Different Ratios of Docosahexaenoic and Eicosapentaenoic Acids Do Not Alter Growth,Nucleic Acid and Fatty Acids of Juvenile Cobia (<Emphasis Type="Italic">Rachycentron canadum</Emphasis>)

An experiment was performed to study the effect of different ratios of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) on the growth, nucleic acid and fatty acids of cobia (Rachycentron canadum) juveniles. The juveniles were fed for 8 weeks using seven treatment diets (D-1–D-7) with the same amount of DHA and EPA (1.50 ± 0.1% of dried diet), but varying ratios of DHA to EPA (0.90, 1.10, 1.30, 1.50, 1.70, 1.90, 2.10, respectively) and a control diet (D-0, DHA + EPA = 0.8% of dried diet, DHA/EPA = 1.30). At the end of the experiment, the mean body weight (BW) of juveniles fed D-0–D-7 increased significantly (from 6.86 ± 1.64 in the week 0 to 58.52 ± 16.45 g at the end of week 8, P < 0.05). The mean RNA amount and RNA/DNA ratio in the muscle (from 39.62 ± 1.30 μg mg⁻¹ and 2.29 ± 0.11 in the week 0 to 272.55 ± 10.70 μg mg⁻¹ and 14.54 ± 1.75 at the end of week 8, respectively) and the mean weight in the liver (from 117.70 ± 11.15 μg mg⁻¹ and 3.14 ± 0.25 in the week 0 to 793.07 ± 13.38 μg mg⁻¹ and 13.16 ± 0.76 at the end of week 8, respectively) of cobia juveniles fed D-0–D-7 were significantly higher at the end of 8-week experiment than initially (P < 0.05). The RNA/DNA ratio in the muscle and liver of cobia juveniles increased with their growth and appeared an obvious positive relationship, especially in the muscle, based on regression analysis. The mean lipid content increased significantly in the liver (from 29.82 ± 0.99 to 37.47 ± 3.25% totally) and muscle (from 6.74 ± 0.25 to 10.63 ± 0.23% totally) of cobia juveniles (P < 0.05). However, no significant difference was found on the lipid contents of juveniles fed different diets for 8 weeks (P > 0.05). In the muscle and liver of juveniles, EPA decreased with its reduction in the diet; DHA, DHA/EPA ratio and poly unsaturated fatty acids (PUFAs) generally increased with their increment in the diet. The conclusion was drawn that the growth, nucleic acid and fatty acids of cobia juveniles were not significantly affected by different DHA/EPA ratios in our experiments.     

Estradiol Favors the Formation of Eicosapentaenoic Acid (20:5n-3) and n-3 Docosapentaenoic Acid (22:5n-3) from Alpha-Linolenic Acid (18:3n-3) in SH-SY5Y Neuroblastoma Cells

Whether neurosteroids regulate the synthesis of long chain polyunsaturated fatty acids in brain cells is unknown. We examined the influence of 17-β-estradiol (E2) on the capacity of SH-SY5Y cells supplemented with α-linolenic acid (ALA), to produce eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA). Cells were incubated for 24 or 72 h with ALA added alone or in combination with E2 (ALA + E2). Fatty acids were analyzed by gas chromatography of ethanolamine glycerophospholipids (EtnGpl) and phosphatidylcholine (PtdCho). Incubation for 24 h with ALA alone increased EPA and DPA in EtnGpl, by 330 and 430% compared to controls (P < 0.001) and DHA by only 10% (P < 0.05). Although DHA increased by 30% (P < 0.001) in ALA + E2-treated cells, the difference between the ALA and ALA + E2 treatments were not significant after 24 h (Anova-1, Fisher’s test). After 72 h, EPA, DPA and DHA further increased in EtnGpl and PtdCho of cells supplemented with ALA or ALA + E2. Incubation for 72 h with ALA + E2 specifically increased EPA (+34% in EtnGpl, P < 0.001) and DPA (+15%, P < 0.001) compared to ALA alone. Thus, SH-SY5Y cells produced membrane EPA, DPA and DHA from supplemental ALA. The formation of DHA was limited, even in the presence of E2. E2 significantly favored EPA and DPA production in cells grown for 72 h. Enhanced synthesis of ALA-elongation products in neuroblastoma cells treated with E2 supports the hypothesis that neurosteroids could modulate the metabolism of PUFA.     

