共查询到20条相似文献，搜索用时 62 毫秒
1.
大菱鲆幼鱼蛋白质消化特征及其对水环境的影响 总被引：2，自引：0，他引：2
采用单因素随机区组设计,选择平均初重34.5±5.5g的大菱鲆幼鱼225尾,平均分为5组(A~E),每组3重复。分别饲喂蛋白质水平45%,48%,50%,52%和54%的5种膨化颗粒饲料,研究大菱鲆幼鱼的蛋白质消化特征及其对水环境的影响。结果表明:随着饲料蛋白质水平的提高,幼鱼的生长性能提高,饲料系数相应降低;蛋白质消化率先升后降,在50%蛋白组取得最大;蛋白质摄入量、消化量以及粪氮排出量明显增加;养殖水环境中氨氮和亚硝氮的浓度也不断提高。特别是在50%蛋白质水平以上时,幼鱼生长性能提高幅度缓慢,而粪氮排出量和水环境中氨氮含量显著提高(p<0.05)。试验表明,大菱鲆幼鱼环保饲料中蛋白质的适宜水平为50%。 相似文献
2.
蛋白质营养对工业化养殖大菱鲆生长、消化和免疫的效应 总被引：1，自引：0，他引：1
在封闭循环水养殖条件下, 选用体质量为(145.08±0.56)g 大菱鲆(Scophthatmus maximus L.)幼鱼,进行4 种蛋白质梯度水平(41%、46%、50%、55%, 即I、II、III、IV 组)的单因素试验74 d, 研究蛋白质营养对工业化养殖大菱鲆生长、消化酶、免疫机能的影响。结果表明: (1) 试验鱼增质量率随日粮蛋白质含量升高而提高, 中高蛋白水平(III、IV 组)增质量率分别极显著或显著高于I、II 组18.46%~65.75%,III、IV 组间无显著差异; 饲料系数则相应下降, III、IV 组分别极显著低于I 组21.15%~27.73%(P<0.01),II、III、IV 组间无显著差异;(2)大菱鲆胃肠、肝胰脏的蛋白酶活力随蛋白水平升高而显著增强, 其中IV组胃蛋白酶活力分别极显著高于其他组15.28%~31.96% (P<0.01), 肝胰脏胰蛋白酶活力分别显著或极显著高于其他组9.74%~26.29%; 胃肠淀粉酶、肝胰脏淀粉酶及脂肪酶活性受饲料蛋白水平影响不显著;(3)随日粮蛋白含量提高, 各试组鱼成活率与主要免疫器官溶菌酶活力呈先上升后缓降的趋势, III 组最优, 其成活率高于低、高蛋白水平组2.86%~9.34%, 但4 组间差异不显著; 肝脏溶菌酶活力分别极显著高于I 组80.07%(P< 0.01), 显著高于II 组43.56%(P< 0.05); 头肾溶菌酶活力极显著高于I、II 组67.78%和35.76%(P< 0.01); 与IV 组差异不显著;(4)血清ACP 及LYZ 活力随日粮蛋白水平提高先升后降, III组LYZ 活力极显著高于I 组31.92%(P< 0.01), 显著高于II 组18.72%(P< 0.05); 血MDA 随蛋白水平提高显著降低, IV 组分别极显著低于I、II、III 组13.26%~31.61%; 血清SOD 活力及C3 补体含量随日粮蛋白含量增加而提高, 但各组间差异不显著。结果表明, 日粮中、高蛋白质含量显著促进大菱鲆幼鱼的生长性能和蛋白质消化酶活力, 而中等蛋白水平更加有利于幼鱼重要免疫机能的发挥和成活率的提高。因而, 日粮中等蛋白质含量更适宜于工业化循环水养殖大菱鲆幼鱼的蛋白质营养和健康生长。 相似文献
3.
