degrees and inhibited IPNV or IHNV entry in a large percentage of cells treated for 30 min. Tributylamine also inhibited IHNV cytopathic effects in a dose-dependent manner, decreasing the virus yield by 4 log of the 50% endpoint titre, at 10 mm concentration. IPNV was also inhibited, but at a lower level. The results of this study support the hypothesis that IHNV, in contrast to VHSV or IPNV, is less efficient at completing its growth cycle in cells with a simultaneous infection with IPNV. It can be affected at several stages of viral infection and is more sensitive to the action of antiviral compounds.     

Effects of Acholeplasma laidlawii and an unidentified mycoplasma on selected fish cell cultures and the replication of fish viruses

Abstract. An unidentified mycoplasma was isolated from cultures of Atlantic salmon (AS) cells and implicated as the cause of cytopathic effects (CPE). The agent did not visibly affect RTG-2 cells. Experimental infection of RTG-2 cells with Acholeplasma laidlawii resulted in increased cellular granularity and destruction. Scanning electron microscopic (SEM) examination of infected RTG-2 and AS cultures revealed typical mycoplasmas distributed on cell surfaces and a marked effect on the cell surface topography, characterized by a loss of microvilli and cellular processes. SEM also revealed mycoplasmal contamination that was not detected by culturing. Comparisons of contaminated and uncontaminated RTG-2 cells showed enhanced (2–100 fold) replication of infectious pancreatic necrosis virus (IPNV) and infectious haematopoietic necrosis virus (IHNV) in the presence of A, laidlawii .     

海水网箱养殖高体鱼师弧菌病致病菌研究

从患病高体鱼师病灶上分离到７株可疑致病菌，人工感染试验证明，菌株９５－５－３和９５－５－５为强毒菌株，这２株菌进行人工感染，死亡率均为１００％，症状与自然发病相似。这２株菌的特征一致，根据形态有主生理生化特征，应归入哈维氏弧菌。药敏实验的结果表明，磺胺类药物和先锋必素对致病菌有较强的抑制作用。     

Studies on the ultrastructure of spermiogenesis and spermatozoon of tongue fish,Cynoglossus semilaevis günther

Ultrastructures of spermiogenesis and spermatozoon of commercially valuable tongue fish Cynoglossus semilaevis Günther were investigated by means of transmission electron microscopy. The study shows that the spermiogenesis of C. semilaevis can be divided into four stages, and the course of spermatid differentiation included flagellum development, chromatin compaction, nuclear fossa formation, migration of diplosome and mitochondria with structural change and disappearance of residual cytoplasm. No acrosome was observed in spermatozoon of C. semilaevis. The nucleus of sperm was U‐shaped; the nuclear fossa was deep with a centriolar complex at the bottom composed by proximal centriole and basal body. Five to six mitochondria were located behind the nucleus in a circle, forming the midpiece of sperm. The sperm tail, 43±2.4 μm (n=5) long, had lateral fins and sacciform tissues in some parts of the tail, with axoneme shown of a typical ‘9+2’ pattern. The ultrastructural observation revealed that the sperm of C. semilaevis is of a primitive type among teleostean fish species.     

工厂化循环水养殖预排污系统与排水系统研究与设计

一种新型的用于工厂化养殖固体颗粒预去除系统研制成功.该水处理系统最大的特点是:不需要任何的外在动力.该系统主要包括两部分:(1)靠养鱼池外置竖管设定水位来实现自动排水的排水系统;(2)靠养鱼池排水管口附近放置的筛网和转动水轮上的毛刷的共同作用,去除养殖循环水中的较大的固体颗粒(残饵和粪便)的排污系统.在去除过程中,耗水率均在5%以内;固体颗粒的去除率也均在80%以上.     

