Mechanisms underlying the cardioprotective effects of omega-3 polyunsaturated fatty acids

Typical omega 3 polyunsaturated fatty acids (n-3 PUFAs) are docosahexaenoic acid and eicosapentaenoic acid in the form of fish oils and α linolenic acid from flaxseed oil. Epidemiological studies suggested the benefits of n-3 PUFA on cardiovascular health. Intervention studies confirmed that the consumption of n-3 PUFA provided benefits for primary and secondary prevention of cardiovascular disease. Evidence from cellular and molecular research studies indicates that the cardioprotective effects of n-3 PUFA result from a synergism between multiple, intricate mechanisms that involve antiinflammation, proresolving lipid mediators, modulation of cardiac ion channels, reduction of triglycerides, influence on membrane microdomains and downstream cell signaling pathways and antithrombotic and antiarrhythmic effects. n-3 PUFAs inhibit inflammatory signaling pathways (nuclear factor-κ B activity) and down-regulate fatty acid (FA) synthesis gene expression (sterol regulatory element binding protein-1c) and up-regulate gene expression involved in FA oxidation (peroxisome proliferator-activated receptor α). This review examines the various mechanisms by which n-3 PUFA exert beneficial effects against CVD.     

Double enrichment of chicken eggs with conjugated linoleic acid and n-3 fatty acids through dietary fat supplementation

Yolk fat fatty acid (FA) concentrations, sensory quality and firmness of eggs and laying hen performance were evaluated with respect to the combined inclusion in the diet of conjugated linoleic acid (CLA), high n-3 oil sources and high-oleic sunflower oil (HOSO). Nine diets were arranged factorially, with three levels of n-3 FA supplementation (2.9, 3.7 and 4.5 g/kg) from three different sources (two fish oils highly concentrated in eicosapentanoic (EPA) or docosahexanoic acid (DHA) and one algae oil with a very high-DHA content) in diets added with fixed amounts of CLA (2.5 g/kg) and HOSO (30 g/kg). A commercial feed with no CLA, n-3 or HOSO added, and another one containing 4.5 g/kg of high-DHA fish oil but not CLA or HOSO were also formulated. An increase in n-3 FA supplementation had little effect on proportions of CLA, monounsaturated FA, saturated FA or total polyunsaturated FA in yolk fat, but increased (P<0.005) long-chain n-3 FA and decreased (P<0.001) long-chain n-6 FA. An increment of dietary n-3 FA also impaired linearly (P<0.001) egg acceptability by consumers. An increment in the proportion of DHA with respect to total n-3 FA from 0.28 to 0.96 increased yolk concentrations of DHA (P<0.001) and total n-3 FA (P<0.01), but decreased (P<0.001) concentrations of EPA and docosapentanoic acid FA. Current data indicate that addition of HOSO to diets supplemented with moderate amounts of CLA and n-3 FA allows the production of double enriched eggs while maintaining sensory quality for consumers at acceptable levels.     

N-3 fatty acid supplementation decreases plasma homocysteine in diabetic dyslipidemia treated with statin-fibrate combination

The aim of this study was to study the effect of adding polyunsaturated fatty acid (PUFA) n-3 or placebo (containing oleic acid) to a combined statin-fibrate treatment on plasma lipoproteins, lipoperoxidation, glucose homeostasis, total homocysteine (tHcy) and microalbuminuria (MA) in patients with diabetic dyslipidemia (DDL). Twenty-four patients, who did not fulfill the recommended target lipid values with combined hypolipidemic therapy (pravastatin 20 mg+micronized fenofibrate 200 mg daily), were supplemented with 3.6 g PUFA n-3 daily for 3 months or placebo (olive oil) for the next 3 months. The concentrations of plasma lipids, fatty acid (FA) profiles of phosphatidylcholine (PC), cholesteryl esters (CE) and triglycerides (TG), tHcy levels, concentrations of conjugated dienes (CD) in low-density lipoprotein (LDL), and MA were determined in baseline state, after the PUFA n-3 and placebo treatment period. Supplementation with PUFA n-3 led to a significant decrease in plasma tHcy (-29%, P < .01) and TG (-28%, P < .05) levels, as well as to a significant decrease in MA (-24%, P < .05). The decrease in MA correlated significantly with the increase in total PUFA n-3 (r = -.509, P < or = .05) and docosahexaenoic acid (r = -.52, P < .01) in TG. The concentrations of CD in LDL increased significantly (+15%, P < .05). The supplementation with PUFA n-3 to the combined statin-fibrate treatment in patients with DDL decreased the TG and tHcy levels as well as MA. It could lead to decreased risk of atherothrombosis and delay of diabetic nephropathy onset and progression.     

