Showing papers in "Lipids in 2006"
TL;DR: The results of this study demonstrate that the proportion of saturated and monounsaturated FA are relatively constant across a large number of countries, whereas the level of some of the PUFA, especially DHA, are highly variable.
Abstract: Many published studies of breast milk FA composition are limited to populations from one or two countries We aimed to examine the degree to which FA compositions vary across a number of diverse populations Because diet and maternal adipose stores influence breast milk FA composition, differences in FA composition between groups most likely reflect habitual dietary differences Approximately 50 breast milk samples (full breast expression) were collected from women in Australia, Canada, Chile, China, Japan, Mexico, Philippines, the United Kingdom, and the United States The proportion of saturated FA was relatively constant among countries, with the exception of the Philippines, where levels of lauric and myristic acids were elevated (means greater than two times the mean of most other countries) Monounsaturated FA also varied little, with the exception of low levels of oleic acid in the Philippines and high levels of erucic acid in China Although arachidonic acid (C20:4n-6) levels were similar among all countries (means ranging from 036 wt % to 049 wt %), mean DHA (C22:6n-3) levels ranged from 017 to 099 wt %, with the highest levels in Japanese milk and the lowest levels in Canadian and US samples The results of this study demonstrate that the proportion of saturated and monounsaturated FA are relatively constant across a large number of countries, whereas the level of some of the PUFA, especially DHA, are highly variable
339 citations
TL;DR: The current understanding of the terminal step in TAG formation in plants and the development of molecular genetic approaches aimed at altering TAG yield and FA composition of TAG are discussed.
Abstract: Many plants deposit TAG in seeds and fruits as the major form of storage lipid. TAG production is of tremendous socioeconomic value in food, nutraceutical, and industrial applications, and thus numerous conventional and molecular genetic strategies have been explored in attempts to increase TAG content and modify the FA composition of plant seed oils. Much research has focused on the acyl-CoA-dependent reaction catalyzed by diacylglycerol acyltransferase (DGAT), which is an integral endoplasmic reticulum protein and has also been shown to be present in oil bodies and plastids. DGAT enzymes exhibit diverse biochemical properties among different plant species, many of which are summarized here. In addition to catalyzing a critical step in TAG biosynthesis, there is evidence that DGAT has roles in lipid metabolism associated with germination and leaf senescence. TAG can also be formed in plants via two different acyl-CoA-independent pathways, catalyzed by phospholipid: diacylglycerol acyltransferase and diacylglycerol transacylase. The current understanding of the terminal step in TAG formation in plants and the development of molecular genetic approaches aimed at altering TAG yield and FA composition of TAG are discussed.
306 citations
TL;DR: Quantitative real-time PCR assay of gene expression in cod showed that the Δ6 desaturase gene was expressed highly in brain, to a slightly lesser extent in liver, kidney, intestine, red muscle, and gill, and at much lower levels in white muscle, spleen, and heart.
Abstract: This study reports the cloning, functional characterization, tissue expression, and nutritional regulation of a Δ6 fatty acyl desaturase of Atlantic cod (Gadus morhua). PCR primers were designed based on the sequences of conserved motifs in available fish desaturases and used to isolate a cDNA fragment from cod liver, with full-length cDNA obtained by rapid amplification of cDNA ends. The cDNA for the putative desaturase was shown to comprise 1980 bp, including a 261-bp 5′-UTR, a 375-bp 3′-UTR, and an ORF of 1344 bp that specified a protein of 447 amino acids. The protein sequence included three histidine boxes, two transmembrane regions, and an N-terminal cytochrome b5 domain containing the heme-binding motif HPGG, all characteristic of microsomal fatty acyl desaturases. The cDNA displayed Δ6 desaturase activity in a yeast expression system. Quantitative real-time PCR assay of gene expression in cod showed that the Δ6 desaturase gene was expressed highly in brain, to a slightly lesser extent in liver, kidney, intestine, red muscle, and gill, and at much lower levels in white muscle, spleen, and heart. The expression of the Δ6 desaturase gene did not appear to be under significant nutritional regulation, with levels in liver and intestine being barely altered in fish fed a vegetable oil blend, in comparison with levels in fish fed fish oil. This was reflected in enzyme activity, as hepatocytes or enterocytes showed very little highly unsaturated FA biosynthesis activity irrespective of diet. Further studies are required to determine why the Δ6 desaturase appears to be barely functional in cod under the conditions tested.
210 citations
TL;DR: Data is shown to support the view that the DHA, as well as docosapentaenoic acid, that accumulate in Schizochytrium are products of a multi-subunit polyunsaturated fatty acid (PUFA) synthase, and other aspects of fatty acid synthesis in this organism are provided.
Abstract: Schizochytrium sp. is a marine microalga that has been developed as a commercial source for docosahexaenoic acid (DHA, C22∶6 ω−3), enriched biomass, and oil. Previous work suggested that the DHA, as well as docosapentaenoic acid (DPA, C22∶5 ω−6), that accumulate in Schizochytrium are products of a multi-subunit polyunsaturated fatty acid (PUFA) synthase (1). Here we show data to support this view and also provide information of other aspects of fatty acid synthesis in this organism. Three genes encoding subunits of the PUFA synthase were isolated from genomic DNA and expressed in E. coli along with an essential accessory gene encoding a phosphopantetheinyl transferase (PPTase). The resulting transformants accumulated both DHA and DPA. The ratio of DHA to DPA was approximately the same as that observed in Schizochytrium. Treatment of Schizochytrium cells with certain levels of cerulenin resulted in inhibition of 14C acetate incorporation into short chain fatty acids without affecting labeling of PUFAs, indicating distinct biosynthetic pathways. A single large gene encoding the presumed short chain fatty acid synthase (FAS) was cloned and sequenced. Based on sequence homology and domain organization, the Schizochytrium FAS resembles a fusion of fungal FAS β and α subunits.
150 citations
TL;DR: The ex vivo study revealed that BRE had significantly stronger ability to inhibit LDL oxidation than white rice extract (WRE) and antioxidative effects exerted by BRE are mediated through decreases in free-radical generation as well as increases in SOD and CAT activities both in vitro and in vivo.
