饵料中高不饱和脂肪酸在海水鱼苗培育中的作用

大量研究表明，海水鱼苗对饵料中的某些高不饱和脂肪酸(HUFA)有特殊的需要，如果饵料中缺乏这些HUFA，如DHA(docoaahexaenoic acid 22：6n-3)、EPA(eicosapentaenoic acid 20：5n-3)和AA(arachidonic acid 20：4n-6)，将严重影响其营养价值。主要介绍了HUFA对海水鱼苗的营养和生理作用以及饵料中的各种HUFA水平在海水鱼苗培育中的作用，并且给出了某些海水鱼苗对饵料中HUFA的需要量和各种HUFA之间的适宜比例。     

从鲢鱼中提取高不饱和脂肪酸的研究

ω-3高不饱和脂肪酸在营养学和医学上具有重要的药用价值,特别是二十碳五烯酸(Eicosapentaenoic acd,EPA)和二十二碳六烯酸(Docosahexaenoic acid,DHA).在我国主要淡水鱼中,鲢鱼体内脂肪含量较高,特别在内脏中,脂肪含量高达20%,是提供油脂的良好来源,并且鱼油中高不饱和脂肪酸如EPA、DHA含量也较高.因此在鲢鱼油中提取EPA和DHA具有很高的开发应用价值.     

关于廿碳五烯酸(EPA)、廿二碳六烯酸(DHA)的生理机制研究及利用的探讨

国外生化专家经过多年的研究表明,EPA、DHA是我们人类健康需求的重要物质。服用鱼油或精制成的EPA、DHA可改善血清类脂物和防止血栓形成,可预防和治疗动脉硬化等血液循环系统疾病。本文重点概述日本研究机构对EPA、DHA的生理作用及利用方面的研究成果,仅供参考。     

鱼类消费健康风险研究进展

与陆地动物相比,鱼类含有更多的ω-3系列多不饱和脂肪酸(ω-3 PUFA),尤其是DHA(C22∶6ω3)和EPA(C20∶5ω3),其中DHA可以促进婴幼儿神经系统、视觉系统的发育,EPA对于预防心血管系统疾病(CVD)有重要作用。经常食用鱼类有益于人体的健康,但水环境中各种有机的和无机的污染物通过食物链及生物放大作用在鱼体内累积,对人类健康有潜在的威胁。文章综述了PUFA对人体的生理作用,食用鱼类存在的风险,鱼类消费风险评估以及如何平衡食用鱼类的益处和风险。     

饲料中DHA/EPA值对星斑川鲽幼鱼生长、体组成及血清生理指标的影响

为研究饲料DHA/EPA值对星斑川鲽幼鱼生长、体组成和血液生理指标的影响,实验配制等氮、等能的5种不同DHA/EPA值(0.64、0.97、1.18、1.59和1.91)的饲料,每个比值设3个重复,饲养周期56 d。结果显示:(1)随着饲料DHA/EPA值的升高,星斑川鲽幼鱼增重率、饲料效率、蛋白质效率均呈先上升后下降的趋势(P0.05)。当饲料DHA/EPA值为0.97~1.59时实验鱼增重最快,饲料效率最高。蛋白质效率则在DHA/EPA值为0.97~1.18时达到最高。蛋白质沉积率(protein retention efficiency,PRE)与饲料DHA/EPA值呈显著二次回归关系(y=-1.589 5x2+2.858 3x+45.184;R2=0.910 8,x=饲料DHA/EPA值,y=PRE),当饲料DHA/EPA值大于0.90时呈下降趋势。肝体比呈先下降后小幅回升的趋势(P0.05),在饲料DHA/EPA值为1.18时达到最低,为2.85%,脾脏指数呈显著上升趋势(P0.05),于饲料DHA/EPA值为1.59组最高(0.12%);(2)肝脏粗脂肪含量随饲料DHA/EPA值的增加呈明显下降趋势(P0.05),且在饲料DHA/EPA值为1.18时降到最低,为8.60%,而后又显著上升,但仍显著低于饲料DHA/EPA值为0.64时的水平(13.44%)。二次回归分析(y=5.199 6x2-15.652x+20.866;R2=0.634 8,x=饲料DHA/EPA值,y=肝脏脂肪含量)显示,当饲料中DHA/EPA值为1.51时肝脏脂肪含量最低。脂肪酸分析结果显示,随着饲料DHA/EPA值的升高,肝脏及肌肉中EPA含量均呈线性下降趋势(P0.05),而DHA含量及DHA/EPA均呈直线上升趋势(P0.05)。肝脏和肌肉组织n-3 HUFA总量不受饲料处理的影响(P0.05);(3)血清总蛋白、球蛋白含量在饲料DHA/EPA值为1.59时显著高于其他各组(P0.05),白蛋白在饲料DHA/EPA值为0.64、0.97和1.59水平最高。溶菌酶(LSZ)活性在饲料DHA/EPA值为1.18时达到峰值(P0.05),为2.76μg/mL。谷丙转氨酶(ALT)活性在饲料DHA/EPA值1.91时无显著变化,而当饲料DHA/EPA1.18时,血清谷草转氨酶(AST)活性提高了65%左右。研究表明,在本实验条件下,以增重率为参考指标,采用二次回归(y=-31.066x2+77.26x+76.541;R2=0.957 4,x=饲料DHA/EPA值,y=增重率)分析可得,当饲料脂肪水平为8.3%,n-3 HUFA含量为0.74%时,星斑川鲽幼鱼[初始体质量(31.70±0.12)g]对DHA/EPA值的最适需要量应为1.24。     

