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1.
初始密度对微小亚历山大藻生长及产麻痹性贝类毒素的影响 总被引：1，自引：1，他引：0
为研究微小亚历山大藻生长和产麻痹性贝类毒素(PSP)的规律,采用不同初始密度对微小亚历山大藻进行培养,综合采用显微镜计数、小鼠生物检测(MBA)、高效液相色谱—柱后衍生(HPLC-FLD)等方法分析微小亚历山大藻在不同接种密度条件下的生长和产毒特性.结果表明,随着初始密度增加微小亚历山大藻通过静止期的时间缩短,到达最大生长密度的时间提前,但是生长的最大细胞密度和平均比生长率却呈下降趋势,增值模型反应的情况与观测结果相一致,随着初始密度的增加,依赖于初始种群密度的参数(a)减少,环境容量(K)减少,种群瞬时增殖速度(r)下降.4种不同初始密度(0.05×104、0.10×104、0.15×104、0.30×104cells/mL)条件下,微小亚历山大藻细胞的毒性呈现先增大后减小趋势,在初始密度为0.1×104 cells/mL条件下,同一生长期内细胞毒性比其他3个密度条件下高.HPLC检测微小亚历山大藻含有的毒素为GTX1-4,含量分别为2.14、2.08、4.97、5.04 fmol/cell.综合考虑微小亚历山大藻在生长过程中的细胞最大密度、达到最大密度所用时间以及细胞毒性大小等因数,采用(0.10～0.15)×104 cells/mL接种密度培养微小亚历山大藻,能够达到较好的产毒效果. 相似文献
2.
杜氏盐藻和亚心型扁藻混合培养生长的初步研究 总被引：3，自引：0，他引：3
在实验室条件下研究了杜氏盐藻和亚心型扁藻在单独培养和相同接种比例混合培养下的生长情况。结果显示,单独培养盐藻的生长经历了3个明显的阶段,生长曲线呈现"S"型;单独培养扁藻与混合培养藻在18 d内还未到达稳定期,仍保持一定的生长态势。混合培养、单独培养盐藻以及单独培养扁藻的最大光密度值(OD680)分别为0.784、0.702和0.765。混合培养藻的生物量(0.841 mg/ml)也稍高于单独培养盐藻(0.582 mg/ml)和单独培养扁藻的生物量(0.819 mg/ml)。试验结果表明,混合培养盐藻和扁藻具有一定的促进藻生长和提高生物量产出的潜力。 相似文献
3.
不同氮、磷浓度下亚心形扁藻的生长及水体中氮、磷变化 总被引：2，自引：0，他引：2
自然条件下,采用湛水107-13营养液为基础配方,在经消毒处理的天然海水中添加不同氮、磷质量浓度的营养盐进行亚心形扁藻的培养。结果表明,当氮、磷质量比为17时,最适合亚心形扁藻的生长。不同磷质量浓度梯度对亚心形扁藻的生长和生长率K具有显著性的影响(P<0.05)。当磷质量浓度为8 mg/L时,其相对生长常数和生长率K值均高于其他质量浓度处理。不同氮质量浓度梯度对亚心形扁藻生长具有显著性影响(P<0.05),但对亚心形扁藻生长率K的影响不显著(P>0.05)。高质量浓度氮对亚心形扁藻的生长影响作用最大(P<0.05)。在培养过程中,高质量浓度氮、磷培养液中NO3--N和PO43--P的下降速率高于低质量浓度中NO3--N和PO43--P浓度的变化,并呈现出显著性的差异(P<0.05)。表明在高质量浓度营养盐条件下培养亚心形扁藻,会导致营养盐相对利用率的下降。 相似文献
4.
实验室条件下，分别以面包酵母和扁藻为饵料培养褶皱臂尾轮虫（以下简称轮虫）。结果表明，轮虫摄食扁藻的生长繁殖效果要好于摄食酵母。以扁藻为食物，其带卵率和带卵数分别为45．5％和3．1个，而以酵母为食物，其带卵率和带卵数仅分别为32．5％和2．2个。在轮虫接种密度情况下（经一个培养周期7天），轮虫密度分别为54个／ml、32．5／ml。 相似文献
5.
