微生态调节剂对提高中国对虾抗病力的研究

应用从健康中国对虾肠道中分离筛选出的无毒、无害菌群（ＪＸ５、ＪＸ６）制成微生态调节剂,将其作为饲料添加剂饲养中国对虾,对感染暴发性流行病的抗病力进行试验研究。结果表明：（１）微生态调节剂能够明显地提高中国对虾感染后的成活率,使死亡高峰时间延迟;（２）感染后的血液病理指标显示,病虾的血清总蛋白、白蛋白、球蛋白等指标下降,甘油三酯、碱性磷酸酶、乳酸脱氢酶等指标上升;（３）投喂微生态调节剂的试验组与对照组经感染致病后,其血液指标与健康虾比较变化幅度不同,试验组虾血液指标变化幅度小于对照组。本文同时对微生态调节剂抗病力的作用机制进行了初步探讨。     

碳酸盐碱度和pH值对凡纳滨对虾仔虾存活率的影响

采用静态急性毒理学方法,探讨了碳酸盐碱度和pH值对凡纳滨对虾(Litopenaeus vannamei)仔虾存活率的影响。结果表明:在pH值为7.5、8.0、8.5、9.0、9.5、10.0及10.5的试验组中,凡纳滨对虾仔虾存活率随着pH值的升高而下降,碳酸盐碱度在3mmol·L-1、pH值在9.0以上时,凡纳滨对虾仔虾的存活率受到影响显著;在碳酸盐碱度0～44.43mmol·L-1各试验组中,随着碳酸盐碱度升高,凡纳滨对虾仔虾的存活率下降,凡纳滨对虾仔虾对碳酸盐碱度的耐受性随着pH的升高明显下降;pH值为8.8时,碳酸盐碱度的48hLC50为36.81mmol·L-1,pH值为9.2时,碳酸盐碱度的48hLC50为33.05mmol·L-1,pH值为9.6时,碳酸盐碱度的48hLC50为5.55mmol·L-1;在本试验范围内,凡纳滨对虾对高碳酸盐碱度显示出较强的耐受性,是一种适宜移植到盐碱水域的养殖品种;碳酸盐碱度和pH对凡纳滨对虾的致毒作用是一个综合致毒效应,其中CO32-为主要致毒因子。     

盐度对日本囊对虾仔虾生长发育和Na+-K+-ATPase活力的影响

研究了盐度对日本囊对虾仔虾(Marsupenaeus Japonicus)的生长发育和Na -K -ATPase活力的影响。结果表明,盐度对日本囊对虾仔虾存活率、增重率和Na -K -ATPase活力的影响显著(P<0.05)。随着向低盐度变化的增加,仔虾的存活率和增重率明显下降,而向高盐度变化无显著差异;在盐度变化48h内,随着盐度变化的增加仔虾Na -K -ATPase活力变化增大,各处理组仔虾Na -K -ATPase活力随着取样时间的增加呈峰值变化,至24h时低盐度处理组酶活力达到最大值,而高盐度处理组达到最小值:至48h~72h时,不同盐度下仔虾Na -K -ATPase活力趋于稳定,而且盐度越低酶活力越大。由此表明日本囊对虾仔虾在低盐度地下卤水中的适宜盐度为20‰—24‰。     

海蜇幼体与对虾幼体相食关系的实验观察

本文于１９９２年和１９９３年４月下旬至５月上旬，在莱州市对虾育苗增殖场对海蜇幼体与对虾幼体的相食关系进行了实验观察。结果表明：对虾各期幼体均不摄食海蜇各期幼体。海蜇各期幼体摄食对虾各期幼体的能力不同，其中以伞径１０－２０ｍｍ的后期碟状幼体摄食对虾无节幼体和蚤状幼体的比率最高，摄食糠虾幼体和仔虾的比率较低；而伞径２０ｍｍ以上的幼蜇不能吃掉仔虾。文中还对今后合理放流增殖海蜇和对虾资源提出了初步看法。     

