溶藻细菌控藻作用及其在对虾养殖池塘中的应用前景

浮游微藻与养殖池塘的水质及对虾的健康状况密切相关,控制有害微藻的过度繁殖,维持优良的藻相对于养殖水环境的稳定、减少对虾疾病的发生具有重要意义。文章对浮游微藻与对虾养殖的关系及溶藻细菌的研究进展进行了概述,分析了溶藻细菌在对虾养殖中的应用前景,提出了利用溶藻细菌控制对虾养殖池塘有害微藻的研发思路。     

微藻的固定化及在水产养殖中的应用

主要对微藻的固定化的基本方法,以及微藻固定化在水产养殖上作为种质保存、养殖水质净化和对海洋细菌等方面的影响进行了总结,并提出今后固定化微藻主要的发展动态。     

斑节对虾养殖池塘藻-菌关系初探

本研究通过对斑节对虾养殖系统中的异养细菌、浮游微藻进行为期3个月的监测，发现浮游微藻和异养细菌的总量都表现为养殖后期高于养殖前期，其中浮游微藻增加了2个数量级，异养细菌增加了1个数量级，施放有益芽孢杆菌群对池塘菌群和藻群的变动有明显的影响。施放有益芽孢杆菌群的池塘，异养细菌总数略低，弧菌数量维持在10^3 CFU／mL以下，浮游微藻平稳增长，蓝藻占20％以下；对照池异养细菌的总数略高，弧菌数量达到10^3 CFU／mL，浮游微藻数量波动，养殖后期蓝藻占60％，为绝对优势种群。表明有益芽孢杆菌群有促进浮游微藻平稳繁殖的作用，但对浮游蓝藻和弧菌的繁殖起抑制作用，浮游蓝藻与弧菌之间具有一定的繁殖相关性。     

酵素菌调水养殖技术

酵素菌是包括细菌、放线菌、酵母菌等3大类24种菌的复合有益微生物,相对单个菌种的调水产品而言,它具有“集团军”的功效。酵素菌能促进水体中优良微藻、有益细菌及浮游动物增长,具有改良水质,净化水体,平衡藻相、菌相,抑制有害菌、病原微生物生长,均衡养殖动物营养,提高水产品品质的作用。     

固定化微藻对养殖对虾细菌数量的影响

以固定化技术为基础,人工制成微藻藻珠,引入波吉卵囊藻(Oocystisborgeisnow)和微绿球藻(Nannochloropsis oculata)于凡纳对虾(Litopenaeusvannamei)养殖环境中,采用直接计数法研究了养殖水体、对虾肌肉、对虾肝胰脏中异养菌及弧菌的数量变化。结果表明,引入藻珠能抑制异养菌和弧菌的生长,并能改善水质。试验末期,试验1、2、3组水样中弧菌数量分别降低了95%、95%、81.7%,异养菌数量降低了72.3%、77.1%、95.6%。可见固定化微藻在一定程度上能改善虾池细菌生态系,有助于预防对虾疾病。     

对虾养殖池塘藻与菌的调控技术

<正>传统的养虾理念是"养虾先养水",养水则培藻。随着养殖模式的改变和养殖密度的增加,通过现代生物技术实验证明,营造优良养殖池塘环境的关键是"培藻"和"培菌",构建藻菌平衡的生态。一、对虾养殖池塘藻和菌的重要性通过浮游微藻和有益细菌的共同作用,降解转化养殖代谢产物,调节水质,抑制有害细菌和有害微藻的滋生,营造适宜对虾健康生长的良好生态环境(如图1所示)。"培藻"的作用:(1)能保持养殖水体中高含量的溶解氧;(2)消除     

硫酸铜对海洋微藻生长的影响

本文初步研究了硫酸铜对海洋微藻扁藻、角刺藻、小球藻和角毛藻生长的影响。研究结果表明,硫酸铜抑制不同微藻生长的最低浓度具有种类特异性,在生产实际中可以利用铜的抑制作用来提高微藻的分离效果。     

硫酸铜对海洋微藻生长的影响

初步研究了硫酸铜对海洋微藻扁藻、角刺藻、小球藻和角毛藻生长的影响。结果表明,硫酸铜抑制不同微藻生长的最低浓度具有种类特异性,在生产实际中可以利用铜的抑制作用来提高微藻的分离效果。     