轮虫是一些水生动物或其幼体的良好食饵,其大量培养供应的技术,无疑是很重要的。本文报告一种海水和咸淡水种——褶皱臂尾轮虫(B.Plicatilis)的繁殖生态条件和大量培养技术的实验结果。此种轮虫为广盐性生物,能在2—50‰的盐度范围内生长繁殖,但其适宜的繁殖盐度为10—30‰,而尤以15—25‰为最适宜。休眠卵子能在1.5—35‰的盐度范围内孵化,但以15—20‰为最适宜;最高的孵化率为10.47％。在5—35℃的温度范围内,休眠卵子都能孵化,但孵化时间则随温度的不同而有明显差异。最适宜的孵化温度为20—25℃,时间短,孵化率高;在适宜温度范围内,变温似较恒温对孵化更有利。最高的孵化率为17.53％。在5—40℃的实验温度范围内,此种轮虫都能繁殖生长。但以高温者繁殖快,低温者很慢。较适宜的繁殖温度为25—40℃,而以30—35℃条件下繁殖最快。在温度超越30℃时,轮虫的个体显著变小,这种体形变异是可逆的。实验证实:小新月摄氏菱形硅藻、亚心形扁藻,衣藻和小球藻都是此种轮虫的好饵料;而从大量培养角度看,以扁藻为饵则尤为适宜。较适宜的饵料密度为:扁藻1—15万个/毫升;硅藻5—100万个/毫升。而以扁藻2.5—5万个/毫升左右和硅藻50万个/毫升左右为最适宜的饵料密度。轮虫分布密度小者,其繁殖速度快;分布密度大者,繁殖慢。大量培养中兼顾繁殖速度和数量的关系,以每升培养基中含有1,000个轮虫的接种密度较为适宜。在饵料条件突变、过多或过缺的情况下,轮虫即进行有性生殖,形成休眠卵子。培养中利用此特点,突然停止给饵,一般在二、三日内即可采收得休眠卵子。在大玻璃交瓶、水族箱、水泥池和土池中都能进行不同规模的大量培养,实验中都已取得培养效果。大量培养中最重要的问题为饵料条件,要维持适宜且经常的饵料密度,才能保证轮虫及时、迅速地繁殖生长。在大量培养中,在饵料培养基(或轮虫和饵料混同培养基)中加入2—5‰的人尿,则培养效果更好。培养中最高密度达到324,000个/升的活体轮虫,在培养容器的水底腐渣中最高达到1,400,000个/升的个体很小的褶皱臂尾轮虫。在饵料与轮虫同池培养时,如作高密度培养,则必须另外备有可以补充的饵料来源,以防突然饵料不足,影响轮虫大量培养使用的效果。 相似文献
6.
选用底栖硅藻菱形藻(Nitzschiasp.)为实验对象,分别研究了CaCl2浓度、胶珠直径、接种密度及胶珠密度对其生长的影响及后两因素对其主要营养成分含量变化的影响。结果表明:(1)随培养时间的延长,CaCl2浓度对菱形藻生长有极显著影响,在2%CaCl2溶液中形成的胶珠里菱形藻比生长速率最高;(2)胶珠直径对菱形藻在初期和指数期的生长影响显著,且较小直径(2.5～3.0mm)的胶珠较适宜菱形藻生长;(3)随接种密度和胶珠密度的提高,菱形藻的比生长速率都有先增高后下降的变化趋势,接种密度较高(2.50×104～5.50×104mL-1)时,固定化组的比生长速率是对照组的2倍左右。胶珠密度为220粒/(100mL培养液)左右较适宜(胶珠直径3.0mm);(4)初始接种密度和胶珠密度试验中,蛋白质、总糖及粗脂肪的含量固定化组低于或相当于对照组,而叶绿素的含量固定化组高于对照组。 相似文献
7.
为进一步提高湛江等鞭金藻室外规模化培养效率,对管道式光生物反应器、聚乙烯桶和水泥池3种微藻室外规模化培养模式下湛江等鞭金藻的藻密度进行了评估比较.试验将接种藻密度控制为10.0×104 cells/mL,培养周期为16 d.结果显示:管道式光生物反应器培养模式下,生产力相对最高为0.0543 g/L/d、比生长速率为0... 相似文献
8.