n-3 Fatty Acids Abrogate Dyslipidemia-Induced Changes in Bile Acid Uptake,Synthesis, and Transport in Young and Aged Dyslipidemic Rats

In this study, the effect of n-3 fatty acids (FA) [α-linolenic acid (ALA) and eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA)] on the intestinal bile acid (BA) uptake, hepatic BA synthesis, and enterohepatic bile acid transporters (BAT) was assessed in young and aged dyslipidemic rats. Dyslipidemia was induced in young and aged rats by feeding a high-fat (HF) diet. Experimental groups received diets containing canola oil (HF + CNO) and fish oil (HF + FO) as a source of ALA and EPA + DHA, respectively. After 60 days of feeding, intestinal BA uptake and expression of apical sodium-dependent bile acid transporter (Asbt), organic solute transporter-alpha/beta (Osta/b) messenger RNA (mRNA), and hepatic expression of Na⁺ taurocholate cotransporting polypeptide (Ntcp), bile salt export pump (Bsep), cholesterol 7-α hydroxylase A1 (Cyp7a1), Farnesoid X receptor (Fxr), small heterodimer partner-1 (Shp), liver receptor homolog-1 (Lrh-1), and hepatic nuclear factor-4 alpha (Hnf4a) mRNA were measured. Hepatic 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase activity and total BA in serum, liver, and feces were assessed. The dyslipidemic HF group had: (1) increased intestinal BA uptake and Asbt and Osta/b mRNA expression, (2) increased BA in serum, (3) decreased hepatic expression of Ntcp, Bsep, and Cyp7a1 mRNA, (4) increased activity of HMG-CoA reductase, (5) increased hepatic expression of Fxr and Shp mRNA, (6) decreased hepatic expression of Lrh-1 and Hnf4a mRNA, and (7) decreased BA in feces, when compared to control, HF + CNO, and HF + FO groups. Immunostaining revealed increased expression of intestinal Asbt and hepatic Ntcp protein in the HF group when compared to control, HF + CNO, and HF + FO groups. n-3 FA abrogated dyslipidemia-induced changes in the intestinal uptake, hepatic synthesis, and enterohepatic transporters of BA in both young and aged rats. EPA + DHA was more effective than ALA in modulating dyslipidemia-induced changes.     

Confusion over different types of n‐3 polyunsaturated fatty acids

There are two kinds of n‐3 polyunsaturated fatty acid (PUFA). Alpha‐linolenic acid (ALA) is the parent n‐3 PUFA; it cannot be synthesized by the human body and as a result is an essential fatty acid. The two long chain n‐3 PUFA eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) can in principle be synthesized from ALA or obtained from the diet. While the cardioprotective effects of long chain n‐3 PUFA are well established the effects of ALA on the cardiovascular system are more controversial. The Lyon Diet Heart Study which it is claimed provides evidence for beneficial effects of ALA on the cardiovascular system is flawed. The argument that ALA conversion into EPA and DHA provides significant quantities of the two long chain n‐3 PUFA is unsustainable as rates of conversion are too low. To avoid confusion a distinction needs to be drawn between ALA and the long chain n‐3 PUFA. Health claims for foods rich in EPA and DHA cannot be extended to foods rich in ALA nor is ALA a substitute for EPA and DHA in vegetarian diets.     

Dietary Supplementation of Tetracarpidium conophorum (African Walnut) Seed Enhances Muscle n‐3 Fatty Acids in Broiler Chickens