鱼油中EPA、DHA浓缩方法的研究

1978年,丹麦学者Dyerber通过调查发现,同属丹麦领地的格陵兰岛爱斯基摩人的心血管病的发病率远低于丹麦人,而前者的膳食以鱼、海豹等海洋动物为主,后者则以典型的西方人高脂、高胆固醇膳食为主。后来证实,爱斯基摩人的膳食含有丰富的EPA和DHA等n-3系列不饱和脂肪酸,并以此推论该人群心血管病发病率低与大量摄取EPA和DHA有关。从那以后,有关EPA和DHA的研究引起了广泛的重视,从它们的作用、作用机制以及提取方法等都进行了大量的研究。研究结果表明,EPA和DHA有降低人体血浆甘油三脂、胆固醇及低密度脂蛋白、健脑、抗癌等多项生理功…     

海水鱼专用营养强化剂的应用研究

<正>轮虫和卤虫是海水育苗不可替代的鲜活饵料。研究表明,轮虫体内EPA和DHA的含量与饵料藻类所含的二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)呈正相关,轮虫体内的EPA、DHA主要是从其摄食的饵料中获取的。卤虫体内含有丰富的β-胡萝卜素、核黄     

中国对虾卵巢发育过程中脂肪酸组成的分析及比较研究

通过分析中国对虾亲虾在卵巢发育的不同阶段的卵巢、肝胰脏和肌肉的脂肪酸组成来评估中国对虾在性腺成熟过程中对脂质的需要。从中国对虾亲虾不同组织的脂肪酸组成可见,棕榈酸(16:0)、棕榈油酸(16:1ω7)、油酸(18:1ω9)、二十碳五烯酸(20:5ω3,EPA)及二十二碳六烯酸(22:6ω3,DHA)占主要比例,这与其它海洋甲壳类的脂肪酸组成相类似。中国对虾亲虾的主要脂肪酸组成比例与日本对虾亲虾的主妥脂肪酸组成比例相近似。中国对虾亲虾在不同的卵巢成熟期同一器官中的主要脂肪酸组成比例没有明显的差别,而不同组织的主要脂肪酸组成中都含有大量的ω-3系列的高度不饱和脂肪酸。从成熟卵巢的脂肪酸组成中含有高比例的EPA、DHA含量可见,EPA、DHA在亲虾性腺发育过程中的必需性。     