三十烷醇对亚心形扁藻生长的影响 总被引：4，自引：0，他引：4
本文报道了三十烷醇对亚心形扁藻生长的促进作用。其最佳施用浓度为0.1ppm,接种后第4天,藻细胞浓度较对照组提高了51.7%;在扩大培养时,其藻细胞在接种后第12天,较对照组可提高133.4%。 相似文献
9.
变温对刺参幼参生长、呼吸代谢及生化组成的影响 总被引：11，自引：0，他引：11
为研究刺参对温度周期性波动的响应,本实验测定了在12,15,18,21,24℃5个恒温处理组和15±2℃,18±2℃,21±2℃3个变温处理下刺参幼参的生长、呼吸代谢和生化组成。结果表明,在恒温条件下,随着温度的升高,刺参生长逐渐加快,在18℃生长最快,然后随温度增加,生长逐渐降低。在15~21℃恒温条件下,幼参呼吸代谢无显著差异。在不同恒温处理组中,幼参脂肪含量随体重增加而增加。与恒温对照组相比,变温对幼参生长有显著性影响(P<0.05)。与相应的恒温相比,平均温度低于最适温度的变温(15±2℃,18±2℃)可促进刺参的生长,而平均温度高于最适温度时的变温(21±2℃)会抑制刺参生长。变温使幼参耗氧率有增加的趋势,但未达到显著水平。变温造成刺参脂肪含量降低,可能与变温条件下呼吸代谢增加有关。 相似文献
10.
为探讨pH和氮磷比对青岛大扁藻(Tetraselmis helgolandica)和微小原甲藻(Prorocentrum minimum)生长竞争的影响,本研究首先根据对虾养殖水体pH值的范围设置了7.5,8.0,8.5和9.0共4个pH梯度,获得了青岛大扁藻抑制微小原甲藻的最佳pH;在该pH条件下,设置了氮磷比分别为3:2(高富磷组),6:1(富磷组),24:1(对照组)和96:1(富氮组)等4个梯度,其中,单种培养体系中只接种青岛大扁藻或者微小原甲藻,混合培养体系中同时按照1:1的比例接种青岛大扁藻和微小原甲藻。结果表明,混合培养体系中,青岛大扁藻在pH 8.5和pH 9.0时,出现拐点时间最晚,均为7 d;而微小原甲藻在pH 8.5和pH 9.0时,出现拐点时间最早,均为3 d。pH 8.5时青岛大扁藻对微小原甲藻的竞争抑制参数最大,青岛大扁藻抑制微小原甲藻的最佳pH为8.5。单种培养体系中,微小原甲藻拐点出现的时间在高富磷组、对照组和富氮组中均晚于青岛大扁藻;混合培养体系中,对照组中微小原甲藻和青岛大扁藻拐点出现时间分别为4 d和3 d,而其他处理组2种微藻拐点出现的时间分别相同。氮磷比影响混合培养中2种微藻的竞争抑制参数,其中,96:1(富氮组)中拐点之后青岛大扁藻对微小原甲藻的竞争抑制参数(α)的平均值为9.2063,微小原甲藻对青岛大扁藻的竞争抑制参数(β)为3.4886。以上研究表明,对虾养殖水体中,青岛大扁藻抑制微小原甲藻的最佳条件是:pH为8.5,氮磷比为96:1。 相似文献
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12.
José Luis Arredondo-Figueroa Angélica Vásquez-González Irene de los A. Barriga-Sosa Claudia Carmona-Osalde Miguel Rodríguez-Serna 《Journal Of Applied Aquaculture》2013,25(1):66-73
The acocil C. montezumae is a freshwater crayfish endemic to the Central Plateau of Mexico, but, in recent years, the natural population of this species has diminished considerably. In this work was investigated growth performance and feeding of this crayfish reared at high densities. A random block experimental design with two repetitions and three treatments (77, 154 and 231 crayfish/m2) was carried out. Organisms were fed every third day with 15% of their total biomass of shrimp commercial food with 25% of crude protein, and individual food consumption (IFC) was calculated. Significant differences (ANOVA, P < 0.05) were detected in final weight, absolute increase, relative rate of increase, instantaneous rate of increase, yield and survival rate between the densities, with those reared at a density of 77 organisms/m2 reaching the largest sizes. There were no-significant differences (P > 0.05) among treatments in terms of initial weight, specific growth rate and feed conversion l rate. 相似文献
13.
