杂色鲍健康苗种与患病苗种异养细菌致病毒力因子的比较研究

2002年以来,南方杂色鲍苗出现大规模死亡的问题,严重影响到南方鲍产业的发展。为寻找病因,于2004年自广东深圳下沙鲍鱼场培苗过程中变白掉板的杂色鲍苗以及官湖养殖场健康鲍苗各分离到19株和15株异养细菌,在此基础上研究了它们蛋白酶、淀粉酶、明胶酶、磷脂酶的产酶能力及溶血现象,并对它们的产酶能力及溶血能力进行了比较分析。结果表明,虽然来自下沙病鲍苗的菌株比来自官湖的健康鲍苗的溶血能力差;但它们大多数具有较强的分泌蛋白酶、明胶酶、淀粉酶、磷脂酶的能力。考虑到胞外酶是细菌的毒力因子之一,据此推测,下沙鲍鱼场鲍苗发生脱板死亡的原因可能与这些菌株能分泌胞外酶有关。     

鲍育苗用底栖硅藻的研究进展

鲍是珍贵的海产贝类之一，具有很高的营养价值。但近几年，我国台湾、福建、广东以及海南等省发生大规模九孔鲍苗掉板死亡的现象，很多鲍鱼场连续多月多批培苗，但或颗粒无收或每批次收获率极低，不到正常的10％。鲍苗掉板已是南方养鲍业中的一个非常普遍的问题，给我国南方各省鲍鱼养殖业带来极大的负面影响。     

九孔鲍苗脱板病防治的几点建议

近年来,我国南方地区九孔鲍育苗连续出现严重脱板和剥离后暴发性死亡等现象,致使九孔鲍苗育苗量大幅度减少,已严重制约我国南方地区鲍鱼养殖业的发展。为此,笔者根据近年对海南省九孔鲍育苗病害调查及鲍苗病害防治试验结果,对九孔鲍苗“脱板病”的病因进行浅析,并提出几点病害防治的建议,以供科研与生产人员参考。一、应注重亲鲍的培育工作亲鲍培育是繁育优质鲍苗的一项极为重要的前提性工作,没有培育出性腺成熟的亲鲍,就不能获得优质的受精卵,而劣质的受精卵孵化出的幼体容易出现发育不良、大量死亡的现象。培育优质亲鲍可采取如下措施:1.…     

淡水生态系统附着细菌研究述评

细菌是地球上最古老的生物类群之一,数量和种类数量也最为庞大.水下的各种基质上常附着有各种微生物组成的微生物群聚,其中包含了相当数量且并不完全为人所知的细菌群落,这些附着细菌是水生生态系统中最为活跃的组成成分,对水生生态系统的其他组成部分存在不可忽视的重要影响,如造成沉水植物死亡,驱动富营养化湖泊从草型湖泊向藻型湖泊转换...     

九孔鲍苗“脱板症”病原的初步研究

本文研究近年来在九孔鲍人工育苗中出现的大量死亡现象“脱板症”的病原。采用了组织病理学研究方法，通过电子显微镜观察，发现九孔鲍苗组织细胞中发生内质网膨大现象、具纤毛结构细胞层下的细胞质中有大量的球形病毒存在。鉴于九孔鲍育苗生产现场已使用多种抗菌性药物治疗无明显的效果，初步认为九孔鲍幼苗大量死亡的病原体为一种球型病毒。本文还探讨了九孔鲍苗脱板症的防治措施。     

患病九孔鲍苗中异养菌产胞外酶的分析

为探寻南方九孔鲍(Haliotis diversicolor supersicolor supertexta)苗大规模掉板死亡病因,从鲍鱼场患病掉板九孔鲍苗中分离到28株异养菌,并对其分泌胞外酶的能力进行分析.结果表明,分离得到的异养菌中有46.4%能分泌(酪)蛋白酶,60.7%能分泌明胶酶,3.57%分泌卵磷脂酶,17.86%分泌溶血素,但均不能分泌脂肪酶和淀粉酶.推测胞外蛋白酶为鲍苗患病的主要致病因子之一.综合考虑每一种胞外酶的潜在致病作用,以及菌株分泌多种胞外酶的能力,初步确认有5株异养菌为鲍苗掉板的潜在致病菌.     

鲍苗死亡原因的研究进展及对策

本文从细菌、病毒和寄生虫导致的病害,底栖硅藻膜、鲍苗的种群密度、水环境中的理化条件、赤潮等方面入手,综述了国内外学者近几年对鲍苗死亡原因的研究进展,并提出相应的防治对策。     

海南西岛九孔鲍养殖水体中细菌胞外产物的分析

2004年11月,自海南西岛的鲍养殖水体中分离出90株菌株。TCBS和2116E培养基分别分离40株(弧菌)和50株(异养菌)。比较了不同分离方法所得到的2批菌株分泌胞外产物的能力。试验结果表明,鲍苗掉板死亡期间,养殖水体中TCBS培养基分离的菌株能分泌脂肪酶、淀粉酶、磷脂酶和明胶酶的比例总体上高于2116E培养基分离的菌株,2116E培养基分离的菌株中能分泌溶血素的比例要略高于TCBS培养基分离的菌株。总体上,后者具有较强分泌胞外产物的能力。因此,这部分具有较强分泌胞外产物能力的菌株应视为鲍苗的潜在致病菌。此外,在对鲍的细菌性病害研究中,除了具有较强分泌胞外产物的菌株外,养殖环境中的菌群结构也是不可忽视的因素。     