The influence of dietary Tetracarpidium conophorum (African Walnut) seed meal (TCSM) on fatty acids, productivity parameters, and physicochemical properties of breast and thigh muscles in broiler chickens are assessed. A total of 180, 28‐d‐old Arbor acre broiler chickens are randomly assigned to dietary treatments containing 0% (control), 2.5%, and 5% w/w TCSM, fed for 28 d, and euthanized. Dietary TCSM reduces (p < 0.05) feed intake, body weight gain (BWG), carcass weight, and abdominal fat. Diet does not affect feed efficiency and hematological parameters. The control birds have higher (p < 0.05) serum total cholesterol and triglycerides than do the supplemented birds. Diet has no effect on pH, water holding capacity, carbonyl and malondialdehyde contents, and organoleptic properties of breast and thigh muscles. The 5% TCSM has higher redness in breast muscle than do other treatments. Dietary TCSM improves (p < 0.05) the concentration of C18:3n‐3 (4.80–8.76% vs 1.56%), C20:5n‐3 (0.54–0.79% vs 0.39%), C22:5n‐3 (0.64–0.89% vs 0.18%), and C22:6n‐3 (0.75–0.97% vs 0.19%), and reduces (p <  0.05) the fat content (2.15–2.45% vs 3.15%) in breast and thigh muscles. Dietary TCSM enhances muscle n‐3 fatty acids without instigating oxidative deterioration, but reduces BWG in broiler chickens. Practical Application: Albeit that broiler meat is rich in polyunsaturated fatty acids (PUFA), its omega 6 (n‐6)/omega 3 (n‐3) is >4. Elevated n‐6/n‐3 could have adverse effect on human physiology thereby promoting the pathogenesis of certain diseases. This heightens the need to enhance the n‐3 PUFA content of broiler meat. Dietary TCSM induced up to a fourfold increase in n‐3 PUFA content of the breast and thigh muscles in broiler chickens. Moreover, dietary TCSM induced up to a tenfold decrease in the n‐6/n‐3 of the breast and thigh muscles in broiler chickens. This finding assumes great significance because the health concerns regarding dietary fat are the foremost factors responsible for the bad image suffered by meat. These results provide insights on the potential of TCSM to improve the nutritional quality without compromising the oxidative shelf life, organoleptic traits, and physicochemical properties of broiler meat.     

Dietary Monounsaturated Fatty Acids but not Saturated Fatty Acids Preserve the Insulin Signaling Pathway via IRS-1/PI3K in Rat Skeletal Muscle

Saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) show different effects on the development of insulin resistance. In this study, we compared the effect of dietary SFA and MUFA on the insulin signaling pathway in the skeletal muscle of a type 2 diabetic animal model. Twenty-nine-week-old male Otsuka Long-Evans Tokushima fatty (OLETF) rats were randomly divided into three groups and fed one of the following diets for 3 weeks; a normal chow diet, an SFA (lard oil) enriched or a MUFA (olive oil) enriched high-fat diet. The vastus lateralis muscle was used for analyses. Insulin tolerance test showed improved insulin sensitivity in rats fed the MUFA diet, as compared to those fed the SFA diet (p < 0.001). The SFA diet reduced IRS-1 expression and phosphorylated PI3K levels in skeletal muscle, as compared with a chow diet (p < 0.001, respectively). On the contrary, muscle IRS-2 expression and phosphorylated ERK1/2 was significantly increased in rats fed the SFA diet (p < 0.001, respectively). Membrane translocation of glucose transporter type 4 decreased in the skeletal muscle of rats fed the SFA diet, as compared to those fed a chow diet (p < 0.001). These changes in insulin signaling pathway in skeletal muscle were not observed in rats fed the MUFA diet. In conclusion, the beneficial effect of dietary MUFA on insulin sensitivity is associated with a conserved IRS-1/PI3K insulin signaling pathway which was altered by dietary SFA.     

Fatty fish intake,n‐3 fatty acids and self‐rated health in middle‐aged adults

Background – Since n‐3 fatty acids, abundant in fatty fish, may improve health, we raised the question whether self‐reported intake frequency of fatty fish (FF) might be related to the percentage of n‐3 fatty acids in serum phospholipids (PL‐n‐3), and also to self‐rated health (H). Design – The study followed a cross‐sectional design. Methods – In the cross‐sectional Oslo Health Study, PL‐n‐3 were determined in 121 middle‐aged ethnic Norwegians and 102 immigrants from the Indian subcontinent and correlated with FF and H. Logistic regression was used to study the relationship between PL‐n‐3 and H (dichotomized, i.e. Poor vs. Good health). Results – FF correlated positively with PL20:5n‐3 (PL‐EPA, r = 0.467, p <0.001) and PL22:6n‐3 (PL‐DHA, r = 0.499, p <0.001), and negatively with PL20:4n‐6 (PL‐AA, r = –0.350, p = 0.001). H was positively associated with PL‐EPA (r = 0.321, p <0.001) and PL‐DHA (r = 0.275; p <0.001), but negatively with PL‐AA (r = –0.220, p = 0.001). The odds ratio for reporting Poor vs. Good health was significantly higher in subjects with low levels of PL‐EPA (OR = 1.49; 95% confidence interval = 1.17–1.89, p = 0.001), persisting after adjusting for sex, physical activity, ethnicity and length of education. Conclusion – The intake frequency of fatty fish is related to n‐3 fatty acids in the serum phospholipids, and to self‐rated health.     