大型海藻对赤潮微藻的克生作用研究进展

大范围、高频率爆发的赤潮已对海洋环境构成了严重威胁,而且有毒、有害的赤潮原因种也在不断增加,寻求科学有效的、对环境无害的赤潮防治措施成为目前迫切需要解决的重大问题。生物防治是赤潮治理的的发展趋势,目前研究的热点是通过赤潮微藻同大型海藻之间的相互作用来处理这类问题。大型海藻能与微藻进行营养盐和光照竞争,抑制微藻的爆发性生长,当光照和营养盐充足时大型海藻能够向环境中释放相生相克类化合物,对赤潮微藻具有明显的生化抑制效应。本文综述了近些年来大型海藻对赤潮微藻之间相互作用的研究。     

微藻的应用与封闭式培养方式

微藻是一种微型单细胞植物，通常具有太阳能利用率高、个体小、营养丰富、生长繁殖迅速、对环境的适应能力强、容易培养等优点，因此受到人们的重视。自１８９０年荷兰细菌学家 Ｂｅｉｊｅｒｒｉｎｃｋ用培养细菌的方法进行小球藻（Ｃｈｌｏｒｅｌｌａ）和其他单细胞绿藻的分离培养以来，微藻的培养研究经历了一百多年的曲折历程。Ｗａｒｂｕｒｇ（１９１９）曾报道过高密度培养小球藻来研究植物和光合作用，并由此发现某些种类的微藻其生物量每天可以增加几倍，并且粗蛋白的含量可达到５０％以上。德国首先进行了大规模的微藻培养，其目的…     

龙须菜苯丙烷类抑藻活性物质的分离纯化及其对6种赤潮微藻的抑藻活性

采用溶剂浸提、液液萃取、硅胶柱层析和硅胶薄层层析等分离方法以及红外光谱、质谱和核磁共振谱等光谱技术,初次从龙须菜中纯化得到4种苯丙烷类化合物:邻苯二丙酸、gossonorol、7,10-epoxy-ar-bisabol-11-ol和对羟基苯乙醇,并进一步分析了此4种苯丙烷类化合物对强壮前沟藻、赤潮异弯藻、米氏凯伦藻、球形棕囊藻、东海原甲藻和中肋骨条藻生长的影响。结果表明,它们对以上6种赤潮微藻的生长表现出明显的选择性抑制作用。其中,邻苯二丙酸、gossonorol和对羟基苯乙醇表现出更为广泛的抑藻活性。比较此4种苯丙烷类化合物和重铬酸钾对赤潮微藻生长的半抑制效应浓度EC50-96 h,发现邻苯二丙酸对强壮前沟藻、赤潮异弯藻和球形棕囊藻,gossonorol和羟基苯乙醇对赤潮异弯藻和球形棕囊藻,7,10-epoxy-ar-bisabol-11-ol对赤潮异弯藻和米氏凯伦藻在生长抑制方面比重铬酸钾更具有优势。     

Bioprospection of Microalgae and Cyanobacteria as Biocontrol Agents Against Vibrio campbellii and Their Use in White Shrimp Litopenaeus vannamei Culture

Vibrio spp. are the most common and harmful shrimp pathogenic bacteria; however, microalgae and cyanobacteria have the ability to produce antimicrobial substances against these species. In this study, the organic and aqueous extracts of 28 species of marine microalgae and cyanobacteria were screened against Vibrio campbellii M1. Two of these phytoplankton species with antibacterial activity in aqueous extracts (Dunaliella tertiolecta and Skeletonema costatum) and nontoxic to brine shrimp Artemia franciscana nauplii were used to evaluate their anti‐Vibrio effect when used as green‐water cultures in Vibrio‐challenged white shrimp Litopenaeus vannamei cultures. No differences in mortality of juvenile L. vannamei were observed between treatments tested, suggesting that the pathogenicity of V. campbellii could be related to the growth stage of shrimp. The proximal composition of D. tertiolecta and S. costatum was in the recommended range for penaeid shrimp nutrition, allowing shrimp supplemented with these microalgae to have significantly greater total length and weight than control shrimp. Shrimp supplemented with S. costatum presented the highest values of organic mass (11.48 mg/organism) and growth rate (0.31 mg/d) in comparison to D. tertiolecta. These results indicate that microalgae are not only capable of producing antibacterial compounds against Vibrio but can also help shrimp nutrition.     

