近江牡蛎等3种贝类的脂类成分分析

分析3种贝类的脂类成分,以期为贝类的高值化加工利用提供基础数据。采用氯仿甲醇法提取近江牡蛎、波纹巴菲蛤和马氏珠母贝中的脂质成分,分析脂质中的胆固醇和磷脂含量,采用液液萃取技术分离中性脂和极性脂,并用GC-MS分析其脂肪酸组成。研究结果表明,3种贝类的粗脂肪含量基本在1%左右;脂质成分中胆固醇含量在0.07~0.12 mg/g;脂质中磷脂含量在14%~34%,极性脂含量在27%~45%;脂质中EPA和DHA总含量在12%~22%,近江牡蛎和波纹巴菲蛤脂质中EPA含量高于DHA,而马氏珠母贝脂质中DHA含量高于EPA。     

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。     

三种不同海洋脂质对溃疡性结肠炎小鼠及其肠道菌群的影响

为了研究3种不同海洋脂质——二十碳五烯酸(eicosapentaenoic acid,EPA)、二十二碳五烯酸(docosapentaenoic acid,DPA)和二十二碳六烯酸(docosahexaenoic acid,DHA)对溃疡性结肠炎(UC)小鼠及其肠道菌群的影响,本实验采用葡聚硫酸钠(dextran su...     

日粮中裂殖壶藻油配伍外源性EPA对草鱼幼鱼脂肪酸组成、FAD、ELO基因表达及脂质代谢的影响

摄食含有裂殖壶藻硬脂油日粮的草鱼可能通过节省DHA合成所需的能量和促进脂解作用供应能量以减少蛋白质分解的共同作用下,刺激蛋白质沉积,获得比摄食鱼油更好的生长效果。为探究草鱼日粮中应用富含DHA的裂殖壶藻硬脂油后是否需要配伍EPA及其可能机制,实验配制5组等氮等能日粮饲养草鱼[(22.70 g±0.80) g]49 d,分别以鱼油(F-O);藻油硬脂(S-O);藻油硬脂(DHA)∶EPA=3∶2(SE1-O);藻油硬脂(DHA)∶EPA=1∶1(SE2-O);EPA(E-O)提供5组饲料中的0.52%n-3长链多不饱和脂肪酸(LC PUFA)。结果显示:(1)增重率(WG)、特定生长率(SGR)及饲料系数(FCR)在各组间均无差异;(2) S-O组肌肉粗蛋白含量显著高于E-O组;(3) S-O组肌肉DHA含量显著高于F-O组、SE1-O组和E-O组;(4)动脉粥样硬化指数在各组间无显著差异,SE2-O组血栓形成指数显著高于F-O组,S-O组和SE2-O组胆固醇血症指数显著低于F-O组;(5) E-O组的腹腔脂肪细胞显著大于F-O组和SE1-O组,且甘油三酯水解酶(ATGL)和肉碱棕榈酰转移酶(CPT1)转录水平显著下调;肌肉中的脂肪酸去饱和酶(FAD)转录水平在E-O组显著高于S-O组,脂肪酸延长酶(ELO)转录水平在S-O组显著下调。研究表明,裂殖壶藻油单独或配伍EPA使用对草鱼生长、n-3 LC PUFA含量及脂肪组织水解无显著影响。仅以EPA为n-3LC PUFA来源时,会减弱脂肪组织的水解并降低肌肉粗蛋白的含量。日粮中高水平的DHA会减弱机体合成LC PUFA的能力。相对于EPA,草鱼可能更需要DHA,生产中可以单独使用裂殖壶藻油,而无需配伍EPA。     

大连超市水产品及加工品市场调查初探

本文是对大连市的水产品及水产加工品进行调查,共调查到水产品及水产加工品7个大类154个品种,针对其种类、价格市场、消费等方面等方面进行了分析,并对大连水产品向精深发展进行探讨.     