SNPs of the FADS Gene Cluster are Associated with Polyunsaturated Fatty Acids in a Cohort of Patients with Cardiovascular Disease

Polymorphisms of the human Δ-5 (FADS1) and Δ-6 (FADS2) desaturase genes have been recently described to be associated with the level of several long-chain n-3 and n-6 polyunsaturated fatty acids (PUFAs) in serum phospholipids. We have genotyped 13 single nucleotide polymorphisms (SNPs) located on the FADS1–FADS2–FADS3 gene cluster (chromosome 11q12–13.1) in 658 Italian adults (78% males; mean age 59.7 ± 11.1 years) participating in the Verona Heart Project. Polymorphisms and statistically inferred haplotypes showed a strong association with arachidonic acid (C20:4n-6) levels in serum phospholipids and in erythrocyte cell membranes (rs174545 adjusted P value for multiple tests, P < 0.0001 and P < 0.0001, respectively). Other significant associations were observed for linoleic (C18:2n-6), alpha-linolenic (C18:3n-3) and eicosadienoic (C20:2n-6) acids. Minor allele homozygotes and heterozygotes were associated to higher levels of linoleic, alpha-linolenic, eicosadienoic and lower levels of arachidonic acid. No significant association was observed for stearidonic (C18:4n-3), eicosapentaenoic (C20:5n-3) and docosahexaenoic (C22:6n-3) acids levels. The observed strong association of FADS gene polymorphisms with the levels of arachidonic acid, which is a precursor of molecules involved in inflammation and immunity processes, suggests that SNPs of the FADS1 and FADS2 gene region are worth studying in diseases related to inflammatory conditions or alterations in the concentration of PUFAs. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Vitamin A deficiency enhances docosahexaenoic and Osbond acids in liver of rats fed an α-linoleic acid-adequate diet

The synthesis of docosahexaenoic (DHA, 22∶6n−3) and Osbond acid (OA, 22∶5n−6) is regulated by the heterodimer of peroxisome proliferator-activated receptor and retinoid X receptor (RXR). 9-Cis retinoic acid, a metabolite of vitamin A, is the most potent ligand of RXR. We tested whether vitamin A deficiency impairs DHA and OA synthesis in rats fed a vitamin A- and α-linolenic acid (ALA)-sufficient (VASALAS), vitamin A-sufficient and ALA-deficient (VASALAD), vitamin A-deficient and ALA-sufficient (VADALAS), or vitamin A- and ALA-deficient (VADALAD) diet. After 7 wk of feeding, liver and colon choline (CPG) and ethanolamine (EPG) phosphoglyceride FA were analyzed. The VADALAS compared with the VASALAS rats had elevated levels of both DHA (P<0.05) and OA (P<0.05) in liver CPG and EPG. In contrast, the VADALAD group had a lower DHA (P<0.01) and higher OA (P<0.005) level in CPG and EPG of both tissues than their VASALAD counterparts. ALA deficiency reduced DHA and enhanced OA levels in liver and colon CPG and EPG in both the vitamin A-sufficient (VASALAS vs. VASALAD) and-deficient (VADALAS vs. VADALAD) rats (P<0.005). The study demonstrates that ALA deficiency reduced DHA and enhanced OA levels in tissue membranes, and dietary vitamin A deficiency has a profound effect on membrane DHA and OA in rat tissues. Both vitamin A and DHA are involved in a myriad of vital physiological functions pertaining to growth and development and health. Hence, there is a need for a further study to unravel the mechanism by which vitamin A influences membrane DHA and OA.     