Predicting duodenal flows and absorption of fatty acids from dietary characteristics in ovine and bovine species: a meta-analysis approach

Dietary and ruminal factors modify the ruminal biohydrogenation (RBH) of polyunsaturated fatty acids (FA), with duodenal FA flows being quantitatively and qualitatively different from FA intake. Using a meta-analysis approach from a database on duodenal flows of FA in ruminants, this study aimed to determine predictive equations for duodenal and absorbed flows of saturated FA, C18:1, C18:2 and C18:3 isomers, odd- and branched-chain FA (OBCFA), C20:5n-3, C22:5n-3 and C22:6n-3 and to quantify the effects of dietary and digestive factors on those equations. The database was divided into four subsets: forage, seed, vegetable oils or animal fats (oil/fat), and fish products (fish) subsets. Models of duodenal and absorbed FA flows were obtained through variance–covariance analysis. Effects of potential interfering factors (conservation mode and botanical families of forages, lipid source, technological processing of lipid supplements, diet composition and animal characteristics) were analysed. We obtained 83 models for duodenal FA flows as a function of FA intake for saturated FA (C14:0, C16:0 and C18:0), C18:1, C18:2 and C18:3 isomers and seven other models for OBCFA. For the seed/oil/fat subset, intakes of total C18:3, C18:2 and starch content increased the duodenal t11-C18:1 flow with 0.08, 0.16 and 0.005 g/kg of dry matter intake (DMI), respectively, whereas intake level [(DMI×100)/BW] decreased it. The c9c12c15-C18:3 RBH was higher for oil/fat than seed (96.7% v. 94.8%) and a protective effect of Leguminosae v. Gramineae against RBH for that FA appeared in the forage subset. The duodenal C17:0 flow increased with starch content and decreased with ruminal pH, respectively, whereas duodenal iso-C16:0 flow decreased with dietary NDF content for the seed/oil/fat subset. The duodenal C20:5n-3, C22:5n-3 and C22:6n-3 flows depended on their respective intake and the inhibitory effect of C22:6n-3 on duodenal C18:0 flow was quantified. Thirteen models of absorbed FA flows were performed depending on their respective duodenal flows. This study determined the effects of different qualitative and quantitative dietary and digestive factors, allowing for improved predictions of duodenal and absorbed FA flows.     

K-FGF mediated transformation and induction of metastatic potential involves altered ornithine decarboxylase and S-adenosylmethionine decarboxylase expression – role in cellular invasion

Adult male Wistar rats were exposed to intermittent high altitude hypoxia of 7000 m simulated in a hypobaric chamber for 8 h/day, 5 days a week; the total number of exposures was 25. The concentration of individual phospholipids and their fatty acid (FA) profile was determined in right (RV) and left (LV) ventricles. Adaptation to hypoxia decreased the concentration of diphosphatidylglycerol (DPG) in hypertrophied RV by 19% and in non-hypertrophied LV by 12% in comparison with normoxic controls. Chronically hypoxic hearts exhibited lower phospholipid n-6 polyunsaturated FA (PUFA) content mainly due to decreased linoleic acid (18:2n-6), which was opposed by increased n-3 PUFA mainly due to docosahexaenoic acid (22:6n-3) in phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylinositol (PI). The content of arachidonic acid (20:4n-6) was unchanged in total phospholipids, but in PC it was increased in both ventricles (by 22%) and in PE decreased in LV only (by 20%). Chronic hypoxia increased the un-saturation index of PC and PE in both ventricles. The content of monounsaturated FA (MUFA) was increased and 18:2n-6 decreased in DPG. The proportion of saturated FA was increased in PC and PI of hypoxic RV but not LV. The FA composition of phosphatidylserine was not altered in hypoxic ventricles. It is concluded that chronic hypoxia led to only minor changes in individual phospholipid concentration in rat ventricular myocardium, but markedly altered their FA profile. These changes, in particular the greater incorporation of n-3 PUFA into phospholipids and increased un-saturation index, may lead to a better preservation of membrane integrity and thereby contribute to improved ischemic tolerance of chronically hypoxic hearts.     