Abstract: Our ex vivo study revealed that BRE had significantly stronger ability to inhibit LDL oxidation than white rice extract (WRE). The purpose of this study was to investigate whether black rice extract (BRE) supplementation might ameliorate oxidative stress and enhance antioxidant enzyme activities in HepG2 cells and in C57BL/6 mice. In the cellular study, superoxide anions (O2.−) and reactive oxygen species (ROS) in the BRE group were significantly suppressed. The BRE group also showed significant increases in superoxide dismutase (SOD) and catalase (CAT) activities by 161.6% and 73.4%, respectively. The major components responsible for the free-radical-scavenging and antioxidative properties might be cyanidin−3-O-glucoside chloride and peonidin-3-O-glucuside chloride. In the animal study, male C57BL/6 mice were divided into three groups (control, BRE, and WRE). Plasma HDL-cholesterol was significantly higher, and thiobarbituric, acid-reactive substances were significantly lower in the BRE group, whereas plasma levels of total cholesterol and triglyceride were not affected by BRE supplementation. Increased hepatic SOD and CAT activities were observed in BRE-treated mice as compared to the control mice. However, no changes were detected for the protein expression of antioxidant enzymes by Western blot analysis. Our data suggest that antioxidative effects exerted by BRE are mediated through decreases in free-radical generation as well as increases in SOD and CAT activities both in vitro and in vivo.
127 citations
TL;DR: The mean LA and overall n-6 PUFA intake corresponded with the recommendation, with part of the population exceeding the upper level, and the population showed a large deficit for LNA and n-3 PUFA.
Abstract: The intake of fat, saturated and monounsaturated FA (SFA and MUFA), and omega-6 and omega-3 PUFA has been estimated in 641 Belgian women (age 18-39 y). Their food intake was recorded using a 2-d food diary. The PUFA included were linoleic (LA), alpha-linolenic (LNA), arachidonic (AA), eicosapentaeonoic (EPA), docosapentaenoic (DPA) and docosahexaenoic (DHA) acids. The mean total fat intake corresponded to 34.3% of total energy intake (E). The mean intake of the FA groups corresponded to 13.7%, 13.1%, and 6.0% of E, for SFA, MUFA, and PUFA, respectively. The mean intake of LA was 5.3% of E and of LNA was 0.6% of E, with a mean LA/LNA ratio of 8.7. The mean intake of AA was 0.03% of E. The mean intake of EPA, DPA, and DHA was 0.4%, 0.01%, and 0.06% of E, respectively. According to the Belgian recommendations, the total fat and SFA intake was too high for about three-quarters of the population. The mean LA and overall n-6 PUFA intake corresponded with the recommendation, with part of the population exceeding the upper level. Conversely, the population showed a large deficit for LNA and n-3 PUFA. The major food source for LA and LNA was fats and oils, followed by cereal products. The main sources of long-chain PUFA were fish and seafood, and meat, poultry, and eggs. From a public health perspective, it seems desirable to tackle the problem of low n-3 PUFA intake.
127 citations
TL;DR: It is shown that long-term exposure to cold temperature causes a significant increase in EPA, HUFA such as ARA and EPA, which are highly conserved during starvation and therefore, D. pulex has the biosynthetic capacity to adjust and to maintain the content of HU FA required to survive at low temperatures.
Abstract: Poikilothermic organisms accumulate highly unsturated FA (HUFA) in their lipids at reduced temperatures to maintain cell membrane fluidity. In this study we investigated the effect of temperature on temporal trajectories of FA of fasting Daphnia pulex cultured on a HUFA-free diet. Daphnia pulex populations were maintained for 1 mon at 22 and 11°C and were fed the chlorophyte Ankistrodesmus falcatus. We observed conversion of C18 FA precursors to EPA (20∶5n3) and arachidonic acid (ARA; 20∶4n6) in D. pulex. We showed that long-term exposure to cold temperature causes a significant increase in EPA, HUFA such as ARA and EPA are highly conserved during starvation. Therefore, D. pulex has the biosynthetic capacity to adjust and to maintain the content of HUFA required to survive at low temperatures.
123 citations
TL;DR: This review presents structures and describes cytotoxic and anticancer activities only for more than 300 acetylenic lipids and their derivatives isolated from living organisms.
Abstract: This review is a comprehensive survey of acetylenic lipids and their derivatives, obtained from living organisms, that have anticancer activity. Acetylenic metabolites belong to a class of molecules containing triple bond(s). They are found in plants, fungi, microorganisms, and marine invertebrates. Although acetylenes are common as components of terrestrial plants, fungi, and bacteria, it is only within the last 30 years that biologically active polyacetylenes having unusual structural features have been reported from plants, cyanobacteria, algae, invertebrates, and other sources. Naturally occurring aquatic acetylenes are of particular interest since many of them display important biological activities and possess antitumor, antibacterial, antimicrobial, antifouling, antifungal, pesticidal, phototoxic, HIV-inhibitory, and immunosuppressive properties. There is no doubt that they are of great interest, especially for the medicinal and/or pharmaceutical industries. This review presents structures and describes cytotoxic and anticancer activities only for more than 300 acetylenic lipids and their derivatives isolated from living organisms.
120 citations
TL;DR: It is shown that a high amount of olive oil consumption is not associated with higher weight gain or a significantly higher risk of developing overweight or obesity in the context of the Mediterranean food pattern.