海洋大型绿藻条浒苔与微藻三角褐指藻相生相克作用的研究

以种群密度为变量,采用实验生态学手段研究了大型海藻条浒苔与赤潮藻类三角褐指藻间的生长竞争关系,以及条浒苔水溶性抽提液对三角褐指藻生长的影响。结果表明,在无营养盐限制条件下,低密度条浒苔(0.3~0.7 g/L)均能抑制三角褐指藻(起始浓度104cell/ml)的生长,最大抑制率为74.5%;低起始浓度(102~103cell/ml)的三角褐指藻,对条浒苔具有促生长效应,而高起始浓度(104~105cell/ml)的三角褐指藻在一定程度上抑制条浒苔的生长。条浒苔水溶性抽提液(0.3~0.7 g/L)对三角褐指藻的生长皆表现出明显的抑制效应,平均抑制率为75.2%,抑制效果较条浒苔鲜组织更为明显;其最大抑制效应(84.8%)表现在接种后的第8天,三角褐指藻的生长抑制量随条浒苔水溶性抽提液浓度的增加而增大。表明条浒苔可能通过相生相克作用影响共培养体系中三角褐指藻的生长。     

Antibacterial activity in microalgae cultures

Five cultures of microalgae (Chlorella minutissima, Tetraselmis chui, Nannochloropsis sp., Arthrospira platensis and Isochrysis sp.) with no culturable bacteria were tested for their ability to inhibit the growth of six Vibrio bacterial strains (V. parahaemolyticus, V. anguillarum, V. splendidus, V. scophthalmi, V. alginolyticus and V. lentus). The influence of light on the antibacterial activity of the microalgae was investigated. All microalgae cultures inhibited the growth of bacteria compared with the control treatments (P < 0.05), and their antibacterial activity was not influenced by the presence or absence of light. In the control groups, the numbers of bacteria increased exponentially during the experimental period in the absence of microalgae cells demonstrating that the bacterial cells were able to utilize the growth medium of microalgae cultures. The present results may explain the low levels or absence of Vibrio strains in microalgae cultures, and the positive effect of addition of microalgae in rearing of fish larvae, and implicate the production of antibacterial compounds by microalgae cells.     

Effect of particulate organic carbon on heterotrophic bacterial populations and nitrification efficiency in biological filters

Competition between heterotrophic and nitrifying bacteria is of major practical importance in aquaculture biofilter design and operation. This competition must be understood to minimize the negative impact of heterotrophic bacteria on an aquaculture system. On the other hand, the heterotrophic population is suspected of having a positive effect against pathogenic bacteria. Little information is available on the bacterial communities present within aquaculture systems, except for nitrifying bacteria, but a combination of traditional aquacultural engineering research methods and novel microbiological techniques offers new opportunities for the study of these communities.

The heterotrophic bacterial population activity and the nitrification efficiency of a submerged biological filter were studied for an influent TAN concentration of 2 mg/l and varying C/N ratios. The TAN removal rate was found to be 30% lower at a C/N ratio of 0.5 than at a C/N ratio of 0. For higher C/N ratios the reduction in nitrification efficiency was 50% while the attached bacterial abundance was doubled. Moreover, results confirm that abundance of sheared and attached bacteria are correlated. It is not known to what extent biofilter configuration might influence the relationship between heterotrophic and nitrifying bacteria, and further work will be carried out with moving bed and fluidized filters. A better understanding of the role of the heterotrophic bacteria in RAS will help to optimize any positive “biocontrol” effect and to minimize the microbial degradation of rearing water and the reduction of nitrification rates.     

抗菌性海藻酸钠涂膜在罗非鱼片保鲜中的应用

采用测定涂膜抑菌性能、缓释效果来探讨抗菌性海藻酸钠涂膜的抑菌机理并将其应用在罗非鱼片的涂膜保鲜中。实验结果表明,抗菌膜是一种具有缓释效果的保鲜膜,对大肠杆菌Esche-richia coli、金黄色葡萄球菌Staphylococcus aureus、枯草芽孢杆菌Bacillus subtilis、腐败希瓦氏菌Shewanella putrefaciens及鱼片表面其他杂菌均有较好的抑制效果,保鲜剂在40h内可从涂膜中完全释放;与未经涂膜处理的对照组相比,抗菌膜可以明显控制鱼片细菌总数的增长、维持较低的挥发性盐基氮值和改善鱼片的感官质量,综合考虑鲜度指标并本着以感官评分为基础的原则,抗菌涂膜处理可以将罗非鱼片的保鲜期延长约5.5d。     

Quantitative and Qualitative Aspects of Bacterial Communities Associated with Cultures of Chlorella minutissima