《中国海洋大学学报(自然科学版)》2016,(1)
本文旨在研究新型复合动植物蛋白源在大菱鲆饲料中替代部分鱼粉对大菱鲆幼鱼生长和肌肉质地的影响。实验设计了4组等氮等能的饲料,以含鱼粉60%的处理组为对照饲料(FM),以小麦粉、豆粕等作为植物蛋白与酶解动物软骨蛋白粉复合分别替代其中40%、50%和60%鱼粉,设置了40I、50I和60I3个试验组。选用初始体质量(8.63±0.03)g的大菱鲆幼鱼(Scophthalmus maximus L.),分别用上述4种饲料饲养8周。试验表明:与鱼粉组相比,随着替代水平的升高,大菱鲆幼鱼的终末体重、增重率和特定生长率显著降低(P0.05),50I和60I鱼粉替代处理组饲料效率显著低于FM组和40I处理组(P0.05)。各处理组大菱鲆幼鱼水分、粗蛋白、脂肪和灰分无显著差异(P0.05),肥满度、肝体比和脏体比无显著差异(P0.05)。饲料干物质和蛋白的消化率随着替代水平的升高呈下降趋势。以酶解动物软骨蛋白粉和植物蛋白复合替代鱼粉对大菱鲆幼鱼肌肉硬度、咀嚼性和弹性没有显著影响(P0.05)。结果表明,酶解动物软骨蛋白粉与植物蛋白复合后可替代大菱鲆幼鱼饲料中40%鱼粉而不影响其生长、摄食、存活和体组成,并能保持其肉质。 相似文献
4.
《中国海洋大学学报(自然科学版)》2016,(4)
为研究饲料中糊精替代鱼油对大菱鲆(Scophthalmus maximus)幼鱼代谢及免疫反应的影响,在饲料中蛋白质含量为45%的基础上,配制4组等氮等能的饲料(D1、D2、D3和D4),饲料中可溶性糖含量分别为1.93%、5.80%、15.98%和28.27%,脂肪含量分别为16.48%、12.82%、10.78%和6.64%,其中糊精为糖源,鱼油和大豆卵磷脂为脂肪源。在室内流水系统中养殖大菱鲆幼鱼((8.32±0.06)g),检测大菱鲆幼鱼的血液和肝脏中糖、脂肪和蛋白质代谢及抗氧化指标,试验周期为9周。研究表明:随着饲料中糊精替代鱼油水平的升高,大菱鲆的血糖含量、血浆胰岛素含量、血浆谷草转氨酶(AST)和谷丙转氨酶(ALT)活性(P0.05)显著升高。其中,D4组AST活性显著高于其余3组(P0.05),D1组ALT活性显著高于其余3组(P0.05)。饲料中糊精替代鱼油水平的升高对血浆中总氨基酸、总胆固醇(CL)和甘油三酯(TGs)的含量无显著影响(P0.05)。随着饲料中糊精含量的不断上升,血浆中溶菌酶、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)活性和总抗氧化能力(T-AOC)呈下降趋势。肝脏中碱性磷酸酶(AKP)和CAT活性以及T-AOC也有一定程度下降(P0.05),但肝脏溶菌酶活性显著上升(P0.05)。当饲料可溶性糖含量为15.98%时,肝脏SOD活性最高(P0.05)。结果表明:饲料中,糊精替代鱼油既影响大菱鲆幼鱼的糖和脂类代谢,又影响其免疫力。在实际生产中,除了关注饲料中糖对鱼体生长的影响,还应关注糖对鱼体代谢及免疫的影响。 相似文献
5.
不同脂肪水平下添加胆汁酸对大菱鲆(Scophthalmus maximus)幼鱼生长、体组成和脂肪代谢的影响 总被引：2，自引：0，他引：2
在10%和18%两个脂肪水平下,分别添加0%、1.5%的胆汁酸,配制成四种等氮饲料,投喂初始平均体重为(45.78±0.11)g的大菱鲆(Scophthalmus maximus)幼鱼8周,研究两个脂肪水平下添加胆汁酸对大菱鲆幼鱼生长、体组成和脂肪代谢的影响。结果表明:饲料脂肪水平升高或添加胆汁酸均能显著提高大菱鲆幼鱼增重率、特定生长率、蛋白质效率,降低饵料系数(P0.05);相同脂肪水平下,添加胆汁酸显著提高了实验鱼的生长,降低了肝体比(P0.05)。随着饲料脂肪水平的升高,组织中粗脂肪含量呈上升的趋势;而添加胆汁酸降低了组织中脂肪的蓄积,但全鱼与肌肉中水分、粗蛋白含量主要受饲料中胆汁酸水平的影响(P0.05)。胆汁酸能显著降低大菱鲆幼鱼肌肉PUFA含量(P0.05),增加SFA、MUFA含量。饲料添加胆汁酸能降低实验鱼血清甘油三酯、总胆固醇、高密度脂蛋白胆固醇、低密度脂蛋白胆固醇含量及谷草转氨酶、谷丙转氨酶活性(P0.05),但饲料脂肪水平对血液生化指标的影响呈相反趋势。饲料脂肪水平的升高或添加胆汁酸均能提高实验鱼肝脏脂蛋白脂酶、肝脂酶、总脂酶和肠道脂肪酶活性(P0.05),且胆汁酸和脂肪二者之间的交互作用对脂肪代谢有显著影响(P0.05)。综上所述,在2个脂肪水平下添加胆汁酸均能促进大菱鲆幼鱼的生长,提高饲料利用状况,促进脂肪消化吸收,降低组织中粗脂肪含量。 相似文献
6.