中国对虾球状病毒垂直传播的初步研究

应用透射电镜技术在越冬中国对虾雌性亲虾体内检测出一种球状病毒,直径为80nm左右。人工感染实验证实该病毒颗粒具有感染性。对带毒亲虾在室内隔离条件下进行了暂养催产,并对其所产的卵子、幼虫和的虾进行了隔离培育。带毒亲虾的卵子孵化率、幼虫成活率和幼虾生长速度均明显低于不带毒亲虾的子代。电镜观察发现．在带毒亲虾卵巢、各期幼虫和幼虾的细胞内存在球状病毒颗粒,在刚产的卵子的卵黄颗粒中可看到一种似球状病毒颗粒。研究表明：带球状病毒的对虾呈隐性感染,在胁迫条件下带毒幼虾可暴发病害,带毒亲虾可正常发育产卵,病毒可能通过卵巢、卵子进行垂直传播。     

虾蟹育苗的藻饵料培养

对虾和蟹,肉鲜味美,营养价值高,是人们所喜爱的海珍品。我国对虾养殖面积达100多万亩。对虾属我国有10余种,人工养殖的种类主要有：东方对虾、斑节对虾、墨吉对虾、日本对虾及长毛对虾等。虾生长较快,寿命短,正龄便开始繁殖后代。从受精卵孵化形成的幼体到初具虾形的仔虾要经过无节幼体、蚤状幼体和糠虾游体等几个发育阶段。无节幼体是不摄食的,靠卵黄营养自已,到蚤状幼体才开始摄食微小的藻类植物。蟹如以人工养殖的锯缘青蟹为例,它的发育过程没有对虾那么复杂,受精的卵孵化成蚤状幼体时,离开母体在水中浮游生活,经过几个时期…     

盐度波动对中国对虾稚虾蜕皮、生长和能量收支的影响

采用实验生态学方法研究了在盐度为20的条件下,4个盐度波动幅度（2、4、6、8）对中国对虾稚虾蜕皮和生长的影响.结果表明：中国对虾的蜕皮率为13.3%～15.4%,处理间差异未达到显著水平;盐度波动幅度为4的情况下,对虾的特定生长率最大,用在生长上的能量最高,用于呼吸的能量最低,生长迅速;盐度波动幅度为2的情况下,中国对虾的摄食量最低;盐度波动幅度为2和4的情况下,对虾的食物转化效率最高;不同处理中国对虾用在蜕皮上的能量差异不显著.盐度波动幅度过大不利于中国对虾稚虾的生长,但对蜕皮无影响.     

渤海西岸急性致死性对虾病的病毒病原研究

目前,在全世界养殖及野生对虾中已发现至少有10～20种病毒。近年来,我国沿海省份相继发生养殖对虾大批死亡现象,造成大部分虾场严重减产甚至绝收,对滩涂对虾养殖业造成巨大经济损失。虾病已成为对虾养殖业的重要限制因素。因此研究虾病的病原,传染途径,对有效防治暴发流行性虾病,发展对虾养殖业具有重要意义。本文报导我们对渤海西岸养殖的中国对虾暴发流行病病原的部分研究结果。1材料与方法1．五病好和病虾组织的超薄切片观察病虾取自辽宁锦西首钢前所虾场加工厂冰冻中国对虾,以及上海东海水产研究所固定保存的活病虾组织。从已死…     

莱州湾中国对虾生长特性及其空间分布

根据2010年5月—10月调查资料,对山东莱州湾中国对虾(Fenneropenaeus chinensis)的资源状况、生长特性及其空间分布进行了研究。莱州湾放流前本底调查资料表明,目前山东莱州湾中国对虾捕捞产量主要来源于增殖放流,且在一定条件下捕捞产量与放流数量成正相关关系。依据2010年中国对虾生物学数据,应用R语言命令对中国对虾体长体重关系和体长生长方程进行了拟合,并对拟合系数进行了显著性检验,结果表明中国对虾体长与体重系数a、b处于显著水平(P0.05),中国对虾体长生长方程拟合系数K、t_0、L_∞处于极显著水平(P0.001),故拟合效果明显,获得为中国对虾生长参数雌虾为K=0.0226、t_0=37.45d、L_∞=200.77 mm、W_∞=80.50 g、t_r=85.18d(8月4日),雄虾为:K=0.0419、t_0=40.25d、L_∞=145.81 mm、W_∞=23.37 g、tr=67.24d(7月18日),与20世纪80年代相比,中国对虾个体明显减小,生长速度加快,生长拐点提前了1个月。另外,根据大面调查体长数据,对各个站位体长组出现频率进行Ward聚类分析,利用R语言聚类树的融合水平值定义划分水平,选择具有最大跳跃的分组水平,将中国对虾虾群大致可分为两个组群,河口组和深水组,同时按照各体长组的多度值大小,探讨了各组内具有代表性的分类体长组,结果表明,河口组的中国对虾以体长125—135 mm为主,深水组以体长115—125 mm和105—115mm为主,河口组个体明显大于深水组;河口组分布区入海河流较多,饵料生物丰富,以软泥底质为主,有利于中国对虾的摄食和前期保护,深水组分布于莱州湾中东部,蟹类资源相对较高,且以沙质底质为主,对中国对虾的生长与保护产生一定的影响。     