Mostafa A. R. Hossain Malcolm C. M. Beveridge Graham S. Haylor 《Aquaculture (Amsterdam, Netherlands)》1998,160(3-4):251-258
The effects of stocking density, light and shelter on the growth and survival of Clarias gariepinus fingerings was evaluated. In this experiment African catfish with initial individual mean weight 0.79±0.1 g were reared at two different stocking densities—5 fish l−1 and 10 fish l−1 in either sheltered or unsheltered tanks with reduced and normal light condition. In all conditions growth rate was significantly affected by stocking density. The growth rate was significantly higher at low densities and in reduced light conditions where shelter was provided. Survival rate was in excess of 79% in all treatments and was not affected by treatment. 相似文献
14.
Christina Thoisen Jakob Skov Pedersen Lars Jrgensen Anker Kuehn Benni Winding Hansen Sren Laurentius Nielsen 《Aquaculture Research》2020,51(8):3367-3375
The microalga Rhodomonas salina is widely used in aquaculture. There is a need for optimization of the growth of the microalgae and its content of essential fatty acids. Here, the fatty acid profile of Rhodomonas in relation to cell density during cultivation in a tubular PBR is investigated. It is expected that cell density is an important factor in controlling productivity and fatty acid content of the microalgae because cell density is important in determining light availability due to the self‐shading of the algae. The carbon productivity as a function of cell density is described by a saturation curve. The carbon productivity and the productivity of total fatty acids are lowest at the lowest cell density, and independent of cell density at higher cell densities. The relative contribution of the two poly‐unsaturated fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) increases with increasing cell density and saturates at 1 × 106 cells/ml. We conclude that large‐scale production of Rhodomonas in this tubular PBR should take place at cell densities of 1 × 106 cells/ml, while there are indications for increasing difficulties in maintaining steady‐state production in this PBR at higher cell densities. 相似文献
15.
基于对虾生物絮团集约化养殖尾水含有高浓度硝态氮和磷酸盐的特征，比较分析钝顶螺旋藻（Spirulina platensis）、牟氏角毛藻（Chaetoceros muelleri）、盐藻（Dunaliella sp.）3种微藻在配制尾水中的存活生长状况及其对无机氮磷的去除效果，以期筛选出适宜的微藻用于后续尾水净化技术。采用显微镜计数法测定藻细胞密度，国标法测定总无机氮、氨氮、硝态氮、亚硝态氮和磷酸盐的含量。结果显示，钝顶螺旋藻在实验前后的藻细胞密度变化不大（P>0.05），约为3.32×106 个/mL和5.88×106 个/mL；牟氏角毛藻和盐藻细胞密度有明显增加（P<0.05），分别从初始的4.00×104 个/mL和2.50×105 个/mL升高至实验结束时的1.66×106 个/mL和1.06×107 个/mL。经过16 d实验，钝顶螺旋藻组对硝态氮和总无机氮去除率分别为79.60%和46.06%，显著高于其他各组（P<0.05），第8天时对磷酸盐的去除率可高达98.55%；牟氏角毛藻组16 d的磷酸盐去除率为98.25%，显著高于其他各组（P<0.05）。研究表明，3种微藻均可在对虾养殖尾水环境中存活，且对尾水氮磷具有较好的净化效果。 相似文献
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Groups of salmon (Salmo salar) from two localities were kept at five different densities during the initial feeding period of 42 days and a subsequent growth period of 205 days. They were then kept at the same density for 95 days. Differences in mean weight between fish from different localities were found as early as the end of the initial feeding period. No marked differences were found between mean weights of fish held at different densities during the initial feeding period, while the mortality rate of fry decreased with higher densities for both strains. At the end of the 205-day growth period the differences in mean weight between strains and between density groups within a strain were large. Significant interaction between locality and density was also found. Part of this interaction is due to scale effects.When groups were kept at the same density, those originally at high densities showed the highest relative growth, and also had the highest K-factor at the end of this period. It is concluded that high densities depressed the growth rate, and that compensatory growth occurred when the densities were standardized. It is important to take density into account when ranking families or progeny groups for growth performance in selective breeding trials. 相似文献
17.