半滑舌鳎不同家系肌肉中脂肪酸含量的分析

为了研究半滑舌鳎(Cynoglossus semilaevis)不同家系肌肉中脂肪酸的组成与含量,并选育出高营养品系的半滑舌鳎家系,用气相色谱法对同一养殖环境中的半滑舌鳎15个不同家系(164个样本)肌肉中的脂肪酸的组成和含量进行了检测和比较分析,同时对高EPA、DHA、EPA+DHA含量的家系进行筛选,并研究了半滑舌鳎性别与EPA、DHA含量的关系。结果表明:(1)15个家系肌肉中脂肪酸种类没有区别,但脂肪酸的组成和含量存在若干差异。其特征均为多不饱和脂肪酸(PUFA)饱和脂肪酸(SFA)单不饱和脂肪酸(MUFA)。PUFA以ω-3系脂肪酸为主,且ω-3系脂肪酸与ω-6系脂肪酸比值达到4.16~5.03,其中的2种重要ω-3系脂肪酸EPA和DHA在15个家系中均具有显著性差异,且DHA含量远大于EPA含量;筛选出了3个高EPA、DHA、EPA+DHA含量家系,分别为F13012、F13023及F13031。(2)EPA的含量与半滑舌鳎性别不具有显著性相关关系。本研究对于选育半滑舌鳎优良品种家系具有重要意义。     

南美白对虾卵和无节幼体脂肪酸组成及其与饵料的关系

为探讨南美白对虾 (Penaeusvannamei)在幼体发育过程中对多不饱和脂肪酸的需求及饵料对卵、无节幼体脂肪酸组成的影响 ,对南美白对虾卵和无节幼体脂肪酸的组成进行测定和分析 ,并比较幼体阶段主要脂肪酸含量及其变化。在卵脂肪中占主要比例的脂肪酸为棕榈酸、棕榈油酸、亚油酸、花生四烯酸和DHA ,而在无节幼体中则为棕榈酸、棕榈油酸、亚油酸、花生四烯酸、EPA和DHA。在从卵到无节幼体的发育过程中 ,除EPA和DHA占总脂肪酸比例有较明显的上升外 ,其他脂肪酸所占比例均有不同程度的变化 ,总体变化特点为饱和脂肪酸的比例逐渐下降 ,而多不饱和脂肪酸的比例上升。亲虾饵料沙蚕 (Nereisspp .)的脂肪酸组成分析表明 ,沙蚕与卵及无节幼体脂肪酸的组成具有一定的相关性。     

二十碳四烯酸研究

花生四烯酸（Arachidonic acid，AA）是n-6多不饱和脂肪酸（PUFAs）。AA的系统命名是全顺-5，8，11，14-二十碳四烯酸，又名5，8，11，14-花生酸，简记为20：4n-6，分子量304．5，分子式C20H32O2，结构式如图1所示.     

Estimating Amino Acid Requirement of Brazilian Freshwater Fish from Muscle Amino Acid Profile

Information on nutritional requirement of some Brazilian farmed fish species, especially essential amino acids (EAA) requirements, is scarce. The estimation of amino acids requirements based on amino acid composition of fish is a fast and reliable alternative. Matrinxa, Brycon amazonicus, and curimbata, Prochilodus lineatus, are two important Brazilian fish with potential for aquaculture. The objective of the present study was to estimate amino acid requirements of these species and analyze similarities among amino acid composition of different fish species by cluster analysis. To estimate amino acid requirement, the following formula was used: amino acid requirement = [(amount of an individual amino acid in fish muscle tissue) × (average totalEAA requirement among channel catfish, Ictalurus punctatus, Nile tilapia, Oreochromis niloticus, and common carp, Cyprinus carpio)]/(average fish muscle totalEAA). Most values found lie within the range of requirements determined for other omnivorous fish species, in exception of leucine requirement estimated for both species, and arginine requirement estimated for matrinxa alone. Rather than writing off the need for regular dose–response assays under the ideal protein concept to determine EAA requirements of curimbata and matrinxa, results set solid base for the study of tropical species dietary amino acids requirements.     

