Effect of (n-3) PUFA and vitamin A Artemia enrichment on pigmentation success of turbot, Scophthalmus maximus (L).

Emulsions with different content of (n-3) PUFA and vitamin A were used to enrich Artemia and examine the effect of these nutrients on pigmentation success in turbot, Scophthalmus maximus (L.). The best pigmentation rates were obtained using an overdose of vitamin A (500 000 IU L^?1), but coincided with a high incidence of skeletal deformations. Higher growth and pigmentation rates were achieved by increasing the quantity of (n-3) PUFA oil in the emulsion. The use of (n-3) PUFA-deficient diet caused the highest occurrence of albinism as well as a cessation of metamorphosis.     

Influence of partial substitution of dietary fish oil by vegetable oils on the metabolism of [1-14C] 18:3n-3 in isolated hepatocytes of European sea bass (Dicentrarchus labrax L.)

The static or declining supply of fish oil from industrial fisheries demands the search of alternatives, such as plant (vegetable) oils, for diets in expanding marine aquaculture. Vegetable oils are rich in C₁₈ polyunsaturated fatty acids but devoid of the n-3 highly unsaturated fatty acids in fish oils. Previous studies, primarily with salmonids, have shown that including vegetable oils in their diets increased hepatocyte fatty acid desaturation. In the present study, we have investigated the effects of dietary partial substitution of fish oil (FO) with rapeseed oil (RO), linseed oil (LO) and olive oil (OO) on the desaturation /elongation and, -oxidation capacities of [1-¹⁴C]18:3n-3 in isolated hepatocytes from European sea bass (Dicentrarchus labrax L.), in a simultaneous combined assay. Fish were fed during 34 weeks with diets containing 100% FO, or RO, LO and OO, each included at 60% with the balance being met by FO, with no detrimental effect upon growth or survival. The highest total desaturation rates were found in hepatocytes of fish fed FO diet (0.52±0.08 pmol/h/mg protein) and OO diet (0.43±0.09 pmol/h/mg protein), which represented 3.2% and 2.7% of total [1-¹⁴C]18:3n-3 incorporated, respectively. In contrast, lowest desaturation rates were presented by hepatocytes of fish fed LO and RO diets (0.23±0.06 and 0.14±0.05 pmol/h/mg protein, respectively) represented 1.4% and 0.9% of total [1-¹⁴C]18:3n-3 incorporated, respectively. The rates of [1-¹⁴C]18:3n-3 β-oxidized were between 11-fold and 35-fold higher than desaturation. However, no significant differences were observed among β-oxidation activities in hepatocytes of fish fed any of the diets. The present study demonstrated that the European sea bass, as a carnivorous marine fish, presented a ‘marine’ fish pattern in the metabolism of 18:3n-3 to 20:5n-3 and 22:6n-3. This species appeared to have all the enzymic activities necessary to produce 22:6n-3 but presented only extremely low rates of fatty acid bioconversion. Furthermore, nutritional regulation of hepatocyte fatty acid desaturation was minimal, and dietary vegetable oils did not increase desaturase activities, and in RO and LO treatments the activity was significantly lower. This revised version was published online in July 2006 with corrections to the Cover Date.     

Fatty acid composition of New Zealand green-lipped mussels, Perna canaliculus: Implications for harvesting for n-3 extracts

Marine bivalves offer a potentially important source of long-chained polyunsaturated fatty acids (PUFA) for human health supplements. Lipid extracts from individual New Zealand green-lipped mussels (NZGLM) were analyzed as fatty acid methyl esters (FAME) by gas chromatography to assess geographical and seasonal differences between large (86 ± 1 mm) male and female and small (44 ± 1 mm) mussels. PUFAs dominated in spring and summer, comprising ∼ 50% of total fatty acids. Moreover, the commercially important n-3 fatty acids, 20:5n-3 (eicosapentaenoic acid, EPA) and 22:6n-3 (docosahexaenoic acid, DHA) together accounted for 70-79% of total PUFAs in spring and summer. During winter there was a marked decrease in condition and total n-3 PUFAs and a concomitant increase in saturated fatty acids in mussels, suggesting they had already spawned, had increased metabolic demands and limited PUFA-rich phytoplankton as food. While total n-3 content was not significantly different, there were geographical differences in individual n-3 fatty acids. Mussels collected from the cooler waters of Stewart Island had greater levels of 20:5n-3 (EPA), while those collected in Marlborough had greater concentrations of 22:6n-3 (DHA), which was attributed mainly to differences in phytoplankton composition. Total n-3 content and the condition index varied seasonally with greater concentrations of n-3 PUFAs, especially EPA, recorded in large mussels in spring, coincident with spring diatom blooms. Total PUFA levels and condition indices remained high in summer. There was no significant difference in condition indices, total n-3 content, DHA or EPA levels between large male and female mussels. Conversely, large mussels had significantly greater amounts of n-3 PUFAs than small mussels at Marlborough Sounds, while small mussels had marginally greater total n-3 concentrations than large mussels at Stewart Island. Taken together, these results suggest that the NZGLM offers a potentially important source of n-3 PUFAs for human health supplements. Our findings suggest that optimal harvesting conditions occur in spring when mussel condition and n-3 content peak for large mussels. Although DHA and EPA levels varied geographically, total n-3 content was not significantly different between sites, which implies that harvesting mussels for n-3 extracts would be driven more by logistical considerations.     