《中国海洋大学学报(自然科学版)》2016,(2)
以初始体重(9.19±0.01)g的大菱鲆幼鱼为研究对象,研究玉米蛋白粉部分替代饲料中的鱼粉蛋白对大菱鲆幼鱼的生长性能、血浆生化指标、组织游离氨基酸含量及氨基酸分解关键酶基因表达的影响。设计2种等氮、等能的实验饲料组:鱼粉对照组(FM)和玉米蛋白粉替代45%鱼粉蛋白组(CGM),分别饱食投喂大菱鲆幼鱼30天。研究表明:与FM组相比,CGM组大菱鲆幼鱼的特定生长率、饲料效率、以及蛋白质和脂肪沉积率显著降低,且全鱼粗蛋白和粗脂肪含量也显著降低(P0.01),但CGM组的全鱼水分和灰分含量显著高于FM组(P0.01)。CGM组血浆总蛋白、葡萄糖、甘油三酯和总胆固醇含量均较FM组显著降低(P0.05)。大菱鲆摄食CGM组饲料后,其血浆和肌肉游离氨基酸含量均较FM组显著降低,且肌肉氨基酸降幅度更大(P0.05)。CGM组肠道支链α-酮酸脱氢酶二氢硫辛酸转乙酰基酶(BCKD-E2)mRNA表达量较FM组显著升高。结果表明:玉米蛋白粉替代45%鱼粉蛋白显著抑制了大菱鲆幼鱼的生长,降低了饲料效率,影响了鱼体营养物质的组成和代谢,加快了肠中氨基酸的分解代谢,降低了组织游离氨基酸的平衡性和总量。 相似文献
7.
为探究亮氨酸和精氨酸作为信号分子参与调控mTOR信号通路对大菱鲆(Scophthalmus maximus)生长的作用,本研究以大菱鲆幼鱼(初始体质量(13.50±0.19) g)为实验对象,设置50%蛋白水平饲料作为阳性对照组,45%蛋白水平饲料作为阴性对照组,设置两个实验组,分别为在阴性对照组中添加1%亮氨酸的实验组和添加1%精氨酸的实验组,饲养周期为56 d,测量大菱鲆的生长性能和饲料利用水平。研究表明,添加亮氨酸、精氨酸均能一定程度提高因饲料蛋白水平不足导致的大菱鲆的特定生长率、蛋白质效率和增重率下降。添加1%亮氨酸和1%精氨酸均能在摄食后有效增强大菱鲆肌肉与肝脏mTOR信号通路中的雷帕霉素靶蛋白(mTOR)、核糖体蛋白S6和真核起始因子4E结合蛋白1(4E-BP1)的磷酸化。添加1%精氨酸还能够提高大菱鲆肠道淀粉酶和脂肪酶活性,显著提高血清过氧化氢酶和溶菌酶水平并增加血清总抗氧化能力。研究结果表明,在低蛋白饲料中添加1%亮氨酸、1%精氨酸能够激活大菱鲆mTOR信号通路,有效提高其生长性能和蛋白质效率;此外,添加1%精氨酸还能够提高大菱鲆的消化酶活性、增强非特异性免疫反应。 相似文献
8.