Enrichment of Rotifers Brachionus plicatilis with Eicosapentaenoic Acid and Docosahexaenoic Acid Produced by Bacteria

Abstract— Two bacterial strains, rich in either eicosapentaenoic acid [EPA, 20:5(n-3)] ( Shewanella gel-idimarina ACAM 456) or docosahexaenoic acid [DHA, 22:6(n-3)] ( Colwellia psychroeryrhrus ACAM 605) were tested for their ability to enrich rotifers Erachionus plicatilis in these polyunsaturated fatty acids. Rotifers were exposed for 24 h to each bacterial strain and to a mixture of the two strains. They were then harvested and their fatty acid compositions were analysed and compared to those of rotifers that had been either starved or fed yeast Saccharomyces cerevisiae or microalgae Tetraselmis suecica in 2-L glass flasks. Exposure to 1.4 × 10⁹ cells/ml of the EPA-producing bacterium only resulted in rotifer EPA levels increasing from 0.1% to 1.2% of total dry weight (%dw). Similarly, following exposure to 1.0 × 10⁹ cells/mL of the DHA-producing bacterium only, rotifer DHA levels increased from below detection to 0.1% dw. When exposed to a mixture of the two bacterial strains, containing 7.0 × 10⁸ celldml of the EPA producer and 5.0 × 10⁸ cells/mL of the DHA producer, the rotifers'final EPA and DHA levels were 0.5% dw and 0.3% dw respectively. Although feeding strategies need refining, these results show, for the first time, that rotifers can be enriched with DHA from bacteria, and that rotifers can be enriched simultaneously with both DHA and EPA from different bacterial strains.     

微藻花生四烯酸的研究进展

微藻蕴量丰富、种类繁多,在地球上大约存在3万余种不同门类的微藻。近年来的研究表明,微藻中存在着丰富的、结构独特的有机化合物,如多不饱和脂肪酸酸(PUFA)、多糖、抗生素、毒素等。尤其是微藻体内含有的多不饱和脂肪酸越来越引起人们的重视,并且日渐成为人们获取PUFA的重     

Comparison of Lactic Acid Bacteria Fermentation with Acid Treatments for Chitosan Production from Shrimp Waste

The traditional procedure for chitosan production involves use of a strong acid (HCl) for demineralization of chitin. This study reports application of a mixed culture of lactic acid bacteria (Lactobacillus plantarum, Lactobacillus acidophilus, and Lactobacillus lactis) fermentation in demineralization of chitin for chitosan production from shrimp waste. Chitosan produced from shrimp waste with lactic acid bacteria fermentation at 30°C for 72 h or 1 M lactic acid treatment at room temperature for 2 h followed by alkaline treatments (0.5 M NaOH at 25°C for 4 h followed by 12.5 M NaOH at 70°C for 10 h) contained very low protein (0.8–1.1%) and ash (<0.01%) contents with the same solubility (100%) as those of chitosan produced with hydrochloric acid treatment. Lactic acid bacteria fermentation and lactic acid treatment may be utilized in chitosan production from shrimp waste to reduce use of strong chemicals.     

Folic Acid and Pteroic Acid Related to Anemia of Cultured Channel Catfish,Ictalurus punctatus

The objective of this study was to analyze channel catfish feeds for folic acid and pteroic acid concentrations and correlate these substances with anemia in channel catfish, Ictalurus puncratus. From 1983 to 1987, feed-related anemia was diagnosed 298 times in cultured channel catfish in Alabama. Analysis of eight brands of anemia-associated feeds (AAF) and nonanemia-associated feeds (NAAF) suggested that AAF were either lower in folic acid or were higher in pteroic acid concentrations than the NAAF. AAF contained a folic acid: pteroic acid ratio of less than 1.8:1, compared to a folic acid:pteroic acid ratio of greater than 10:1 in NAAF. Low folic acid concentrations were due either to insufficient addition at the feed mill or due to degradation during storage.     

短期饥饿对大鳍鱯生化组成、氨基酸和脂肪酸组成的影响

在水温(21±1)℃条件下,研究了大鳍鱯(Mystus macropterus)在短期饥饿胁迫下生化组成、氨基酸和脂肪酸含量的变化。实验时间分别为饥饿0d(S0)、饥饿3d(S3)、饥饿6d(S6)、饥饿9d(S9)和饥饿12d(S12)。随着饥饿时间延长,水分显著升高(P<0.05),蛋白质、肝糖原和肌糖原显著降低(P<0.05),脂肪和灰分先显著降低(P<0.05),饥饿9d均出现回升(P<0.05)。氨基酸总量、必需氨基酸和非必需氨基酸含量均呈规则波动,饥饿12d均出现反弹现象,略高于实验起始值。饱和脂肪酸(SFA)呈先下降、后上升、再下降的趋势,单不饱和脂肪酸(MUFA)先上升后呈规则波动,多不饱和脂肪酸(PUFA)变化规律与饱和脂肪酸恰好相反,饥饿12d时仅高不饱和脂肪酸被保留,略高于实验起始值。双键位置不同的脂肪酸在饥饿过程中的损失速度也有差异,具体为∑n-9PUFA>∑n-3PUFA>∑n-6PUFA。     

