饲用鱼油脂肪酸营养成分分析

本文应用气相色谱对鱼油的脂肪酸组成进行分析,结果表明:①鱼油中主要脂肪酸含量SFA为C16∶0和C14∶0,MUFA为C16∶1和C18∶1,PUFA为EPA和DHA.②由于产地及加工工艺等原因,鱼油脂肪酸成分含量有较大的差异,但总体上EPA和DHA含量较高,在15.6%~28.3%之间,而C18∶2和C18∶3含量较低,只有0.4%~3.1%.③饲用鱼油的配制应针对不同鱼用饲料中必需脂肪酸的组成进行适当调制,以期达到理想的养殖效果.     

条石鲷(Oplegnathus fasciatus)发育早期的脂肪酸组成变化研究

采用GC/MS法分析了条石鲷(Oplegnathus fasciatus)的未受精卵、胚胎、仔鱼、稚鱼及幼鱼各阶段的脂肪酸组成特点及含量变动,旨在研究条石鲷发育早期脂肪酸的组成和变化规律。共检测到28种脂肪酸,其中饱和脂肪酸(SFA)13种,单不饱和脂肪酸(MUFA)7种,多不饱和脂肪酸(PUFA)8种。结果表明:(1)鱼卵中主要脂肪酸依次为C16:0、C22:6(n-3)(DHA)、C20:5(n-3)(EPA)和C18:1(n-9)(油酸);(2)胚胎及内源性营养阶段,主要利用C16:0、C18:0以及C18:1作为能量来源,EPA和DHA被优先保存下来;(3)摄食轮虫和桡足类AA、EPA、DHA含量显著提高,摄食卤虫则C18:1(n-9)、C18:2(n-6)及C18:3(n-3)含量迅速增加;(4)在稚鱼期必需脂肪酸AA、DHA含量不足,而EPA过高,可能引起细胞膜磷脂中DHA与EPA比例失衡,出现稚鱼"死亡高峰"。     

温度、光照、pH值对后棘藻生长及脂肪酸含量的影响

报道了环境因子对富含 EPA (2 0∶ 5ω3)的海洋微藻后棘藻 (Ellipsoidion sp.) 70 - 0 1的生长速度、总脂及脂肪酸含量的影响。结果表明 ,后棘藻具有较快的生长速度和较高的脂肪酸含量 ,总脂含量为 31～ 36 % ,主要脂肪酸为 14∶ 0、16∶ 0、16∶ 1、18∶ 1ω9、18∶ 1ω7、18∶ 2 ω6、2 0∶ 4 ω6、2 0∶ 5ω3。生长的温度范围为 15～ 30℃ ,2 5℃时生长速度最快。温度对总脂含量影响很小 ,但对EPA和 PUFA含量影响较大。在 2 5℃时有最大的 EPA和 PUFA含量。适宜光强为 10 8.75μmolm-2 s-1～ 2 4 4 .15μmolm-2 s-1,在 145.54μmolm-2 s-1时 EPA产率较大。在起始 p H6 .5～ 9范围内 ,p H8.5时有最大的生长速率和总脂含量 ,而 EPA和 PUFA在起始 p H7.5时最大 ,分别占脂肪酸的 18.77%和 2 3.38%。实验条件下后棘藻 EPA产率最大的条件为温度 2 5℃ ,光强 145.54μmolm-2 s-1,p H为 7.5～ 8.5。     