椒江口海域春秋季虾类群落结构及其影响因素

依据2010年春季(4月)和秋季(10月)椒江口海域渔业资源调查资料,分析了虾类的种类组成、优势度、物种数量的空间分布及多样性、相似性等群落结构特征,并对其影响因素进行探讨.结果表明: 椒江口海域春秋两季共出现虾类16种,隶属于8科12属,其中春季14种,秋季12种;春季优势种有中国毛虾、鲜明鼓虾、哈氏仿对虾、细螯虾、日本鼓虾、葛氏长臂虾6种,秋季优势种依次为中华管鞭虾、哈氏仿对虾、周氏新对虾3种.椒江口海域虾类以广温广盐生态类群为主,其次为广温低盐生态类群.多样性分析表明,Margalef种类丰富度指数和Shannon多样性指数较高的站位主要集中在大陈岛西侧海域,整个调查海域的均匀性指数较为稳定.运用聚类和多维标度对群落结构的相似性进行分析,结合水深等环境因子对椒江口虾类的群聚类型进行了讨论,椒江口虾类群落结构的季节变化明显、空间分异显著,水深是导致椒江口海域春秋季虾类群落结构组成差异的主要原因.
     

Detection by PCR of hepatopancreatic parvovirus (HPV) and other viruses in hatchery-reared Penaeus monodon postlarvae

The prevalence of hepatopancreatic parvovirus (HPV), monodon baculovirus (MBV) and white spot syndrome virus (WSSV) in samples of Penaeus monodon postlarvae (PL10 to PL20, 10 to 20 d old postlarvae) in India was studied by PCR. Samples collected from different hatcheries, and also samples submitted by farmers from different coastal states, were analyzed. HPV was detected in 34%) of the hatchery samples and 31% of the samples submitted by farmers, using a primer set designed for detection of HPV from P. monodon in Thailand. However, none of these samples were positive using primers designed for detection of HPV from P. chinensis in Korea. This indicated that HPV from India was more closely related to HPV from P. monodon in Thailand. MBV was detected in 64% of the samples submitted by the farmers and 71% of the hatchery samples. A total of 84 % of the samples submitted by farmers, and 91% of the hatchery samples, were found positive for WSSV. Prevalence of concurrent infections by HPV, MBV and WSSV was 27% in hatchery samples and 29%, in samples submitted by farmers. Only 8% of the hatchery samples and 16% of the samples submitted by farmers were negative for all 3 viruses. This is the first report on the prevalence of HPV in P. monodon postlarvae from India.     

Multiple viral infection in Penaeus monodon shrimp postlarvae in an Indian hatchery

Moribund Penaeus monodon postlarvae (PL8-PL10) in a hatchery in India were found to be simultaneously infected by 3 different viruses. They were highly infected with monodon baculovirus (MBV) and hepatopancreatic parvovirus (HPV) by histology and with white spot syndrome virus (WSSV) by non-nested polymerase chain reaction (PCR). Apparently healthy postlarvae tested from the same hatchery were positive for MBV and WSSV by nested PCR only. Tissue sections of such postlarvae did not show any histopathological changes. The simultaneous occurrence of these 3 viruses in hatchery-reared postlarval P. monodon is being reported for the first time.     