紫外线消毒海水培育九孔鲍苗的研究

2000年以来自福建省南部海域至广东、海南岛沿海，陆续发生九孔鲍人工培育种苗大量死亡现象一“脱板症”，造成九孔鲍苗的严重短缺。经研究初步认为“脱板症”是一种疑似病毒性疾病。本文针对九孔鲍人工培育种苗疑似病毒性疾病，利用紫外线发生装置消毒海水培育九孔鲍苗，取得了一定的成效，比较药物处理海水培育九孔鲍苗提高出苗率达50％以上。     

杂色鲍苗掉板症病原分离鉴定及毒力因子分析

2003年跟踪观察了深圳一鲍养殖场培苗过程,并从变白病鲍苗中分离到1株优势菌(9号菌株),2次回归感染试验均证明其可引发鲍苗死亡掉板,API条带分析表明其为副溶血弧菌,胞外毒力因子分析揭示该菌株可分泌蛋白酶、脂肪酶、明胶酶以及有明显的溶血能力。本研究结果证明了副溶血弧菌可引发我国南方杂色鲍苗的掉板死亡。     

鲍养殖水体中致病性弧菌的调查

在18份鲍鱼养殖厂的各种水样和不同生长期的鲍样品中,共分离出17株弧菌:溶藻性弧菌11株,副溶血弧菌3株,霍乱弧菌2株,拟态弧菌1株。其中,溶藻性弧菌分布比较广,存在于各种样品;副溶血弧菌主要分布于鲍的肠道内;而非O1 O139群霍乱弧菌和拟态弧菌则分布于源头水中。鲍养殖水体中细菌总数的计数可以作为监测细菌性病害的指标之一。副溶血弧菌在鲍肠道内的高检出率提示鲍与副溶血弧菌的关系值得深入研究。     

健康和患病稚黑鲍中微生物产胞外酶的分析比较

2005年初自福建漳浦鲍鱼场患病以及健康稚黑鲍中各分离到27和56株异养细菌,在此基础上研究了它们产胞外蛋白酶、淀粉酶、明胶酶、磷脂酶及溶血能力。结果表明,虽然来自健康鲍的菌株产胞外酶的数量明显大于来自病鲍的菌株,但来自病鲍的菌株具有强分泌胞外酶能力的比例明显大于来自于健康鲍的菌株。综合考虑每一种胞外酶的潜在致病作用,以及菌株分泌多种胞外酶的能力,最后确认10株菌为潜在的致病菌。     

Temperature and size range for the transport of juvenile donkey's ear abalone Haliotis asinina Linne

Live transport of hatchery‐produced juvenile donkey's ear abalone Haliotis asinina Linne was examined to evaluate the effect of transportation on the survival of juvenile abalone. Simulated transport experiments were conducted to determine the appropriate temperature using 5, 10 and 20 g L^?1 of ice to air volume for 8 h and the appropriate size using two size groups (Size A, 15–20 mm, 0.5–1.3 g, and Size B, 30–35 mm, 5.3–8.5 g) up to 24‐h out‐of‐water live transport. Survival was significantly higher (P<0.001) when 10 g L^?1 of ice was used to decrease the temperature to the range of 17–23 °C. At this temperature, both size groups subjected to simulated transport for 8 and 10 h had 100% survival after 48 h, while mortality occurred in abalones subjected to 16 and 24 h of simulated transport. The Size B abalone subjected to 24 h of transport had significantly higher survival (64.4 ± 2.9%) (P<0.001) than the Size A abalone (5.5 ± 1.6%) after 48 h. Live juvenile abalone were successfully transported to the field applying the protocols developed in the lab experiment. This study serves as a guide for handling and shipping live juvenile abalone.     

Pathogenesis of vibriosis in cultured juvenile red abalone, Haliotis rufescens Swainson

Abstract. Morbidity of intensively cultured red abalone, Haliotis rufescens , as well as experimentally stressed (elevated temperature and hyper-oxygenation) abalone, was studied using clinical, histological, immunofluorescent and bacteriological techniques. Histological study showed a typical pattern of bacterial infection from all groups studied, characterized by epithelial exfoliation or rupture and systemic growth of the bacteria along vascular sinuses and along neural sheaths. Peripheral neurons degenerated rapidly and a responsive host cellular infiltrate did not appear to effectively retard the advancement of the infection. Nine bacterial isolates from the culture system water or sick animals were characterized biochemically. All were Gram-negative, facultatively anaerobic, non-aerogenic, oxidase-positive rods with single polar flagella and thus appeared related to the Vibrio group. Further characterization showed that most isolates did not correspond to specifically characterized vibrios, Antiserum prepared to the isolates contained antibody both to common group antigens (from all nine strains) and to strain-specific antigens. Selection of antiserum and subsequent absorption permitted the use of the antiserum for specific recognition of each isolate. Immunofluorescent studies clearly demonstrated that antiserum to an isolate corresponding to Vibrio alginolyticus was the predominant antiserum producing positive staining of infecting bacteria in the typical lesions in abalone tissues. The pattern of positive staining corresponded to histopathological observations of the disease. The disease can be managed in husbandry systems by both limiting the number of potentially pathogenic bacteria and by limiting the exposure of the animals to physico-chemical stresses.     