Abstract: The aim of this dynamic prospective follow-up study was to assess the association between olive oil consumption and the likelihood of weight gain or the incidence of overweight or obesity in a large Mediterranean cohort of 7,368 male and female Spanish university graduates (the SUN Project) who were followed for a median period of 28.5 mon. A validated Food Frequency Questionnaire was administered at baseline, and respondents also completed a follow-up questionnaire after 28.5 mon. Changes in participants' consumption of olive oil and their weight were assessed during follow-up. A higher baseline consumption of olive oil was associated with a lower likelihood of weight gain, although the differences were not statistically significant. The adjusted difference in weight gain (kg) was -0.16 [95% confidence interval (CI): -0.42 to +0.11] for participants in the upper quintile of olive oil consumption (median: 46 g/d) compared with those in the lowest quintile (median: 6 g/d). For participants with a high baseline consumption of olive oil whose olive oil consumption also increased during follow-up, we found a slightly increased but nonsignificant risk of incidence of overweight or obesity (adjusted odds ratio = 1.19, 95% CI: 0.73 to 1.95). Our study, carried out in a sample of free-living people, shows that a high amount of olive oil consumption is not associated with higher weight gain or a significantly higher risk of developing overweight or obesity in the context of the Mediterranean food pattern.
103 citations
TL;DR: These observations suggest that dietary AP at 0.5 or 1.0% level exerts hypocholesterolemic and antiatherogenic effects through the promotion of cholesterol catabolism and inhibition of intestinal absorption of cholesterol.
Abstract: The dose-dependent hypocholesterolemic and antiatherogenic effects of dietary apple polyphenol (AP) from unripe apple, which contains approximately 85% catechin oligomers (procyanidins), were examined in male Sprague-Dawley rats (4 wk of age) given a purified diet containing 0.5% cholesterol. Dietary AP at 0.5 and 1.0% levels significantly decreased the liver cholesterol level compared with that in the control (AP-free diet-fed) group. Dietary AP also significantly lowered the serum cholesterol level compared with that in the control group. However, the HDL cholesterol level was significantly higher in the 1.0% AP-fed group than in the control group. Accordingly, the ratio of HDL-cholesterol/total cholesterol was significantly higher in the 0.5% AP-fed group and 1.0% AP-fed group than in the control group. Moreover, the atherogenic indices in the 0.5 and 1.0% AP-fed groups were significantly lower than those in the control group. The activity of hepatic cholesterol 7alpha-hydroxylase tended to be increased by dietary AP in a dose-dependent manner. In accord with this observation, dietary AP increased the excretion of acidic steroids in feces. Dietary AP also significantly promoted the fecal excretion of neutral steroids in a dose-dependent manner. These observations suggest that dietary AP at a 0.5 or 1.0% level exerts hypocholesterolemic and antiatherogenic effects through the promotion of cholesterol catabolism and inhibition of intestinal absorption of cholesterol.
101 citations
TL;DR: Challenges to the food industry in replacing trans FA in foods are to develop formulation options that provide equivalent functionality, are economically feasible, and do not greatly increase saturated FA content.
Abstract: Dietary trans FA at sufficiently high levels have been found to increase low density lipoprotein (LDL)-cholesterol and decrease high density lipoprotein (HDL)-cholesterol (and thus to increase the ratio of LDL-cholesterol/HDL-cholesterol) compared with diets high in cis monounsaturated FA or PUFA. The dietary levels of trans FA at which these effects are easily measured are around 4% of energy or higher to increase LDL-cholesterol and around 5 to 6% of energy or higher to decrease HDL-cholesterol, compared with essentially trans-free control diets. Very limited data at lower levels of intake (less than 4% of energy) are available. Most health professional organizations and some govemments now recommend reduced consumption of foods containing trans FA, and effective January 1, 2006, the U.S. Food and Drug Administration requires the labeling of the amounts of trans FA fer serving in packaged foods. In response, the food industry is working on ways to eliminate or greatly reduce trans FA in food products. Current efforts focus on four technological options: (i) modification of the hydrogenation process, (ii) use of interesterification, (iii) use of fractions high in solids from natural oils, and (iv) use of trait-enhanced oils. Challenges to the food industry in replacing trans FA in foods are to develop formulation options that provide equivalent functionality, are economically feasible, and do not greatly increase saturated FA content.
TL;DR: Experiments indicate that the charge aerosol detector has the potential to become a valuable tool for the quantitative HPLC analysis of lipids, and long-term studies are needed to evaluate full instrument performance.
Abstract: Because most lipid extracts are a mixture of saturated and unsaturated molecules, the most successful strategies for the quantitative analysis of lipids have involved the use of so-called “mass” or universal detectors such as flame ionization detectors and evaporative light scattering detectors. Recently a new type of HPLC “mass” detector, a charge aerosol detector (CAD), was developed and is now commercially available. This detection method involves nebulizing the HPLC column effluent, evaporating the solvents charging the aerosol particles, and measuring the current from the charged aerosol flux. In the present study, the CAD was evaluated with several normal phase and reverse phase HPLC methods commonly used for the quantitative analysis of lipid classes and lipid molecular species. The CAD detected common lipids such as triacylglycerols, diacylglycerols, glycolipids, phospholipids, and sterols. Lower molecular weight lipids such as free FA had smaller peak areas (50–80% lower). FAME were not detected by the CAD, probably because they were completely evaporated and did not form aerosol particles. The minimum limits of detection of the CAD with lipids varied with different mobile phase solvents. Using solvent systems that were predominantly hexane, the minimum limits of detection of triacylglycerols, cholesterol esters, and free sterols were about 1 ng per injection and the mass-to-peak area ratio was nearly linear from the range of about 1 ng to about 20 mg per injection. Three other solvents commonly used for HPLC lipid analysis (methanol, isopropanol, and acetonitrile) caused higher levels of background noise and higher minimum limits of detection. These experiments indicate that the CAD has the potential to become a valuable tool for the quantitative HPLC analysis of lipids. Long-term studies are needed to evaluate full instrument performance.
TL;DR: It is proposed that the ceramide level in human plasma is a risk factor at the early stages of atherosclerosis.
