Proportion Of Alpha-linolenic Acid Research Articles

Species-specific responses in pigments and fatty acids of five freshwater chlorophytes exposed to varying cultivation conditions

Microalgae have attracted increasing interests within several industrial sectors. Their diversity, underpinned by complex polyphyletic origins, represents an under-exploited source of high-value metabolites. Five freshwater chlorophytes (Ankistrodesmus sp., Pediastrum sp., Kirchneriella sp., Chloromonas sp. and Scenedesmus sp.) were grown under varying cultivation conditions including high nitrate supply, phytohormone supplementation, exposure to the herbicide molinate and exposure to blue LED light.When exposed to molinate (2.5 μg. mL−1), Kirchneriella sp. returned the highest lutein cellular content (4.9 mg. g−1). Zeaxanthin production (4.1 mg. g-1) was also highest for Scenedesmus sp. when molinate was introduced to the cultivation medium. Only Chloromonas sp. contained eicosapentaenoic acid (EPA), which returned the highest cellular content (2.6 mg. g−1) when the culture was supplemented with the phytohormone indole-3-acetic acid (2.5 μg. mL−1). Scenedesmus sp. showed an increase in the proportions of alpha-linolenic acid (∼55 %) when grown in medium enriched in nitrate. Overall, molinate supplementation enhanced the accumulation of lutein, β-β-carotene and chlorophyll a in Kirchneriella sp.These chlorophytes showed a species rather than treatment-specific response with regards to pigment cellular contents and fatty acid profiles, re-enforcing the notion that the optimisation of intracellular contents of valuable metabolites as part of a tailored biorefinery strategy needs to be considered at the species level.

390 Effects of dietary-induced pH changes on feed digestion, nitrogen metabolism, fermentation, and biohydrogenation of polyunsaturated fatty acids in dual-flow continuous culture fermenters

Abstract Ruminal pH decreases as greater concentrations of grain are consumed, and as a result, reduces biohydrogenation of polyunsaturated fatty-acids. Our objective was to investigate effects of diet on pH and biohydrogenation activity in vitro. Eight dual-flow, continuous culture fermenters were blocked by side of the room and randomly assigned, within block, to 1 of 4 treatments. Treatments consisted of 100:0 roughage-to-concentrate (Grass), 50:50 roughage-to-concentrate plus flax oil supplement (Mix+F), 10:90 roughage-to-concentrate plus corn oil supplement (Con+C), or 10:90 roughage-to-concentrate plus flax oil supplement (Con+F). Fermenter pH, area under the curve, and maximum pH were lowest for Con+C and Con+F (P < 0.05). Apparent and true DM, OM, and NDF digestibility were greater with grain inclusion (P < 0.05) while ADF digestibility was not affected by treatment (P > 0.10). Protein degradation was lowered as grain inclusion increased (P < 0.05). Total VFA concentrations were lowest for Grass, highest for Con+C and Con+F, and intermediate for Mix+F (P < 0.05). Acetate-to-propionate was lowest for Con treatments (P < 0.05). Biohydrogenation of 18:2n-6 and 18:3n-3 fatty-acids were reduced (P < 0.01) with inclusion of concentrate regardless of roughage-to-concentrate ratio. Concentrations of stearic acid recovered from effluent were greatest for Grass, intermediate for Mix+F, and lowest for both Con+C and Con+F (P < 0.05). Linoleic acid proportions in effluent were greatest for Con+C and Con+F and intermediate for Mix+F (P < 0.05), and inclusion of concentrate, regardless of amount, increased the amount linoleic acid recovered from fermenter overflow (P < 0.01). Between Con+C and Con+F concentrations of alpha-linolenic acid (ALA) was greater when flax oil was supplemented (P < 0.01). Proportions of ALA in effluent was similar (P > 0.10) between Grass and Con+C; however, between Mix+F and Con+F ALA concentrations tended (P = 0.06) to be greater for Con+F. Omega6-to-omega3 ratios were similar across Grass, Mix+F, and Con+F (P > 0.10) and greatest for Con+C (P < 0.05).

Camelina sativa Oil, Fatty Fish, and Lean Fish Do Not Markedly Affect Urinary Prostanoids in Subjects with Impaired Glucose Metabolism.

