条斑紫菜(Pyropia yezoensis)绿斑病病原菌的分离鉴定

绿斑病(Green spot disease)是一种常见的海区栽培条斑紫菜(Pyropia yezoensis)病害,在整个紫菜栽培期间都可能发生,以每年11～12月份最为严重,主要出现在幼叶期和成叶期。首先,在叶状体上出现红色或淡红色小斑,而后逐渐转变为绿色,病斑继续扩展,在叶状体表面形成若干孔洞,后期几乎整个藻体变绿。本研究对日照地区患绿斑病的条斑紫菜进行病原菌分离纯化,得到5株优势菌(编号为Y1～Y5),人工回感实验结果显示,Y1可以引起健康条斑紫菜发生绿斑病。对Y1进行了生理生化检测、16S rRNA、dnaA和dnaN基因序列分析,确定病原菌为海洋假交替单胞菌(Pseudoalteromonas marina)。对绿斑病的发病进程进行了观察,并检测了培养温度、海水比重和养殖密度等环境因子对绿斑病发生的影响,结果显示,高温和高密度养殖会加速绿斑病病情的发展,海水比重为1.022时,绿斑病发病较严重。本研究确定了一株引起条斑紫菜绿斑病的病原菌,并分析了部分理化因子对感染的影响,为条斑紫菜绿斑病的防控提供了基础数据。     

条斑紫菜绿斑病及其相关生态因子的初步研究

对2004—2005年度江苏南部的条斑紫菜绿斑病进行了研究。该病主要出现在幼叶期和成叶期,发病时间从晚秋到早春。肉眼观察患病部位呈绿色,不久腐烂分解,留下带绿缘的孔洞。显微镜观察发现其主要症状为在藻体的中部和边缘出现圆形的绿色病斑,以最初患病处为中心成放射状,不久便从中心部脱落。不同生态因子下的实验结果表明,海水温度下降和减低养殖密度可以在一定程度上抑制该病原菌的蔓延。冷藏网的使用是防治绿斑病在高温季节发生和蔓延的主要措施。     

1株引起条斑紫菜绿斑病的柠檬假交替单胞菌

从栽培海区采回的发病条斑紫菜 (Porphyraeyezoensis)上共分离筛选出 5 1株菌株 ,全部进行人工感染 ,其中 17# 菌株发病症状最典型 ,而感染对照组没有可见变化。初步确定 ,17# 菌株是条斑紫菜绿斑病的主要致病菌。17# 菌株为短杆状、极生单鞭毛可运动的革兰氏阴性菌 ,产生紫褐色色素 ,可水解明胶、酪蛋白、淀粉等大分子物质。葡萄糖氧化发酵试验 (O/F)为氧化性、氧化酶阳性、ONPG反应阳性 ,V -P反应阴性 ,生长需Na 等生化特性 ,G C含量 4 0 .5mol% ,脂肪酸主要成分为C17∶1ω8c和C16∶1ω7c。基于 16SrRNA的系统进化分析均表明 ,从患绿斑病的条斑紫菜叶状体上分离到的致病菌株 17# 与柠檬假交替单胞菌 (Pseudoalteromonascitrea)为同种的不同菌株     

一起条斑紫菜拟油壶菌病的诊断

赤腐病(red rot disease)和拟油壶菌病(Oplidiopsis disease)是海上栽培紫菜(Pyropia)的主要病害,常引起紫菜大面积病烂。2019年1月江苏省盐城市大丰区某条斑紫菜(Pyropia yezoensis)栽培海区有134 hm2发生了紫菜病烂,本研究对该起病烂进行了病害调查和病原鉴定。结果显示,患病紫菜的病症与拟油壶菌病一致,主要表现为发病初期,在叶片边缘、基部和中部出现粉红色的病斑,随着病程发展,病斑逐渐褪色并扩大;发病后期,整个叶片颜色变浅,叶片组织溃烂脱落;在显微镜下可观察到紫菜细胞内寄生1~4个圆球状菌体,菌体内有多个油滴状物质。以病烂紫菜叶片或其匀浆液为感染源,分别在10℃和20℃条件下进行人工感染实验,二者均能使正常紫菜出现拟油壶菌病的病症。对现场采集及人工侵染后的病烂紫菜疑似病原进行cox1基因测序和系统发育学分析。研究表明,所测cox1基因均与紫菜拟油壶菌(Oplidiopsis porphyrae、O. pyropiae、O. porphyrae var. koreana)聚为一支,相似度为100%。综上所述,该起条斑紫菜的病烂由紫菜拟油壶菌(Oplidiopsis sp.)引起。     