Abstract: Atherosclerosis is a multifactorial disorder. Recent studies indicate that the plasma level of sphingomyelin, which yields ceramide, correlates with the risk of coronary heart disease. Therefore, ceramide, a well-known lipid causing apoptosis in various cell types, may contribute to atherogenesis. We examined the relationship between ceramide concentration and risk factors of atherosclerosis in normal human plasma using electrospray tandem mass spectrometry (LC-MS/MS). Major ceramides in human plasma were C24:0 and C24:1. The ceramide concentration showed a significant positive correlation with total cholesterol (TC) and triglycerides (TG). In addition, plasma ceramide level increased drastically at a high level of LDL cholesterol (more than 170 mg/dL). Our previous studies demonstrated that the sum of fragmented and conjugated apolipoprotein B-100 proteins (B-ox), which were products of a radical reaction of LDL as well as plasma, was a reliable index of atherosclerosis. B-ox showed a significant positive correlation with the plasma ceramide level. Based on these results, we propose that the ceramide level in human plasma is a risk factor at the early stages of atherosclerosis.
TL;DR: Fish consumption is more effective in increasing serum EPA and DHA than supplementing the diet with fish oil, and it is suggested that the larger uptake from fish than CLO is due to differences in physiochemical structure of the lipids.
Abstract: This work was undertaken to study the impact of the source of n-3 FA on their incorporation in serum, on blood lipid composition, and on cellular activation. A clinical trial comprising 71 volunteers, divided into five groups, was performed. Three groups were given 400 g smoked salmon (n = 14), cooked salmon (n = 15), or cooked cod (n = 13) per week for 8 wk. A fourth group was given 15 mL/d of cod liver oil (CLO) (n = 15), and a fifth group served as control (n = 14) without supplementation. The serum content of EPA and DHA before and after intervention revealed a higher rise in EPA and DHA in the cooked salmon group (129% rise in EPA and 45% rise in DHA) as compared with CLO (106 and 25%, respectively) despite an intake of EPA and DHA in the CLO group of 3.0 g/d compared with 1.2 g/d in the cooked salmon group. No significant changes were observed in blood lipids, fibrinogen, fibrinolysis, or lipopolysaccharide (LPS)-induced tissue factor (TF) activity, tumor necrosis factor-alpha (TNFalpha), interleukin-8 (IL-8), leukotriene B4 (LTB4), and thromboxane B2 (TxB2) in whole blood. EPA and DHA were negatively correlated with LPS-induced TNFalpha, IL-8, LTB4, TxB2, and TF in whole blood. In conclusion, fish consumption is more effective in increasing serum EPA and DHA than supplementing the diet with fish oil. Since the n-3 FA are predominantly in TAG in fish as well as CLO, it is suggested that the larger uptake from fish than CLO is due to differences in physiochemical structure of the lipids.
TL;DR: The new FFQ is a valid method that can be used to estimate the LC n−3 PUFA intake of adults and is also an effective ranking tool.
Abstract: Long-chain omega-3 PUFA (LC n-3 PUFA) are beneficial for health. To date there is no specific food frequency questionnaire (FFQ) to assess LC n-3 PUFA intakes. The objective of this study is to validate our newly developed FFQ by comparison with LC n-3 PUFA content of both red blood cells (RBC) and plasma, expressed as a percentage of total FA. Fifty-three healthy male and female subjects were recruited from Wollongong, Australia. Average LC n-3 PUFA intakes (mg/d) were estimated using the new FFQ. RBC and plasma FA were assessed using GC. Spearman correlation coefficients were used to assess the linear relationship between FFQ intakes and both RBC and plasma FA. The results show that there were significant Spearman's correlation coefficients between the FFQ intakes and RBC (and plasma) FA for total LC n-3 PUFA, EPA, and DHA (0.50 (0.54), 0.39 (0.54) and 0.40 (0.48), respectively) but not for docosapentaenoic acid. The FFQ was also an effective ranking tool. The FFQ is a valid method based on erythrocyte and plasma FA as biochemical markers. In conclusion, the new FFQ is a valid method that can be used to estimate the LC n-3 PUFA intake of adults.
TL;DR: Raman spectroscopy has been used for the first time to predict the FA composition of unextracted adipose tissue of pork, beef, lamb, and chicken, and it was found that the bulk unsaturation parameters could be predicted successfully.
Abstract: Raman spectroscopy has been used for the first time to predict the FA composition of unextracted adipose tissue of pork, beef, lamb, and chicken. It was found that the bulk unsaturation parameters could be predicted successfully [R2 = 0.97, root mean square error of prediction (RMSEP) = 4.6% of 4 sigma], with cis unsaturation, which accounted for the majority of the unsaturation, giving similar correlations. The combined abundance of all measured PUFA (> or = 2 double bonds per chain) was also well predicted with R2 = 0.97 and RMSEP = 4.0% of 4 sigma. Trans unsaturation was not as well modeled (R2 = 0.52, RMSEP = 18% of 4 sigma); this reduced prediction ability can be attributed to the low levels of trans FA found in adipose tissue (0.035 times the cis unsaturation level). For the individual FA, the average partial least squares (PLS) regression coefficient of the 18 most abundant FA (relative abundances ranging from 0.1 to 38.6% of the total FA content) was R2 = 0.73; the average RMSEP = 11.9% of 4 sigma. Regression coefficients and prediction errors for the five most abundant FA were all better than the average value (in some cases as low as RMSEP = 4.7% of 4 sigma). Cross-correlation between the abundances of the minor FA and more abundant acids could be determined by principal component analysis methods, and the resulting groups of correlated compounds were also well-predicted using PLS. The accuracy of the prediction of individual FA was at least as good as other spectroscopic methods, and the extremely straightforward sampling method meant that very rapid analysis of samples at ambient temperature was easily achieved. This work shows that Raman profiling of hundreds of samples per day is easily achievable with an automated sampling system.
TL;DR: The results indicate that the predominant bacteria, mainly Bacteroides, in human feces comprise one of the main bacterial groups for the deconjugation of bile acid, and clostridia may play an important role in 7α-dehydroxylation of free-form primary bile acids in the intestine although these strains are not predominant.