Microbiological conditions in 200 L cultures of microalgae Chlorella minutissima in polyethylene sleeves were examined. The influence of addition of antibiotic (nitrofurantoin) was studied. Samples were taken 2, 5, 9, and 14 d after inoculation and were spread on solid Zobell medium and on thiosulfate citrate bile salts sucrose agar for the enumeration of total numbers of bacteria and numbers of presumptive Vibrio bacteria, respectively. Microalgae grew well in the cultures and high numbers of culturable bacteria (about 10⁷ bacteria/mL) were present in all microalgae cultures. Addition of antibiotic in 200‐L cultures of C. minutissima did not result in a significant decrease of total counts of bacteria per unit volume (P > 0.05), while the numbers of presumptive Vibrio were higher in cultures added antibiotic compared with the control treatment (P < 0.05). The numbers of presumptive Vibrio per unit volume and the percentage of fast‐growing bacteria were higher in microalgae supernatant than in noncentrifuged samples. Representative colonies were taken from all samples and in total 649 bacterial strains were isolated during this study. A range of phylotypes was identified by amplification and sequencing of the 16S rDNA gene and phylogenetic trees were constructed. Several members of the Roseobacter clade were dominant among the culturable isolates.     

3种细菌对小球藻生长和脱氮除磷效率的影响

鉴于水资源日益紧缺且水污染问题日渐加剧的现状,藻菌共生系统作为一种节能环保的污水处理方式,有助于提高污水处理效率。通过人工模拟城市污水,选取3种污水处理中常用细菌地衣芽孢杆菌(Bacillus licheniformis)、枯草芽孢杆菌(Bacillus subtilis)和沼泽红假单胞菌(Rhodopseudomonas palustris)与小球藻构建藻菌共生系统,探究了不同细菌对蛋白核小球藻(Chlorella pyrenoidosa FACHB-5)生长以及污水脱氮除磷效率的影响。结果显示,在3种藻菌共生系统中,地衣芽孢杆菌为小球藻促生长菌,而枯草芽孢杆菌对小球藻生长有抑制作用,沼泽红假单胞菌对小球藻生长无显著影响(P>0.05),且沼泽红假单胞菌的生长受到小球藻的显著抑制(P<0.05)。在3个共生系统中,地衣芽孢杆菌-小球藻共生系统中小球藻生物量最高,第2天水体的总氮和总磷去除率分别达到79.84%和83.48%,显著高于小球藻单独培养试验组(P<0.05)。研究表明,3种藻菌共生系统中,细菌与微藻间的关系具有特异性,应选择适宜的促生菌与微藻共培养,合适的藻菌共生系统可提高水体总氮和总磷的去除率。     

Ceramic clay reduces the load of organic matter and bacteria in marine fish larval culture tanks

Ceramic clay has been increasingly used to improve contrast and prey detection in tanks for rearing of fish larvae. In contrast to live microalgae or algae pastes, clay increases turbidity without contributing to the organic matter load. In addition, clay may aggregate and sediment organic matter and bacteria, facilitating its removal. Marine larvae are sensitive to infections by opportunistic bacteria. Fish, algae, and live feed increase the microbial carrying capacity of the rearing water which allow exponential growth of bacteria and favor fast-growing opportunists. Reducing substrate levels by replacing microalgae with clay may reduce bacteria proliferation and benefit larvae. We compared the effects of three rearing regimes including live Isochrysis galbana, Nannochloropsis oculata paste, and ceramic clay on the bacterial community, concentration of organic matter, and growth and survival of Atlantic cod larvae (Gadus morhua L.). The application of clay resulted in reduced substrate levels for bacteria in the rearing water compared to the addition of live algae or algae paste. To some extent, clay aggregated and transported organic matter to the bottom of the larval fish tanks, where it could be effectively removed. Fish tanks receiving clay showed a lower abundance of bacteria in the water than tanks added algae paste or live algae. Fish tanks with algae paste showed a higher abundance of bacteria and a higher share of cultivable bacteria and TCBS counts than the other two treatments. Tanks with live algae showed low relative abundances of opportunistic bacteria and TCBS counts in both water and rotifers. Cod larvae in tanks with clay or live algae initiated exponential growth earlier than larvae in tanks with algae paste. Larvae in tanks receiving clay had significantly higher dry weight than larvae in tanks receiving algae paste at day 5 and 20 post hatching. The survival of larvae in the tanks added clay was variable. Two of the three tanks with clay had significantly higher larval survival than the tanks with live algae or algae paste. However, one tank with clay underwent 100% mortality. It is not possible to conclude whether this was related to the use of clay or an incidental development of a harmful microbial community in this tank. The effects of clay addition on larval performance should be studied further. Clay addition appears to be an easy way to reduce bacterial load during early first feeding of marine larvae without compromising the beneficial effects of turbidity.