Contrasting effects of membrane enrichment with polyunsaturated fatty acids on phospholipid composition and cholesterol efflux from cholesterol-loaded J774 mouse or primary human macrophages

A high consumption of polyunsaturated fatty acids (PUFAs), particularly n-3 PUFAs, is atheroprotective. PUFAs incorporation into membrane phospholipids alters the functionality of membrane proteins. We studied the consequences of the in vitro supplementation of several PUFAs on the FA profiles and on ABCA1-dependent cholesterol efflux capacities from cholesterol-loaded macrophages. Arachidonic acid (AA, C20:4 n-6) and, to a lesser extent, eicosapentaenoic acid (EPA, C20:5 n-3), dose-dependently impaired cholesterol efflux from cholesterol-loaded J774 mouse macrophages without alterations in ABCA1 expression, whereas docosahexaenoic acid (DHA, C22:6 n-3) had no impact. AA cells exhibited higher proportions of arachidonic acid and adrenic acid (C22:4 n-6), its elongation product. EPA cells exhibited slightly higher proportions of EPA associated with much higher proportions of docosapentaenoic acid (C22:5 n-3), its elongation product and with lower proportions of AA. Conversely, both EPA and DHA and, to a lesser extent, AA decreased cholesterol efflux from cholesterol-loaded primary human macrophages (HMDM). The differences observed in FA profiles after PUFA supplementations were different from those observed for the J774 cells. In conclusion, we are the first to report that AA and EPA, but not DHA, have deleterious effects on the cardioprotective ABCA1 cholesterol efflux pathway from J774 foam cells. Moreover, the membrane incorporation of PUFAs does not have the same impact on cholesterol efflux from murine (J774) or human (HMDM) cholesterol-loaded macrophages. This finding emphasizes the key role of the cellular model in cholesterol efflux studies and may partly explain the heterogeneous literature data on the impact of PUFAs on cholesterol efflux.     

Effect of botanical composition of silages on rumen fatty acid metabolism and fatty acid composition in longissimus muscle and subcutaneous fat of lambs

To study the effect of feeding silages with different botanical composition, on rumen and lamb fat, 30 male lambs were assigned to five different silage groups for 11 weeks: botanically diverse silage (BDS); white clover silage (WCS); red clover silage (RCS), intensive English ryegrass silage (IRS) and crushed linseed and maize silage (MSL). Besides the silages, animals received organic wheat and barley and the MSL group additionally received bicarbonate (15 g/day). Silages were sampled when the bales were opened and analysed for fatty acid (FA) content and chemical composition. At slaughter, ruminal contents were sampled and 24 h after slaughter, longissimus muscle and subcutaneous (SC) fat were sampled. All samples were analysed for FA composition. The MSL group ingested the highest amount of FA (35.8 g/day v. 13.5, 19.4, 17.2 and 30.4 g/day for MSL v. BDS, WCS, RCS and IRS, respectively) and the sum of the major polyunsaturated FA, C18:2 n-6 and C18:3 n-3, was similar for groups BDS, WCS, RCS and MSL (61.3 g/100 g, 62.3 g/100 g, 62.3 g/100 g, 63.7 g/100 g of FA methylesters (FAME), respectively), while group IRS ingested higher proportions of these FA (74.5 g/100 g of FAME). Rumen data showed that animals fed BDS presented higher proportions of biohydrogenation intermediates, particularly C18:1 t11 and CLA c9t11, suggesting partial inhibition of rumen biohydrogenation. In the MSL group, the content of C18:3 n-3 in the rumen was highest, most probably due to reduced lipolysis and hence biohydrogenation through the combined effect of esterified C18:3 n-3 and seed protection. Additionally, C18:3 n-3 proportions were higher in rumen contents of RCS animals compared with WCS animals, which could be due to the activity of the polyphenol oxidase enzyme in the RC silages. Proportions of C18:3 n-3 were similar between treatments both for SC and intramuscular (IM) fat, whereas CLA c9t11 content was higher in the SC fat of BDS animals and lower in the IM fat of IRS animals compared with the other forage groups. No differences were found for C20:4 n-6, C20:5 n-3, C22:5 n-3 and C22:6 n-3 in the IM fat of the animals. Nevertheless, indices for desaturation and elongation activity in muscle of BDS animals suggest some stimulation of the first three steps of desaturation and elongation (Δ6-desaturase, elongase and Δ5-desaturase) of long-chain FA.     