一株引起坛紫菜绿斑病病原的分离鉴定及致病性研究

为了明确引起坛紫菜绿斑病的病原,对2012年发生在福建省莆田养殖海区坛紫菜叶状体绿斑病开展了病原的分离鉴定和致病性研究。利用2216E海水培养基平板,从患病藻体分离得到一株优势细菌X5;在实验室条件下将X5进行回接感染实验,在显微镜下观察到坛紫菜叶状体发生组织病理变化,出现绿斑病症状:感染初期出现黄绿色小斑点,病斑逐渐扩大出现空洞,最后导致紫菜叶片流失;用浓度为10⁴~10⁸ cfu/mL的X5感染坛紫菜时,在7 d内引起紫菜出现10%~100%病斑面积,这些结果表明X5为坛紫菜绿斑病的病原。利用生理生化和多基因序列分析方法对X5进行鉴定,结果显示该菌为革兰氏阴性菌,大小为0.6 μm×0.4 μm~1.0 μm×0.4 μm,无鞭毛,在温度4~42℃、盐度50~150、pH6~10范围内生长,最适生长温度为16℃,最适生长盐度为50,最适pH为7,对甲硝唑、林可霉素和青霉素耐药,对25种抗生素敏感,Biolog和API ID-32E细菌鉴定系统的结果显示X5为弧菌属细菌(Vibriosp.);基于多基因序列(16S rRNA,rpoA,recA,pyrH)构建的系统进化树分析显示,X5与V.casei、V.litoralis、V.rumoiensis聚为一支,进化距离为0.095~0.108,这些结果说明X5为弧菌属的一个新种或是V.casei、V.litoralis、V.rumoiensis之一的一个新亚种。本研究报道了弧菌X5能够引起坛紫菜绿斑病,为紫菜流行病学及疾病防治提供了理论支撑。     

坛紫菜叶状体的细菌性红烂病研究

本实验对发生在福建省平埠岛自然海区的野生坛紫菜（Porphyra haitanensis）叶状体上的红烂病进行了研究。患病叶状体上存在大小不等、肉眼可见的圆形或亚圆形病斑，镜检发现病斑内存在大量铁锈红色的死细胞和少量已解离的发绿或发白死细胞。将患病叶状体与健康坛紫菜叶状体共培养3d后，后者也出现了相同的红烂病，表明该病是由传染性病原侵入引起的。从患病叶状体中分离到一种病原菌，能感染健康叶状体使其出现相同的病症。该病原菌具有分泌毒素和微弱的消化琼胶能力，经高压灭菌或煮沸后的病原菌液，其杀死紫菜细胞的能力比未处理的病原菌液增加了数倍，这说明该菌可能通过释放内毒素来杀死叶状体细胞。鉴于此病是由于病原菌侵入叶状体并释放内毒素杀死紫菜细胞，且死亡细胞呈铁锈红色，故将其命名为“坛紫菜细菌性红烂病”。[中国水产科学，2008，15（2）：313—322]     

五种生态因子对条斑紫菜壳孢子附着率的影响

条斑紫菜壳孢子生长和附着的好坏与生产有密切的关系,壳孢子阶段是紫菜栽培当中最重要的一步,壳孢子附着受多种生态因子的影响,本文探讨了pH值、离子组成、浑浊度、海水比重、光照强度五种生态因子对条斑紫菜壳孢子附着率的影响,以期对条斑紫菜育苗生产提供理论依据和技术支撑。     

条斑紫菜人工育苗与生态栽培技术

２０００～２００１年，我们在城阳区红岛镇２ ０００亩浅海滩涂进行了条斑紫菜立体生态养殖，获得了总产值１４４０万元，总利润７４０万元，亩利润３ ７００元的好成绩。１ 生物学特征 条斑紫菜的生活史为２个明显不同的生长发育阶段组成，即人们叫做“紫菜”的叶状体阶段和生长在贝壳里微观的丝状体阶段。 条斑紫菜的叶状体为藻膜状，大体上可分为叶片、基部、固着器３部分，以其基部细胞向下延伸的假根丝固着在生长基质上，体形叶片状、卵形或长卵形，体高一般为 １２～３０ ｃｍ，藻体厚 ３５～５０ μｍ。 丝状体是由叶状体产生的果抱…     