Increased α-linolenic acid intake increases tissue α-linolenic acid content and apparent oxidation with little effect on tissue docosahexaenoic acid in the guinea pig

The essential fatty acids do not have identical roles in nutrition. Linoleic acid (LA) accumulates throughout the body of most mammals, whereas α-linolenic acid (ALA) is rarely found in tissue lipids to the same extent as LA. It has been argued that this is the result of metabolism of ALA to docosahexaenoic acid (DHA) or that ALA is rapidly β-oxidized to acetyl CoA and CO₂. In this study, we consider the effect of high and low ALA levels on the tissue distribution of ALA and other n-3 polyunsaturated fatty acids (PUFA) in all tissues. Guinea pigs were fed one of two defined diets for 3 wk from wearning with both diets containing 1.8% (by weight) of LA and either 1.7% ALA or 0.03% ALA. The high ALA diet was associated with significantly increased ALA levels in all tissues except the brain and significantly increased levels of long-chain n-3 PUFA in all tissues except intestines, brain, carcass, and skin. The long-chain n-3 PUFA content of the whole body was less than 5% of that of the ALA content in both diet groups, and the major long-chain n-3 PUFA (>66% of total) in the body was 22∶5n−3. The brain was the only tissue where the DHA content exceeded that of 22∶5n−3. On the low ALA diet, there appeared to be conservation of ALA based on a comparison of the ratio of LA to ALA in the tissues compared with that in the diet. On the high ALA diet there was a loss of ALA relative to LA in the tissues compared with the diet. These studies suggest that the low levels of tissue ALA in the guinea pig are likely the result of β-oxidation or excretion via the skin and fur rather than metabolism to DHA.     

Diet,Plasma, Erythrocytes,and Spermatozoa Fatty Acid Composition Changes in Young Vegan Men

There has been increasing interest in vegan diets, but how this dietary pattern regulates tissue fatty acids (FA), especially in men, is unclear. Our aim was to evaluate the effect of a vegan diet on plasma, erythrocyte, and spermatozoa FA composition in young men. Two groups consisting of 67 young (18–25 years old) men were studied. One group following an omnivore diet but did not consume fish, shellfish or other marine foods (control, n = 33), and another group following a vegan diet (vegan, n = 34) for at least 12 months were compared. Dietary intake was assessed via a food frequency questionnaire and a 24-h recall. FA composition was measured in plasma, erythrocyte phospholipids, and spermatozoa by gas–liquid chromatography. Compared to controls, the vegan group had higher reported intakes of carbohydrate, dietary fiber, vitamins (C, E, K, and folate), and minerals (copper, potassium) but lower intakes of cholesterol, trans FA, vitamins B₆, D, and B₁₂, and minerals (calcium, iron, and zinc). Vegan's reported a lower saturated FA and not arachidonic acid intake, both groups did not intake eicosapentaenoic acid and docosahexaenoic acid (DHA), but vegan's showed a higher alpha linolenic acid ALA intake. Vegans had higher plasma, erythrocyte phospholipid, and spermatozoa ALA, but lower levels of other n-3 polyunsaturated fatty acid (PUFA), especially DHA. Vegans were characterized by higher ALA, but lower levels of other n-3 PUFA, especially DHA in plasma, erythrocytes, and spermatozoids. The biological significance of these findings requires further study.     

Dietary Fish Oil Supplements Increase Tissue n-3 Fatty Acid Composition and Expression of Delta-6 Desaturase and Elongase-2 in Jade Tiger Hybrid Abalone

This study was conducted to investigate the effects of fish oil (FO) supplements on fatty acid composition and the expression of ∆6 desaturase and elongase 2 genes in Jade Tiger abalone. Five test diets were formulated to contain 0.5, 1.0, 1.5, 2.0 and 2.5% of FO respectively, and the control diet was the normal commercial abalone diet with no additional FO supplement. The muscle, gonad and digestive glands (DG) of abalone fed with all of the five test diets showed significantly high levels of total n-3 polyunsaturated fatty acid (PUFA), eicosapentaenoic acid (EPA), docosapentaenoic acid n-3 (DPAn-3), and docosahexaenoic acid (DHA) than the control group. In all three types of tissue, abalone fed diet supplemented with 1.5% FO showed the highest level of these fatty acids (P < 0.05). For DPAn-3 the higher level was also found in muscle and gonad of abalone fed diet supplemented with 2% FO (P < 0.05). Elongase 2 expression was markedly higher in the muscle of abalone fed diet supplemented with 1.5% FO (P < 0.05), followed by the diet containing 2% FO supplement. For ∆6 desaturase, significantly higher expression was observed in muscle of abalone fed with diet containing 0.5% FO supplement (P < 0.05). Supplementation with FO in the normal commercial diet can significantly improve long chain n-3 PUFA level in cultured abalone, with 1.5% being the most effective supplementation level.     