Endocrinology and fish culture

In the current practice of fish culture the use of hormones is mainly limited to the field of reproduction, and more precisely to induce or synchronize ovulation and stimulate spermiation. The practice of pituitary homogenates injection (called hypophysation) which started in the early 1930's has allowed spectacular developments in the culture of some cyprinid species, especially in China, India and Europe. HCG has been used successfully in a limited number of species and LHRH-A, often associated with antidopaminergic compounds, started to be used in some species, especially cyprinids, on a commercial scale. Sex steroids are now commonly used to reverse the sex of some species in salmonids, cyprinids, tilapias. Due to legal restriction and consumer opposition, the tendency is to limit the use of steroids, especially in fish which are later offered to consumption. GH, which significantly stimulates growth and reduces the food conversion rate in laboratory experiments, will possibly be used on a large scale in fish farms. Endocrinology has considerably increased the knowledge of the mechanisms controlling some physiological functions; this has allowed the identification of sensitive phases in fish in captivity, and helps in the management and the process of domestication (most of the cultured fish species have been taken form the wild recently).     

Seasonal stratification in fish culture and irrigation reservoirs: potential dangers for fish culture

Dual-purpose reservoirs for field irrigation and fish culture are characterized by the simultaneous (a) increase in standing crop biomass and feeds during the fish culture period and (b) decrease of water level due to irrigation. This management practice affects stratification, which in turn affects water quality and may affect the fish stocked. To study the limnology of dual-purpose reservoirs, an extensive sampling programme including automatic continuous recording and manual water sampling in deep and shallow reservoirs was carried out. This paper describes limnological changes during the week in which a 3 month long seasonal stratification ended and fish kills occurred. Management implications of stratification are also discussed. The data presented are the first continuous records of this process in this particular type of water body.     

拟态弧菌的致病性、耐药性及中草药防治弧菌病应用

拟态弧菌性腹水病是中华绒螯蟹、海水鱼类和淡水鱼类养殖过程中普遍流行、危害最大的细菌性疾病。在研究拟态弧菌的致病性和耐药性的基础上,研制开发既能有效防治弧菌病,又能解决药物残留和细菌耐药性问题的绿色生物渔药具有重要意义。重点概述了拟态弧菌的致病性、耐药性、中草药防治弧菌病的机理与应用现状,并对中草药的存在问题与对策进行了探讨。     

鳜脑组织细胞系的建立及其病毒敏感性研究

鱼类细胞是开展鱼类病毒分离鉴定、功能基因分析以及生物制品制备等研究的重要物质基础。鳜(Siniperca chuatsi)是深受养殖者和消费者欢迎的养殖品种。随着鳜鱼养殖产量的逐年增加,其病害问题尤其是病毒病问题也日趋严重,但是,可用于鳜鱼病毒分离和基因功能分析的鳜细胞系缺乏。本研究采用组织块消化法,对来源鳜脑组织的细胞进行原代培养,建立了鳜脑组织细胞系,命名为MFB。MFB细胞在28℃含10%胎牛血清的L-15中已稳定传代超过70次,第25代鳜脑组织细胞的染色体众数为56。采用免疫荧光细胞化学技术(β-tubulin和Neu-N)鉴定MFB细胞的神经元纯度,结果显示,培养的MFB细胞为神经元类细胞。病毒敏感性实验结果显示,鳜蛙虹彩病毒(MFRaIV)、大口黑鲈蛙虹彩病毒(LMBRaIV)和大鲵虹彩病毒(GSIV)均可在MFB细胞中产生典型细胞病变效应,病毒滴度分别为108.68±0.12、108.36±0.15、1010.15±1.85 TCID50/mL。使用脂质体Lipofectamine®2000将pEGFP-N1转入MFB细胞,转染效率可达20%。本研究建立的鳜脑组织细胞系不仅对多种蛙虹彩病毒敏感,而且转染质粒效率较高,为鳜病毒性病原的分离及基因功能研究奠定了前期基础。     

九孔鲍消化道及养殖水体中弧菌胞外毒力因子的分析

从汕尾健生鲍鱼养殖场成鲍养殖水体和消化道中分离筛选到22株弧菌,其中14株来自成鲍消化道,8株来自养殖水体。本文对这两种不同来源的菌株进行了致病因子(胞外酶及溶血毒素)的分析比较,同时采用API条带法对其进行了种类鉴定。结果发现,消化道中除1株溶藻弧菌和3株最小弧菌外,其余均为河流弧菌;而水体中除副溶血弧菌和创伤弧菌各1株外,其他也均为河流弧菌。实验还发现,在5株胞外酶分泌能力最强的弧菌中,只有Sh031株是副溶血弧菌,另外4株(Bh14、Sh02、Sh08、Sh05)均为的河流弧菌。结果显示,无论是养殖水体还是消化道,河流弧菌都应视为一种海水养殖贝类(鲍)的主要条件致病菌,是能力较强的胞外致病因子生产者。     