Dietary fatty acids are suggested to affect oxidative stress; however, results from interventions have been inconclusive. The aim was to examine if fatty fish, lean fish, and Camelina sativa oil (CSO) affect the urinary prostanoid levels in subjects with impaired glucose metabolism. Altogether 79 participants aged 43-72 years completed a randomized controlled study lasting 12 weeks. There were four parallel groups, fatty fish, lean fish (four fish meals/week in both), CSO providing 10 g/day alpha-linolenic acid (ALA), and control diet with limited fish and ALA containing oil consumption. Urinary prostanoids (prostaglandin F2α , 5-F2t -isoprostanes and 15-F2t -isoprostane metabolites, isofuran, 8-F3t -isoprostanes, and 4-(RS)-4-F4t -neuroprostane) of 72 participants (age: mean (±SD) 58.9 ± 6.5 years; body mass index: 29.3 ± 2.5 kg/m2 ) collected over 12-h were measured using liquid chromatography tandem-mass spectrometry. Plasma phospholipid fatty acids were determined using gas chromatography. Our study showed that the proportion of ALA in plasma phospholipids increased in the CSO group (overall difference among the groups p-value <0.001). In the fatty fish group, proportions of eicosapentaenoic and docosahexaenoic acids increased (overall p-value <0.001 for both). Prostaglandin F2α was higher in the CSO group than in the control group (p < 0.05), however, there were no other significant changes in urinary excretion of other prostanoids among the study groups. At baseline, arachidonic acid in plasma phospholipids was positively (r = 0.247, p < 0.05) and ALA negatively (r = -0.326, p < 0.05) associated with urinary total isoprostanes. In conclusion, CSO, fatty fish, and lean fish consumption do not cause major changes in oxidative stress markers in subjects with impaired glucose tolerance.

Niveau de consommation en acides gras polyinsaturés de la femme allaitante en France : étude de consommation INCA 2 et évolution du contenu en acides gras essentiels du lait maternel de 1997 à 2014

Polyunsaturated fatty acid (PUFA) composition data of the breast milk are rare but essential for assessing the adequate intake of fatty acids in the newborn and possibly directing the mother to a suitable diet or even supplementation with essential fatty acids. The raw data for lactating women from the national study on individual food consumption 2006-2007 (INCA 2) were combined with the French food composition table (Ciqual 2013) to assess their fatty acid intakes. Although this is a limited number of subjects, these data are still interesting to analyze and compare with current Anses recommendations. According to these results, omega 3 PUFA consumption is not sufficient for the purposes of the Recommended Dietary Intakes (RDI). In addition, it has been shown that the fatty acid composition of breast milk is a proven marker of dietary lipid consumption and a good reflection of the consumption's level of omega-6 and omega-3 PUFAs. Epidemiological data on quantity and quality of lipids consumed in France are rare. In the context of different observational and interventional studies conducted on breast milk, ITERG has been able to estimate the evolution of French food habits for nearly 17 years. A synthesis work has taken over all the data acquired during 3 clinical studies carried out between 1997 and 2014. This synthesis showed a positive evolution of the proportions in omega-3 PUFA in 17 years (1997-2014). However, the proportions of alpha-linolenic acid (ALA) and docosahexaenoic acid (DHA) in breast milk remain below nutritional recommendations for the newborn.

The effect of camelina sativa oil and fish intakes on fatty acid compositions of blood lipid fractions

Background and aimsBlood lipid fractions serve as objective biomarkers of dietary fat intake. It is unclear which fatty acid pool most accurately reflects the dietary intakes of different n-3 PUFAs. We aimed to investigate the effect of fish and camelina sativa oil (CSO) intakes on fatty acid composition of erythrocyte membranes (EM), plasma phospholipids (PL), cholesteryl esters (CE) and triglycerides (TG). We also aimed to identify the most appropriate blood lipid fraction for assessing n-3 PUFA intake. Methods and resultsAltogether 79 volunteers with impaired glucose metabolism were randomly assigned either to CSO, fatty fish, lean fish or control groups for 12 weeks. Fatty acid compositions of lipid pools were measured by gas chromatography. The proportion of alpha-linolenic acid (ALA) increased in all lipid pools in the CSO group (false discovery rate (FDR) p < 0.001 for all). Similarly, the proportions of EPA and DHA increased in all lipid fractions in the fatty fish group (FDR p < 0.001 for EM, PL and CE; FDR p = 0.005 for TG; FDR p < 0.001 for EM, PL, CE; FDR p < 0.007 for TG, respectively). Changes in the dietary intakes of ALA, EPA and DHA correlated with the changes in their proportions in all lipid pools (r = 0.3–0.5, p < 0.05). ConclusionThere is no difference in the ability of blood lipid fractions in reflecting the dietary intake of different n-3 PUFAs over a time period of 12 weeks in subjects with high baseline omega-3 index.This trial was registered in Clinicaltrials.gov (NCT01768429)