淡水鱼脑营养与功能研究进展

<正>鱼脑营养丰富,被视为补脑佳品,而目前在鱼加工下脚料的利用中,鱼脑通常未经分离直接和鱼头作为饲料处理或简单加工为低值产品,对其有价值的功能性成分尚未提取和利用。国家大宗淡水鱼产业技术体系加工研究室深加工岗位专家及其研究团队对青、草、鲢、鳙鱼四大淡水鱼脑进行了全面的组成分析和营养评价。研究发现,鱼脑富含多不饱和脂肪酸,其中二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)含量较高,丰富的ω-3脂肪酸含量及良好比例是鱼     

响应面法提取南极磷虾磷脂及其分子种组成的测定

南极磷虾(Euphausia superba)生物储量巨大,含有丰富的磷脂酰胆碱(phosphatidylcholine,PC),而PC是生物生长的必需磷脂。现今南极磷虾的研究主要针对磷虾油和蛋白,尚未见有PC分子组成的系统研究报道。该研究使用超声辅助Bligh Dyer脂质提取法提取南极磷虾中磷脂,并采用Box-Benhnken设计原理优化提取工艺,以正离子模式下胆碱碎片(m/z 184)为特异性碎片,利用鸟枪脂质组学法鉴定南极磷虾组织中的PC分子组成。结果表明,南极磷虾磷脂的最佳提取条件为超声时间21.0 min、超声温度30℃、溶剂用量3.1 mL,此条件下磷脂实际提取率的平均值为(7.59±0.03)%。利用鸟枪脂质组学法鉴定出南极磷虾中共含有36种PC分子,其中EPA/DHA脂肪酸链含量占47.75%,质量分数为269.82μg·g~(-1)。研究表明南极磷虾组织中含有丰富的EPA和DHA,而磷脂状态存在的ω-3脂肪酸具有较高的利用效率,这为开发南极磷虾类营养保健产品提供数据支持和理论基础。     

南极大磷虾粉对褶皱臂尾轮虫生长及脂肪酸组成的影响

以活性干酵母培养的褶皱臂尾轮虫(Brachionus plicatilis)为对照,并以南极大磷虾粉对轮虫进行强化,设定轮虫培养液中南极大磷虾粉质量浓度分别为30、50和70 mg/L。分别测定强化12 h和18 h时轮虫的密度、带卵率以及强化后6 h、12 h、18 h轮虫的脂肪酸组成与含量。结果表明,12 h和18 h时,50 mg/L组的轮虫密度急剧升高,并显著高于其他3组,依次表现为50 mg/L组>30 mg/L组>对照组>70 mg/L组。带卵率方面:第12小时和18小时带卵率由高到低依次为50 mg/L组、30 mg/L组、70 mg/L组、对照组(P<0.05)。脂肪酸方面:6 h时,除了70 mg/L组的ARA与对照组、50 mg/L组和70 mg/L组的ω6-系列多不饱和脂肪酸总量(∑ω6-PUFA)与对照组没有显著差异外,其余强化组的ARA、EPA、DHA、ω3-系列多不饱和脂肪酸总量(∑ω3-PUFA)和∑ω6-PUFA都显著高于对照组(P<0.05);尤其是50 mg/L组的DHA和∑ω3-PUFA显著高于其他两个强化组和对照组(P<0.05),含量几乎达到对照组的10倍。12 h和18 h时,所有强化组的ARA、EPA、DHA、∑ω3-PUFA含量都显著高于对照组(P<0.05),而且50 mg/L组的上述脂肪酸含量都是最高的,或者与30 mg/L组和70 mg/L组并列第一。3个强化组的DHA/EPA比值、EPA/ARA比值也显著高于对照组(P<0.05)。结论认为,南极大磷虾粉的强化剂量以50 mg/L为优,强化时间则以12 h和18 h为宜,南极大磷虾粉对褶皱臂尾轮虫具较好的营养强化效果。     