Abstract: In humans and animals, intestinal flora is indispensable for bile acid transformation. The goal of our study was to establish gnotobiotic mice with intestinal bacteria of human origin in order to examine the role of intestinal bacteria in the transformation of bile acids in vivo using the technique of gnotobiology. Eight strains of bile acid-deconjugating bacteria were isolated from ex-germ-free mice inoculated with a human fecal dilution of 10−6, and five strains of 7α-dehydroxylating bacteria were isolated from the intestine of limited human flora mice inoculated only with clostridia. The results of biochemical tests and 16S rDNA sequence analysis showed that seven out of eight bile acid-deconjugating strains belong to a bacteroides cluster (Bacteroides vulgatus, B. distasonis, and B. uniformis), and one strain had high similarity with Bilophila wadsworthia. All five strains that converted cholic acid to deoxycholic acid had greatest similarity with Clostridium hylemonae. A combination of 10 isolated strains converted taurocholic acid into deoxycholic acid both in vitro and in the mouse intestine. These results indicate that the predominant bacteria, mainly Bacteroides, in human feces comprise one of the main bacterial groups for the deconjugation of bile acids, and clostridia may play an important role in 7α-dehydroxylation of free-form primary bile acids in the intestine although these strains are not predominant. The gnotobiotic mouse with bacteria of human origin could be a useful model in studies of bile acid metabolism by human intestinal bacteria in vivo.
TL;DR: The combination of detailed regiospecific and lipid analyses demonstrated adaptation of cell membrane structure in Atlantic salmon grown at an elevated water temperature.
Abstract: Regiospecific and traditional analysis, of both storage and membrane lipids, was performed on gill, white muscle, and red muscle samples taken from Atlantic salmon (Salmo salar) to gauge the effect of elevated water temperature. The fish, fed a commercial diet, were held at an elevated water temperature of 19°C. Total n-3 PUFA, total PUFA, and n-3/n-6 and unsaturated/saturated fatty acid (UFA/SFA) ratios in the FA profile of the total lipid extract in the white muscle were fairly low compared with fish grown at 15°C. Adaptation of structural and storage lipids at elevated temperatures was shown by a significant (P<0.01) reduction in PUFA especially in the percentage of EPA (6–8%). Further adaptation was indicated by the percentages of SFA, which were significantly (P<0.05) higher in gill (56%) and white muscle (58%) polar lipid fractions and coincided with lower percentages of n-3, n-6, and total PUFA. The regiospecific profiles indicated a high affinity of DHA to the sn-2 position in both the TAG (61–68%) and polar lipid (35–60%) fractions. The combination of detailed regiospecific and lipid analyses demonstrated adaptation of cell membrane structure in Atlantic salmon grown at an elevated water temperature.
TL;DR: Marine oil-based finishing diets can rapidly augment beneficial FA levels in sunshine bass fillets; however, simple dilution models do not fully describe selective FA metabolism observed for this lean-fleshed fish.
Abstract: Marine oil-based finishing diets have been used to restore fillet FA profile in several “medium-fat” fleshed aquaculture species, and a simple dilution model describing FA turnover has been established to predict and tailor final fillet composition. We evaluated finishing diet efficacy and suitability of the dilution model to describe patterns of FA change in a lean-fleshed model, sunshine bass. Two practical diet (45% crude protein, 15% crude lipid) were formulated, respectively containing corn oil (CO) or menhaden oil (MO) as the primary lipid sources. Sunshine bass (age 1 [⊃ 14 mo], 347 ±8.6 g, mean individual weight ±SEM) were stocked in a recirculating system and fed the diets according to different feeding regimens during the final 28 wk of the production cycle. Control groups were fed the CO or the MO feeds exclusively; whereas, the remaining treatment groups were transitioned from the CO diet to the MO diet at 4−, 8−, or 12-wk intervals. Upon completion of the feeding trial, fish were harvested, and production performance and fillet composition were assessed. Replacing MO with CO as the primary lipid source in sunshine bass diets yielded fillets with distinctly different FA profiles; however, finishing with a MO-based diet offered significant compensation for CO-associated reductions in fillet long-chain highly unsaturated FA (LC-HUFA). Although complete restoration was not observed, we achieved significant augmentation of endogenous n−3 FA within 4 wk of feeding the MO diet, and observed a significant increase in LC-HUFA and a beneficial shift in n−3∶n−6 FA ratio after 8 weeks. Simple dilution accurately predicted tissue composition for most FA; however, deviations from the model were noted, suggesting selective retention of n−3, PUFA, and LC-HUFA and preferential catabolism of saturates. We conclude marine oil-based finishing diets can rapidly augment beneficial FA levels in sunshine bass fillets; however, simple dilution models do not fully describe selective FA metabolism observed for this lean-fleshed fish.
TL;DR: To elucidate some of the important genetic components, reverse transcriptase (RT)-PCR and real-time PCR were used to determine the expression profiles of two key FA biosynthetic genes during seed development and the environmental impact on the production of FA in flax was evaluated.
Abstract: Flax's recent popularity in human and animal foods is mostly due to its desirable FA composition. Flax is an excellent source of omega-3 FA, which have been shown to have many health benefits. To date, little is known about the genetic and environmental factors that control the FA composition of flax seeds. To elucidate some of the important genetic components, reverse transcriptase (RT)-PCR and real-time PCR were used to determine the expression profiles of two key FA biosynthetic genes during seed development. Plants of flax cultivar AC McDuff were grown under field conditions, and RNA was extracted from ovaries and developing bolls collected from 2 d after anthesis (DAA) to maturity. Desaturation enzymes stearoyl-ACP desaturase (SAD) and Δ12 FA desaturase 2 (FAD2) were both expressed in ovaries, and their expression was differentially modulated throughout seed development. SAD was most highly expressed in ovaries. Its expression quickly decreased until 4 DAA; this was followed by a slight peak at 8 DAA, only to return to relatively low levels of expression in maturing bolls, ranging from 2.1% to 4.5% relative to the level observed in ovaries. FAD2 expression displayed a different temporal pattern. While expression of FAD2 did decrease in the early stages of seed development, expression increased starting at 8 DAA, peaking at 16 DAA, when it was 158% relative to the level observed in ovaries. FAD2, which desaturates oleic acid (18∶1 cisΔ9) into linoleic acid (18∶2 cisΔ9, 12), is therefore controlled at the transcription level. To relate enzyme expression with FA profile, GC was performed on the same subsamples used for RT-PCR and real-time PCR, and proportions of palmitic, stearic, oleic, linoleic, and linolenic acids were determined for the same developmental stages. Although FAD2 expression increased from 8 to 16 DAA, relative changes in linoleic acid (18∶2 cis Δ9, 12) were not observed. However, linolenic acid (ALA; α-18∶3; 18∶3 cisΔ9, 12, 15) levels increased steadily, meaning that linoleic acid (18∶2 cisΔ9, 12) is a transient substrate converted by FAD3 as quickly as it is produced by FAD2. Phenotypes are the result of genotypes, environment, and the interaction of the two. To evaluate the environmental impact on the production of FA in flax, FA profiles were assessed in a total of four environments (two locations, two years). Warm and dry environmental conditions resulted in lower levels of PUFA 18∶2 cisΔ9, 12 and 18∶3 cisΔ9, 12, 15, and higher levels of 18∶1 cisΔ9. FAD2 expression and/or activity may therefore be affected by the environment.