Milk and meat fatty acids from sheep fed a plantain–chicory mixture or a grass-based permanent sward

Plantain and chicory are interesting forage species since they present good nutritional quality and are more resistant to drought than many temperate grasses. The fatty acid (FA) profile in milk and meat is related to a growing concern for the consumption of healthy foods, that is, with a lower content of saturated FA, higher polyunsaturated FA (PUFA) and a favourable n-6 : n-3 FAs ratio. Our objective was to evaluate the FA content in ewe’s milk and lamb’s meat fed a plantain–chicory mixture (PCH) or a grass-based permanent sward (GBS) dominated by perennial ryegrass. Eighteen Austral ewes in mid-lactation were allocated to PCH and GBS treatments. Milk samples were obtained during September (spring). Thirty weaned lambs were finished on both treatments from November to December (7 weeks), slaughtered and their meat sampled. Fat from milk and meat samples was extracted and stored until analysed by gas chromatography. Milk fat from GBS was higher than from PCH (P < 0.05) in C18:0 (11 385 v. 5874 mg/100 g FA), 9c-18:1 (15 750 v. 8565 mg/100 g FA), 11 t-18:1 (4576 v. 2703 mg/100 g FA) and 9c,11 t-18:2 (1405 v. 921 mg/100 g FA) and lower in 18:2n-6 (827 v. 1529 mg/100 g FA) and 18:3n-3 (943 v. 1318 mg/100 g FA) FA. Total mono-unsaturated FA was higher in GBS than PCH (P < 0.05). Meat fat from PCH swards presented a higher (P < 0.05) content than GBS for 18:2n-6 (46.8 v. 28.2 mg/100 g FA), linolenic (24.6 v. 14.2 mg/100 g FA), polyunsaturated FA (119.7 v. 73.4 mg/100 g FA), n-6 (65.9 v. 40.8 mg/100 g FA) and n-3 (53.8 v. 32.5 mg/100 g FA), respectively. No effect of treatment (P > 0.05) was detected for 9c-18:1 (283.9 v. 205.8 mg/100 g FA), 11 t-18:1 (26.2 v. 19.3 mg/100 g FA) and 9c,11 t-18:2 (10.1 v. 7.6 mg/100 g FA), for PCH and GBS. These results suggest that grazing a PCH mixture results in a higher concentration of PUFA in ewes’ milk and in lambs’ fat, as compared to a GBS sward.     

