DHA对高脂饲粮诱导肝脏脂肪积累的预防作用

【目的】探索二十二碳六烯酸(DHA)对高脂饲粮诱导肝脏脂肪积累的预防机制。【方法】将32只雄性SPF级C57BL/6小鼠均分为4组,对照组(Con)饲喂普通饲粮,模型组(Model)饲喂高脂饲粮,DHA组分别在高脂饲粮中添加0.2 g DHA(DHAL)和1.0 g DHA(DHAH),饲喂周期为20周。饲喂期间每天称量体重及食物重量,计算摄食量;饲喂结束,采集肝脏和血液,ELISA法检测肝脏脂联素和血清甘油三酯(TG)的含量,实时荧光定量PCR检测新生脂肪合成关键酶(SREBP-1c、FAS)、脂肪酸氧化关键基因(PPARα、PPARγ、CPT-1A和ACOX)、线粒体基因(PGC-1α)、褐色脂肪化基因(Prdm16、UCP1)的表达,Western blotting法检测肝脏磷酸化ACC、AMPK和AKT蛋白的表达。【结果】与Con组相比,Model组终体重、体脂重量和TG含量均显著增加(P<0.05),肝脏脂联素浓度显著降低(P<0.05)。与Model组相比,DHAL和DHAH组终体重、体脂重量和TG含量均显著降低(P<0.05),肝脏脂联素水平显著增加(P...     

Growth, survival and pigmentation of turbot （Scophthalmus maximus） larvae fed live-prey enriched with ESP and S. S

用两种营养强化剂(ESP,S．S)强化轮虫、卤虫活饵料,以探讨这两种强化剂对大菱鲆生长、存活及色素沉积情况。结果发现ESP组能明显改善大菱鲆的色素异常,两组大菱鲆生长相似。用ESP强化组的存活率高于S．S强化组。     

饲料中添加维生素E和二十二碳六烯酸对鲤鱼生长和抗病力的影响

以建鲤鱼种为研究对象,采用3×3双因子试验设计,在基础饲料中分中分别添加0、62.5、185.5 mg·kg-1维生素E(VE),每种维生素E水平分别添加0%、0.5%、1.5%二十二碳六烯酸(DHA)共制成9种试验饲料,探讨饲料中添加不同水平维生素E和DHA对建鲤生产性能、饲料利用和抗病力的影响.结果表明,维生素E的添加对各组特定生长率没有显著影响(p＞0.05).DHA的添加显著影响鲤鱼的特定生长率(P＜005),随DHA的添加,鲤鱼特定生长率显著高于对照组fPDHA的添加亦显著影响鲤鱼的攻毒存活率(p＜0.05).随DHA的添加,鲤鱼攻毒存活率逐渐提高,当添加量达到1.5%时,鲤鱼攻毒存活率显著高于对照组(p<0.05).维生紊E和DHA相互作用对鲤鱼的攻毒存活率的影响达到显著(p<0.05),其中维生素E187.5 mg·kg-1和DHA 1.5%添加的相互作用显著高于对照组和其他各组(p＜0.05).在本试验条件下,鲤鱼饲料中添加DHA对其生长有正面效应,维生素E和DHA对鲤鱼的抗病能力具有明显的协同保护作用.维生素E的添加能增强抗病能力,但对生长的影响不明显,过量的添加亦没有促进鱼体的生长.     

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.     

Use of commercial fermentation products as a highly unsaturated fatty acid source in practical diets for the Pacific white shrimp Litopenaeus vannamei

Removal or reduction of marine ingredients (MI) from feed formulations is critical to the sustainability of the aquaculture industry. By removing MI, diets may become limiting in several nutrients including highly unsaturated fatty acids (HUFA) such as docosahexaenoic acid (DHA) and arachidonic acid (ArA). To reduce reliance on MI in shrimp diets, two trials were conducted with Litopenaeus vannamei juveniles to determine the feasibility of using fermentation meals rich in DHA and ArA as the primary source for HUFA. A practical diet with no MI was formulated with/without DHA and ArA supplements and fed in the first trial. A diet with menhaden fish oil or a combination of plant oil with/without DHA and ArA supplements was used in the second trial. To determine whether HUFA is only needed in the early growth stages, we also fed one group a HUFA‐supplemented diet to 5 g and then switched them to a HUFA‐supplement‐free diet. In both trials, the weights were reduced when HUFA supplements were not provided either throughout the trial or from 5 g to harvest (<16 g). These results suggest that supplementation of plant oils with DHA‐ and ArA‐rich oils from fermented products is a viable option to replace marine fish oil for L. vannamei.     