壳聚糖对虹鳟(Oncorhynchus mykiss)幼鱼生长性能、体组成及非特异性免疫的影响 总被引：2，自引：0，他引：2
用壳聚糖添加量为0.00%(D0)、0.25%(D1)、0.50%(D2)、1.00%(D3)和2.00%(D4)的实验饲料投喂虹鳟幼鱼50d,研究其对虹鳟幼鱼生长性能、体组成及非特异性免疫的影响。结果显示,各实验组增重率(WGR)、特定生长率(SGR)显著高于对照组(P<0.05),饲料系数(FCR)、脏体比(VSI)呈显著降低趋势(P<0.05),而肝体比(HSI)、脾体比(SSI)、肥满度(CF)及存活率(SR)无明显差异(P>0.05)。全鱼、肌肉及肝脏粗脂肪含量显著降低(P<0.05)。D3组和D4组碱性磷酸酶(ALP)活性显著低于其它各组(P<0.05);酸性磷酸酶(ACP)活性显著降低(P<0.05),溶菌酶(LZM)活性则显著升高(P<0.05);D4组总抗氧化能力(T-AOC)显著高于对照组及D1组(P<0.05);超氧化物歧化酶(SOD)活力差异不显著(P>0.05)。在本实验条件下,饲料中添加壳聚糖可显著提高虹鳟幼鱼生长性能、增强非特异性免疫能力,以增重率及非特异性免疫为综合评价指标,虹鳟饲料中壳聚糖的适宜添加量为0.50%。 相似文献
9.
为研究水解鱼蛋白(FPH)对大菱鲆(Scophthalmus maximus L.)幼鱼生长的影响,本实验以60%的鱼粉(FM)组为正对照组,以复合植物蛋白源替代40%的FM作为负对照组(含36%的FM),在负对照组的基础上添加3个梯度水平(3%、6%、9%)的FPH作为实验组,分别喂养大菱鲆幼鱼74 d。研究表明,与负对照组相比,添加6%和9%的FPH可显著提高大菱鲆幼鱼的生长性能,并达到与正对照组相似的效果。添加不同含量的FPH会改善大菱鲆幼鱼的后肠形态,且改善状况随添加量的增加而愈加明显,当FPH添加水平达到9%时,可显著增加大菱鲆幼鱼后肠的肠绒毛直径比、肠上皮细胞高度和微绒毛高度。与负对照组相比,9%FPH组显著提高了血浆和肌肉中必需氨基酸、非必需氨基酸和总氨基酸浓度。此外,饲料中添加6%和9%的FPH显著促进了PepT1的基因表达量。研究结果表明,水解鱼蛋白是一种潜在的替代鱼粉的有效蛋白源,可起到改善大菱鲆幼鱼生长指标、提高机体游离氨基酸含量和促进肠道吸收能力的作用。 相似文献
10.
在高密度养殖条件下,进行单因素随机设计动物试验.用5种饲料(蛋白质水平31%、35%、39%、43%、47%,以A～E组表示)分别投喂平均体质量6.2 g+0.2 g、平均养殖密度3.1 kg/m3的凡纳滨对虾(Litopenaeus vannamei),探寻蛋白质营养对虾生长、免疫、水质、抗胁迫的影响特征.结果表明:(1)中高蛋白质水平具有显著促进对虾生长的效果,随着蛋白水平的提高,特定生长率先增加后降低,饲料系数正好相反,D组两指标最佳,分另q为110.98%和2.54;C、D、E组差异不显著.(2)中高蛋白质水平有利于提高对虾多数免疫指标的活力,血淋巴中血细胞浓度、T-AOC活力、POD活力、总蛋白含量、白蛋白、血蓝蛋白含量,随着蛋白质水平提高先增加后降低,前5指标含量均以D组最高,比A组显著提高16.8%～33.9%;而血蓝蛋白含量C组最高,比A组提高15.0%.(3)高蛋白质水平有利于提高对虾SOD活力,也显著增强抗低盐胁迫的能力,但同时极显著加大了水环境中氨氮和亚硝氮的污染.(4)在我国北方集约化高密度养殖条件下,凡纳滨对虾中后期生长阶段适宜的饲料蛋白质营养水平为39%～43%. 相似文献
11.
Chandralata Raghukumar G. Sheelu P. A. Loka Bharathi Shanta Nair C. Mohandass 《Marine Georesources & Geotechnology》2001,19(1):1-16
In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance. 相似文献
12.