Metabolic fate of yolk fatty acids in the developing king penguin embryo

This study examines the metabolic fate of total and individual yolk fatty acids (FA) during the embryonic development of the king penguin, a seabird characterized by prolonged incubation (53 days) and hatching (3 days) periods, and a high n-3/n-6 polyunsaturated FA ratio in the egg. Of the approximately 15 g of total FA initially present in the egg lipid, 87% was transferred to the embryo by the time of hatching, the remaining 13% being present in the internalized yolk sac of the chick. During the whole incubation, 83% of the transferred FA was oxidized for energy, with only 17% incorporated into embryo lipids. Prehatching (days 0-49), the fat stores (triacylglycerol) accounted for 58% of the total FA incorporated into embryo lipid. During hatching (days 49-53), 40% of the FA of the fat stores was mobilized, the mobilization of individual FA being nonselective. At hatch, 53% of the arachidonic acid (20:4n-6) of the initial yolk had been incorporated into embryo lipid compared with only 15% of the total FA and 17-24% of the various n-3 polyunsaturated FA. Similarly, only 32% of the yolk's initial content of 20:4n-6 was oxidized for energy during development compared with 72% of the total FA and 58-66% of the n-3 polyunsaturated FA. The high partitioning of yolk FA toward oxidization and the intense mobilization of fat store FA during hatching most likely reflect the high energy cost of the long incubation and hatching periods of the king penguin. The preferential partitioning of 20:4n-6 into the structural lipid of the embryo in the face of its low content in the yolk may reflect the important roles of this FA in tissue function.     

Dietary lipid quality and mitochondrial membrane composition in trout: responses of membrane enzymes and oxidative capacities

To examine whether membrane fatty acid (FA) composition has a greater impact upon specific components of oxidative phosphorylation or on overall properties of muscle mitochondria, rainbow trout (Oncorhynchus mykiss) were fed two diets differing only in FA composition. Diet 1 was enriched in 18:1n-9 and 18:2n-6 while Diet 2 was enriched in 22:6n-3. The FA composition of mitochondrial phospholipids was strongly affected by diet. 22:6n-3 levels were twice as high (49 %) in mitochondrial phospholipids of fish fed Diet 2 than in those fed Diet 1. 18:2n-6 content of the phospholipids also followed the diets, whereas 18:1n-9 changed little. All n-6 FA, most notably 22:5n-6, were significantly higher in fish fed Diet 1. Nonetheless, total saturated FA, total monounsaturated FA and total polyunsaturated FA in mitochondrial phospholipids varied little. Despite a marked impact of diet on specific FA levels in mitochondrial phospholipids, only non-phosphorylating (state 4) rates were higher in fish fed Diet 2. Phosphorylating rates (state 3), oxygen consumption due to flux through the electron transport chain complexes as well as the corresponding spectrophotometric activities did not differ with diet. Body mass affected state 4 rates and cytochrome c oxidase and F ₀ F ₁ ATPase activities while complex I showed a diet-specific effect of body mass. Only the minor FA that were affected by body mass were correlated with functional properties. The regulated incorporation of dietary FA into phospholipids seems to allow fish to maintain critical membrane functions even when the lipid quality of their diets varies considerably, as is likely in their natural environment.     

Reduced G protein-coupled signaling efficiency in retinal rod outer segments in response to n-3 fatty acid deficiency

The fatty acid (FA) docosahexaenoic acid (DHA, 22: 6n-3) is highly enriched in membrane phospholipids of the central nervous system and retina. Loss of DHA because of n-3 FA deficiency leads to suboptimal function in learning, memory, olfactory-based discrimination, spatial learning, and visual acuity. G protein-coupled receptor (GPCR) signal transduction is a common signaling motif in these neuronal pathways. Here we investigated the effect of n-3 FA deficiency on GPCR signaling in retinal rod outer segment (ROS) membranes isolated from rats raised on n-3-adequate or -deficient diets. ROS membranes of second generation n-3 FA-deficient rats had approximately 80% less DHA than n-3-adequate rats. DHA was replaced by docosapentaenoic acid (22:5n-6), an n-6 FA. This replacement correlated with desensitization of visual signaling in n-3 FA-deficient ROS, as evidenced by reduced rhodopsin activation, rhodopsin-transducin (G(t)) coupling, cGMP phosphodiesterase activity, and slower formation of metarhodopsin II (MII) and the MII-G(t) complex relative to n-3 FA-adequate ROS. ROS membranes from n-3 FA-deficient rats exhibited a higher degree of phospholipid acyl chain order relative to n-3 FA-adequate rats. These findings reported here provide an explanation for the reduced amplitude and delayed response of the electroretinogram a-wave observed in n-3 FA deficiency in rodents and nonhuman primates. Because members of the GPCR family are widespread in signaling pathways in the nervous system, the effect of reduced GPCR signaling due to the loss of membrane DHA may serve as an explanation for the suboptimal neural signaling observed in n-3 FA deficiency.     