鲍弧菌病的防治研究

在实验室进行鲍人工感染弧菌病的防治试验。结果说明:使用鲍防病配合饲料对于防治养殖鲍弧菌病效果显著。并从东山养鲍场患病的九孔鲍体上分离到一种致病菌,经鉴定为溶藻弧菌(Vibrio alginolyticus)。     

Modulation of gut microbiota associated with abalone Haliotis gigantea by dietary administration of host-derived Pediococcus sp. Ab1

In the present study, we evaluated how dietary administration of host-derived Pediococcus sp. Ab1 has an effect on the abalone gut microbiota using a culture-dependent method and 16S rRNA gene library analysis. The culturable lactic acid bacteria number in the probiotic sample was 10⁵ higher than that in the non-probiotic sample, and we speculate that this significant increase was due to colonization of Ab1 into abalone gut. The result of a culture-dependent method showed that the proportion of Vibrio halioticoli clade, which is known to be a beneficial resident bacterium to abalone, was much higher in the probiotic sample than in the non-probiotic sample. 16S rRNA gene clone sequences revealed that gut microbiota in the probiotic sample was obviously diverse compared to the non-probiotic sample, probably due to improvement of the gut environment by Ab1 colonization. In addition, some beneficial bacteria–like sequences such as V. halioticoli were only found in the probiotic sample. These results suggest that the dietary administration of Ab1 to abalone gut has a great effect on modulation of not only culturable but also unculturable gut microbiota. Our results are useful for future investigations into understanding the effect of probiotics on gut microbiota.     

Temporal fluctuation in the abundance of alginate‐degrading bacteria in the gut of abalone Haliotis gigantea over 1 year

In this study, we identified and enumerated alginate‐degrading bacteria in the gut of abalone over 1‐year period. From a total of 360 colonies growing on agar medium enriched with alginate, 251 isolates (70%) had the ability to degrade alginate. In addition, a high number of viable alginate‐degrading bacteria were detected throughout the survey period. Alginate‐degrading bacteria were more abundant in the cold season relative to the summer season (10⁷ vs. 10⁴ CFU g^?1, respectively). Strong positive correlation was also observed between the number of alginate‐degrading bacteria and feed intake (R = 0.854; P < 0.01). The identified alginate‐degrading bacteria comprised of 35 species grouped into 11 genera including Algibacter, Formosa, Polarybacter, Tamlana, Tenacibaculum (CFB group), Roseobacter, Ruegeria, Silicibacter (α‐proteobacteria), Agarivorans, Shewanella and Vibrio (γ‐proteobacteria) respectively. More than 80% of the isolated alginate‐degrading bacteria belonged to the genus Vibrio, showing high homology to Vibrio cyclotorophicus, Vibrio splendidus, Vibrio halioticoli and Vibrio neonatus. Based on the results, it was suggested that algal‐polysaccharide (alginate) degrading bacteria (mainly Vibrio) commonly exist in the gut of abalone and may play an important role in the degradation and digestion of the host's feed.     

引起南方九孔鲍苗大规模死亡的一株病原菌的分离鉴定及其致病性研究

从汕尾一鲍鱼场的变白掉板九孔鲍苗中分离到一批菌株,对其中的21号菌株进行了深入的研究。回归感染试验证明其为病原菌,API条带分析表明该菌为副溶血弧菌,药敏试验揭示该菌对诺氟沙星、阿米卡星、四环素、新生霉素、新霉素有抗药性,但对头孢唑啉、庆大霉素、氯霉素、多粘霉素敏感。     

Isolation and characterization of pathogenic Vibrio alginolyticus from diseased postlarval abalone, Haliotis diversicolor supertexta (Lischke)

Outbreaks of serious mortality among cultured abalone postlarvae have occurred across Southern China since July 2002. Five motile bacterial strains were isolated from diseased abalone postlarvae on tryptic soy agar supplemented with 1% NaCl (TSA1) and/or thiosulphate citrate bile salt (TCBS) sucrose agar plates during an outbreak in August 2003 in Shanwei, Guangdong province. All isolates were characterized and identified as Vibrio alginolyticus on the basis of biochemical characteristics and comparisons with those of the reference strain V. alginolyticus ATCC 17749. Strain 19 (a representative of five similar isolates) was virulent to abalone postlarvae with an LD₅₀ value of1.00 × 10⁴ colony‐forming units mL^?1. All abalone postlarvae exhibited the same signs as in natural outbreaks. The same bacterium could be re‐isolated from abalone postlarvae after bacterial challenge using TSA1 and TCBS plates. The results reveal that V. alginolyticus is an infectious agent of abalone postlarvae.