Arne Schnack-Friedrichsen Angela M. Davis Jim D. Bennell Dei G. Huws 《Marine Georesources & Geotechnology》2001,19(4):221-243
The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths. 相似文献
13.
Derek V. Ellis 《Marine Georesources & Geotechnology》2001,19(1):51-63
This article reviews information recently available from existing marine and coastal mining for responses to environmental issues affecting marine mining at different depths. It is particularly but not exclusively concerned with those issues affecting seabed biodiversity impact and recovery. Much information has been gathered in the past 10 years from shallow mining operations for construction aggregate, diamonds, and gold, from coastal mines discharging tailings to shallow and deep water, and from experimental deep mining tests. The responses to issues identified are summarized in a series of eight tables intended to facilitate site-specific consideration. Since impacts can spread widely in the surface mixing layer SML, and can affect the biologically productive euphotic zone, the main issues considered arise from the depth of mining relative to the SML of the sea. Where mining is below the SML, the issue is whether it is environmentally better to bring the extraction products to the surface vessel for processing (and waste discharge), or to process the extraction products as much as possible on the seabed. Responses to the issues need to be sitespecific, and dependent on adequate preoperational environmental impact and recovery prediction. For deep tailings disposal from a surface vessel, there are four important environmental unknowns: (1) the possible growth of "marine snow" (bacterial flocs) utilizing the enormous quantities of fine tailings particles (hundreds or thousands of metric tons per day) as nuclei for growth, (2) the possibility that local keystone plankton and nekton species may migrate diurnally down to and beyond the depth of deep discharge and hence be subjected to tailings impact at depth, (3) the burrow-up capability of deep benthos and their ability to survive high rates of tailings deposition, and (4) the pattern and rate of dispersion of a tailings density current through the deep water column from discharge point to seabed. Actions to obtain relevant information in general and site-specifically are suggested. 相似文献
14.
G. Parthiban 《Marine Georesources & Geotechnology》2000,18(3):223-235
Particle fluxes were measured 7 m above the sea bottom during the predisturbance, disturbance, and postdisturbance periods by using time series sediment traps attached to seven deep-sea moorings deployed in the INDEX experiment site in the Central Indian Basin. The predisturbance particle fluxes varied between 22.3 to 55.1 mg m -2 day -1 . Increased and variable particle fluxes were recorded by the sediment traps during the disturbance period. The increase observed was 0.5 to 4 times more than the background predisturbance fluxes. The increases in particle fluxes (~4 times) recorded by the sediment trap located in the southwestern direction (DMS-1) were the greatest, which could be the result of preferential movement of resuspended particles generated during the deep-sea benthic disturbance along the general current direction prevailing in this area during the experimental period. Also, the traps located closer to the disturbance area recorded greater fluxes than did the traps far away, across the Deep Sea Sediment Resuspension System path. This variability in recorded particle fluxes by the traps around the disturbance area clearly indicates that physical characteristics such as grain size and density of the resuspended particles produced during the disturbance had an important effect on particle movement. The postdisturbance measurements during ~5 days showed a reduction in particle fluxes of ~50%, indicating rapid particle settlement. 相似文献
15.
海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。 相似文献
16.
Geoacoustic Inversion via Genetic Algorithm and Its Application to Manganese Sediment Identification
An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm. 相似文献
17.
The advanced piston corer (APC) has been used by the Ocean Drilling Program since 1985 for recovering soft sediments from the ocean floor. The pullout force measured on extracting the core barrel from the sediment is shown to correlate with the average shear strength of the sediment core measured in the ship's laboratory. A simple rule of thumb is derived relating the shear strength of the sediment to the pullout force. Multiple APC holes at individual sites allow the consistency of the pullout measurements to be assessed. The effects of different operational procedures during APC coring are also explored. Although generally applicable, the correlation between pullout force and laboratory measurements of shear strength breaks down for some APC holes, possibly because of the disturbance of some sediment types during the APC coring process. A better understanding of the physical process of APC coring, and its effect on the properties of the sediment both inside and immediately outside the core barrel, would indicate what confidence can be put on the measurement of pullout force as a way of evaluating the in situ shear strength of deep sea sediments. 相似文献
18.
Shigehisa Nakamura 《Marine Geodesy》2000,23(1):55-61
Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone. 相似文献
19.
The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics. 相似文献
20.