摄食紫菜粉等4种单一饵料的蚤状溞脂肪酸组成的比较

用GC/MS法分析比较了紫菜粉、小球藻、酵母、Banta液(牛粪1.5g+干稻草2g+沃土20g+水1 000 cm3)4种食物条件下蚤状溞的脂肪酸组成.结果表明:4种食物培养下,蚤状溞的总脂含量依次为39.80、60.10、44.60、52.30mg/g.一共检测出脂肪酸14种,其中8种饱和脂肪酸(SFA),2种单不饱和脂肪酸(MUFA),4种多不饱和脂肪酸(PUFA).紫菜粉培养组与小球藻组PUFA含量显著高于酵母组和Banta液组(p0.05),占总脂肪酸的1/3以上,酵母组MUFA质量分数最高(p0.05),达55.73%,Banta液组以SFA质量分数最高(p0.05),为52.45%.其中紫菜粉组的PUFA中缺乏C18:3,但C20:5(EPA)和C20:4(AA)质量分数高达22.67%和9.02%是小球藻组的1.6倍和4.5倍(p0.05),而且EPA和AA的实际含量也显著高于小球藻组(p0.05),达到9.02 mg/g和3.59mg/g;比较得出,紫菜粉培养组的20碳以上必需不饱和脂肪酸含量丰富,明显高于其他3组.本实验证实蚤状溞的脂肪酸组成与食物脂肪酸成正相关.分析认为,用紫菜粉培养枝角类用于海水育苗会取得更佳的营养效果.     

7株海洋微藻强化褶皱臂尾轮虫效果的研究

该文用 7株富含 EPA、DHA的海洋微藻对褶皱臂尾轮虫 (Brachionus plicatilis)进行强化 ,通过检测轮虫的脂肪酸组成和含量来研究这几种微藻对轮虫的营养价值。结果表明 :轮虫中的脂肪酸组成和含量与所用饵料密切相关 ,尤其是 EPA、DHA等多不饱和脂肪酸 (PUFA)主要取决于这些脂肪酸在藻中的含量 ;强化 12 h后 ,轮虫中的 n- 3PUFA含量一般为饵料中含量的 75 %左右 ,强化 2 4 h达 80 %以上 ,强化 7d的轮虫可达 90 %以上。     

摄食紫菜粉等4种单一饵料的蚤状潘脂肪酸组成的比较

用GC／MS法分析比较了紫菜粉、小球藻、酵母、Banta液（牛粪1．5g＋干稻草2g＋沃土20g＋水1000cm3）4种食物条件下蚤状潘的脂肪酸组成．结果表明：4种食物培养下,蚤状潘的总脂含量依次为39．80、60．10、44．60、52．30mg／g．一共检测出脂肪酸14种,其中8种饱和脂肪酸（SFA）,2种单不饱和脂肪酸（MUFA）,4种多不饱和脂肪酸（PUFA）．紫菜粉培养组与小球藻组PUFA含量显著高于酵母组和Banta液组（P〈0．05）,占总脂肪酸的1／3以上,酵母组MUFA质量分数最高（P〈0．05）,达55．73％,Banta液组以SFA质量分数最高（P〈0．05）,为52．45％．其中紫菜粉组的PUFA中缺乏C18：3,但C20：5（EPA）和C20：4（AA）质量分数高达22．67％和9．02％是小球藻组的1．6倍和4．5倍（P〈0．05）,而且EPA和AA的实际含量也显著高于小球藻组（P〈0．05）,达到9．02mg／g和3．59mg／g;比较得出,紫菜粉培养组的20碳以上必需不饱和脂肪酸含量丰富,明显高于其他3组．本实验证实蚤状潘的脂肪酸组成与食物脂肪酸成正相关．分析认为,用紫菜粉培养枝角类用于海水育苗会取得更佳的营养效果．     

不同氮浓度条件下红色赤潮藻脂肪酸含量及组成特征

在不同氮浓度条件下对红色赤潮藻(Akashiwosanguinea)进行了一次性培养,研究了其生长过程中脂肪酸含量及组成变化。结果表明:红色赤潮藻脂肪酸含量及组成受初始氮浓度及生长阶段的影响。低氮处理组(0—25μmol/L)脂肪酸含量[(150.02±54.84)—(166.83±46.46)mg/gdw]显著高于其他处理组(P0.05),883μmol/L组最低,约为(86.70±5.66)mg/gdw;各培养组脂肪酸含量随着培养时间的延长而增加,稳定期时脂肪酸含量最高,指数生长前期含量最低。红色赤潮藻含28种脂肪酸,以C16:0、C18:1、C20:5ω3(EPA)和C22:6ω3(DHA)为主,且DHA相对含量较高,最高可占总脂肪酸含量的30.46%。随着初始氮浓度的增加,红色赤潮藻饱和脂肪酸(SFA)和单不饱和脂肪酸(MUFA)在总脂肪酸中所占比例下降,而多不饱和脂肪酸(PUFA)所占比例升高。在红色赤潮藻生长过程中,MUFA相对含量在稳定期时较高,而PUFA相对含量在指数生长前期较高。研究结果可为进一步揭示红色赤潮藻赤潮应对环境胁迫的生理响应机制提供依据。     