坛紫菜的主要病害与对策

莆田市坛紫菜的人工养殖具有３０多年历史，随着养殖面积的不断增加，渔业环境的恶化、养殖管理的人为失控及集约化程度的提高，养殖病害年年都有不同程度的发生。笔者为此进行多次实地调查，初步总结分析了紫菜的主要病害及发生原因，并提出相应的对策，以期有助于坛紫菜人工养殖的健康、持续发展。一、坛紫菜的主要病害坛紫菜的病害大致可以分为三种类型：一种是由病原菌的侵袭引起的，如分别由紫菜的腐霉菌、壶状菌及变形菌引起的赤腐病、壶状菌病及绿斑病等；一种是由于环境条件不适宜而引起的，如常见的缺氮绿变病，由网帘受光不足、海…     

不同植物激素对条斑紫菜体细胞生长发育的影响

用添加不同浓度植物激素(IBA和6一BA)的PES培养液对条斑紫菜体细胞进行培养，观察其对条斑紫菜体细胞生长发育的影响。结果表明：酶解的条斑紫菜近基部体细胞离体培养可发育成细胞团和叶状体，低浓度的IBA有利于体细胞向叶状体方向发育，而低浓度的6一BA有利于体细胞发育成细胞团。     

条斑紫菜拟油壶菌病的初步研究

1960年新崎盛敏首先报道了寄生在紫菜叶状体细胞内的病原菌是壶状菌Olpidiopsis sp.,之后不少学者对这种病害的病症、发生情况及环境条件等进行了较深入的调查研究。其中右田清治在"养殖紫菜的壶状菌病"以及"紫菜的病害"中较详细描述了该病的病症、病原菌的     

一株条斑紫菜丝状体黄斑病致病菌病原学研究#br#

采集山东省日照市岚山区藻类养殖合作社某紫菜育苗场的患有黄斑病的条斑紫菜(Pyropia yezoensis)丝状体,经2216E、TSB和TCBS 3种培养基体外培养,筛选获得优势菌株PZ201809121102,通过革兰氏染色、电镜负染观察、16S rDNA鉴定、生理生化分析、药物敏感性等技术方法对菌株进行鉴定分析,并结合回归感染实验确认菌株PZ201809121102的致病能力。结果表明:1)分离纯化后的优势菌株PZ201809121102在2216E海水培养基上的菌落形态呈细小圆形、中间突起、表面光滑呈亮黄色、匍匐镶嵌生长、属革兰氏阴性菌、短杆状、细胞大小(0.5~1.0)μm×(1.5~5.0)μm,透射电镜下观察到该菌株孢外具有单端生鞭毛;2)16S rDNA测序分析表明,该菌在所建16S rDNA系统发育树中与假单胞菌属聚为一支,与浅黄假单胞菌(Pseudomonas luteola)同源性最高,为100%;3)生理生化显示,该菌株在6%NaCl胰胨水、10%NaCl胰胨水中均生长,氧化酶反应阳性,鸟氨酸脱羧酶、赖氨酸脱羧酶、精氨酸双水解酶反应阳性;3%NaCl ONPG反应阳性。能同化利用葡萄糖,不能利用蔗糖、乳糖、密二糖、山梨醇等多糖;4)进行回归感染实验时,用10³~10⁸CFU·mL^-1的PZ201809121102菌悬液浸泡感染健康条斑紫菜丝状体。在13 d时,10⁸CFU·mL^-1感染试验组的条斑紫菜丝状体出现大小不一的黄色斑点,与自然发病的丝状体黄斑病症状一致,且可再次分离得到与自然发病丝状体中相同优势分离株,证明PZ201809121102有致病性,是引发条斑紫菜丝状体黄斑病的一种病原,菌悬液浓度小于10⁸CFU·mL^-1的各试验组丝状体中无明显黄斑病患病症状。5)药敏实验结果显示,PZ201809121102对罗美沙星和氟罗沙星两种药物高度敏感,对头孢唑啉、头孢氨苄、头孢拉定不敏感。本研究发现了导致条斑紫菜育苗期丝状体黄斑病的一株浅黄假单胞菌(P.luteola),可丰富对紫菜丝状体黄斑病的认识,以为今后对条斑紫菜育苗期丝状体黄斑病的防治提供参考。     

Long-term effects of stocking density on somatic growth,gonad index and survival of the juvenile sea urchin, <Emphasis Type="Italic">Strongylocentrotus droebachiensis</Emphasis>

Juvenile Strongylocentrotus droebachiensis (average wet weight = 4.0 g) were held at three initial stocking densities (15, 30 and 60 animals per tray, which equates to 0.25, 0.5 and 1 kg sea urchins/m² surface area, respectively) under constant light and temperature conditions (LD 24:0 and 8.8°C) for 380 days. The somatic growth and survival of the urchins were monitored during this period, and the gonad index (GI) was measured at the conclusion of the experiment. The sea urchins in the two lowest stocking density groups had 100% survival after 380 days in contrast to the highest stocking density group, which only had 67% survival at the conclusion of the experiment. Somatic growth was significantly higher in the lowest density group than in the medium density group, and this in turn was significantly higher than in the high-density group. The injury occurrence was highest in the high-density group (20%), lower in the medium group (7%), and there were no injuries observed (0%) in the low density groups. There were no significant differences in GI between the groups at the end of the experiment. In conclusion, the present study showed that stocking density has significant effects on somatic growth and survival of juvenile green sea urchin, S. droebachiensis and should be taken into consideration when designing sea urchin holding systems.     

Influence of rearing conditions on Flavobacterium columnare infection of rainbow trout, Oncorhynchus mykiss (Walbaum)

The influence of rearing conditions on Flavobacterium columnare infection of rainbow trout, Oncorhynchus mykiss (Walbaum), was studied experimentally in the laboratory and at a fish farm. In experiment I, the effect of parasitic infection on columnaris disease was studied using F. columnare carrier fish. The fish were exposed to Diplostomum spathaceum cercariae and a set of other stressors in order to induce clinical columnaris infection. Parasitic infection and other stressors failed to induce the disease. Disease occurred when the fish were challenged with F. columnare, but D. spathaceum infection did not enhance the severity of the infection. In experiment II, the influence of rearing density and water temperature was studied. Overall mortality was highest in fish at normal rearing density with high temperature (+23 degrees C). At low temperature (+18 degrees C) mortality was not affected by rearing density, but the transmission of columnaris disease was faster at normal rearing density at both temperatures. This supports the view that reduction of fish density could be used in prevention of columnaris disease especially if water temperature is high. Because the lower rearing density can also decrease the transmission of ectoparasites and penetrating endoparasites, it could be an efficient tool in ecological disease management.     

放养密度和投饲率对南美白对虾单产的影响

为了提高养殖南美白对虾的单产水平,采用梯度设计法和回归分析法研究了放养密度和日投饲率对养殖南美白对虾单产的影响。结果表明,新疆北疆地区南美白对虾单产(Y)与放养密度(SD)呈极显著二次曲线关系Y=-0.0461SD2+11.204SD-78.959(R2=0.9707)(F>F0.01),当地南美白对虾最佳放养密度为122 ind./m2;新疆北疆地区南美白对虾单产Y与日投饲率(DFR)呈显著二次曲线关系Y=-24882DFR2+3628.2DFR+133.71(R2=0.8128)(F>F0.05),当地南美白对虾最佳日投饲率为7.29%。     

水温和藻类对马粪海胆摄食、呼吸及排氨率的影响

在水温10.1℃,将初始体质量为(0.55±0.16)g的马粪海胆幼胆,随机放入0.3 m×0.4 m×0.5 m的白色塑料桶中,每桶100个,过量投喂新鲜孔石莼、粘膜藻、肠浒苔、裙带菜和珠状硬毛藻,计算各种藻类的摄食量(以干质量计),研究马粪海胆对藻类的摄食选择性。再将初始体质量为(0.67±0.32)g的马粪海胆置于水温为10.1、15.6、20.3℃的容器中,投喂相同的5种藻类2 d后,挑选10个规格相似个体放入1 L锥形瓶中,适应0.5 h后密封测定耗氧率和排氨率,研究不同温度和藻类饵料下马粪海胆的耗氧率和排氨率。试验结果表明,马粪海胆的摄食选择率依次为裙带菜>粘膜藻>孔石莼>肠浒苔>珠状硬毛藻,马粪海胆明显偏好裙带菜;马粪海胆摄食量受温度及藻类种类影响显著(P<0.05),在15.6℃时,日相对摄食率最大,摄食裙带菜的组别显著大于其他组别(P<0.05),摄食珠状硬毛藻的组日相对摄食率最低;各组别马粪海胆耗氧率均随着水温的升高而增大,相同温度条件下,孔石莼组耗氧率最大;各组排氨率随着水温的升高呈现先增大后减小,15.6℃时最大。研究结果将为开展马粪海胆生态增养殖、构建刺参池塘绿色综合养殖模式提供参考。     