Survival and growth of geoduck clam larvae (Panopea generosa) in flow‐through culture tanks under laboratory conditions 
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下载免费PDF全文 Gabriel Enrique Nava‐Gómez Zaúl Garcia‐Esquivel Eugenio Carpizo‐Ituarte Tatiana N Olivares‐Bañuelos 《Aquaculture Research》2018,49(1):294-300
The geoduck clam, Panopea generosa, is a species from the west coast of Baja California, Mexico, and the optimization of seed production systems is still a limiting factor for its aquaculture. In this study, a flow‐through culture system was designed and tested in P. generosa larvae. Survival and growth was compared in triplicate 45‐L fiberglass tanks using three larval densities (5, 10 and 15 larvae/ml). A head tank kept constant the water inflow, with a daily renewal rate of 1.8× tank volume. The food (Isochrysis spp.) was dosed according to the ingestion rate of larvae and the dilution rate. Survival decreased linearly during the first 10 days and reached asymptotic values of ca. 20% (15 larvae/ml) and 50% (densities of 5 and 10 larvae/ml) afterwards. Mean shell length at the end of the experiment (243 ± 1.8 to 270 ± 0.7 μm) was not statistically different among treatments, even though a trend towards higher gross growth rate was observed in the treatment with the lowest density (9.5 μm/day) relative to the rest of the treatments (8.5 μm/day). It is concluded that P. generosa larvae can be successfully grown in flow‐through systems at maximum densities of 10 larvae/ml without significantly affecting their survival and growth rates. The system design was reliable, kept a constant water flow with reduced maintenance, and may represent an important option in the laboratory for increasing the stocking density of Panopea species during the larval phase. 相似文献
18.
Abstract. Production of Pacific oysters was studied under pilot-scale conditions in Baynes Sound, British Columbia, using common bottom culture strategies. Four seeding treatments, each with a different seed per cultch density were cultured: wild-caught seed 5mm in shell height at 10 seed per cultch piece and hatchery produced seed 1-2 mm in shell height at densities of 11, 40 and 105 per cultch piece. The cultch material for all treatments was Pacific oyster shell. All seed was reared for approximately 1 year in a seed nursery located at the 2.2-m tidal level then transferred to a 1-m tidal level grow-out plot until harvest 4 years later in May 1988, Clusters of large numbers of oysters were separated and evenly distributed within the plots when the oysters attained a shell height of 60-100 mm. During the first year, growth was slow and mortalities were relatively high. All treatments produced oysters of similar size at harvest. The proportion surviving at harvest was substantially higher for the wild oysters which were initially larger at time of planting. Within the hatchery treatments proportional survival per cultch piece was inversely related to initial density on the shell; however, total production per cultch piece was positively related to initial density. Most efficient use of seed is attained at lower densities per shell; however, most efficient use of cultch and effort to handle cultch is attained at high densities. 相似文献
19.
饵料和养殖密度对中国对虾幼虾生长及存活率的影响 总被引：6，自引：0，他引：6
在实验用虾遗传背景一致的情况下,分析了3种饵料(配合饲料、冰冻鲜鱼肉和活卤虫)和4个不同的养殖密度对小水体中国对虾幼虾生长和存活率的影响。结果表明,饵料和饲养密度对中国对虾幼虾生长及存活率有显著影响。在饵料、养殖密度单因子实验及饵料和养殖密度相结合的双因子实验中,幼虾的生长均表现出极其显著的差异(P<0.01),活卤虫对幼虾生长的效应尤为突出。而养殖密度对中国对虾的行为生物学、个体间体重增量均有影响。随着养殖密度的提高,中国对虾增重变慢;同时,个体间体重增量差异变大。随着养殖密度的增加,中国对虾幼虾的存活率呈下降趋势,但不同饵料对存活率影响变化幅度较大,波动在58.1%～85.2%之间,其中投喂活卤虫养殖密度为50尾/桶的存活率最高(85.2%);投喂配合饵料4个养殖密度梯度的存活率变化不明显;而投喂冰冻鱼肉4个养殖密度梯度的存活率变化较大。因此,采用合适的饵料和养殖密度,能够提高中国对虾的生长速度,提高对虾养成存活率,改善生长过程中对虾群体体长、体重的整齐度。 相似文献