短期饥饿对大鳍鱯生化组成、氨基酸和脂肪酸组成的影响

在水温(21±1)℃条件下,研究了大鳍鱯(Mystus macropterus)在短期饥饿胁迫下生化组成、氨基酸和脂肪酸含量的变化.实验时间分别为饥饿0 d(S0)、饥饿3 d(S3)、饥饿6 d(S6)、饥饿9 d(S9)和饥饿12 d(S12).随着饥饿时间延长,水分显著升高(P<0.05),蛋白质、肝糖原和肌糖原显著降低(P<0.05),脂肪和灰分先显著降低(P<0.05),饥饿9 d均出现回升(P<0.05).氨基酸总量、必需氨基酸和非必需氨基酸含量均呈规则波动,饥饿12 d均出现反弹现象,略高于实验起始值.饱和脂肪酸(SFA)呈先下降、后上升、再下降的趋势,单不饱和脂肪酸(MUFA)先上升后呈规则波动,多不饱和脂肪酸(PUFA)变化规律与饱和脂肪酸恰好相反,饥饿12 d时仅高不饱和脂肪酸被保留,略高于实验起始值.双键位置不同的脂肪酸在饥饿过程中的损失速度也有差异,具体为∑n-9PUFA＞∑n-3PUFA＞∑n-6PUFA.     

Amino Acid and Fatty Acid Composition of Cultured Beluga (Huso huso) of Different Ages

The amino acids (AA) and fatty acids (FA) of Beluga (Huso huso) flesh at different ages were investigated as a source of AA and FA for human consumption. The analysis of Huso huso lipids (chloroform extracted) showed significant differences (p < .05) for specific FA with age. At all ages, the major saturated FA in Huso huso fillets was palmitic acid and the major unsaturated FA were oleic and docosahexanoic acid (DHA). Protein analysis indicated that the Huso huso muscle is well balanced with good levels of essential AA and appears to be a source of high quality protein (tryptophan was not measured) with methionine/cysteine as the first limiting AA. The major AA were glutamic acid, aspartic acid, and lysine. The results obtained from the present study show that Huso huso is an excellent protein and fat source when compared with other sturgeons.     

Effect of Source and Dietary Concentration of Ascorbic Acid on Tissue Concentrations of Ascorbic Acid in Channel Catfish

Semipurified diets containing either no ascorbic acid or supplemental amounts of 11, 22, 44 and 132 mg/kg from Gascorbic acid (AA), L-ascorbyl-2-monophosphate (AAP) or L-ascorbyl-2-sulfate (AAS) were fed to channel catfish fingerlings (13 ± 2.1 g average initial weight) in aquaria. After a feeding period of 14 wk, weight gain was measured and ascorbic acid content of liver and anterior kidney of the fish was determined. Growth was normal for fish fed all dietary levels of AA and AAP, but lower in fish fed the control and diets supplemented with all levels of AAS; however, growth improved as the concentration of AAS increased. Liver and kidney ascorbic acid increased with level of dietary supplementation in fish fed AA and AAP but only traces or no detectable levels were found in the tissues of fish fed AAS or the controls. Liver and kidney levels of ascorbic acid were significantly higher in fish fed AAP than in fish fed corresponding levels of ascorbic acid from AA. Regression of liver ascorbic acid content on diet concentration indicated that the potency of AAP for maintaining liver storage of ascorbic acid at a minimum acceptable level is 1.74 times higher than that of AA on an ascorbic acid equivalent basis. These results demonstrate that AAP and AA have similar vitamin activity for growth in channel catfish, but AAP is markedly more effective for maintaining tissue levels of ascorbic acid, and that AAS has limited vitamin activity for growth and its contribution to the tissue ascorbic acid pool is negligible.