TL;DR: The results suggest that lipids may be important in the control of S. aureus during an infection.
Abstract: Staphylococcus aureus causes a variety of human infections including toxic shock syndrome, osteomyelitis, and mastitis. Mastitis is a common disease in the dairy cow, and S. aureus has been found to be a major infectious organism causing mastitis. The objectives of this research were to determine which FA and esterified forms of FA were inhibitory to growth of S. aureus bacteria. FA as well as their mono-, di-, and triacylglycerol forms were tested for their ability to inhibit a human toxic shock syndrome clinical isolate (MN8) and two S. aureus clinical bovine mastitis isolates (305 and Novel). The seven most potent inhibitors across all strains tested by minimum inhibitory concentration analysis included lauric acid, glycerol monolaurate, capric acid, myristic acid, linoleic acid, cis-9, trans-11 conjugated linoleic acid, and trans-10, cis-12 conjugated linoleic acid. Some of these lipids were chosen for 48-h growth curve analysis with a bovine mastitis S. aureus isolate (Novel) at doses of 0, 20, 50, and 100 microg/mL except myristic acid, which was tested at 0, 50, 100, and 200 microg/mL. The saturated FA (lauric, capric, myristic) and glycerol monolaurate behaved similarly and reduced overall growth. In contrast, the polyunsaturated FA (linoleic and cis-9, trans-11 conjugated linoleic acid) delayed the time to initiation of exponential growth in a dose-dependent fashion. The results suggest that lipids may be important in the control of S. aureus during an infection.
TL;DR: The data suggest that dietary fish oil-derived n−3 fatty acids have immunomodulatory effects and could be useful in inflammatory disorders.
Abstract: The higher incidence of inflammatory diseases in Western countries might be related, in part, to a high consumption of saturated fatty acids and n−6 polyunsaturated fatty acids (PUFA) and an insufficient intake of n−3 fatty acids. The purpose of this study was to examine the effects of dietary n−3 fatty acids on innate and specific immune response and their anti-inflammatory action in models of contact and atopic dermatitis. Balb/C mice were fed for 3 wk either n−6 or n−3 PUFA-fortified diets. After inducing a contact or an atopic dermatitis, immunological parameters were analyzed to evaluate the anti-inflammatory potential of these n−3 PUFA. n−3 PUFA reduced innate and specific immune responses through inhibition of TH1 and TH2 responses, increase of immunomodulatory cytokines such as IL-10, and regulation of gene expression. The inhibition of both kinds of responses was confirmed by the anti-inflammatory effect observed in contact and atopic dermatitis. Reduction in weight, edema, thickness, leukocyte infiltration, and enhancement of antioxidant defenses in the inflamed ears of mice from both models along with the prevention of delayed-type hypersensitivity induced in atopic dermatitis proved n−3 PUFA efficacy. Our data suggest that dietary fish oil-derived n−3 fatty acids have immunomodulatory effects and could be useful in inflammatory disorders.
TL;DR: The enhanced levels of the two FA in the placenta of the GDM group suggests that these FA are taken up from the maternal circulation and retained after esterification into phosphoglycerides instead of being transferred to the fetus.
Abstract: In previous studies, we reported that neonates of women with gestational diabetes mellitus (GDM) have reduced blood levels of arachidonic acid (AA) and docosahexaenoic acid (DHA) that were unrelated to maternal status. Since both AA and DHA are selectively transferred from maternal to fetal circulation by the placenta, we have investigated whether the FA composition of the placenta is altered by GDM. Thirty-six women, 11 with and 25 without GDM, were recruited from Newham General Hospital, London. The women with GDM had higher levels of di-homo-γ-linolenic (P<0.05), docosate-traenoic (n-6 DTA; P<0.0001), docosapentaenoic n-6 (P<0.005), total n-6 (P<0.005), docosapentaenoic (n-3 DPA; P<0.005), and total n-3 (P<0.01) FA, as well as higher levels of AA (P<0.05) and DHA (P<0.01), in placental choline phosphoglycerides (CPG) compared with the healthy women who served as controls. Similarly, the women with GDM had elevated n-6 DTA (P<0.005), AA, total n-6 metabolites (P<0.05), DHA, total n-3 metabolites, and total n-3 FA (P<0.005) in ethanolamine phosphoglycerides (EPG). In contrast to CPG and EPG, the placental TG of the women with GDM had higher linoleic acid (P<0.05) and lower AA, n-6 metabolites, and n-3 DPA (P<0.01). The placenta is devoid of desaturase activity, and it is thought to be reliant on maternal circulation for both AA and DHA. Hence, the enhanced levels of the two FA in the placenta of the GDM group suggests that these FA are taken up from the maternal circulation and retained after esterification into phosphoglycerides instead of being transferred to the fetus. Further study is needed to elucidate the mechanism involved and the effect of the phenomenon on postnatal growth and development of the offspring.
TL;DR: All changes in oyster hemocyte parameters reported in the present study suggest that ArA and/or eicosanoid metabolites affect oysters hemocyte functions.