Increasing proportion of alpha-linolenic acid in red blood cells relates to a lower prevalence of carotid plaque

Increasing proportion of alpha-linolenic acid in red blood cells relates to a lower prevalence of carotid plaque

Content and Fatty Acid Composition of Sulfoquinovosyldiacylglycerol in Conifer Leaves Grown in Hokkaido, Japan

Sulfoquinovosyldiacylglycerol (SQDG) contents in conifer leaves and their fatty acid (FA) compositions were determined. The SQDG content was 16-36 mg/100 g, and was high in Picea glehnii. Palmitic and alpha-linolenic acid were the usually predominant FAs. In Picea, the proportion of alpha-linolenic acid was low, and those of oleic and linoleic acid were high. The essential oil residues of Abies sachalinensis leaves were found to be a potential source of SQDG material.

High proportions of n‐6 polyunsaturated fatty acids in mature milk of mothers in Ouagadougou, Burkina Faso

Milk from 101 mothers living in Ouagadougou (Burkina Faso) showed a mean lipid content of 33.42 g/l and a fatty acid composition strongly related to the mothers' dietary habits: high proportions of linoleic acid (19.80%), n-6 long-chain polyunsaturated fatty acids (1.90%), and 8:0-14:0 saturated fatty acids (26.94%). The proportions of alpha-linolenic acid (0.45%) and n-3 long-chain polyunsaturated fatty acids (0.44%) were low. The 18:2/18:3 and n-6/n-3 long-chain polyunsaturated fatty acids ratios (53:1 and 5:1, respectively) were well above recommendations.

The Significance of Alpha-Linolenic Acid for Humans.

The omega 3 polyunsaturated fatty acids have had a major impact on thinking in medicine in the last twenty-five years. The parent fatty acid in the omega 3 fatty acid family is alpha-linolenic acid (ALA) which is an essential fatty acid found in high concentrations in certain plant oils, such as flaxseed oil, walnut oil and canola oil. Several longer chain or derived omega 3 fatty acids are formed in the body from ALA, including eicosapentaenoic acid, EPA, decosapentaenoic acid and docosahexaenoic acid, DHA. Dietary sources of these longer-chain fatty acids are fish, fish oils and from other marine organisms. DHA is specifically localised in the retina and the brain in humans and other mammals where it has a primary role via effects on membrane order (fluidity), the activity of membrane-bound enzymes, ion channels and signal transduction. For many years, ALA has been considered to be important only as a precursor of these longer chain compounds, however it is now recognaised that ALA is metabolished by other pathways which may be quantiatively more important than the formation of DHA. For example, ALA is extensively β-oxidised in mammals including humans, especially on diets rich in polyunsaturated fatty acids. ALA appears to play an important role in the nervous system (carbon recycling) for the synthesis of saturated and monounsaturated fatty acids and cholesterol, with estimates of the proportion of ALA being matabolised via this pathway being several fold greater than that to DHA. Furthermore, recent studies have indicated that ALA is deposited in the skin of small mammals and may also play a role in fur. Since ALA is extensively metabolised via these pathways (β-oxidation, carbon recycling and deposition in skin/fur) and is subject to competitive inhibition from linoleic acid in metabolism via the delta-6 desaturase, it is not surprising tha dietary DHA is substantially more effctive than an equivalent dose of dietary ALA in maintaining neural DHA levels. Despite the limited efficiency of DHA formation from ALA, it is clear that certain tissues possess the capacity to synthesise DHA at rates greater than other tissues. The brain, retina and reproductive tissue may be able to synthesis sufficient DHA to meet the DHA demands of these tissues, although in infants at the peak of brain growth and DHA deposition, a dietary supply of DHA (as in milk) may be important to maintain the brain DHA level. In plants, ALA is a substrate for lipoxygenase enzymes leading to the poduction of bioactive hydroxy compounds. This information might provide a clue to other routes of ALA metabolism in mammals. It is concluded that it may no longer be appropriate to consider the function for ALA to be solely a precursor of EPA and DHA.