池塘养殖金鱼实用技术

随着市场形势的不断变化，金鱼养殖正在成为渔业结构调整的一支生力军。池塘养金鱼因其管理简便、鱼体生长快、生产规模大、经济效益高等特点正在被广大农民朋友采用。但因技术普及不到位，各地养殖水平参差不齐、养殖效益普遍偏低。现就池塘养殖金鱼实用技术介绍如下。     

Rice with fish culture in the semi-deep waters of the Mekong Delta, Vietnam: interaction of rice culture and fish husbandry management on fish production

Fish husbandry and rice culture management factors influencing the yield of introduced fish in ricefields of the Vietnamese Mekong Delta were studied by multiple regression analysis. A significant (P < 0.001) regression model was computed in which feed input and duration of culture period positively and ricefield area, rice seeding rate and the year of the survey negatively affected the yield of introduced, as well as indigenous, fish. The negative impact of larger ricefields is probably the result of the escape of fish. This is also probably the reason for the year of survey since the average yield of introduced fish was 92.5 kg ha^?1 in 1995 (because of an extreme flood) as compared to 164.8 kg ha^?1 in 1994. A high seeding rate of rice results in a dense stand which suppresses the growth of fish. Opportunities for improvement of fish production are proper ricefield construction, reduced seeding rates, stocking fingerlings early in the dry season and more intensive feeding.     

益生素及其在鱼类养殖中的应用

论述了益生素的概念 ,益生素在鱼体内的作用机理及特点 ,益生素在鱼类养殖业中的应用 ,使用益生素应注意的问题     

鱼塘中后期水质管理

鱼塘中后期水质管理的标准是：水质清新，肥度适宜，池水呈黄褐、油绿、草绿带黄色，透明度20～40cm，无油膜，不形成水华，无腥臭味。即所谓的“肥、活、嫩、爽”。依据笔者几年的亲身实践，做好鱼塘中后期水质管理工作应从以下六个方面人手：     

冷水鱼的养殖种类

按照鱼类生长对水温的要求,水产养殖管理上把生长水温要求不高于20°C水温的鱼类称为冷水性鱼类,如鲑鳟鱼类。我国冷水鱼的养殖至今已有40多年的历史,但多年来一直以虹鳟鱼为主要养殖品种。目前这种养殖局面已经满足不了市场对冷水鱼食品多样化的需求。因此,引进新品种,丰富养殖种类,提高养殖技术已经成为各省市发展冷水鱼养殖业亟待解决的问题。本文拟将国内外养殖成功的冷水鱼种类作一介绍,供选择养殖冷水鱼品种时参考。1虹鳟虹鳟属于硬骨鱼纲,鲱形目,鲑亚目,鲑科,大麻哈鱼属。虹鳟鱼原产于北美洲太平洋沿岸,1874年在美国移养驯化成功,是…     

鱼类细胞的旋转管培养法

用圆柱形细胞培养瓶,对草鱼吻端组织ZC—7901细胞适应旋转培养条件进行了研究,测定了细胞接种浓度、旋转速度及细胞生长速度等有关参数。试验表明ZC—7901细胞能适应于旋转培养,适应后的细胞对草鱼出血病病毒仍具有敏感性。     

我国海水鱼类养殖大产业架构与前景展望

我国的海水鱼类养殖,自新中国成立至今,经历了几代人半个世纪的奋力开拓,取得了由传统养殖向工业化养殖方向的转变。20世纪90年代兴起的第4次海水养殖产业浪潮,向世人昭示中国人已经扭转了海水鱼类养殖长期滞后(与藻、贝、虾类相比)的局面,形成了北方以工厂化为主,南方以网箱为主的养殖热潮,成功开辟了海水鱼类养殖主流产业,产生了巨大的经济和社会效益。为使我国的海水鱼类养殖产业持续、健康发展,当前最重要的是要以科学发展观为指导,加快转变经济增长方式,根据各海区和岸带的特点和发挥各自的资源优势,去构筑符合国情的海水鱼类养殖大产业。