Density-Dependent Growth and Survival of Penaeus setiferus and Penaeus vannamei in a Semi-Closed Recirculating System

Abstract.— Two growth trials utilizing Penaeus vannamei and Penaeus setiferus were conducted at densities of 28.4, 56.8, 85.2, 113.6, 170.4, 227.3 and 284.1/ m² in an indoor recirculating system. There was an inverse linear relationship between stocking density and growth among both species. The relationship between final weight and stocking density is described by the following linear equation: P. setiferus , Y =−0.00619X ± 4.46, adj. r²= 0.8572;. P. vannamei, Y =−0.00717X ± 7.39, adj. r²= 0.6230. Although the responses in terms of growth depressions were similar, P. setiferus growth was lower than that of P. vannamei . There was an inverse relationship between stocking density and survival for P. setiferus . Survival of P. vannamei was highly variable but was negatively correlated with density. Based on the results of the present study, P. setiferus has a similar tolerance of high density as that of P. vannamei and hence may be suitable for intensive culture systems. However, depressed growth rates of P. setiferus , which do not appear to be due to effects of water quality or density, must be solved if growth rates similar to P. vannamei are to be realized.     

The effects of sediment redox potential and stocking density on Pacific white shrimp Litopenaeus vannamei production performance and white spot syndrome virus resistance

Redox potential represents the intensity of anaerobic condition in the pond sediment, which may affect the dominant microbial transformations of substances, the toxins production, mineral solubility, as well as the water quality in the sediment–water interface inhabited by the shrimp. This study evaluates the effect of sediment redox potential in conjunction with stocking density on shrimp production performance, immune response and resistance against white spot syndrome virus (WSSV) infection. A completely randomized two factors experimental design was applied with three different sediment redox potential, i.e. ?65, ?108 and ?06 mV, and two shrimp densities, i.e. low (60 shrimp m^?2) and high (120 shrimp m^?2). Shrimp juveniles with an initial mean body weight of 5.32 ± 0.22 g were maintained in semi‐outdoor fibre tanks (270 L in capacity) for 35 days of experimental periods. At the bottom of each tank, 5‐cm deep soil substrate with different redox potential was added according to the treatments. The survival and biomass production were significantly reduced at ?206 mV sediment redox potential, regardless of stocking density. Highly negative sediment redox potential (?206 mV) and higher stocking density significantly reduced total haemocyte counts and phenoloxydase activity, and shrimp resistance to WSSV infection. We recommend to maintain the redox potential of pond sediment at a level of more than ?206 mV.     

南方海区刺参养殖关键技术研究

利用福建宁德市南方海区冬季水温高、适合刺参生长的自然条件，秋后引进北方大规格苗种，采用海区筏式吊笼养殖模式，在选择养殖场所、饵料种类及投喂量、苗种及运输方法、确定合理养殖密度、适宜温度、养殖周期、病害防治与日常养殖管理措施等方面进行了研究，首次提出了在人工投喂以海带为主的饵料基础上，“定期添加鱼糜、糠虾粉、麦麸、面粉混合物补充营养”的人工投喂饵料方法，周期缩短到100～110d，获得良好成效。     

Overwintering tilapia, Oreochromis spilurus (Günther), fingerlings using warm underground sea water

Abstract.
The study was conducted to develop guidelines for high-density overwintering of tilapia in tanks using warm underground sea water. Seawater-acclimated fish of 20 g were stocked in 36 tanks at 250, 500 and 750/m³. Water flow was regulated at 0.1 and 0.2 l/kg fish/min. Fish were fed at the rates of 0.75% and 1.0% of biomass per day.
After 135 culture days, the mean individual weight gain and specific growth rate decreased, whereas feed conversion increased significantly ( P <0.0001) with the increase in stocking density. The condition factor at 500 and 750 fish/m³ was significantly lower ( P <0.0005) than at 250 fish/m³. However, stocking density had no significant effect on the survival rate. Significantly better specific growth rate, condition factor and feed conversion were observed at a water flow rate of 0.2 l/kg fish/min than at 01 l/kg fish/min. Significantly higher mean individual weight gain, specific growth rate, and survival rate were observed at 1.0%/day than at the 0.75%/day feeding rate. The findings indicate that the optimum stocking density for overwintering tilapia in tanks using warm underground sea water is 750 fish/m³ with a water flow rate of 0.1 l/kg fish/min and a feeding rate of 0.75%/day.