冬闲稻田 养虾技术

冬闲稻田养青虾,即头年11月底放养当年达不到上市规格的青虾,到次年5月底收获商品虾,一般每667m2水域产商品青虾25～30kg,增加效益600～800元。现将其主要技术要点介绍如下：     

为发展养鹅产业鼓与呼……

为了适应我国养鹅产业的发展形势，《水禽世界》与“全国鹅业专家咨询服务团”合作开办了“百问百答话养鹅”专栏。     

为发展养鹅产业鼓与呼……

为了适应我国养鹅产业的发展形势,《水禽世界》与“全国鹅业专家咨询服务团”合作开办了“百问百答话养鹅”专栏。专栏采用一问一答、一题一议的形式,力求以通俗易懂、言简意赅的表述,结合我国养鹅产业发展进程中必然出现的热点、难点问题和可能会出现的倾向和偏差,为养鹅企业和广大农民朋友提供及时、准确、可靠、     

为发展养鹅产业鼓与呼……

为了适应我国养鹅产业的发展形势，《水禽世界》与“全国鹅业专家咨询服务团”合作开办了“百问百答话养鹅”专栏。     

为发展养鹅产业鼓与呼……

为了适应我国养鹅产业的发展形势,《水禽世界》与＂全国鹅业专家咨询服务团＂合作开办了＂百问百答话养鹅＂专栏。     

为发展养鹅产业鼓与呼……

为了适应我国养鹅产业的发展形势，《水禽世界》与“全国鹅业专家咨询服务团”合作开办了“百问百答话养鹅”专栏。     

为发展养鹅产业鼓与呼……

为了适应我国养鹅产业的发展形势，《水禽世界》与“全国鹅业专家咨询服务团”合作开办了“百问百答话养鹅”专栏。     

专业户养虾高产经验谈

(一)养虾是系统工程养虾的全过程是一个大整体,每一个阶段每一个环节每一项工作都是这个整体的一部分,是不能分割的。从虾苗到饲料到管理,从清塘到肥水到调水,从季节到盐度到酸碱度,从水质环境到营养均衡到提高免疫力等等。只有把这些方方面面的知识都掌握了才能把养虾风险降到最低。在这个系统工程中,苗、料、管这3     

内地养鹅产业已进入整合与转型期

连续两年活禽不能顺利运送到都会型城市,严重影响了家禽产业的生计。总体来说,家禽产业中养鹅业应该是受伤较轻的,不过也不可能完全躲过风浪。建议养鹅产业要认真面对现有的问题,有效解决。     

对虾白斑综合征病毒研究概况

对虾白斑综合征病毒(WSSV)引起世界范围内养殖对虾的急性、致死性传染病,造成对虾养殖业的巨大损失,在我国这种情况尤为严重。WSSV是同一类紧密相关的无包埋体类杆状病毒,与杆状病毒并无同源性。2001年,中国和荷兰科学家分别报道了WSSV的全基因组DNA序列,启动了WSSV后基因组研究。已有多种检测方法用于WSSV的检测和致病机理的研究。WSSV感染宿主谱广,以多种传播途径感染宿主,目前还没有用于病毒增殖的细胞系,但已有成熟的动物模型,从而方便了对WSSV的研究。本文就该病毒的命名、病毒特性、检测方法、病毒感染增殖、感染宿主、传播途径及感染动物模型等方面的研究现状和进展作一综述。     