日本鬼鲉胚胎及卵黄囊仔鱼发育过程中脂肪及脂肪酸特性变化

以野生日本鬼鲉人工催产获得的受精卵为实验材料,定量检测了日本鬼鲉胚胎及卵黄囊仔鱼发育过程中脂肪组成及脂肪酸含量.结果表明:日本鬼鲉胚胎及卵黄囊仔鱼的总脂肪含量为13.85％～ 11.66％,极性脂肪占总脂肪含量为75.39％～ 72.20％.总脂肪及极性脂肪含量在胚胎发育阶段无显著变化,在卵黄囊仔鱼阶段随发育而显著下降.中性脂肪含量在胚胎发育阶段有显著变化,在卵黄囊仔鱼阶段其含量相对稳定.野生日本鬼鲉胚胎及卵黄囊仔鱼总脂肪的主要脂肪酸为DHA(22∶6n-3),16∶0,ARA(20∶4n-6),EPA(20∶5n-3),18∶0和18∶1n-9.总脂肪及极性脂肪的DHA,ARA,EPA含量(mg/gDW)均随胚胎和卵黄囊仔鱼的发育而显著下降,且DHA和ARA含量均在胚胎囊胚期至尾芽期大幅降低.中性脂EPA和DHA含量随发育呈先升后降,其峰值分别出现在初孵仔鱼和2日龄(2DPH)卵黄囊仔鱼.中性脂ARA含量随发育逐步升高,峰值出现在3日龄(3DPH)卵黄囊仔鱼.在胚胎发育前期,总脂肪DHA和ARA相对EPA被选择性消耗,饱和脂肪酸(SFAs)和多不饱和脂肪酸(PUFAs)相对单不饱和脂肪酸(MUFAs)被机体选择性消耗,N-6PUFA相对N-3 PUFA被选择性消耗;在胚胎发育后期及卵黄囊仔鱼阶段,总脂肪EPA相对DHA和ARA被选择性消耗.在胚胎和卵黄囊仔鱼发育过程中,SFAs中16∶0相对18∶0被选择性消耗.胚胎发育后期阶段和卵黄囊仔鱼阶段,总脂肪MUFAs中16∶1相对18∶1被选择性消耗.实验表明日本鬼鲉胚胎及卵黄囊仔鱼发育阶段极性脂肪中DHA、ARA和EPA可以向中性脂肪中转移,胚胎和卵黄囊仔鱼对不同类别脂肪中的重要脂肪酸的消耗具有选择性,且其选择性与发育阶段相关.     

附石生物营养质量对干旱胁迫的响应及机制

在全球气候变暖的大背景下,干旱事件的发生频率显著提高。附石生物是河流生态系统最重要的初级生产者之一,它作为食物网物质循环的基础,为上层消费者提供碳源。干旱造成水体面积的缩小势必会对附石生物的生境产生影响,而干旱对附石生物的营养质量产生的潜在影响目前鲜有研究。基于脂肪酸和化学计量学两种食物营养质量指示方法,利用中宇宙控制实验模拟野外干旱情景,本研究明确了干旱对附石生物营养质量的影响,并从宏观的附石生物膜的藻类群落结构和微观的宏基因组技术两个层面阐明了影响机制。研究结果表明,干旱后多不饱和脂肪酸(Polyunsaturated fatty acid,PUFA)中的二十二碳六烯酸(Docosahexaenoic acid,DHA)、花生四烯酸(Arachidonic acid,ARA)和二十碳五烯酸(Eicosapentaenoic acid,EPA)等含量减少;附石生物中磷(P)含量显著减少(p<0.05),C/P、N/P比值增加。硅藻是附石生物膜中的优势类群,是优质脂肪酸的生产者,富含EPA、DHA,干旱后硅藻密度和丰度显著减少(p<0.05)。基于宏基因组KEGG功能注释结果,附石生物脂质代谢通路中脂肪酸生物合成显著减少(p<0.05),脂肪酸降解显著增加(p<0.05),花生四烯酸代谢等通路减少,这导致EPA、DHA含量的下降。该研究指出干旱导致河流生态系统基础资源营养质量下降,进而可能对整个河流生态系统食物网中消费者的生长和繁殖产生影响。该研究从基础资源碳质量新视角下为研究水生态系统食物网的碳源及传递提供了重要依据。     

Effects of dietary levels of 20:5n-3 and 22:6n-3 on tissue lipid composition in juvenile Atlantic salmon, Salmo salar, with emphasis on brain and eye

Four dietary groups of juvenile Atlantic salmon, Salmo salar L., each with three replicates, were fed diets with increasing levels of docosahexaenoic acid (22:6n-3; DHA) and eicosapentaenoic acid (20:5n-3; EPA). Fatty acid composition of brain and eye was determined at the start and approximately every 3 weeks during the experimental period, and fatty acid composition of liver and fillet was determined in fish from the final sampling. Lipid class composition of brain and eye, and fatty acid composition of these lipid classes was determined at the end of the experiment. There was no effect of increasing dietary DHA content on fatty acid composition, lipid class composition or DHA levels in the lipid classes in the juvenile Atlantic salmon brain. The increasing dietary EPA content, however, was reflected in both the total fatty acid composition and in the EPA content in neutral lipids, phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylinositol (PI). A minor effect of the increasing dietary DHA content was found in the lipid composition of the juvenile salmon eye. Both EPA and 18:2n-6 levels in eye, however, clearly reflected the increasing and decreasing, respectively, dietary levels of these two fatty acids. The dietary EPA levels also affected the EPA levels in neutral lipids, PC, PE, PI and PS (phosphatidylserine) in the juvenile salmon eye. The results demonstrate that these dietary levels of DHA had no effect on brain lipid composition and only a minor effect on eye lipid composition. Furthermore, the dietary EPA levels significantly affected the lipid composition of both brain and eye. The fillet fatty acid composition reflected the dietary fatty acid composition, except for the DHA/EPA ratio, which was reversed in fillet compared with that in the diets. The liver fatty acid composition was also affected by the increasing dietary EPA and DHA levels.     

Importance of the relative levels of dietary arachidonic acid and eicosapentaenoic acid for culture performance of gilthead seabream (Sparus aurata) larvae

The effect of different arachidonic acid (ARA) dietary contents at several dietary eicosapentaenoic acid (EPA) levels on the growth, survival and biochemical composition of gilthead seabream larvae was studied to better define the importance of this fatty acid as a function of EPA. Larvae of 18 days were fed one of the five isonitrogenous and isolipidic microdiets with three different EPA (0.3%, 2% and 4%) and ARA amounts (0.1%, 0.6% and 1.2%). Although a dietary increase in either ARA or EPA alone did not improve survival significantly, the increase in both fatty acids significantly enhanced growth and survival, suggesting an optimum dietary value of EPA:ARA close to 4:1.2. Dietary ARA was more efficiently incorporated into larval tissues than EPA. Increased dietary EPA or ARA contents reduced the incorporation of ARA or EPA into larval lipids, indicating their competition as substrates for different enzymes. The possible negative effect of further elevation of dietary ARA and its competition with EPA for phospholipids synthesis deserves further studies in marine fish larvae.     

A study of the arachidonic acid requirements of the giant tiger prawn, Penaues monodon

This study examined the dietary requirement of arachidonic acid (ARA) when that of linoleic acid (LOA), the natural precursor to ARA, was also satisfied with linolenic acid (LNA) and also with and without the other key dietary highly unsaturated fatty acids (HUFA). Growth by prawns fed diets supplemented with ARA was poorer than in diets where it was not present. Supplementation of ARA to diets with either optimized HUFA or just optimised poly unsaurated fatty acids (PUFA) (i.e. LOA, LNA) resulted in poorer growth. Growth was poorest by prawns (215 ± 13%) fed diets with ARA supplemented at 20% of the total fatty acids but including 7% LOA, 21% LNA and 4% of both eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Growth was best in prawns fed diets devoid of ARA but with 7% LOA and 21% LNA (350 ± 19%). Prawns fed the reference diet (348 ± 21%) and the other diet devoid of ARA but containing about 7% LOA, 21% LNA and 4% of both EPA and DHA (345 ± 18%) had similar growth. The growth responses were not effects of altered lipid or fatty acid digestibilities. Indeed supplementation of ARA to the diet marginally improved the digestibility of the total neutral lipid in the diet and the digestibilities of some other dietary fatty acids. The amount of lipid in the digestive glands of prawns fed with the diets was reduced by the inclusion of ARA in the dietary lipids. Composition of the lipids in the digestive gland (DG) of the prawns was almost directly related to the composition of their dietary lipids. The proportion of ARA in the total fatty acids increased with level of supplementation of dietary ARA. An increased level of dietary ARA reduced the proportion of EPA, DHA in the DG lipid and also the total n‐3 and n‐6 fatty acids in the DG lipid. The results of this study support that addition of ARA to the diet of Penaues monodon when the other key essential fatty acids (EFA) have been optimized, does not improve their growth performance. It is suggested that key cause for this response may lie in the importance of the balance of the n‐3 to n‐6 fatty acids in the diet of these animals.     