Stearidonic acid (18:4n‐3): Metabolism,nutritional importance,medical uses and natural sources

Stearidonic acid (SA, 18:4n‐3) is a polyunsaturated fatty acid (PUFA) that constitutes the first metabolite of α‐linolenic acid (ALA, 18:3n‐3) in the metabolic pathway leading to C_20–22 PUFA, such as eicosapentaenoic acid (EPA, 20:5n‐3), and docosahexaenoic acid (DHA, 22:6n‐3), which recently have received much attention because of their various physiological functions in the human body. Recently, several studies indicated that dietary SA increased EPA more efficiently than ALA. Thus, vegetable oils containing SA may become a dietary source of n‐3 fatty acids that is more effective in increasing tissue n‐3 PUFA concentrations than the current ALA‐containing vegetable oils. Nevertheless, few SA sources occur in nature, although there are still a large number of species untested to date. SA has been detected in variable amounts in several species of algae, fungi and animals tissues, but the seeds of some plant families seem to be better sources of SA, especially Echium (Boraginaceae) species. This work reviews the nutritional significance, medical uses and natural occurrence of SA.     

n-3 Polyunsaturated Fatty Acids and Atopy in Korean Preschoolers

Atopy is a growing problem for Korean children. Since eicosapentaenoic acid is a precursor of less active inflammatory eicosanoids, n-3 polyunsaturated fatty acids (PUFA) may have a protective effect on atopy. This study was undertaken to determine whether n-3 PUFA in red blood cells (RBC) is lower in atopic than in non-atopic preschoolers. Three hundred and eight Korean children aged 4–6 years were enrolled. Total RBC fatty acid composition was measured by gas chromatography. The prevalence of atopic dermatitis, allergic rhinitis, or asthma was 29%. Total RBC n-3 PUFA were lower in preschoolers with atopy than controls (9.8 ± 1.2 vs. 11.4 ± 1.6%; P < 0.05), while n-6 PUFA (33.0 ± 1.4 vs. 32.2 ± 1.0%; P < 0.05) and n-6/n-3 PUFA ratio (3.4 ± 0.6 vs. 2.8 ± 0.5; P < 0.05) were greater. The following factors were also associated with an increase in atopy: higher saturated fatty acids (39.6 ± 1.4 vs. 40.6 ± 1.9; P < 0.05) and arachidonic acid (15.3 ± 1.6 vs. 16.0 ± 2.9; P < 0.05), and lower total PUFA (43.8 ± 0.7 vs. 42.8 ± 1.4; P < 0.05) and omega-3 index (EPA + DHA; 9.1 ± 0.8 vs. 7.8 ± 0.5; P < 0.05) in RBC. Maternal history of atopy was a significant (P < 0.05) risk factor, while lactation was not. The results suggest that a reduced content of n-3 PUFA in the RBC membrane could play a role in early children atopy.     

Decreasing the Linoleic Acid to α-Linolenic Acid Diet Ratio Increases Eicosapentaenoic Acid in Erythrocytes in Adults

The n-6/n-3 fatty acid (FA) ratio has increased in the Western-style diet to ~10–15:1 during the last century, which may have contributed to the rise in cardiovascular disease (CVD). Prior studies have evaluated the effects on CVD risk factors of manipulating the levels of n-6 and n-3 FA using food and supplements or investigated the metabolic fate of linoleic acid (LNA) and α-linolenic acid (ALA) by varying the n-6/n-3 ratios. However, no previous studies have investigated the potential interaction between diet ratios and supplementation with eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3). We used a factorial design approach with adults (n = 24) in a controlled feeding trial to compare the accretion of EPA and DHA into red blood cell membranes (RBC) by adding a direct source (algal oil supplement) of EPA and DHA in a diet with a 10:1 versus 2:1 ratio of n-6/n-3 FA. Subjects were randomized into 8-week crossover diet sequences and each subject consumed three of four diets [10:1, 10:1 plus supplement (10:1 + S), 2:1 and 2:1 + S]. LNA and ALA intakes were 9.4 and 7.7%, and 1.0 and 3.0% during the low and high ALA diets, respectively. Compared to the Western-style 10:1 diet, the 2:1 diet increased EPA by 60% (P < 0.0001) in RBC membranes without the direct EPA source and a 34% increase (P = 0.027) was observed with the 10:1 + S diet; however, DHA levels increased in both diet ratios only with a direct DHA source. Shifting towards a 2:1 diet is a valid alternative to taking EPA-containing supplements.     