White Spot Syndrome Virus Infection of Cultured Shrimp in China

Abstract

In 1993 and 1994, an epizootic of disease (white spot) occurred among cultured shrimp in China, resulting in mass mortality. During the periods of outbreak epizootiological surveys were undertaken. Based on these surveys it is known that the disease occurred among populations of cultured Penaeus chinensis, P. japonicus, and P. monodon, infecting shrimp from 2.4 cm to adult. The disease presumably spread among farms as a result of transport of contaminated shrimp seedlings and seawater. Water temperatures exceeding 25°C caused the disease to spread more rapidly. Challenge experiments showed the causative agent was highly virulent. Both naturally and experimentally infected shrimp exhibited white spots on the carapace. Moribund shrimp contained turbid hemolymph, hypertrophied lymphoid organ, and a necrotic hepatopancreas. By electron microscopy, viral particles were observed in gills, stomach, lymphoid organ, and hypodermal tissue of infected shrimp. The virions were slightly ovoid with an envelope and averaged 350 × 150 nm and nucleocapsids measured 325 × 120 nm in size. By use of negative stains, complete virions were 375 × 157 nm and unenveloped nucleocapsids averaged 395 × 83 nm.     

Virulence Variation of White Spot Syndrome Virus in Pacific White Shrimp Litopenaeus vannamei

Abstract

The virulence of seven geographic isolates of white spot syndrome virus (WSSV; genus Whispovirus; China (strain CH1995), Nicaragua (strain N2000), Honduras (strain H2000), Ecuador (strains E-L1999 and E-LT2002), and Mexico (strains M-M2001 and M-LP2001)) was compared using a series of challenge experiments, each lasting 10 d. For each isolate, four quantified dilutions (10^?6, 10^?7, 10^?8, and 10^?9) of a viral inoculum were prepared from WSSV-infected shrimp tissue. Each viral inoculum was injected into 10 specific pathogen-free juvenile Pacific white shrimp Litopenaeus vannamei (0.25–1.50 g); controls received injections of marine crustacean physiological saline (3.2%). The minimum dose of viral inoculum that killed 50% of injected shrimp (LD50) was calculated for dilution, tissue concentration, and viral DNA amount. The CH1995 and M-M2001 isolates were the least virulent, with LD50 values of 10^?6 to 10^?7 of viral inoculum. The isolates could be grouped into three virulence clusters (CH1995 and M-M2001; N2000 and E-LT2002; and H2000, E-L1999, and M-LP2001). Virulence clusters were not altered by LD50 values based on viral DNA concentration, although a slight shifting of order in regards to virulence was seen among the three most virulent isolates (E-L1999, H2000, and M-LP2001). Overall, results indicate that there is a measurable virulence difference among WSSV isolates, which may correspond to geographical region.     

应用多重PCR检测鉴别对虾白斑综合征病毒和桃拉病毒

研究建立了一种可同时检测对虾白斑综合征病毒(WSSV)和桃拉病毒(TSV)的多重聚合酶链式反应(多重PCR)技术。根据WSSV和TSV基因序列，设计合成了2对分别与WSSV和TSV某段基因序列互补的引物，用这2对引物对同一样品中的WSSV DNA和TSV RNA模板进行多重PCR扩增。结果均同时得到了2条特异的与实验设计相符的306bp(WSSV)和231bp(TSV)多重PCR扩增带，而对其他对虾病病原的PCR扩增结果均为阴性；敏感性测定结果表明，该多重PCR技术能检出10pg的WSSV DNA和1pg的TSV RNA模板。     

应用原位杂交技术检测感染中国对虾和克氏原鳌虾体内的白斑综合征病毒

用PCR制备地高辛（DIG）标记探针，采用原位杂交技术检测感染中国对虾和克氏原鳌虾体内的白斑综合征病毒（WSSV）。患病严重的淑死中国对虾的角化上皮、胃上皮、触角腺、肝胰腺上皮、疏松结缔组织、肌肉、造血组织、鳃、卵巢之结缔组织细胞和滤泡细胞、精巢之结缔组织细胞原位杂交呈阳性；人工注射感染克氏原鳌虾的角化上皮、胃上皮、肝胰腺上皮、疏松结缔组织、肌肉、造血组织、鳃原位杂交检测呈阳性。PCR制备DIG标记探针与健康中国对虾和克氏原鳌虾无交叉反应，相应样品未加入探针杂交和未加入DIG抗体杂交均为阴性反应。     