Online prediction of fatty acid profiles in crossbred Limousin and Aberdeen Angus beef cattle using near infrared reflectance spectroscopy

The objective of this study was to examine the online use of near infrared reflectance (NIR) spectroscopy to estimate the concentration of individual and groups of fatty acids (FA) as well as intramuscular fat (IMF) in crossbred Aberdeen Angus (AA×) and Limousin (LIM×) cattle. This was achieved by direct application of a fibre-optic probe to the muscle immediately after exposing the meat surface in the abattoir at 48 h post mortem. Samples of M. longissimus thoracis from 88 AA× and 106 LIM× were scanned over the NIR spectral range from 350 to 1800 nm and samples of the M. longissimus lumborum were analysed for IMF content and FA composition. Statistically significant differences (P < 0.001) were observed in most FA between the two breeds studied, with FA concentration being higher in AA× meat mainly. NIR calibrations, tested by cross-validation, showed moderate to high predictability in LIM× meat samples for C16:0, C16:1, C18:0, trans11 C18:1, C18:1, C18:2 n-6, C20:1, cis9, trans11 C18:2, SFA (saturated FA), MUFA (monounsaturated FA), PUFA (polyunsaturated FA) and IMF content with R(2) (SE(CV), mg/100 g muscle) of 0.69 (146), 0.69 (28), 0.71 (62), 0.70 (8.1), 0.76 (192), 0.65 (13), 0.71 (0.9), 0.71 (2.9), 0.68 (235), 0.75 (240), 0.64 (17) and 0.75 (477), respectively. FA such as C14:0, C18:3 n-3, C20:4 n-6, C20:5 n-3, C22:6 n-3, n-6 and n-3 were more difficult to predict by NIR in these LIM× samples (R(2) = 0.12 to 0.62; SECV = 0.5 to 26 mg/100 g muscle). In contrast, NIR showed low predictability for FA in AA× beef samples. In particular for LIM×, the correlations of NIR measurements and several FA in the range from 0.81 to 0.87 indicated that the NIR spectroscopy is a useful online technique for the early, fast and relatively inexpensive estimation of FA composition in the abattoir.     

Chemical composition of eggs of the Olive Ridley Lepidochelys olivacea (Testudines: Cheloniidae) and it's potential as a food source

The Olive Ridley is a worldwide distributed species with high nesting production per season, and in La Escobilla Oaxaca, México, there is a 70% of non-hatched eggs that are lost. In order to evaluate their potential use as a source for human and animal food products, their chemical composition was analyzed. Lyophilized egg samples from 25 turtles were obtained and were analyzed following the analytical methods for fatty acids, protein, fat, ash, moisture, amino acids, vitamins, cholesterol and microbiological agents. The analytical composition obtained was (g/100g): moisture (4.7), ash (3.8), protein (53.7), and fat (47.4). The essential amino acid (g aa/100g protein) content was: Ile (4.4), Lys (6.6), Leu (7.4), Met+Cys (8.8), Phe+Tyr (10.8). The vitamin content was: retinol (340 microg/100g), cholecalciferol (5.91 microg/100g) and 8.6 mg/100 tocopherol, 0.3 mg/100g thiamine and 1.1 mg/100g riboflavin. The total lipid content (TL), fatty acids (FA), and cholesterol (Chol) were divided into three groups based on the weight of the turtle: (TL) (44.3-48.7-49.1g/100g) and (Chol) (518.4-522.5 mg/100g-728.7). A total of 17 Saturated FA (SFA), 8 Monounsaturated FA (MUFA) and 11 Polyunsaturated FA (PUFA) were identified. The most abundant SFA (mg/100g) were: C14:0 (445-772), C16:0 (485-1263); MUFA: C16:1 (456-716), C18:1n-9c (904-1754), and PUFA: C20:4n-6 (105-217); two n-3 fatty acids were identified EPA (48-103) and DHA (97-189).There were significant differences (Fisher, p < 0.05) for: (Chol), total FA, SFA, MUFA, PUFAs and n-3 (EPA + DHA) FA. It was not detected any microbiological agent. In conclusion, lyophilized L. olivacea eggs are an option for its inclusion in the development of food products as they can be used as a high quality biological protein and n-3 fatty acid source for fortification and enrichment.     