玉米须萃取物的抗氧化活性

将玉米须乙醇提取物再用氯仿、乙酸乙脂、正丁醇和甲醇分别萃取,获得极性不同的5个组分,比较这5种不同溶剂萃取物在二苯基苦基苯肼(DPPH)体系及在Fe2 诱发卵黄脂蛋白多不饱和脂肪酸(PUFA)过氧化体系中的抗氧化活性。结果表明:在DPPH体系中,正丁醇萃取物的抗氧化活性最强,氯仿萃取物次之;在Fe2 诱发脂蛋白PUFA过氧化体系中,氯仿萃取物的抗氧化活性最强,乙酸乙酯萃取物次之。结果还表明,这5不同溶剂萃取物在不同测试体系中的抗氧化活性顺序不同。     

紫苏籽对鹌鹑肉中脂肪酸种类及含量的影响

【目的】研究紫苏籽对鹌鹑肉中ω-3不饱和脂肪酸富集的影响。【方法】将150羽1日龄鹌鹑随机分成5组,每组3个重复,每重复10羽,其中第1组为对照组,饲喂自配的基础日粮,第2～5组为试验组,分别饲喂在基础日粮中添加质量分数8%,10%,12%和15%紫苏籽（磨碎）组成的试验日粮,于35和50日龄取样,测定鹌鹑肉中的基本营养成分和各脂肪酸含量。【结果】在基础日粮中添加10%紫苏籽可显著提高35和50日龄鹌鹑肉的粗脂肪含量（P＜0.05）,添加12%紫苏籽可显著提高35日龄鹌鹑肉的粗脂肪和50日龄鹌鹑肉的粗灰分含量（P＜0.05）;添加不同量的紫苏籽均可显著提高35和50日龄鹌鹑肉的C18∶3含量及35日龄鹌鹑肉中多不饱和脂肪酸（PUFA）和ω-3 PUFA含量（P＜0.05）,显著降低35和50日龄鹌鹑肉的ω-6 PUFA/ω-3 PUFA值（P＜0.05）。【结论】早期投喂紫苏籽有利于PUFA和ω-3 PUFA的积累,紫苏籽的添加量以10%为宜。     

PUFA对反刍动物CLA代谢影响的研究进展

共轭亚油酸(Conjugated linoleic acid,CLA)具有诸多生理活性,天然的CLA主要来源于反刍动物产品。在日粮中添加富含多不饱和脂肪酸(Polyunsaturated fatty acid,PUFA)的饲料是提高反刍动物产品中CLA含量的一个重要方法。本文通过PUFA对反刍动物CLA机体、消化道及组织等不同代谢层次的影响进行了综述,提出了目前通过PU-FA提高反刍动物CLA中存在的问题,期望为生产中深入利用反刍动物的高CLA这一优势、提高其产品品质提供帮助。     