Influence of 18:2n‐6/20:5n‐3 ratio in diets on growth and fatty acid composition of juvenile abalone,Haliotis discus hannai Ino

A 120‐day feeding trial was conducted to examine the effects of the ratio of dietary linoleic acid (LA, 18:2n‐6) to eicosapentaenoic acid (EPA, 20:5n‐3) on the growth and fatty acid composition of juvenile Haliotis discus hannai (initial shell length 10.23 ± 1.48 mm; initial body weight 0.13 ± 0.05 g) in a recirculation water system. Five semipurified diets with 35 g kg^?1 total lipid were formulated to contain graded LA/EPA ratios (1 : 0, 0.75 : 0.25, 0.5 : 0.5, 0.25 : 0.75, and 0 : 1, respectively). Twenty‐five juveniles were stocked in a rearing unit, a plastic basket (20 × 20 × 10 cm), as a replicate, and there were three replicates for each dietary treatment. The results showed that abalone survival rates were generally high (90.1–98.3%) and independent of the dietary treatments. However, abalone growth was significantly affected by LA/EPA ratio (P < 0.05). The LA/EPA ratio of 0.25 : 0.75 (Diet 4) produced the highest weight gain rate (WGR, 416.3%), closely followed by the ratio of 0 : 1 (Diet 5, 412.9%), the ratio of 0.5 : 0.5 (Diet 3, 399.7%) and the ratio of 0.75 : 0.25 (Diet 2, 372.1%), but no significant differences were observed among these treatments. The abalone fed the diet without 20:5n‐3 (Diet 1) had the lowest WGR (Diet 1, 363.8%), which was significantly lower than that of Diet 4. Fatty acid profiles in abalone body reflected those of dietary lipids, especially for the polyunsaturated fatty acids. The contents of arachidonic acid (AA; 20:4n‐6) in abalone tissues were positively correlated with dietary level of 18:2n‐6 (P < 0.05). Similar correlation was also observed between the level of docosahexaenoic acid (DHA, 22:6n‐3) in abalone tissues and the level of dietary EPA. It is suggested that abalone, H. discus hannai, have the capacity to synthesize 20:4n‐6 from 18:2n‐6, and maybe 22:6n‐3 from 20:5n‐3.     

Growth and fatty acid composition of juvenile Cerastoderma edule (L.) fed live microalgae diets with different fatty acid profiles

The importance of dietary 20:5n‐3 (EPA), 22:6n‐3 (DHA) and 20:4n‐6 (ARA) for growth, survival and fatty acid composition of juvenile cockles (Cerastoderma edule) was investigated. Cockles of 6.24 ± 0.04 mm and 66.14 ± 0.34 mg (live weight) were distributed into three treatments where live microalgae diets were fed constantly below the pseudofaeces production threshold, for three weeks. Diets had distinct fatty acid profiles: high EPA (53% Chaetoceros muelleri + 47% Pyramimonas parkeae), no DHA (47% Brachiomonas submarina + 53% Tetraselmis suecica) and low ARA concentrations (73% P. parkeae + 27% Phaeodactylum tricornutum). Growth was positively affected by high EPA and low ARA diets, whereas no significant growth was observed for the no DHA diet. High mortality of cockles fed no DHA diet raises questions about its suitability for cockles. In balanced diets with EPA and DHA, lower concentrations of ARA do not limit growth. The impact of dietary fatty acids was evident in the fatty acids of neutral and polar lipids of cockles. In polar lipids of all cockles, there was a decrease in EPA, in contrast to an increase in DHA. The combination of EPA and DHA in a live microalgae diet was beneficial for the growth and survival of juvenile cockles.     