Dietary lipids during early pregnancy differently influence adipose tissue metabolism and fatty acid composition in pregnant rats with repercussions on pup's development

Pregnant rats received soybean (SO), olive (OO), fish (FO) and linseed (LO) oil diets from conception to d12 of gestation (early diets) and standard diet thereafter. At d12 and d20 the lipoprotein lipase (LPL) activity was evaluated in maternal adipose tissues (ATs). Fatty Acid (FA) profile was determined in maternal lumbar AT (LAT), in milk and in pup's plasma and brain. LPL activity was higher in ATs at d12 than d20, all groups presenting hypertriglyceridemia at d20. At d12, the LO diet resulted higher LPL activity and incorporation of 18:3 n-3 into LAT. FA profile in maternal LAT at d20 and colostrum was similar to early diets, reflected also in FA composition of pup's plasma. In FO, brain phospholipids had higher 22:6 n-3 without affecting arachidonic acid. These results suggest that specifics dietary FA in early pregnancy modulates lipid metabolism and the provision of LC-PUFA in milk and pups brain.     

Quantitative association between altered plasma esterified omega-6 fatty acid proportions and psychological stress.

Medical students (MS) tested during the first year of medical school showed both greater stress on the Brief Symptom Inventory and lower plasma proportions of total esterified arachidonic acid (AA, C20:4n-6), and its omega-6 fatty acid (FA) precursor, linoleic acid (C18:2n-6) than control laboratory workers. This association suggests that omega-6 FA metabolism may be affected during stress. Low AA values might result from depletion of plasma stores for immunoregulatory prostenoids formation or from modification of metabolic pathways by cortisol or other cytokine compounds implicated in stress. Values for other major FA and the omega-3 neuronal metabolic substrate, docosahexaenoic acid (DHA, C22:6n-3) were similar between students and controls. The clear preservation of the omega-3 FA pathway suggests their programmed availability for neuronal function during stress. Since plasma FA proportions may affect immune cell membrane function(s), we suggest that altered values of plasma FAs may be an important component of the physiological effects of psychological stress.     

Maternal dietary n-3 fatty acids alter immune cell fatty acid composition and leukotriene production in growing chicks

The effect of feeding different amounts of n-6 and n-3 fatty acids (FA) to hens on immune tissue FA composition and leukotriene production of hatched chicks was investigated. Hens were fed diets supplemented with either 3.0% sunflower oil (Diet I), 1.5% sunflower+1.5% fish oil (Diet II), or 3.0% fish oil (Diet III) for 46 days. The hatched chicks were fed a diet containing C18:3n-3, but devoid of longer chain n-6 and n-3 FA, for 21 days. Spleen docosahexaenoic acid (DHA) content was higher in chicks from hens fed Diet III (P<0.05). The bursa content of arachidonic acid was lower in chicks hatched from hens fed Diet III (P<0.05), and the ratio of n-6 to n-3 FA was significantly higher in bursa of chicks hatched to hens fed Diet I (P<0.05). Eicosapentaenoic acid (EPA) and DHA contents were higher in bursa of chicks hatched from hens fed Diet III (P<0.05). Thrombocytes from chicks hatched to hens fed Diet III produced the most leukotriene B(5) (LTB(5)). The ratio of LTB(5) to LTB(4) concentrations was also highest (P<0.05) in chicks hatched to hens fed Diet III. These results indicate that modulating maternal dietary n-6 and n-3 FA may alter leukotriene production in chicks, which could lead to less inflammatory-related disorders in poultry.