芬兰养狐业对我国养狐业的启迪

从饲养规模、劳动效率、饲料加工、日粮营养、环境卫生和疾病预防、产品品质等方面论述了芬兰养狐业的特点与我国养狐业存在的问题 ;从科学饲养管理、良种培育、毛皮加工技术与毛皮拍卖市场四个方面分析了芬兰养狐业成功的原因及给我们的启示     

对虾白斑综合症病毒变性高效液相色谱检测方法的建立与应用

据对虾白斑综合症病毒(WSSV)的基因保守序列,使用Primer Explorer V3软件设计了2条引物,利用PCR的扩增产物,结合变性高效液相色谱(DHPLC)技术,建立了一种对虾白斑综合症病毒的DHPLC快速检测方法。该检测方法特异性好,与传染性皮下和造血器官坏死病毒、斑节对虾杆状病毒、肝胰腺细小病毒、对虾杆状病毒以及对虾基因组DNA无交叉反应;检测灵敏度较高,约为10-5ng/μL,高于常规PCR及荧光定量PCR的灵敏度。用建立的DHPLC方法对100尾对虾样品进行了临床检测,结果与荧光定量PCR检测结果一致。WSSV的DHPLC检测方法,特异性强、灵敏度高,是对WSSV进行有效检测的一种新方法。     

Survey for the presence of White Spot Syndrome virus in Australian crustaceans

Agriculture, Fisheries and Forestry - Australia, GPO Box 858, Canberra, Australian Capital Territory 2611.     

Detection of White Spot Syndrome virus and Yellowhead virus in prawns imported into Australia

Objective To determine whether viable White Spot Syndrome virus (WSSV) or Yellowhead virus (YHV) were present in prawn products imported into Australia.
Procedure A sample of fourteen uncooked prawns was obtained from a consignment imported from southeast Asia. Each of the prawns was examined for WSSV by polymerase chain reaction (PCR), and then a bioassay was conducted in which a 10% homogenate of cuticular epithelium from each of the prawns was inoculated intramuscularly into healthy challenge prawns ( Penaeus monodon ) from Australia. The latter were then monitored for clinical signs of disease, and tissue samples were processed for electron microscopy, histological examination and for detection of WSSV by in situ hybridization (ISH) using a commercial kit. Limited numbers of haemolymph samples from inoculated challenge prawns were also examined by PCR for the presence of WSSV and YHV. All work was carried out under microbiologically secure conditions.
Results Results of the initial PCR examination for WSSV on the imported prawns were not definitive. However, in the bioassay, several of the challenge prawns inoculated with homogenates from the imported prawns showed clinical signs of disease (inappetence and lethargy) within 24 h post inoculation (pi) and died at 1 to 4 days pi. Tissue samples from a number of moribund prawns demonstrated lesions typical of White Spot Disease (WSD), and the presence of the virus was confirmed by electron microscopy, ISH and PCR. YHV was also demonstrated by PCR in two challenge prawns inoculated with homogenates.
Conclusion Viable WSSV and YHV were present in frozen prawn products imported into Australia for human consumption from southeast Asia. Importation of frozen infected products may present a risk of transferring virus to wild and farmed populations of crustaceans in this country. To date, WSD and Yellowhead Disease remain exotic to Australia.     

对虾白斑综合症病毒双抗体夹心ELISA方法的建立

用将纯化的对虾白斑综合症病毒VP28蛋白免疫BALB/c小鼠,分离免疫鼠脾细胞,与SP2/0细胞融合,经间接ELISA筛选,得到了2株（2G9,3E5）可以稳定分泌抗对虾白斑综合症病毒特异性单抗的杂交瘤细胞株。用纯化的VP28蛋白免疫家兔,按常规方法制备多抗。选用单抗（3E5）包被ELISA板,用兔多抗作为捕获抗体,建立了对虾白斑综合症病毒的双抗体夹心ELISA检测方法。该方法具有良好的特异性和敏感性,为对虾白斑综合症病毒的检测提供了有效工具。