Dietary docosahexaenoic acid to eicosapentaenoic acid (DHA/EPA) ratio influenced growth performance,immune response,stress resistance and tissue fatty acid composition of juvenile Japanese seabass,Lateolabrax japonicus (Cuvier)

A 10‐week feeding experiment was conducted to investigate the effects of dietary DHA/EPA ratio on juvenile Japanese seabass reared in sea floating cages. Six practical diets were formulated differing only in DHA/EPA ratio: 0.55 (Diet D/E0.55), 1.04 (D/E1.04), 1.53 (D/E1.53), 2.08 (D/E2.08), 2.44 (D/E2.44) and 2.93 (D/E2.93). All diets had the same contents of total n‐3 long‐chain polyunsaturated fatty acid (LC‐PUFA) and arachidonic acid (ARA). The results showed that the final weight and specific growth rate significantly increased with increasing dietary DHA/EPA ratio from 0.55 to 2.08 and thereafter declined. Activities of lysozyme and superoxide dismutase in serum in groups with DHA/EPA of 1.53–2.93 was significantly higher compared to group D/E0.55 while the activity of serum alternative complement pathway in group D/E2.93 was significantly lower compared with group D/E1.53. However, no difference was observed in activities of both respiratory burst of head kidney macrophage and serum catalase among dietary treatments. The per cent survival after air exposure in group D/E1.53, D/E2.08 and D/E2.93 was significantly higher compared with group D/E0.55. The fatty acid composition of whole body and tissues reflected closely those of diets, while fish accumulated more DHA than EPA in fish tissues, especially in muscle. These results suggested that at the same dietary contents of n‐3 LC‐PUFA (appr. 18% of TFA) and ARA (appr. 0.7% of TFA), moderate dietary DHA/EPA ratios of 1.53–2.08 significantly enhanced growth performances, certain innate immune responses, and the stress tolerance of Japanese seabass, in accordance with the preferential incorporation of DHA into fish tissues.     

Influence of dietary polar lipids' quantity and quality on ingestion and assimilation of labelled fatty acids by larval gilthead seabream

Dietary supplementation of phospholipids seems to be extremely important to promote growth and survival in fish larvae. Several studies also suggest the importance of n-3 highly unsaturated fatty acids (HUFA) rich phospholipids to further enhance larval performance. In the present study, four different diets were formulated in order to compare the effect of total dietary polar lipid contents, of soya bean lecithin supplementation and of feeding n-3 HUFA in the form of neutral or polar lipids on ingestion and incorporation of labelled fatty acids in gilthead seabream larvae. These diets were prepared including radiolabelled fatty acids from palmitoyl phosphatidylcholine, glycerol trioleate, free oleic acid (FOA) and free eicosapentaenoic acid (FEPA) and were fed to 25 day-old larvae. The results of these experiments showed that the elevation of the dietary polar lipid levels significantly improved microdiet ingestion, regardless of the origins of the polar lipids. This effect caused an improved incorporation of phosphatidylcholine fatty acids to the larval polar and total lipids (TL) as the dietary polar lipids increased. Nevertheless, a better incorporation of fatty acids from dietary polar lipids in comparison with that of fatty acids from dietary triglycerides into larval lipids was found in gilthead seabream, whereas a better utilization of dietary triglycerides fatty acids than dietary free fatty acids could also be observed. Besides, the presence of n-3 HUFA rich neutral lipids (NL) significanlty increased the absorption efficiency of labelled oleic acid from dietary triglycerides, but the presence of n-3 HUFA rich polar lipids, particularly improved the incorporation of FEPA. This fatty acid was preferentially incorporated into larval polar lipids in comparison with FOA.     