Temperature-dependent translational regulation of the ER omega-3 fatty acid desaturase gene in wheat root tips.

The proportion of alpha-linolenic acid (18:3) among the total fatty acids in root tissue increases as the growth temperature decreases. Endoplasmic reticulum omega-3 fatty acid desaturase is responsible for the production of most of the 18:3 in root tissue. In this study, the effect of temperature on expression of the TaFAD3 gene, which encodes endoplasmic reticulum omega-3 desaturase in wheat (Triticum aestivum L. cv. Chihoku), was analysed at the mRNA and protein levels. In wheat root tips grown at 30 and 10 degrees C, the proportions of 18:3 among total fatty acids were 22% and 55%, respectively. The level of TaFAD3 protein in microsomal preparations of the root tips grown at 10 degrees C was approximately 7.5 times higher than that of the root tips grown at 30 degrees C. The increased level of TaFAD3 protein at the lower temperature was accompanied by enhanced association of TaFAD3 mRNA with polyribosomes. In contrast, the level of TaFAD3 mRNA in root tips grown at 10 degrees C was slightly higher than in those grown at 30 degrees C. These results suggest that, in root tips, the increase in the 18:3 level at low temperature is achieved directly by an increase in the amount of TaFAD3 protein, and that temperature-dependent translational regulation of the TaFAD3 gene, rather than its transcriptional regulation, contributes to modulation of the TaFAD3 protein accumulation.

Dietary trans Fatty Acids Affect the Essential Fatty-Acid Concentration of Rat Milk

Increasing efforts have been made to determine the distribution and concentration of trans fatty acids in milk, due to the importance of lipids in infant growth and development. In general, trans fatty acid concentration of milk reflects trans fatty acid intake, but insufficient data are available to assess the effects of dietary trans fatty acids on maternal milk. Thus, controlled studies are needed to establish whether there is a dose-response relationship and whether trans fatty acids could affect the concentration of essential fatty acids (EFA), long-chain polyunsaturated fatty acids (PUFA) and the (n-6)/(n-3) ratio in milk. Three groups of six rats each were fed for 10 wk one of three diets differing in trans fatty acid concentration (Control, 0 mol/100 mol; high trans concentration (H), 14.5 mol/100 mol; very high trans concentration (VH), 30 mol/100 mol), but containing the same proportions of linoleic and alpha-linolenic acids and a ratio of 18:2(n-6)/18:3(n-3) of about 7:1. Trans fatty acids were incorporated into maternal milk in a dose-dependent manner. In addition, rats fed trans isomers had greater linoleic acid levels than controls. The proportion of alpha-linolenic acid in milk was lower in the VH group, and the (n-6)/(n-3) cis PUFA ratio in milk of the VH group was greater than that in controls. Total long-chain PUFA levels did not differ among groups. These results suggest that high intakes of trans fatty acids affect the EFA concentration but not that of long-chain PUFA of rat milk, provided that EFA are supplied in sufficient amounts.

Omega-3 fatty acids in adipose tissue and risk of myocardial infarction: the EURAMIC study.