Abstract: Arachidonic acid (20:4n-6, ArA) and its eicosanoid metabolites have been demonstrated to be implicated in immune functions of vertebrates, fish, and insects. Thus, the aim of this study was to assess the impact of ArA supplementation on the FA composition and hemocyte parameters of oysters Crassostrea gigas. Oyster dietary conditioning consisted of direct addition of ArA solutions at a dose of 0, 0.25, or 0.41 microg ArA per mL of seawater into tanks in the presence or absence of T-Iso algae. Results showed significant incorporation of ArA into gill polar lipids when administered with algae (up to 19.7%) or without algae (up to 12.1%). ArA supplementation led to an increase in hemocyte numbers, phagocytosis, and production of reactive oxygen species by hemocytes from ArA-supplemented oysters. Moreover, the inhibitory effect of Vibrio aestuarianus extracellular products on the adhesive proprieties of hemocytes was lessened in oysters fed ArA-supplemented T-Iso. All changes in oyster hemocyte parameters reported in the present study suggest that ArA and/or eicosanoid metabolites affect oyster hemocyte functions.
TL;DR: Dietary CLA has effects on FA metabolism in Atlantic salmon and on PPAR transcription factors, with data suggesting that PPAR are also regulated in response to CLA, and the potential of CLA as a dietary supplement is assessed.
Abstract: The overall objective is to test the hypothesis that conjugated linoleic acid (CLA) has beneficial effects in Atlantic salmon as a result of affecting lipid and FA metabolism. The specific aims of the present study were to determine the effects of CLA on some key pathways of FA metabolism, including FA oxidation and highly unsaturated FA (HUFA) synthesis. Salmon smolts were fed diets containing two levels of fish oil (low, ∼17%, and high, ∼34%) containing three levels of CLA (a 1∶1 mixture of cis-9,trans-11 and trans-10,cis-12 at 0, 1, and 2% of diet) for 3 mon. The effects of dietary CLA on HUFA synthesis and β-oxidation were measured, and the expression of key genes in the FA oxidation and HUFA synthesis pathways, and the potentially important transcription factors peroxisome proliferators activated receptors (PPAR), were determined in selected tissues. Liver HUFA synthesis and desaturase gene expression was increased by dietary CLA and decreased by high diatary oil content. Carnitine palmitoyltransferase-I (CPT-I) activity and gene expression were generally increased by CLA in muscle tissues although they were relatively unaffected by dietary oil content. In general CPT-1 activity or gene expression was not correlated with β-oxidation. Dietary CLA tended to increase PPARα and β gene expression in both liver and muscle tissues, and PPARγ in liver. In summary, gene expression and activity of the FA pathways were altered in response to dietary CLA and/or oil content, with data suggesting that PPAR are also regulated in response to CLA. Correlations were observed between dietary CLA, liver HUFA synthesis and desaturase gene expression, and liver PPARα expression, and also between dietary CLA, CPT-I expression and activity, and PPARα expression in muscle tissues. In conclusion, this study suggests that dietary CLA has effects on FA metabolism in Atlantic salmon and on PPAR transcription factors. However, further work is required to assess the potential of CLA as a dietary supplement, and the role of PPAR in the regulation of lipid metabolism in fish.
TL;DR: Investigating the possibility of a relationship between plasma homocysteine (Hcy) and phospholipid FA (PUFA) in healthy Australian males provided further evidence that increased consumption of dietary n−3 PUFA increases the concentration of n− 3 PUFA in plasma phospholIPid, which is associated with a protective effect on cardiovascular diseases and lower plasma Hcy levels.
Abstract: The aim of this study was to investigate the possibility of a relationship between plasma homocysteine (Hcy) and phospholipid FA (PUFA) in healthy Australian males. One hundred thirty six healthy male subjects aged 20–55 yr were recruited from the Melbourne metropolitan area. Each volunteer completed a semiquantitative food frequency questionnaire and gave a blood sample. Plasma Hcy concentrations were determined by an established HPLC method; the plasma phospholipid FA were determined by standard methods. Plasma Hcy concentration was significantly negatively correlated with plasma phospholipid concentration of the PUFA 20∶5n−3 (r=−0.226, P=0.009), 22∶5n−3 (r=−0.182, P=0.036), 22∶6n−3 (r=−0.286, P=0.001), total n−3 (r=−0.270, P=0.002) and the ratio n−3/n−6 PUFA (r=−0.265, P=0.002), and significantly positively correlated with 20∶4n−6 (r=0.180, P=0.037). In the partial correlation analysis, after controlling for serum vitamin B12 and folate concentration, plasma Hcy was significantly negatively correlated with the plasma phospholipid concentration of 22∶6n−3 (r=−0.205, P=0.019), total n−3 (r=−0.182, P=0.038) and the ratio n−3/n−6 PUFA (r=−0.174, P=0.048). Evidence indicates that an increased concentration of n−3 PUFA in tissues has a beneficial effect on cardiovascular health. Our findings provide further evidence that increased consumption of dietary n−3 PUFA increases the concentration of n−3 PUFA in plasma phospholipid, which is associated with a protective effect on cardiovascular diseases and lower plasma Hcy levels. The mechanism that might explain the association between plasma 22∶6n−3 and Hcy levels is not clear.
TL;DR: The safe dose of various tocotrienols for human consumption might be 200–1,000 mg/d based on this study, and the HDL/LDL cholesterol ratios were markedly improved by the supplements.