Effects of inositol supplementation on growth, chemical composition and blood chemistry in Atlantic salmon, Salmo salar L., fry

The present experiment reports on the effects of inositol supplementation from 0 to 1600 mg kg⁻¹ to a fishmeal-based diet on growth, inositol retention, proximate composition (dry matter, protein and lipid) and blood chemistry in Atlantic salmon, Salmo salar L., fry during a 28-week feeding experiment. Growth was affected to a minor extent, and only during the first 4 weeks of the experiment. Mortality was low and not related to dietary inositol. The inositol concentration in whole fish and liver was affected by dietary inositol supplementation. Proximate composition of whole fish was similar among dietary groups, except for positive correlations between dry matter, lipid and protein and dietary inositol supplementation after 8 weeks. Analyses of hepatic lipid classes after 8 weeks showed non-significant differences among the groups, mostly explained by somewhat reduced total hepatic lipid accumulation with increasing dietary inositol. Triacylglycerol and phosphatidylcholine accounted for 80% and 8–10% of the hepatic lipids (approximately 80 mg lipid g⁻¹ wet weight) in all groups. Blood haemoglobin was positively correlated and plasma triacylglycerol was negatively correlated to dietary inositol supplementation at week 28, while plasma protein and cholesterol were unaffected. The present results indicate that the requirement of Atlantic salmon fry for inositol is covered through the natural content of inositol in practical feed ingredients at around 300 mg inositol kg⁻¹. It may, however, be advisable to supplement starter diets with moderate amounts of inositol, around 200 mg kg⁻¹, to compensate for fluctuations in inositol concentrations in natural ingredients, leaching loss of inositol from the diet and for any potential increased inositol requirement in salmon fry.     

不同脂肪源日粮补充维生素E对罗氏沼虾生长、免疫及肉品质的影响

本研究旨在完善罗氏沼虾（）饲料配方,降低罗氏沼虾饲料成本。研究采用3×2双因素设计,配制6组饲料,分别包含鱼油（fish oil,FO）、豆油（soybean oil,SO）、菜籽油（rapeseed oil,RO）三种脂肪源;200 mg/kg（200VE）和600 mg/kg（600VE）两个维生素E（VE）水平。养殖实验在温室水泥池中进行,每个处理3个重复,养殖期8周,每天定点定量投喂3次。结果显示,相对于FO组,SO和RO组增重率、特定生长率显著升高,饵料系数显著下降（>0.05）。对于血淋巴抗氧化指标,在相同VE水平下,FO组血淋巴总抗氧化能力（T-AOC）和超氧化物歧化酶（SOD）活性均显著低于SO和RO组,谷胱甘肽过氧化物酶（GPX）活性均显著高于SO和RO组（<0.05）。在相同脂肪源下,600VE可显著提高FO组T-AOC活性,RO组GPX活性以及SO和RO组SOD活性（>0.05）。对于血淋巴生理生化指标,谷草转氨酶（AST）、总蛋白（TP）、白蛋白（ALB）和甘油三酯（TC）受日粮影响显著（<0.05）。此外,日粮脂肪源和VE水平对肉质也有显著影响。其中,SO组肌肉鲜度和滋味强度较高;RO组鱼腥味较低;FO组肌肉亮度较高,气味强度较低。在200 mg/kg VE水平下,FO组肌肉硬度、胶黏性、耐咀性、黏性和回复性显著高于植物油组（<0.05）,而对肌肉蒸煮损失和滴水损失无显著影响（>0.05）。上述结果表明,相对于鱼油,豆油和菜籽油等植物油是罗氏沼虾更优质的脂肪源,VE在以鱼油为单一脂肪源的饲料中有一定的促生长和缓解应激的作用,且脂肪源和VE均显著影响肌肉品质。本研究结果将为降低鱼油在罗氏沼虾饲料中的使用提供数据支持。