Omega-3 fatty acids have potential antiatherogenic, antithrombotic, and antiarrhythmic properties, but their role in coronary heart disease remains controversial. To evaluate the association of omega-3 fatty acids in adipose tissue with the risk of myocardial infarction in men, a case-control study was conducted in eight European countries and Israel. Cases (n=639) included patients with a first myocardial infarction admitted to coronary care units within 24 hours from the onset of symptoms. Controls (n=700) were selected to represent the populations originating the cases. Adipose tissue levels of fatty acids were determined by capillary gas chromatography. The mean (+/-SD) proportion of alpha-linolenic acid was 0.77% (+/-0.19) of fatty acids in cases and 0.80% (+/-0.19) of fatty acids in controls (P=0.01). The relative risk for the highest quintile of alpha-linolenic acid compared with the lowest was 0.42 (95% confidence interval [CI] 0.22 to 0.81, P-trend=0.02). After adjusting for classical risk factors, the relative risk for the highest quintile was 0.68 (95% CI 0.31 to 1.49, P-trend=0.38). The mean proportion of docosahexaenoic acid was 0.24% (+/-0.13) of fatty acids in cases and 0.25% (+/-0.13) of fatty acids in controls (P=0. 14), with no evidence of association with risk of myocardial infarction. In this large case-control study we could not detect a protective effect of docosahexaenoic acid on the risk of myocardial infarction. The protective effect of alpha-linolenic acid was attenuated after adjusting for classical risk factors (mainly smoking), but it deserves further research.

Identification of an animal omega-3 fatty acid desaturase by heterologous expression in Arabidopsis.

In animals, fatty acid desaturases catalyze key reactions in the synthesis of arachidonic acid and other polyunsaturated fatty acids. A search of the Caenorhabditis elegans DNA databases, using the sequences of Arabidopsis genes, identified several putative desaturases. Here we describe the characterization of the first of these genes, fat-1. The predicted protein encoded by a fat-1 cDNA showed 32-35% identity with both FAD2 and FAD3 of Arabidopsis. When expressed in transgenic plants, fat-1 resulted in a 90% increase in the proportion of alpha-linolenic acid in root lipids. Wild-type Arabidopsis incorporated omega-6 fatty acids (delta8,11,14-20:3 and delta5,8,11,14-20:4) into membrane lipids but did not desaturate them. By contrast, fat-1 transgenic plants efficiently desaturated both of these fatty acids to the corresponding omega-3 products. These findings indicate that the C. elegans fat-1 gene encodes the first animal representative of a class of glycerolipid desaturases that have previously been characterized in plants and cyanobacteria. The FAT-1 protein is an omega-3 fatty acyl desaturase that recognizes a range of 18- and 20-carbon omega-6 substrates.

The ratio of n-6 to n-3 polyunsaturated fatty acids in the rat diet alters serum lipid levels and lymphocyte functions.

Previous studies have reported that feeding rats diets rich in fish oils, which contain high proportions of the n-3 polyunsaturated fatty acids (PUFA) eicosapentaenoic and docosahexaenoic acids, results in lowering of blood lipid levels and suppression of lymphocyte functions tested ex vivo and in vivo. The effects of other n-3 PUFA, such as alpha-linolenic acid, which is found in high proportions in linseed oil, are not as well documented. Therefore, in the present study, weanling male rats were fed for six weeks on one of five high-fat (20% by weight) diets made by mixing together sunflower and linseed oils; the resulting blends had n-6/n-3 PUFA ratios of 112.5:1 (pure sunflower oil), 14.8:1, 6.5:1, 0.81:1, and 0.33:1 (pure linseed oil); the levels of all other components in the diet were identical. The final body weight and total dissectable fat were lowest in rats fed the pure linseed oil diet. Serum cholesterol, triacylglycerol and nonesterified fatty acid concentrations decreased as the n-6/n-3 PUFA ratio of the diet decreased. The fatty acid composition of the serum and of spleen lymphocytes was influenced by the diet fed-there was a progressive decrease in the proportions of linoleic and arachidonic acids and a progressive increase in the proportion of alpha-linolenic acid as the n-6/n-3 PUFA ratio of the diet decreased. Eicosapentaenoic and docosahexaenoic acids were detected in the serum but not in spleen lymphocytes. Inclusion of alpha-linolenic acid in the diet resulted in significant suppression of spleen lymphocyte proliferation in response to the T-cell mitogen concanavalin A and in spleen lymphocyte natural killer cell activity, both measured ex vivo. The localized graft vs. host response, a measure of cell-mediated immunity in vivo, progressively decreased as the n-6/n-3 PUFA ratio of the diet decreased. Thus, this study shows that dietary alpha-linolenic acid results in lowered blood lipid levels and suppressed lymphocyte functions ex vivo and in vivo. With respect to these effects, alpha-linolenic acid is as potent as dietary fish oil.