Determinants of DHA Incorporation into Tumor Tissue During Dietary DHA Supplementation

Docosahexaenoic acid (DHA), upon incorporation into tumor tissue, has the potential to sensitize tumors to the effects of chemotherapy or radiation therapy. Although DHA has usually been supplied to tumor tissue in the diet, appropriate dietary conditions required to obtain optimal tumor levels have not been established. Hence, we studied mammary tumor tissue responses in rats fed various durations and doses of DHA. Rats fed a palm oil enriched diet (diet 0) were switched to diets providing either 0.8 g DHA/day (diet 1) or 1.5 g DHA/day (diet 2). Tumor tissue fatty acid composition was analysed at baseline (diet 0), at weeks 1, 4 and 9 during diet 1 and at week 4 during diet 2. Dietary DHA supplementation differentially increased DHA within phospholipids (PL) and triacylglycerol (TAG) fractions in tumors. DHA level equilibrated between 2 and 4 weeks in PL while DHA increase was more progressive in TAG and did not reach a steady state. A higher dose of DHA further increased DHA content in tumor PL and TAG (P = 0.018 and P < 0.001, respectively). DHA concentration in plasma PL was positively correlated with DHA in tumor PL (r = 0.72; P = 0.0003) and TAG (r = 0.64; P = 0.003). We conclude that dietary DHA supplementation enhances tumor content of DHA in a time- and dose-dependent manner, and that the DHA level in plasma PL could be used as a proxy for tumor DHA. These findings have implications for dietary DHA supplementations in cancer patients.     

Oral Absorption and Disposition of alpha‐Linolenic,Rumenic and Vaccenic Acids After Administration as a Naturally Enriched Goat Dairy Fat to Rats

Although there is extensive information describing the positive biological effects of conjugated linoleic acid and its main isomer rumenic acid (RA; C18:2 cis 9, trans 11), and alpha‐linolenic acid (ALA) and vaccenic acid (TVA), data about their bioavailability are not available. In this work, we investigated the oral absorption and disposition of these fatty acids in Wistar rats. A naturally enriched goat dairy fat (EDF) was obtained by supplementing ruminant diets with oils or oilseeds rich in polyunsaturated fatty acids (PUFA). The EDF was administered orally (single dose of 3000 mg EDF/kg body weight equivalent to 153 mg TVA/kg body weight, 46 mg RA/kg body weight and 31 mg ALA/kg body weight), and serial blood and liver samples were collected and TVA, RA and ALA concentrations determined by GC/MS. The fatty acids TVA, RA and ALA were rapidly absorbed (t_1/2a, 0.36, 0.66 and 0.76 h, respectively, for plasma) and slowly eliminated (t_1/2β, 17.04, 18.40 and 16.52 h, respectively, for plasma). The maximum concentration (C_max) was detected in liver > plasma > erythrocyte. Our study shows that when orally administered EDF, its components TVA, RA and ALA were rapidly absorbed and distributed throughout the body by the blood circulation to exert systemic effects.     

Moderate Dietary Intake of Myristic and Alpha-Linolenic Acids Increases Lecithin-Cholesterol Acyltransferase Activity in Humans

Cholesterol removal from tissues into HDL depends on the activity of lecithin-cholesterol acyltransferase (LCAT; E.C. 2.3.1.43) that is associated with lower cardiovascular diseases risk. HDL cholesterol concentration and LCAT activity can be modulated by dietary fatty acids. Original data with substrate models have shown a positive effect of myristic acid (MA) on the esterification rate of cholesterol. The purpose of this study was to examine the effect of moderate intakes of MA associated with recommended intake of alpha-linolenic acid (ALA) on LCAT activity in humans. Two experimental diets were tested for 3 months each. Diet 1-MA 1.2% of total energy (TE) and ALA 0.9% TE, diet 2-MA 1.8% and ALA 0.9% TE; a control diet (MA 1.2% and ALA 0.4% TE) was given 3 months before diet 1 and diet 2. The endogenous activity of LCAT was determined at completion of each diet. Compared with the control diet (13.2 ± 3.1 μmol CE/(L.h)), LCAT activity increased significantly (P < 0.001) with diet 1 (24.2 ± 3.6 μmol CE/(L.h)) and diet 2 (33.3 ± 7.4 μmol CE/(L.h)); the increase observed with diet 2 was significantly (P < 0.001) greater than that due to diet 1. These results suggest that ALA (from rapeseed oil, mainly in sn-2 position) and MA (from dairy fat, mainly in sn-2 position) favor LCAT activity, by respective increases of 83 and 38%. When they are supplied together, a complementary effect was observed (average increase of 152%). Moreover, these observations were associated with a decrease of the ratio of total to HDL-cholesterol. In conclusion, our results suggest that moderate supply of MA (1.8% TE) associated with the recommended intake of ALA (0.9% TE) contributes to improve LCAT activity.     