Effects of Ω-3 (n-3) Fatty Acid Supplementation on Insulin Sensitivity in Horses

The objective of this study was to examine the effects of dietary ω-3 fatty acid supplementation on insulin sensitivity (SI) in horses. Twenty-one mares were blocked by age, body weight (BW), and body condition score (BCS) and randomly assigned to one of three dietary treatments. Treatments consisted of (1) 38 g of n-3 fatty acids via fish and algae supplement and diet (MARINE), (2) 38 g of n-3 fatty acids via a flaxseed meal from the supplement and diet (FLAX), and (3) control (CON) no supplemental fatty acid. Treatments were supplemented for 90 days. Frequent sampling intravenous glucose tolerance tests were performed on days 0, 30, 60, and 90. Blood samples were analyzed for glucose and insulin. The minimal model was applied for the glucose and insulin curves using MinMod Millennium. SI increased 39% (P < .007) across all treatment groups. Acute insulin response to glucose decreased 22% (P < .006) between days 30 and 60 and increased (P = .040) again at day 90. Disposition index (combined SI and β pancreatic response) increased (P = .03) by 53% in the MARINE- and 48% in the FLAX-supplemented horses and did not change with time in the CON group. In insulin-resistant mares, MARINE- and FLAX-treated horses had an increase in SI (P = .09). It would be interesting to test this supplement in a larger group of insulin-resistant horses. If proven effective, supplementation with ω-3 fatty acids would help to reduce problems associated with insulin resistance in horses.     

饲粮n-6/n-3多不饱和脂肪酸比例对畜禽健康和产品品质的影响

现今人类膳食中n-6多不饱和脂肪酸(PUFA)大多都是过量的,但n-3 PUFA却严重不足.研究表明,n-6/n-3 PUFA比例平衡对畜禽健康和产品品质有着重要意义,n-6/n-3 PUFA比例平衡成为当下最受关注的问题.本文综述了n-6/n-3 PUFA比例平衡的营养生理作用以及对畜禽产品品质的影响及如何改善畜禽产品中的n-6/n-3 PUFA比例.     

The Effect of Low-Dose Marine n-3 Fatty Acids on Plasma Levels of sCD36 in Overweight Subjects: A Randomized,Double-Blind,Placebo-Controlled Trial

CD36 is a scavenger receptor involved in lipid uptake and inflammation. Recently, non-cell-bound CD36 (sCD36) was identified in plasma and suggested to be a marker of lipid accumulation in the vessel wall. Marine n-3 polyunsaturated fatty acids (PUFA) may have cardioprotective effects. This study evaluated the effect of marine n-3 PUFA on sCD36 levels in overweight subjects. Fifty overweight subjects were randomized to 1.1 g of n-3 PUFA or 2 g of olive oil daily for six weeks. Neutrophils were isolated at baseline and after six weeks of treatment while an adipose tissue biopsy was obtained at baseline. The content of n-3 PUFA in adipose tissue and neutrophils was analyzed by gas chromatography, while plasma levels of sCD36 were determined using an enzyme-linked immunosorbent assay (ELISA). After six weeks of supplement plasma sCD36 did not differ between supplements (P = 0.18). There was no significant correlation between plasma sCD36 levels and n-3 PUFA in neutrophils at baseline (r = −0.02, P = 0.88), after six weeks supplement (r = −0.03, P = 0.85) or in adipose tissue (r = 0.14, P = 0.34). This study therefore does not provide evidence for a cardioprotective effect of n-3 PUFA acting through a CD36-dependent mechanism.     

日粮添加多不饱和脂肪酸对肉仔鸡抗氧化指标的影响

本试验通过观察日粮中添加多不饱和脂肪酸(PUFA)与肉仔鸡抗氧化酶活性及过氧化产物的量的关系,研究PUFA对肉仔鸡抗氧化能力的影响.试验包括3个单因子试验,3个处理组日粮为玉米豆粕型日粮,分别添加4.5%的禽脂、玉米油和鱼油,每个处理组6个重复,每个重复10只鸡.21日龄和42日龄分别检测脾脏、肠道抗氧化酶(谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT))活性和脂质过氧化产物(丙二醛,MDA)水平.综合本试验检测的抗氧化指标(GSH-Px、SOD、CAT和MDA)可知,日粮中添加鱼油和玉米油的肉仔鸡抗氧化酶活性较对照组均有不同程度的提高,而机体脂质过氧化产物(MDA)与对照组比较无显著性差异.这表明虽然添加PUFA易使机体发生过氧化反应,但由于机体抗氧化酶系(GSH-Px、SOD、CAT)功能的增强,可以抵消PUFA过氧化的不良作用.但是肉仔鸡抗氧化酶系功能的增强可能是PUFA具有直接调控机体抗氧化酶的作用,也可能是机体过氧化产物的反馈作用导致其功能代偿性增强.添加PUFA,脾脏CAT和SOD增强主要发生在21日龄;肠道CAT和SOD活性增强则主要发生在42日龄.由此可知,日粮中添加PUFA对肉仔鸡抗氧化酶活性的影响因生长阶段不同而存在组织器官特异性.