The identification of postlarvae of four species of Penaeus (Crustacea: Decapoda) from the Pacific coast of Mexico

Livingand recently preserved postlarvae of Penaeus vannameiBoone, P. stylirostris Stimpson, P. californiensis (Holmes) and P. brevirostris Kingsley may be separated into species on chromatophore patterns and rostral lengths. These and other characters are illustrated and tabulated, and their usefulness and reliability are discussed.     

中国对虾呼肠孤样病毒感染的电镜观察

呼肠孤病毒在自然界广泛存在于脊椎动物、无脊椎动物和植物中.水产动物呼肠孤病毒感染曾见于鱼、贝、蟹.近几年随着对对虾病毒病害研究的日益重视,在对虾中也发现呼肠孤病毒的感染.Tsing等[1]最早于1987年在法国南部养殖的日本对虾(P.japonicus)幼虾中发现呼肠孤病毒感染.Krol等[2]于1990年在试验感染的南美白对虾(P.vannamei)中发现呼肠孤样病毒与对虾杆状病毒混合感染.中国大陆养殖的中国对虾自1993年全面暴发流行病以来,许多学者进行了对虾流行病的病原学、流行病学及诊断和防治方法的研究,部分学者曾在中国对虾(P.chinensis)中观察到呼肠孤样病毒颗粒[3],但未报道较详细的电子显微镜观察资料.     

Solvent extracts of the red seaweed Gracilaria fisheri prevent Vibrio harveyi infections in the black tiger shrimp Penaeus monodon

Vibriosis is a common bacterial disease that can cause high mortality and morbidity in farmed shrimp. Since compounds from seaweed have been reported to have anti-bacterial and immunostimulant activity, this study was conducted to determine whether solvent extracts from the red seaweed Gracilaria fisheri might be a possible alternative for prevention and treatment of shrimp vibriosis caused by Vibrio harveyi. Seaweed extracts prepared using ethanol, methanol, chloroform and hexane were evaluated for anti-V. harveyi activity by the disc-diffusion method. The ethanol, methanol and chloroform extracts showed activity against a virulent strain of V. harveyi with potency (minimal inhibitory concentrations in the range of 90-190 μg ml(-1)) equivalent to the antibiotic norfloxacin. The ethanol extract was not toxic to the brine shrimp Artemia salina when it was fed to them for enrichment prior to their use, in turn, as feed for postlarvae of Penaeus monodon. Postlarvae fed with these enriched Artemia gave significantly lower mortality than control postlarvae after challenge with V. harveyi. In addition, P. monodon juveniles injected with the ethanol extract showed a significant increase in the total number of haemocytes and an increased proportion of semi-granulocytes and granulocytes when compared to control shrimp. The activities of phenoloxidase and superoxide dismutase were also increased, with an accompanying increase in superoxide anion production. When these juvenile shrimp were challenged with V. harveyi, mortality was markedly reduced compared to that of control shrimp. The results indicated that ethanol extracts of G. fisheri had immunostimulant and antimicrobial activity that could protect P. monodon against V. harveyi.     

The effects of dietary astaxanthin on the carotenoid pattern of the prawn Penaeus japonicus during postlarval development

Penaeus japonicus postlarvae, reared under laboratory conditions, were fed an astaxanthin enriched diet to the investigate carotenoid metabolic capabilities during the postlarval development. Animals fed astaxanthin were found to absorb this carotenoid. The decrease of pigment concentration in the carotenoid starved group is related to the duration of the experimental feeding conditions; the carotenoid depletion depends upon the postlarval status at the starting point. As has been shown for adult prawns, the carotenoid pattern of postlarval stages, regardless of the diet, consists mainly of free and esterified astaxanthin; the relative amounts of these fractions undergo slight variations depending on the diet.     

Prevalence and effect of spawner-isolated mortality virus on the hatchery phases of Penaeus monodon and P. merguiensis in Australia