Abstract: The cholesterol-suppressive action of the tocotrienol-rich-fraction (TRF) of palm oil may be due to the effect of its constituent tocotrienols on β-hydroxy-β-methylglutaryl coenzyme A (HMG-CoA) reductase activity. The tocotrienols modulate HMG-CoA reductase activity via a post-transcriptional mechanism. As a consequence small doses (5–200 ppm) of TRF-supplemented diets fed to experimental animals lower serum cholesterol levels. These findings led us to evaluate the safety and efficacy of large supplements of TRF and its constituents. Diets supplemented with 50, 100, 250, 500, 1,000, or 2,000 ppm of TRF, α-tocopherol, α-tocotrienol, γ-tocotrienol, or δ-tocotrienol were fed to chickens for 4 wk. There were no differences between groups or within groups in weight gain, or in feed consumption at the termination of the feeding period. Supplemental TRF produced a dose-response (50–2,000 ppm) lowering of serum total and LDL cholesterol levels of 22% and 52% (P<0.05), respectively, compared with the control group. α-Tocopherol did not affect total or LDL-cholesterol levels. Supplemental α-tocotrienol within the 50–500 ppm range produced a dose-response lowering of total (17%) and LDL (33%) cholesterol levels. The more potent γ and δ isomers yielded dose-response (50–2,000 ppm) reductions of serum total (32%) and LDL (66%) cholesterol levels. HDL cholesterol levels were minimally impacted by the tocotrienols; as a result, the HDL/LDL cholesterol ratios were markedly improved (123–150%) by the supplements. Serum triglyceride levels were significantly lower in sera of pullets receiving the higher supplements. The safe dose of various tocotrienols for human consumption might be 200–1,000 mg/d based on this study.
TL;DR: The effects of season, geographic source, and rearing system (extensive, semiextensive, and intensive systems) on the lipid content and FA composition of fillets of Perca fluviatilis were studied.
Abstract: The effects of season, geographic source (Lake Geneva, Rhine River), and rearing system (extensive, semiextensive, and intensive systems) on the lipid content and FA composition of fillets of Perca fluviatilis were studied. Significant differences in the total lipid content were found between fish coming from the Rhine River and Lake Geneva (1.21 and 1.48%, respectively). Seasonal effects were investigated quarterly for perch sampled in the Rhine River. Intensively reared perch displayed a higher lipid content (1.48%) than the other farmed perch, i.e., 1.26% for a semiextensive system and 1.16% for an extensive system. No significant difference in lipid content was found (i) between lacustrine fish and intensively reared fish or (ii) among fish from the Rhine River and the semiextensive or extensive rearing systems. The main FA were 22:6n-3 (DHA, 21.3-37.1% of total FA), 16:0 (17.7-20.2%), 20:5n-3 (EPA, 9.2-13.2%), 18:1 (8.0-11.5%), 20:4n-6 [arachidonic acid (ARA), 1.9-10.7%], 16:1 (4.3-6.0%), and 18:2n-6 (2.1-6.0%). In comparison with perch coming from the Rhine River, the lacustrine fish were characterized by higher total n-6 PUFA and a lower proportion of both total monounsaturated FA (MUFA) and total n-3 PUFA. Among rearing systems, extensively farmed fish had higher n-6 PUFA and lower n-3 PUFA contents. Wild fish showed higher ARA and 18:2n-6 than farmed fish. They also had significantly more EPA (12.5-13.2%) than farmed perch (9.2-10.9%). For DHA, no difference existed between (i) the lacustrine fish (31.9% of total FA) and the intensively reared fish (33.0%) and (ii) the Rhine (37.1%) and semiextensively reared fish (36%). Effects of size, diet composition, and environmental conditions on the total lipid contents and FA composition are discussed.
TL;DR: Accurate dietary and plasma FA analyses suggest that regular moderate consumption of meat and fish maintains a plasma FA profile possibly more conducive to good health.
Abstract: High-fat diets are implicated in the onset of cardiovascular disease (CVD), cancer, and obesity. Large intakes of saturated and trans FA, together with low levels of PUFA, particularly long-chain (LC) omega-3 (n-3) PUFA, appear to have the greatest impact on the development of CVD. A high n-6:n-3 PUFA ratio is also considered a marker of elevated risk of CVD, though little accurate data on dietary intake is available. A new Australian food composition database that reports FA in foods to two decimal places was used to assess intakes of FA in four habitual dietary groups. Analysis using the database found correlations between the dietary intakes of LC n-3 PUFA and the plasma phospholipid LC n-3 PUFA concentrations of omnivore and vegetarian subjects. High meat-eaters (HME), who consumed large amounts of food generally, had significantly higher LC n-3 PUFA intakes (0.29 g/d) than moderate meat-eaters (MME) (0.14 g/d), whose intakes in turn were significantly higher than those of ovolacto-vegetarians or vegans (both 0.01 g/d). The saturated FA intake of MME subjects (typical of adult male Australians) was not different from ovolacto-vegetarian intakes, whereas n-6:n-3 intake ratios in vegetarians were significantly higher than in omnivores. Thus, accurate dietary and plasma FA analyses suggest that regular moderate consumption of meat and fish maintains a plasma FA profile possibly more conducive to good health.
TL;DR: It is speculated that improved lucose tolerance in rats fed an MCT diet may be, at least in part, ascribed to this higher serum adiponectin level.
Abstract: Previous studies demonstrated that, compared with long-chain TAG (LCT), dietary medium-chain TAG (MCT) could improve glucose tolerance in rats and humans. It has been well established that adiponectin acts to increase insulin sensitivity. The effects of dietary MCT on adiponectin serum concentration and mRNA levels in adipose tissue were studied in rats. Male Spague-Dawley rats were feda diet containing 20% MCT or LCT for 8 wk. After 6 wk of dietary treatment, an oral glucose tolerance test was performed. Rats fed the MCT diet had less body fat accumulation than those fed the LCT diet (P<0.01). The cell diameter of the perirenal adipose tissue, one of the abdominal adipose tissues, was smaller (P<0.01) in the MCT diet group. The serum adiponectin concentration was higher (P<0.01) in the MCT diet group than in the LCT diet group. The adiponectin content in the perirenal adipose tissue was higher (P<0.01) in the MCT diet group. The MCT-fed group had a higher adiponectin mRNA level in their perirenal adipose tissue (P<0.05). The increase of the plasma glucose concentration after glucose administration istration (area under the curve) was smaller (P<0.01) in the MCT diet group than in the LCT diet group. These findings suggest that dietary MCT, compared with LCT, results in a higher serum adiponectin level with trascriptional activation of the adiponectin gene in rats. We speculate that improved lucose tolerance in rats fed an MCT diet may be, at least in part, ascribed to this higher serum adiponectin level.