Application of salicylic acid induces antioxidant defense responses in the phloem of Picea abies and inhibits colonization by Ips typographus

The adaptive plasticity of Norway spruce (Picea abies) against attack by Ips typographus depends on systemic acquired resistance which involves salicylic acid (SA), and an antioxidant system both recognized as valuable stress markers in ecophysiological studies. In the presented field experiment, 100 mM SA was applied to the bark sections of Norway spruce prior to being attacked by bark beetles, in order to study interactions with antioxidants and its significance for mediating stress-tolerance under natural conditions. SA-treatments significantly elevated the total SA levels over the whole sampling period. Total glutathione (tGSH) and total cysteine (tCys) increased by 167% and 80%, respectively, two weeks after treatment, in comparison with controls. In contrast, SA-treatment caused an initial deterioration in total ascorbic acid (tASC) and enhanced the percentage of dehydroascorbic acid (DHA), but activated tASC levels over later sampling dates. The initial bark beetle attack was characterized by a significant decline in total SA levels, which was accompanied by a transient degradation and oxidation of their ascorbate-glutathione system. This initial reaction was significantly alleviated by SA-application and characterized by 175% higher tGSH contents, when compared to moderately-affected untreated trees. One month after pheromone dispensers were placed on trees, an intensification of ascorbate-glutathione system occurred within moderately-affected bark, but to a greater extent after SA-treatment. Total SA levels within SA-treated moderately-affected trees remained at the control level until June. In contrast, strong attack was characterized by a successive increase in total SA up to 252% following SA-treatment in June, whereas a 110% increase of SA was determined within severely affected control-bark. A strong attack was further characterized by a degradation of tGSH and total phenolics (tPH), a moderate increase in tASC and an oxidation of the ascorbate-glutathione pool within untreated bark. In the SA-treated trees the redox state was unaffected by severe colonization and the degradation of antioxidants was significantly alleviated. In addition, SA-treated bark had significantly less entrance holes and exhibited fewer and shorter maternal galleries than control-bark. From this perspective, exogenous SA was successfully implicated as an activator of systemic acquired resistance in Norway spruce, providing tolerance against the complex interactive effects of bark beetle attack and environmental factors.     

n-3脂肪酸的代谢和日粮α-亚麻酸强化鸡蛋的研究

在产蛋鸡日粮中添加０,２％,５％和８％胡麻油,对蛋黄和鸡肝脏的脂肪酸组成有显著影响：蛋黄中的α－亚麻酸直线增加,ＤＨＡ含量也呈增加趋势。肝脏中的ＤＨＡ含量显著提高。在日粮胡麻油添至５％时达最高。试验１４ｄ后蛋黄中ＤＨＡ和ＥＰＡ的转化达到稳定,随胡麻油添加量增加蛋黄中ＤＨＡ达到稳定的时间越长。试验表明：α－亚麻酸在鸡肝脏中进行碳链延长和脱氢过程;产蛋鸡可以将α－亚麻酸优先转化成ＤＨＡ沉积于蛋黄中;日     

The effect of dietary n-3 HUFA levels and DHA/EPA ratios on growth, survival and osmotic stress tolerance of Chinese mitten crab Eriocheir sinensis larvae

The effect of varying levels of dietary n-3 highly unsaturated fatty acid (HUFA) and docosahexaenoic acid/eicosapentaenoic acid (DHA/EPA) ratios on growth, survival and osmotic stress tolerance of Eriocheir sinensis zoea larvae was studied in two separate experiments. In experiment I, larvae were fed rotifers and Artemia enriched with ICES emulsions with 0, 30 and 50% total n-3 HUFA levels but with the same DHA/EPA ratio of 0.6. In experiment II, larvae were fed different combinations of enriched rotifers and Artemia, in which, rotifers were enriched with emulsions containing 30% total n-3 HUFA, but different DHA/EPA ratio of 0.6, 2 and 4; while Artemia were enriched with the same emulsions, but DHA/EPA ratio of 0.6 and 4. In both experiments, un-enriched rotifers cultured on baker's yeast and newly-hatched Artemia nauplii were used as control diets. Larvae were fed rotifers at zoea 1 and zoea 2 stages; upon reaching zoea 3 stage, Artemia was introduced.Experiment I revealed no significant effect of prey enrichment on the survival of megalopa among treatments, but higher total n-3 HUFA levels significantly enhanced larval development (larval stage index, LSI) and resulted in higher individual dry body weight of megalopa. Furthermore higher dietary n-3 HUFA levels also resulted in better tolerance to salinity stress. Experiment II indicated that at the same total n-3 HUFA level, larvae continuously receiving a low dietary DHA/EPA ratio had significantly lower survival at the megalopa stage and inferior individual body weight at the megalopa stage, but no negative effect was observed on larval development (LSI). The ability to endure salinity stress of zoea 3, zoea 5 and megalopa fed diets with higher DHA/EPA ratio was also improved.