Maternal dietary conjugated linoleic acid alters hepatic triacylglycerol and tissue fatty acids in hatched chicks

The effects of feeding CLA to hens on newly hatched chick hepatic and carcass lipid content, liver TAG accumulation, and FA incorporation in chick tissues such as liver, heart, brain, and adipose were studied. These tissues were selected owing to their respective roles in lipid assimilation (liver), as a major oxidation site (heart), as a site enriched with long-chain polyunsaturates for function (brain), and as a storage depot (adipose). Eggs with no, low, or high levels of CLA were produced by feeding hens a corn-soybean meal-basal diet containing 3% (w/w) corn oil (Control), 2.5% corn oil +0.5% CLA oil (CLA1), or 2% corn oil +1.0% CLA oil (CLA2). The egg yolk content of total CLA was 0.0, 1.0, and 2.6% for Control, CLA1, and CLA2, respectively (P<0.05). Maternal dietary CLA resulted in a decrease in chick carcass total fat (P<0.05). Liver tissue of CLA2 chicks had the lowest fat content (P<0.05). The liver TAG content was 8.2, 5.8, and 5.1 mg/g for Control, CLA1, and CLA2 chicks, respectively (P<0.05). The chicks hatched from CLA1 and CLA2 incorporated higher levels of cis-9,trans-11 CLA in the liver, plasma, adipose, and brain than Control (P<0.05). The content of 18∶0 was higher in the liver, plasma adipose, and brain of CLA1 and CLA2 than Control (P<0.05), but no difference was observed in the 18∶0 content of heart tissue. A significant reduction in 18∶1 was observed in the liver, plasma, adipose, heart, and brain of CLA1 and CLA2 chicks (P<0.05). DHA (22∶6n−3) was reduced in the heart and brain of CLA1 and CLA2 chicks (P<0.05). No difference was observed in carcass weight, dry matter, or ash content of chicks (P>0.05). The hatchabilities of fertile eggs were 78, 34, and 38% for Control, CLA1, and CLA2, respectively (P<0.05). The early dead chicks were higher in CLA1 and CLA2 than Control (18 and 32% compared with 9% for Control), and alive but not hatched chicks were 15 and 19% for CLA1 and CLA2, compared with 8% for Control (P<0.05). Maternal supplementation with CLA leads to a reduction in hatchability, liver TAG, and carcass total fat in newly hatched chicks.     

Enzymatic Incorporation of Selected Long-Chain Fatty Acids into Triolein

Acidolysis of triolein (tri C18:1) with selected long-chain fatty acids (LCFA) was carried out using Candida antarctica (Novozym 435), Rhizomucor miehei (Lipozyme RM IM), Pseudomonas sp. (PS-30), Aspergillus niger (AP-12), and Candida rugosa (AY-30). A better incorporation of stearic acid (SA), α-linolenic acid (ALA), γ-linolenic acid (GLA), arachidonic acid (AA), and docosapentaenoic acid (DPA) was achieved using lipase from Rhizomucor miehei. Lipase from Pseudomonas sp. catalyzed a better incorporation of linoleic acid (LA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) into triolein. Thus, Rhizomucor miehei and to a lesser extent Pseudomonas sp. might be considered as providing the most effective enzymes for acidolysis of triolein with selected LCFA. In general, incorporation of LCFA into triolein (tri C18:1) may be affected by chain length, number of double bonds, and the location and geometry of the double bonds as well as reaction conditions and reactivity and specificity of lipases used. As the ratio of the number of moles of a mixture of equimole quantities of C18 FA to triolein changed from 1 to 3, incorporation of C18 FA into triolein increased accordingly with Rhizomucor miehei lipase. Similarly, incorporation of n-3 FA into triolein increased when ALA, DPA, DHA, and EPA were used. The same trend was noticed for a mixture of n-6 FA (LA + GLA + AA) and triolein.