Spawner-isolated mortality virus (SMV) has been associated with mortalities in broodstock of Penaeus monodon and with mid-crop mortality syndrome on grow-out farms. Epidemiological evidence suggested an association between the SMV status of broodstock and subsequent survival of their progeny, and this paper describes investigations into that association. The faeces of 909 broodstock in 9 different groups were tested by a polymerase chain reaction (PCR) for SMV and positive results were confirmed by an internal dot-blot. Seventy-seven spawners (8.5%) were positive for SMV with prevalence ranging from 0 to 24% among groups. The prevalence in spawners of P. monodon was higher (24%) than in P. merguiensis (4%). Three longitudinal studies were undertaken to compare the survival of progeny from broodstock that were positive to SMV with those that were not. Survival in hatchery tanks of progeny from SMV-positive spawners was lower than those from SMV-negative spawners with reductions of 23% (p = 0.01), 7.3% (p = 0.214) and 18.9% (p = 0.129) in the 3 studies. The conclusions were less consistent when examined during each of the later stages of growth in hatchery pools, nursery and grow-out ponds, with progeny from SMV-postive spawners sometimes having better survival rates. However, survival was better overall in progeny from SMV-negative spawners. Simple linear regression showed survival was negatively related to the proportion of postlarvae from SMV-positive spawners, with a decrease in survival of 5.6% for each 10% increase in the proportion of postlarvae coming from SMV-positive spawners (p = 0.006). Data from 38 ponds showed 6.71% of losses were due to SMV. If these losses were consistent across the entire industry, the annual loss due to SMV would have been approximately AUD 3 million in 1999/2000.     

Occurrence, histopathology and experimental transmission of hepatopancreatic parvovirus infection in Penaeus monodon postlarvae

Hepatopancreatic parvovirus (HPV) was detected in samples of Penaeus monodon post-larvae (PL-13, PL-18, PL-19, PL-26) from 2 hatcheries in 2 provinces (Samar and Iloilo) in the Philippines. The percentage of infection was 20 to 100% in postlarvae obtained from the hatchery in Samar in August 2001. Postlarvae from the hatchery in Iloilo, sampled in October and November 2001, had 70 to 99% HPV infection. Wet mounts of squashed hepatopancreatic tissue stained with malachite green (wet-mount technique) and histopathology revealed the presence of large, usually single, basophilic intranuclear inclusion bodies in the distal tubules, which led to displacement of the nucleoli. Light microscopy showed ovoid to spherical inclusion bodies, 5 to 11 mmicrom in diameter. Transmission electron microscopy revealed that the inclusion bodies were composed of electron-dense granular material and virions. The virions appeared roughly spherical and averaged 18 to 22 nm in diameter. An experiment was undertaken to induce HPV infection by feeding P. monodon postlarvae with virus-infected postlarvae. P. monodon postlarvae (PL-16), initially determined as free from HPV, were found HPV-positive 24 h after being fed with infected material. The percentage of infection ranged from 30% at Day 1 post-infection (p.i.) to 100% at Day 7 p.i. determined by the wet-mount technique and by histopathology. This is the first report of a successful horizontal transmission of HPV in P. monodon postlarvae.     

枯草芽孢杆菌微生态制剂发酵研究进展

微生态制剂是饲用抗生素的绿色有效替代品。枯草芽孢杆菌在逆境中可形成抗逆性强的芽孢,在生产和应用过程中保持高活性,是一种高效的微生态制剂菌种。提高枯草芽孢杆菌活菌数及芽孢率是保证微生态制剂产品质量的关键。本文综述了枯草芽孢杆菌芽孢形成的分子生物学机制及影响芽孢形成的重要因素,进一步比较枯草芽孢杆菌微生态制剂不同发酵方式的特点,重点阐述了提高枯草芽孢杆菌有效生物量的工艺优化,最后介绍了枯草芽孢杆菌微生态制剂的应用,并对将来研究思路进行了讨论。     

Salinity and water-type preferences of four species of postlarval shrimp (Penaeus) from west Mexico

Preference for low salinity inland water may be an important factor in the immigration of postlarval penaeid shrimp from the sea to their nursery grounds, such as estuaries, bays, and coastal lagoons. In the present work, it was shown that four species from west Mexico - Penaeus vannamei Boone, P stylirostris Stimpson, P. californiesis (Holmes), and P. brevirostris Kingsley - all prefer salinities less than that of normal sea water. Older or larger postlarvae preferred lower salinities than early postlarvae. Of the four species, P. vannamei has the lowest preference and this species predominates in the coastal lagoon fisheries of the area. Postlarvae of P. californiensis and P. brevirostris were also shown to prefer lagoon water to sea water. The importance of these preferences is discussed in relation to the normal postlarval migrations.