细胞生长时期对两种海洋微藻总脂含量和脂肪酸组成的影响

报道海洋微藻后棘藻 (Ellipsoidion sp.7- 14)和眼点拟微球藻 (N annochloropsis oculata)细胞生长时期对细胞内总脂含量和脂肪酸组成的影响。结果表明 ,两种微藻的总脂均在稳定期含量最高 ,分别占干重的 54.5%和 4 3.3% ,而 EPA、ω- 3多不饱和脂肪酸和总 PUFA的最高比例均出现在对数早期 ,EPA占总脂肪酸的比例可分别高达 2 7.3%和 2 7.7% ,同时总脂的含量却最低 ,分别占干重的 2 2 .9%和 2 2 .0 %。在生长对数期中 EPA是脂肪酸的主要成分 ,而在稳定期中16∶ 0、16∶ 1ω9和 18∶ 1ω9是脂肪酸的主要成分。     

7种(13株)杜氏藻的总脂含量和脂肪酸组成

在实验室条件下培养7种(13株)杜氏藻(Dunaliella),在生长的平衡期收获.分别采用索氏提取法和气相色谱法进行了总脂含量和脂肪酸组成的测定.它们的总脂含量在6.64%~16.18%(m/m,干重,下同)之间,其中7株的总脂含量超过10%.杜氏藻的16碳和18碳脂肪酸含量丰富,有着较高的C16∶0、C18∶1(n-12)、C18∶2(n-6)和C18∶3(n-3)脂肪酸,其中8株的不饱和脂肪酸含量超过总脂肪酸的50%.杜氏藻的EPA和DHA的含量较低,但是有5株超过总脂肪酸的10%.     

渤海银鲳肌肉生化成分分析与营养价值评价

研究采用现代生化分析方法,测定了渤海银鲳肌肉的营养成分,结果表明:肌肉含水量76.22%,蛋白质16.76%,脂肪5.03%,灰分1.31%,无氮浸出物0.68%;肌肉组织中的18种氨基酸中以谷氨酸含量最高,天冬氨酸次之,亮氨酸居于第三位;肌肉组织中的主要脂肪酸排列顺序如下:C18:1(n97)C16:0C22:6n3C16:1n7C18:0,饱和脂肪酸(SFA)占脂肪酸总量的23.32%～33.15%,单烯酸(MUFA)占22.49%～29.97%,多不饱和脂肪酸(PUFA)占13.11%～22.50%,EPA和DHA之和占7.18%～10.08%。根据1973年FAO/WHO推荐的必需氨基酸需要量模式对银鲳肌肉进行评价,氨基酸比值系数分为83,第一限制性氨基酸为亮氨酸。     

Microbial Biomass and Organic Nutrients in the Deep-Sea Sediments of the Central Indian Ocean Basin

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.     

Assessing the Validity of Seismo-Acoustic Predictor Equations for Obtaining Seabed and Sub-Surface Sediment Physical Properties

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.     

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.     

海上大直径钢管桩打桩过程中桩周土强度弱化研究

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。     

Interannual Sea Level Variations and Annual Tides in the Northwestern Pacific

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.     

Flow Cytometric Analysis of Coastal Lagoon Bacterioplankton and Picophytoplankton: Fixation and Storage Effects

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.     

INFORMATION FOR AUTHORS

<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology,     

Deep-Sea Sediment Compression Curves: Some Controlling Factors, Spurious Overconsolidation, Predictions, and Geophysical Reproduction

Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations.