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1.  Dietary ω-3 Fatty Acids Alter Cardiac Mitochondrial Phospholipid Composition and Delay Ca2+-Induced Permeability Transition 
Consumption of ω-3 fatty acids from fish oil, specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), decreases risk for heart failure and attenuates pathologic cardiac remodeling in response to pressure overload. Dietary supplementation with EPA+DHA may also impact cardiac mitochondrial function and energetics through alteration of membrane phospholipids. We assessed the role of EPA+DHA supplementation on left ventricular (LV) function, cardiac mitochondrial membrane phospholipid composition, respiration, and sensitivity to mitochondrial permeability transition pore (MPTP) opening in normal and infarcted myocardium. Rats were subjected to sham surgery or myocardial infarction by coronary artery ligation (n=10–14), and fed a standard diet, or supplemented with EPA+DHA (2.3% of energy intake) for 12 weeks. EPA+DHA altered fatty acid composition of total mitochondrial phospholipids and cardiolipin by reducing arachidonic acid content and increasing DHA incorporation. EPA+DHA significantly increased calcium uptake capacity in both subsarcolemmal and intrafibrillar mitochondria from sham rats. This treatment effect persisted with the addition of cyclosporin A, and was not accompanied by changes in mitochondrial respiration or coupling, or cyclophilin D protein expression. Myocardial infarction resulted in heart failure as evidenced by LV dilation and contractile dysfunction. Infarcted LV myocardium had decreased mitochondrial protein yield and activity of mitochondrial marker enzymes, however respiratory function of isolated mitochondria was normal. EPA+DHA had no effect on LV function, mitochondrial respiration, or MPTP opening in rats with heart failure. In conclusion, dietary supplementation with EPA+DHA altered mitochondrial membrane phospholipid fatty acid composition in normal and infarcted hearts, but delayed MPTP opening only in normal hearts.
doi:10.1016/j.yjmcc.2009.08.014
PMCID: PMC2783943  PMID: 19703463
eicosapentaenoic acid; docosahexaenoic acid; myocardial infarction; mitochondrial permeability transition pore
2.  Polyunsaturated fatty acids in various macroalgal species from north Atlantic and tropical seas 
Background
In this study the efficacy of using marine macroalgae as a source for polyunsaturated fatty acids, which are associated with the prevention of inflammation, cardiovascular diseases and mental disorders, was investigated.
Methods
The fatty acid (FA) composition in lipids from seven sea weed species from the North Sea (Ulva lactuca, Chondrus crispus, Laminaria hyperborea, Fucus serratus, Undaria pinnatifida, Palmaria palmata, Ascophyllum nodosum) and two from tropical seas (Caulerpa taxifolia, Sargassum natans) was determined using GCMS. Four independent replicates were taken from each seaweed species.
Results
Omega-3 (n-3) and omega-6 (n-6) polyunsaturated fatty acids (PUFAs), were in the concentration range of 2-14 mg/g dry matter (DM), while total lipid content ranged from 7-45 mg/g DM. The n-9 FAs of the selected seaweeds accounted for 3%-56% of total FAs, n-6 FAs for 3%-32% and n-3 FAs for 8%-63%. Red and brown seaweeds contain arachidonic (C20:4, n-6) and/or eicosapentaenoic acids (EPA, C20:5, n-3), the latter being an important "fish" FA, as major PUFAs while in green seaweeds these values are low and mainly C16 FAs were found. A unique observation is the presence of another typical "fish" fatty acid, docosahexaenoic acid (DHA, C22:6, n-3) at ≈ 1 mg/g DM in S. natans. The n-6: n-3 ratio is in the range of 0.05-2.75 and in most cases below 1.0. Environmental effects on lipid-bound FA composition in seaweed species are discussed.
Conclusion
Marine macroalgae form a good, durable and virtually inexhaustible source for polyunsaturated fatty acids with an (n-6) FA: (n-3) FA ratio of about 1.0. This ratio is recommended by the World Health Organization to be less than 10 in order to prevent inflammatory, cardiovascular and nervous system disorders. Some marine macroalgal species, like P. palmata, contain high proportions of the "fish fatty acid" eicosapentaenoic acid (EPA, C20:5, n-3), while in S. natans also docosahexaenoic acid (DHA, C22:6, n-3) was detected.
doi:10.1186/1476-511X-10-104
PMCID: PMC3131239  PMID: 21696609
3.  Atlantic salmon require long-chain n-3 fatty acids for optimal growth throughout the seawater period 
The nutritional requirement for n-3 long-chain PUFA in fast-growing Atlantic salmon (Salmo salar) during grow out in the sea is not well documented. Diets were formulated with levels of EPA (20 : 5n-3) and DHA (22 : 6n-3) ranging from 1·3 to 7·4 % of fatty acids (4–24 g/kg feed). Two long-term trials were conducted through the seawater phase, the first at 6 and 12°C, and the second at 12°C. In the first trial, growth at both temperatures was significantly lower in fish fed 1·4 % EPA+DHA of total fatty acids compared with the 5·2 % EPA+DHA group. In the second trial, growth was significantly lower in fish fed 1·3 and 2·7 % compared with 4·4 and 7·4 % EPA + DHA. Fatty acid composition in the fish reflected diet composition, but only after a 7-fold increase in body weight did the fatty acid profile of the fish stabilise according to dietary fatty acids (shown for EPA and DHA). The retention efficiency of DHA increased with decreasing dietary levels, and was 120–190 and 120–200 % in trials 1 and 2, respectively. The retention efficiency of EPA was lower (60–200 %), and values >100 % were only achieved at the lowest dietary levels in both trials. Temperature did not affect fatty acid retention efficiency. These results suggest that Atlantic salmon have a specific requirement for EPA + DHA >2·7 % of fatty acids for optimal long-term growth in seawater, and that short-term growth trials with less weight increase would not show these effects.
doi:10.1017/jns.2016.10
PMCID: PMC4891698  PMID: 27293556
Atlantic salmon; n-3 Fatty acids; Fish requirements; Growth performance in seawater; BW, body weight; EFA, essential fatty acid; FA, fatty acid; FCR, feed conversion ratio; FO, fish oil; LC-PUFA, long-chain PUFA; LNA, α-linolenic acid; PL, phospholipid; SGR, specific growth rate; TGC, thermal growth coefficient; VO, vegetable oil
4.  Is the omega-3 index a valid marker of intestinal membrane phospholipid EPA+DHA content? 
Despite numerous studies investigating n-3 long chain polyunsaturated fatty acid (LCPUFA) supplementation and inflammatory bowel diseases (IBD), the extent to which dietary n-3 LCPUFAs incorporate in gastrointestinal (GI) tissues and correlate to the omega-3 index is unknown. In this study, mice were fed three diets with increasing percent of energy (%en) derived from eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA). Dietary levels reflected recommended intakes of fish/fish oil by the American Heart Association. We analyzed the FA composition of phospholipids extracted from red blood cells (RBCs), plasma, and GI tissues. We observed that the 0.1%en EPA+DHA diet was sufficient to significantly increase the omega-3 index (RBC EPA+DHA) after 5 week feeding. The baseline EPA levels were 0.2 – 0.6% across all tissues increasing to 1.6 – 4.3% in the highest EPA+DHA diet; these changes resulted in absolute increases of 1.4 – 3.9% EPA across tissues. The baseline DHA levels were 2.2 – 5.9% across all tissues increasing to 5.8 – 10.5% in the highest EPA+DHA diet; these changes resulted in absolute increases of 3.2 – 5.7% DHA across tissues. These increases in EPA and DHA across all tissues resulted in strong (r > 0.91) and significant (p < 0.001) linear correlations between the omega-3 index and plasma/GI tissue EPA+DHA content, suggesting that the omega-3 index reflects the relative amounts of EPA+DHA in GI tissues. These data demonstrate that the GI tissues are highly responsive to dietary LCPUFA supplementation and that the omega-3 index can serve as a valid biomarker for assessing dietary EPA+DHA incorporation into GI tissues.
doi:10.1016/j.plefa.2014.04.001
PMCID: PMC4127132  PMID: 24913088
5.  The Microbiota of Freshwater Fish and Freshwater Niches Contain Omega-3 Fatty Acid-Producing Shewanella Species 
Approximately 30 years ago, it was discovered that free-living bacteria isolated from cold ocean depths could produce polyunsaturated fatty acids (PUFA) such as eicosapentaenoic acid (EPA) (20:5n-3) or docosahexaenoic acid (DHA) (22:6n-3), two PUFA essential for human health. Numerous laboratories have also discovered that EPA- and/or DHA-producing bacteria, many of them members of the Shewanella genus, could be isolated from the intestinal tracts of omega-3 fatty acid-rich marine fish. If bacteria contribute omega-3 fatty acids to the host fish in general or if they assist some bacterial species in adaptation to cold, then cold freshwater fish or habitats should also harbor these producers. Thus, we undertook a study to see if these niches also contained omega-3 fatty acid producers. We were successful in isolating and characterizing unique EPA-producing strains of Shewanella from three strictly freshwater native fish species, i.e., lake whitefish (Coregonus clupeaformis), lean lake trout (Salvelinus namaycush), and walleye (Sander vitreus), and from two other freshwater nonnative fish, i.e., coho salmon (Oncorhynchus kisutch) and seeforellen brown trout (Salmo trutta). We were also able to isolate four unique free-living strains of EPA-producing Shewanella from freshwater habitats. Phylogenetic and phenotypic analyses suggest that one producer is clearly a member of the Shewanella morhuae species and another is sister to members of the marine PUFA-producing Shewanella baltica species. However, the remaining isolates have more ambiguous relationships, sharing a common ancestor with non-PUFA-producing Shewanella putrefaciens isolates rather than marine S. baltica isolates despite having a phenotype more consistent with S. baltica strains.
doi:10.1128/AEM.02266-15
PMCID: PMC4702627  PMID: 26497452
6.  Incorporation of EPA and DHA into plasma phospholipids in response to different omega-3 fatty acid formulations - a comparative bioavailability study of fish oil vs. krill oil 
Background
Bioavailability of omega-3 fatty acids (FA) depends on their chemical form. Superior bioavailability has been suggested for phospholipid (PL) bound omega-3 FA in krill oil, but identical doses of different chemical forms have not been compared.
Methods
In a double-blinded crossover trial, we compared the uptake of three EPA+DHA formulations derived from fish oil (re-esterified triacylglycerides [rTAG], ethyl-esters [EE]) and krill oil (mainly PL). Changes of the FA compositions in plasma PL were used as a proxy for bioavailability. Twelve healthy young men (mean age 31 y) were randomized to 1680 mg EPA+DHA given either as rTAG, EE or krill oil. FA levels in plasma PL were analyzed pre-dose and 2, 4, 6, 8, 24, 48, and 72 h after capsule ingestion. Additionally, the proportion of free EPA and DHA in the applied supplements was analyzed.
Results
The highest incorporation of EPA+DHA into plasma PL was provoked by krill oil (mean AUC0-72 h: 80.03 ± 34.71%*h), followed by fish oil rTAG (mean AUC0-72 h: 59.78 ± 36.75%*h) and EE (mean AUC0-72 h: 47.53 ± 38.42%*h). Due to high standard deviation values, there were no significant differences for DHA and the sum of EPA+DHA levels between the three treatments. However, a trend (p = 0.057) was observed for the differences in EPA bioavailability. Statistical pair-wise group comparison's revealed a trend (p = 0.086) between rTAG and krill oil. FA analysis of the supplements showed that the krill oil sample contained 22% of the total EPA amount as free EPA and 21% of the total DHA amount as free DHA, while the two fish oil samples did not contain any free FA.
Conclusion
Further studies with a larger sample size carried out over a longer period are needed to substantiate our findings and to determine differences in EPA+DHA bioavailability between three common chemical forms of LC n-3 FA (rTAG, EE and krill oil). The unexpected high content of free EPA and DHA in krill oil, which might have a significant influence on the availability of EPA+DHA from krill oil, should be investigated in more depth and taken into consideration in future trials.
doi:10.1186/1476-511X-10-145
PMCID: PMC3168413  PMID: 21854650
bioavailability; absorption; uptake; ethyl esters; re-esterified triacylglycerides; fish oil; krill oil
7.  Effect of fish oils containing different amounts of EPA, DHA, and antioxidants on plasma and brain fatty acids and brain nitric oxide synthase activity in rats 
Upsala Journal of Medical Sciences  2009;114(4):206-213.
Background
The interest in n-3 polyunsaturated fatty acids (PUFAs) has expanded significantly in the last few years, due to their many positive effects described. Consequently, the interest in fish oil supplementation has also increased, and many different types of fish oil supplements can be found on the market. Also, it is well known that these types of fatty acids are very easily oxidized, and that stability among supplements varies greatly.
Aims of the study
In this pilot study we investigated the effects of two different types of natural fish oils containing different amounts of the n-3 PUFAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and antioxidants on plasma and brain fatty acids, blood lipids, vitamin E, and in vivo lipid peroxidation, as well as brain nitric oxide synthase (NOS) activity, an enzyme which has been shown to be important for memory and learning ability.
Methods
Sprague-Dawley rats were divided into four groups and fed regular rat chow pellets enriched with 5% (w/w) of butter (control group), a natural fish oil (17.4% EPA and 11.7% DHA, referred to as EPA-rich), and a natural fish oil rich in DHA (7.7% EPA and 28.0% DHA, referred to as DHA-rich). Both of the fish oils were stabilized by a commercial antioxidant protection system (Pufanox®) at production. The fourth group received the same DHA-rich oil, but without Pufanox® stabilization (referred to as unstable). As an index of stability of the oils, their peroxide values were repeatedly measured during 9 weeks. The dietary treatments continued until sacrifice, after 10 days.
Results
Stability of the oils varied greatly. It took the two stabilized oils 9 weeks to reach the same peroxide value as the unstable oil reached after only a few days. Both the stabilized EPA- and DHA-rich diets lowered the triacylglycerols and total cholesterol compared to control (-45%, P < 0.05 and -54%, P < 0.001; -31%, P < 0.05 and -25%, P < 0.01) and so did the unstable oil, but less efficiently. Only the unstable oil increased in vivo lipid peroxidation significantly compared to control (+40%, P < 0.001). Most of the fatty acids in the plasma phospholipids were significantly affected by both the EPA- and DHA-rich diets compared to control, reflecting their specific fatty acid pattern. The unstable oil diet resulted in smaller changes, especially in n-3 PUFAs. In the brain phospholipids the changes were less pronounced, and only the diet enriched with the stabilized DHA-rich oil resulted in a significantly greater incorporation of DHA (+13%, P < 0.01), as well as total n-3 PUFAs (+13%, P < 0.01) compared to control. Only the stabilized DHA-rich oil increased the brain NOS activity (+33%, P < 0.01).
Conclusions
Both the EPA- and DHA-rich diets affected the blood lipids in a similarly positive manner, and they both had a large impact on plasma phospholipid fatty acids. It was only the unstable oil that increased in vivo lipid peroxidation. However, the intake of DHA was more important than that of EPA for brain phospholipid DHA enrichment and brain NOS activity, and the stability of the fish oil was also important for these effects.
doi:10.3109/03009730903268958
PMCID: PMC2852776  PMID: 19961266
Antioxidants; brain; DHA; EPA; fish oil; lipid peroxidation; nitric oxide synthase
8.  Towards the Industrial Production of Omega-3 Long Chain Polyunsaturated Fatty Acids from a Genetically Modified Diatom Phaeodactylum tricornutum 
PLoS ONE  2015;10(12):e0144054.
The marine diatom Phaeodactylum tricornutum can accumulate up to 30% of the omega-3 long chain polyunsaturated fatty acid (LC-PUFA) eicosapentaenoic acid (EPA) and, as such, is considered a good source for the industrial production of EPA. However, P. tricornutum does not naturally accumulate significant levels of the more valuable omega-3 LC-PUFA docosahexaenoic acid (DHA). Previously, we have engineered P. tricornutum to accumulate elevated levels of DHA and docosapentaenoic acid (DPA) by overexpressing heterologous genes encoding enzyme activities of the LC-PUFA biosynthetic pathway. Here, the transgenic strain Pt_Elo5 has been investigated for the scalable production of EPA and DHA. Studies have been performed at the laboratory scale on the cultures growing in up to 1 L flasks a 3.5 L bubble column, a 550 L closed photobioreactor and a 1250 L raceway pond with artificial illumination. Detailed studies were carried out on the effect of different media, carbon sources and illumination on omega-3 LC-PUFAs production by transgenic strain Pt_Elo5 and wild type P. tricornutum grown in 3.5 L bubble columns. The highest content of DHA (7.5% of total fatty acids, TFA) in transgenic strain was achieved in cultures grown in seawater salts, Instant Ocean (IO), supplemented with F/2 nutrients (F2N) under continuous light. After identifying the optimal conditions for omega-3 LC-PUFA accumulation in the small-scale experiments we compared EPA and DHA levels of the transgenic strain grown in a larger fence-style tubular photobioreactor and a raceway pond. We observed a significant production of DHA over EPA, generating an EPA/DPA/DHA profile of 8.7%/4.5%/12.3% of TFA in cells grown in a photobioreactor, equivalent to 6.4 μg/mg dry weight DHA in a mid-exponentially growing algal culture. Omega-3 LC-PUFAs production in a raceway pond at ambient temperature but supplemented with artificial illumination (110 μmol photons m-2s-1) on a 16:8h light:dark cycle, in natural seawater and F/2 nutrients was 24.8% EPA and 10.3% DHA. Transgenic strain grown in RP produced the highest levels of EPA (12.8%) incorporated in neutral lipids. However, the highest partitioning of DHA in neutral lipids was observed in cultures grown in PBR (7.1%). Our results clearly demonstrate the potential for the development of the transgenic Pt_Elo5 as a platform for the commercial production of EPA and DHA.
doi:10.1371/journal.pone.0144054
PMCID: PMC4681182  PMID: 26658738
9.  Determination of biological and physicochemical parameters of Artemia franciscana strains in hypersaline environments for aquaculture in the Colombian Caribbean 
Saline Systems  2005;1:9.
Background
Artemia (Crustacea, Anostraca), also known as brine shrimp, are typical inhabitants of extreme environments. These hypersaline environments vary considerably in their physicochemical composition, and even their climatic conditions and elevation. Several thalassohaline (marine) environments along the Colombian Caribbean coast were surveyed in order to contribute to the knowledge of brine shrimp biotopes in South America by determining some vital biological and physicochemical parameters for Artemia survival. Additionally, cyst quality tests, biometrical and essential fatty acids analysis were performed to evaluate the economic viability of some of these strains for the aquaculture industry.
Results
In addition to the three locations (Galerazamba, Manaure, and Pozos Colorados) reported in the literature three decades ago in the Colombian Caribbean, six new locations were registered (Salina Cero, Kangaru, Tayrona, Bahía Hondita, Warrego and Pusheo). All habitats sampled showed that chloride was the prevailing anion, as expected, because of their thalassohaline origin. There were significant differences in cyst diameter grouping strains in the following manner according to this parameter: 1) San Francisco Bay (SFB-Control, USA), 2) Galerazamba and Tayrona, 3) Kangarú, 4) Manaure, and 5) Salina Cero and Pozos Colorados. Chorion thickness values were smaller in Tayrona, followed by Salina Cero, Galerazamba, Manaure, SFB, Kangarú and Pozos Colorados. There were significant differences in naupliar size, grouping strains as follows (smallest to largest): 1) Galerazamba, 2) Manaure, 3) SFB, Kangarú, and Salina Cero, 4) Pozos Colorados, and 5) Tayrona. Overall, cyst quality analysis conducted on samples from Manaure, Galerazamba, and Salina Cero revealed that all sites exhibited a relatively high number of cysts.g-1. Essential fatty acids (EFA) analysis performed on nauplii from cyst samples from Manaure, Galerazamba, Salina Cero and Tayrona revealed that cysts from all sites exhibited high arachidonic acid:20:4(n-6) (ArA) and eicosapentaenoic acid: 20:5(n-3) (EPA) levels comparable to the control sample (SFB). In contrast, most cysts collected (including SFB) at different locations, and during different months, presented low docosahexaenoic acid: 22:6(n-3) (DHA) levels (Manaure was the only exception with high DHA levels). Some variations in EPA and ArA levels were observed in all sites, contrasting with the much lower DHA levels which remained constant for all locations, except for Manaure which exhibited variable DHA levels. DHA/EPA ratio was overall very low for all sites compared to SFB cysts. All strains had a low DHA/ArA, but a high EPA/ArA ratio, including the control.
Conclusion
The Colombian A. franciscana habitats analyzed were determined to be thalassohaline, and suitable for A. franciscana development. EFA profiles demonstrated that Tayrona, Galerazamba, Manaure and Salina Cero strains are suitable food for marine fish and crustacean culture because of their high EPA/ArA ratio, but might have to be fortified with DHA rich emulsions depending on the nutritional requirements of the species to be cultured, because of their overall low DHA content. The relatively small nauplii are appropriate for marine larvaeculture. In contrast, the strains from Tayrona, Kangarú, Salina Cero, and Pozos Colorados may be of use but limited to Artemia small biomass production quantities, because of the small surface area of their respective locations; Artemia could be exploited at these locations for local aquaculture applications. In general, cyst quality evaluation for Manaure, Salina Cero and Galerazamba cysts revealed that cysts from these three locations could improve their quality by concentrating efforts on cyst processing techniques. Finally, most locations had great A. franciscana production potential and require different degrees of water quality and/or infrastructure management.
doi:10.1186/1746-1448-1-9
PMCID: PMC1280932  PMID: 16250916
10.  Short term effects of different omega-3 fatty acid formulation on lipid metabolism in mice fed high or low fat diet 
Background
Bioactivities of Docosahexaenoic acid (DHA) and Eicosapentaenoic acid (EPA) depend on their chemical forms. The present study was to investigate short term effects of triglyceride (TG), ethyl ester (EE), free fatty acid (FFA) and phospholipid (PL) forms of omega-3 fatty acid (FA) on lipid metabolism in mice, fed high fat or low fat diet.
Method
Male Balb/c mice were fed with 0.7% different Omega-3 fatty acid formulation: DHA bound free fatty acid (DHA-FFA), DHA bound triglyceride (DHA-TG), DHA bound ethyl ester (DHA-EE) and DHA bound phospholipid (DHA-PL) for 1 week, with dietary fat levels at 5% and 22.5%. Serum and hepatic lipid concentrations were analyzed, as well as the fatty acid composition of liver and brain.
Result
At low fat level, serum total cholesterol (TC) level in mice fed diets with DHA-FFA, DHA-EE and DHA-PL were significantly lower than that in the control group (P < 0.05). Hepatic TG level decreased significantly in mice fed diets with DHA-TG (P < 0.05), DHA-EE (P < 0.05) and DHA-PL (P < 0.05), while TC level in liver was significantly lower in mice fed diets with TG and EE compared with the control group (P < 0.05). At high fat level, mice fed diets with DHA-EE and DHA-PL had significantly lower hepatic TC level compared with the control diet (P < 0.05). Hepatic PL concentration experienced a significant increase in mice fed the diet with PL at high fat level (P < 0.05). Furthermore, both at low and high fat levels, hepatic DHA level significantly increased and AA level significantly decreased in all forms of DHA groups (P < 0.05), compared to control groups at two different fat levels, respectively. Additionally, cerebral DHA level in mice fed diets with DHA-FFA, DHA-EE and DHA-PL significantly increased compared with the control at high fat level (P < 0.05), but no significant differences were observed among dietary treatments for mice fed diets with low fat level.
Conclusion
The present study suggested that not only total dietary fat content but also the molecular forms of omega-3 fatty acids contributed to lipid metabolism in mice. DHA-PL showed effective bioactivity in decreasing hepatic and serum TC, TG levels and increasing omega-3 concentration in liver and brain.
doi:10.1186/1476-511X-11-70
PMCID: PMC3393618  PMID: 22676394
Omega-3 fatty acid; DHA; EPA; Lipid metabolism; Triglycerides; Ethyl ester; Phospholipids
11.  Acute appearance of fatty acids in human plasma – a comparative study between polar-lipid rich oil from the microalgae Nannochloropsis oculata and krill oil in healthy young males 
Background
The long-chain n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have human health benefits. Alternatives to fish as sources of EPA and DHA are needed. Oil from the micro-algae Nannochloropsis oculata contains a significant amount of EPA conjugated to phospholipids and glycolipids and no DHA. Krill oil contains EPA and DHA conjugated to phospholipids. We compare the appearance of fatty acids in blood plasma of healthy humans after consuming a high fat meal followed by either algal oil or krill oil.
Methods
Ten healthy males aged 18-45 years consumed a standard high fat (55 g) breakfast followed by either algal oil (providing 1.5 g EPA and no DHA) or krill oil (providing 1.02 g EPA and 0.54 g DHA). All participants consumed both oils in random order and separated by 7 days. Blood samples were collected before the breakfast and at several time points up to 10 hours after taking the oils. Fatty acid concentrations (μg/ml) in plasma were determined by gas chromatography.
Results
Fatty acids derived mainly from the breakfast appeared rapidly in plasma, peaking about 3 hours after consuming the breakfast, and in a pattern that reflected their content in the breakfast. There were time-dependent increases in the concentrations of both EPA and DHA with both algal oil (P < 0.001 for EPA; P = 0.027 for DHA) and krill oil (P < 0.001 for both EPA and DHA). The concentration of EPA was higher with algal oil than with krill oil at several time points. DHA concentration did not differ between oils at any time point. The maximum concentration of EPA was higher with algal oil (P = 0.010) and both the area under the concentration curve (AUC) and the incremental AUC for EPA were greater with algal oil (P = 0.020 and 0.006). There was no difference between oils in the AUC or the incremental AUC for DHA.
Conclusion
This study in healthy young men given a single dose of oil indicates that the polar-lipid rich oil from the algae Nannochloropis oculata is a good source of EPA in humans.
doi:10.1186/1476-511X-12-102
PMCID: PMC3718725  PMID: 23855409
Omega-3; Eicosapentaenoic acid; Docosahexaenoic acid; Algal oil; Krill oil; Polar lipids; Glycolipids; Phospholipids
12.  Bioavailability of fatty acids from krill oil, krill meal and fish oil in healthy subjects–a randomized, single-dose, cross-over trial 
Background
Krill contains two marine omega-3 polyunsaturated fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), mainly bound in phospholipids. Typical products from krill are krill oil and krill meal. Fish oils contain EPA and DHA predominantly bound in triglycerides. The difference in the chemical binding of EPA and DHA has been suggested to affect their bioavailability, but little is known on bioavailability of EPA and DHA in krill meal.
This study was undertaken to compare the acute bioavailability of two krill products, krill oil and krill meal, with fish oil in healthy subjects.
Methods
A randomized, single-dose, single-blind, cross-over, active-reference trial was conducted in 15 subjects, who ingested krill oil, krill meal and fish oil, each containing approx. 1 700 mg EPA and DHA. Fatty acid compositions of plasma triglycerides and phospholipids were measured repeatedly for 72 hours. The primary efficacy analysis was based on the 72 hour incremental area under the curve (iAUC) of EPA and DHA in plasma phospholipid fatty acids.
Results
A larger iAUC for EPA and DHA in plasma phospholipid fatty acids was detected after krill oil (mean 89.08 ± 33.36% × h) than after krill meal (mean 44.97 ± 18.07% x h, p < 0.001) or after fish oil (mean 59.15 ± 22.22% × h, p=0.003). Mean iAUC’s after krill meal and after fish oil were not different. A large inter-individual variability in response was observed.
Conclusion
EPA and DHA in krill oil had a higher 72-hour bioavailability than in krill meal or fish oil. Our finding that bioavailabilities of EPA and DHA in krill meal and fish oil were not different argues against the interpretation that phospholipids are better absorbed than triglycerides. Longer-term studies using a parameter reflecting tissue fatty acid composition, like erythrocyte EPA plus DHA are needed.
Trial registration
NCT02089165
doi:10.1186/s12944-015-0015-4
PMCID: PMC4374210  PMID: 25884846
Omega-3 fatty acids; Eicosapentaenoic acid; Docosahexaenoic acid; Krill oil; Krill meal
13.  Population Sizes and Growth Pressure Responses of Intestinal Microfloras of Deep-Sea Fish Retrieved from the Abyssal Zone 
Applied and Environmental Microbiology  1995;61(12):4480-4483.
The intestinal floras of seven deep-sea fish retrieved at depths of from 3,200 to 5,900 m were examined for population sizes and growth responses to pressure. Large populations of culturable bacteria, ranging from 1.1 x 10(sup6) to 3.6 x 10(sup8) cells per ml of contents, were detected when samples were incubated at conditions characteristic of those of the deep sea. Culturable cell counts at in situ pressures were greater than those at atmospheric pressure in all samples. Most of the strains isolated by the spread-plating method at atmospheric pressure later proved barophilic. Barophilic bacteria were the predominant inhabitants of the abyssal fish intestines.
PMCID: PMC1388664  PMID: 16535199
14.  Similar eicosapentaenoic acid and docosahexaenoic acid plasma levels achieved with fish oil or krill oil in a randomized double-blind four-week bioavailability study 
Background
Long-chain n-3 polyunsaturated fatty acids (LC n-3-PUFA), docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) provide multiple health benefits for heart, brain and eyes. However, consumption of fatty fish, the main source of LC n-3-PUFAs is low in Western countries. Intakes of LC n-3-PUFA can be increased by taking dietary supplements, such as fish oil, algal oil, or krill oil. Recently, conflicting information was published on the relative bioavailability of these omega-3 supplements. A few studies suggested that the phospholipid form (krill) is better absorbed than the fish oil ethyl ester (EE) or triglyceride (TG) forms. Yet studies did not match the doses administered nor the concentrations of DHA and EPA per supplement across such comparisons, leading to questionable conclusions. This study was designed to compare the oral bioavailability of the same dose of both EPA and DHA in fish oil-EE vs. fish oil-TG vs. krill oil in plasma at the end of a four-week supplementation.
Methods
Sixty-six healthy adults (n = 22/arm) were enrolled in a double blind, randomized, three-treatment, multi-dose, parallel study. Subjects were supplemented with a 1.3 g/d dose of EPA + DHA (approximately 816 mg/d EPA + 522 mg/d DHA, regardless of formulation) for 28 consecutive days, as either fish oil-EE, fish oil-TG or krill oil capsules (6 caps/day). Plasma and red blood cell (RBC) samples were collected at baseline (pre-dose on Day 1) and at 4, 8, 12, 48, 72, 336, and 672 h. Total plasma EPA + DHA levels at Week 4 (Hour 672) were measured as the primary endpoint.
Results
No significant differences in total plasma EPA + DHA at 672 h were observed between fish oil-EE (mean = 90.9 ± 41 ug/mL), fish oil-TG (mean = 108 ± 40 ug/mL), and krill oil (mean = 118.5 ± 48 ug/mL), p = 0.052 and bioavailability differed by <24 % between the groups. Additionally, DHA + EPA levels were not significantly different in RBCs among the 3 formulations, p = 0.19, providing comparable omega-3 indexes.
Conclusions
Similar plasma and RBC levels of EPA + DHA were achieved across fish oil and krill oil products when matched for dose, EPA, and DHA concentrations in this four week study, indicating comparable oral bioavailability irrespective of formulation.
Trial registration
Clinicaltrials.gov identifier NCT02427373.
doi:10.1186/s12944-015-0109-z
PMCID: PMC4557744  PMID: 26328782
Docosahexaenoic acid; Eicosapentaenoic acid; Krill; Plasma; Red blood cell; Fish oil; Omega-3; Bioavailability; Bioequivalence
15.  DHA Production in Escherichia coli by Expressing Reconstituted Key Genes of Polyketide Synthase Pathway from Marine Bacteria 
PLoS ONE  2016;11(9):e0162861.
The gene encoding phosphopantetheinyl transferase (PPTase), pfaE, a component of the polyketide synthase (PKS) pathway, is crucial for the production of docosahexaenoic acid (DHA, 22:6ω3), along with the other pfa cluster members pfaA, pfaB, pfaC and pfaD. DHA was produced in Escherichia coli by co-expressing pfaABCD from DHA-producing Colwellia psychrerythraea 34H with one of four pfaE genes from bacteria producing arachidonic acid (ARA, 20:4ω6), eicosapentaenoic acid (EPA, 20:5ω3) or DHA, respectively. Substitution of the pfaE gene from different strain source in E. coli did not influence the function of the PKS pathway producing DHA, although they led to different DHA yields and fatty acid profiles. This result suggested that the pfaE gene could be switchable between these strains for the production of DHA. The DHA production by expressing the reconstituted PKS pathway was also investigated in different E. coli strains, at different temperatures, or with the treatment of cerulenin. The highest DHA production, 2.2 mg of DHA per gram of dry cell weight or 4.1% of total fatty acids, was obtained by co-expressing pfaE(EPA) from the EPA-producing strain Shewanella baltica with pfaABCD in DH5α. Incubation at low temperature (10–15°C) resulted in higher accumulation of DHA compared to higher temperatures. The addition of cerulenin to the medium increased the proportion of DHA and saturated fatty acids, including C12:0, C14:0 and C16:0, at the expense of monounsaturated fatty acids, including C16:1 and C18:1. Supplementation with 1 mg/L cerulenin resulted in the highest DHA yield of 2.4 mg/L upon co-expression of pfaE(DHA) from C. psychrerythraea.
doi:10.1371/journal.pone.0162861
PMCID: PMC5029812  PMID: 27649078
16.  U.S. adults are not meeting recommended levels for fish and omega-3 fatty acid intake: results of an analysis using observational data from NHANES 2003–2008 
Nutrition Journal  2014;13:31.
Background
The American Heart Association’s Strategic Impact Goal Through 2020 and Beyond recommends ≥ two 3.5-oz fish servings per week (preferably oily fish) partly to increase intake of omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). We examined the intake of total fish, fish high in omega-3 fatty acids, α-linolenic acid, EPA, and DHA in U.S. adults (19 + years) using data from the National Health and Nutrition Examination Survey, 2003–2008.
Methods
Usual intakes from foods alone and from foods plus dietary supplements were determined using the methods from the National Cancer Institute.
Results
Mean usual intake of total fish and fish high in omega-3 fatty acids was 0.61 ± 0.03 and 0.15 ± 0.03 oz/day, 0.43 and 0.07 respectively. Total fish and fish high in omega-3 fatty acids median intake was 0.43 and 0.07 oz/day, respectively. Intake from foods alone for ALA, EPA and DHA was 1.5 ± 0.01 g/d, 23 ± 7 mg/d and 63 ± 2 mg/d, respectively. ALA, EPA and DHA from food only median intakes were 1.4 g/d, 18 mg/d and 50 mg/d, respectively. Intake of ALA, EPA and DHA from foods and dietary supplements was 1.6 ± 0.04 g/d, 41 ± 4 mg/d and 72 ± 4 mg/d, respectively. While intakes of fish high in omega-3 fatty acids were higher in older adults (0.13 ± 0.01 oz/d for those 19–50 yrs and 0.19 ± 0.02 oz/d for those 51+ year; p < 0.01) and in males as compared to females (0.18 ± 0.02 vs 0.13 ± 0.01 oz/d, respectively; p < 0.05), few consumed recommended levels. Males also had higher (p < 0.05) intake of EPA and DHA from foods and dietary supplements relative to females (44 ± 6 vs 39 ± 4 and 90 ± 7 vs 59 ± 4 mg/d, respectively) and older adults had higher intakes of EPA, but not DHA compared to younger adults (EPA: 34 ± 3 vs 58 ± 9, p < 0.05; DHA: 68 ± 4 vs 81 ± 6, p < 0.05).
Conclusions
As omega-3 fatty acids are deemed important from authoritative bodies, supplementation in addition to food sources may need to be considered to help U.S. adults meet recommendations.
doi:10.1186/1475-2891-13-31
PMCID: PMC3992162  PMID: 24694001
NHANES; Usual intake; Fish; Omega-3 fatty acids; EPA; DHA; Cardiovascular
17.  Effects of high EPA and high DHA fish oils on changes in signaling associated with protein metabolism induced by hindlimb suspension in rats 
Physiological Reports  2016;4(18):e12958.
Abstract
The effects of either eicosapentaenoic (EPA)‐ or docosahexaenoic (DHA)‐rich fish oils on hindlimb suspension (HS)‐induced muscle disuse atrophy were compared. Daily oral supplementations (0.3 mL/100 g b.w.) with mineral oil (MO) or high EPA or high DHA fish oils were performed in adult rats. After 2 weeks, the animals were subjected to HS for further 2 weeks. The treatments were maintained alongside HS. At the end of 4 weeks, we evaluated: body weight gain, muscle mass and fat depots, composition of fatty acids, cross‐sectional areas (CSA) of the soleus muscle and soleus muscle fibers, activities of cathepsin L and 26S proteasome, and content of carbonylated proteins in the soleus muscle. Signaling pathway activities associated with protein synthesis (Akt, p70S6K, S6, 4EBP1, and GSK3‐beta) and protein degradation (atrogin‐1/MAFbx, and MuRF1) were evaluated. HS decreased muscle mass, CSA of soleus muscle and soleus muscle fibers, and altered signaling associated with protein synthesis (decreased) and protein degradation (increased). The treatment with either fish oil decreased the ratio of omega‐6/omega‐3 fatty acids and changed protein synthesis‐associated signaling. EPA‐rich fish oil attenuated the changes induced by HS on 26S proteasome activity, CSA of soleus muscle fibers, and levels of p‐Akt, total p70S6K, p‐p70S6K/total p70S6K, p‐4EBP1, p‐GSK3‐beta, p‐ERK2, and total ERK 1/2 proteins. DHA‐rich fish oil attenuated the changes induced by HS on p‐4EBP1 and total ERK1 levels. The effects of EPA‐rich fish oil on protein synthesis signaling were more pronounced. Both EPA‐ and DHA‐rich fish oils did not impact skeletal muscle mass loss induced by non‐inflammatory HS.
doi:10.14814/phy2.12958
PMCID: PMC5037913  PMID: 27650250
Hindlimb suspension; muscle atrophy; omega‐3 fatty acids; protein synthesis/degradation
18.  Adaptive Changes in Membrane Lipids of Barophilic Bacteria in Response to Changes in Growth Pressure 
The lipid compositions of barophilic bacterial strains which contained docosahexaenoic acid (DHA [22:6n-3]) were examined, and the adaptive changes of these compositions were analyzed in response to growth pressure. In the facultatively barophilic strain 16C1, phosphatidylethanolamine (PE) and phosphatidylglycerol (PG) were major components which had the same fatty acid chains. However, in PE, monounsaturated fatty acids such as hexadecenoic acid were major components, and DHA accounted for only 3.7% of the total fatty acids, while in PG, DHA accounted for 29.6% of the total fatty acids. In response to an increase in growth pressure in strain 16C1, the amounts of saturated fatty acids in PE were reduced, and these decreases were mainly balanced by an increase in unsaturated fatty acids, including DHA. In PG, the decrease in saturated fatty acids was mainly balanced by an increase in DHA. Similar adaptive changes in fatty acid composition were observed in response to growth pressure in obligately barophilic strain 2D2. Furthermore, these adaptive changes in response were also observed in response to low temperature in strain 16C1. These results confirm that the general shift from saturated to unsaturated fatty acids including DHA is one of the adaptive changes in response to increases in pressure and suggest that DHA may play a role in maintaining the proper fluidity of membrane lipids under high pressure.
PMCID: PMC106069  PMID: 16349499
19.  Fish oil and krill oil supplementations differentially regulate lipid catabolic and synthetic pathways in mice 
Background
Marine derived oils are rich in long-chain polyunsaturated omega-3 fatty acids, in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which have long been associated with health promoting effects such as reduced plasma lipid levels and anti-inflammatory effects. Krill oil (KO) is a novel marine oil on the market and is also rich in EPA and DHA, but the fatty acids are incorporated mainly into phospholipids (PLs) rather than triacylglycerols (TAG). This study compares the effects of fish oil (FO) and KO on gene regulation that influences plasma and liver lipids in a high fat diet mouse model.
Methods
Male C57BL/6J mice were fed either a high-fat diet (HF) containing 24% (wt/wt) fat (21.3% lard and 2.3% soy oil), or the HF diet supplemented with FO (15.7% lard, 2.3% soy oil and 5.8% FO) or KO (15.6% lard, 2.3% soy oil and 5.7% KO) for 6 weeks. Total levels of cholesterol, TAG, PLs, and fatty acid composition were measured in plasma and liver. Gene regulation was investigated using quantitative PCR in liver and intestinal epithelium.
Results
Plasma cholesterol (esterified and unesterified), TAG and PLs were significantly decreased with FO. Analysis of the plasma lipoprotein particles indicated that the lipid lowering effect by FO is at least in part due to decreased very low density lipoprotein (VLDL) content in plasma with subsequent liver lipid accumulation. KO lowered plasma non-esterified fatty acids (NEFA) with a minor effect on fatty acid accumulation in the liver. In spite of a lower omega-3 fatty acid content in the KO supplemented diet, plasma and liver PLs omega-3 levels were similar in the two groups, indicating a higher bioavailability of omega-3 fatty acids from KO. KO more efficiently decreased arachidonic acid and its elongation/desaturation products in plasma and liver. FO mainly increased the expression of several genes involved in fatty acid metabolism, while KO specifically decreased the expression of genes involved in the early steps of isoprenoid/cholesterol and lipid synthesis.
Conclusions
The data show that both FO and KO promote lowering of plasma lipids and regulate lipid homeostasis, but with different efficiency and partially via different mechanisms.
doi:10.1186/1743-7075-11-20
PMCID: PMC4021563  PMID: 24834104
Omega-3 fatty acids; Plasma lipids; High-fat diet; Gene regulation; Krill oil
20.  Combined incubation of Cadmium, docosahexaenoic and eicosapentaenoic acid results in increased uptake of cadmium and elevated docosapentaenoic acid content in Hepatocytes in vitro 
Background
Human hepatocellular cells Hep G2 were used to mimic and investigate the effect of the intake of cadmium (Cd2+) contaminated fish on cytotoxicity, fatty acid (FA) and phospholipid class composition.
Methods
Cells were incubated with a combination of Cd2+ and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) fish specific FA.
Results
We measured a significant increased proportion of EPA and DHA in the treated cells compared to the control line confirming the uptake. While doses of 25 μM DHA showed to be toxic to the cells, repeated short term incubations (2 h) at lower doses resulted in an increased uptake of DHA. The resarzurin assay, evaluating cell viability, showed a significant decrease in cell viability between Cd2+ incubation time and, further, the pre-incubation with BSA-FA complex resulted in significantly increased cell viability. On the metabolic level, increased concentrations of EPA and DHA resulted in an increased proportion of docosapentaenoic acid (DPA) which indicated an increased metabolism. Also 24-h combined incubations of 5 μM Cd2+ and EPA and DHA showed a significant increase DPA in the total lipid fraction of the cells. In addition, incubation with 5 μM Cd2+ for 24 h also decreased the total cardiolipin (CL) fraction from the identified phospholipids.
Conclusions
We confirmed that the applied FA were taken up by the cells. A combination of EPA, DHA and Cd2+ influenced lysosomal integrity, cell viability and lipid metabolism in the cells. The most important finding is that DHA and EPA reduced the detrimental effect of Cd2+ on cell viability. The exact effects and kinetics behind our observations still need further evaluation.
doi:10.1186/s12944-015-0159-2
PMCID: PMC4666081  PMID: 26627047
DHA; EPA; Fish lipids; Hep G2; Omega-3 fatty acids
21.  Dietary fish oil modulates macrophage fatty acids and decreases arthritis susceptibility in mice 
The Journal of Experimental Medicine  1985;162(4):1336-1349.
B10.RIII and B10.G mice were transferred from a diet of laboratory rodent chow to a standard diet in which all the fat (5% by weight) was supplied as either fish oil (17% eicosapentaenoic acid [EPA], 12% docosahexaenoic acid [DHA], 0% arachidonic acid [AA], and 2% linoleic acid) or corn oil (0% EPA, 0% DHA, 0% AA, and 65% linoleic acid). The fatty acid composition of the macrophage phospholipids from mice on the chow diet was similar to that of mice on a corn oil diet. Mice fed the fish oil diet for only 1 wk showed substantial increases in macrophage phospholipid levels of the omega-3 fatty acids (of total fatty acid 4% was EPA, 10% docosapentaenoic acid [DPA], and 10% DHA), and decreases in omega-6 fatty acids (12% was AA, 2% docosatetraenoic acid [DTA], and 4% linoleic acid) compared to corn oil-fed mice (0% EPA, 0% DPA, 6% DHA, 20% AA, 9% DTA, and 8% linoleic acid). After 5 wk this difference between the fish oil-fed and corn oil-fed mice was even more pronounced. Further small changes occurred at 5-9 wk. We studied the prostaglandin (PG) and thromboxane (TX) profile of macrophages prepared from mice fed the two diets just before being immunized with collagen. Irrespective of diet, macrophages prepared from female mice and incubated for 24 h had significantly more PG and TX in the medium than similarly prepared macrophages from male mice. The increased percentage of EPA and decreased percentage of AA in the phospholipids of the macrophages prepared from the fish oil-fed mice was reflected in a reduction in the amount of PGE2 and PGI2 in the medium relative to identically incubated macrophages prepared from corn oil-fed mice. When this same fish oil diet was fed to B10.RIII mice for 26 d before immunization with type II collagen, the time of onset of arthritis was increased, and the incidence and severity of arthritis was reduced compared to arthritis induced in corn oil-fed mice. The females, especially those on the fish oil diet, tended to have less arthritis than the males. These alterations in the fatty acid pool available for PG and leukotriene synthesis suggest a pivotal role for the macrophage and PG in the immune and/or inflammatory response to type II collagen.
PMCID: PMC2187871  PMID: 3930652
22.  Plasma phospholipid pentadecanoic acid, EPA, and DHA, and the frequency of dairy and fish product intake in young children 
Food & Nutrition Research  2016;60:10.3402/fnr.v60.31933.
Background
There is a lack of studies comparing dietary assessment methods with the biomarkers of fatty acids in children.
Objective
The objective was to evaluate the suitability of a food frequency questionnaire (FFQ) to rank young children according to their intake of dairy and fish products by comparing food frequency estimates to the plasma phospholipid fatty acids pentadecanoic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA).
Design
Cross-sectional data for the present study were derived from the prospective cohort ‘Environmental Triggers of Type 1 Diabetes Study’. Infants were recruited from the Norwegian general population during 2001–2007. One hundred and ten (age 3–10 years) children had sufficient volumes of plasma and FFQ filled in within 2 months from blood sampling and were included in this evaluation study. The quantitative determination of plasma phospholipid fatty acids was done by fatty acid methyl ester analysis. The association between the frequency of dairy and fish product intake and the plasma phospholipid fatty acids was assessed by a Spearman correlation analysis and by investigating whether participants were classified into the same quartiles of distribution.
Results
Significant correlations were found between pentadecanoic acid and the intake frequency of total dairy products (r=0.29), total fat dairy products (r=0.39), and cheese products (r=0.36). EPA and DHA were significantly correlated with the intake frequency of oily fish (r=0.26 and 0.37, respectively) and cod liver/fish oil supplements (r=0.47 for EPA and r=0.50 DHA). To a large extent, the FFQ was able to classify individuals into the same quartile as the relevant fatty acid biomarker.
Conclusions
The present study suggests that, when using the plasma phospholipid fatty acids pentadecanoic acid, EPA, and DHA as biomarkers, the FFQ used in young children showed a moderate capability to rank the intake frequency of dairy products with a high-fat content and cod liver/fish oil supplements.
doi:10.3402/fnr.v60.31933
PMCID: PMC4989176  PMID: 27534845
biomarkers; dietary assessment; food frequency questionnaire; fatty acids; plasma phospholipids
23.  Dietary Long-Chain Omega-3 Fatty Acids Do Not Diminish Eosinophilic Pulmonary Inflammation in Mice 
Although the effects of fish oil supplements on airway inflammation in asthma have been studied with varying results, the independent effects of the fish oil components, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), administered separately, are untested. Here, we investigated airway inflammation and hyperresponsiveness using a mouse ovalbumin exposure model of asthma assessing the effects of consuming EPA (1.5% wt/wt), DHA (1.5% wt/wt), EPA plus DHA (0.75% each), or a control diet with no added omega-3 polyunsaturated fatty acids. Consuming these diets for 6 weeks resulted in erythrocyte membrane EPA contents (molar %) of 9.0 (± 0.6), 3.2 (± 0.2), 6.8 (± 0.5), and 0.01 (± 0.0)%; DHA contents were 6.8 (± 0.1), 15.6 (± 0.5), 12.3 (± 0.3), and 3.8 (± 0.2)%, respectively. The DHA group had the highest bronchoalveolar lavage (BAL) fluid eosinophil and IL-6 levels (P < 0.05). Similar trends were seen for macrophages, IL-4, and IL-13, whereas TNF-α was lower in omega-3 polyunsaturated fatty acid groups than the control (P < 0.05). The DHA group also had the highest airway resistance, which differed significantly from the EPA plus DHA group (P < 0.05), which had the lowest. Oxylipins were measured in plasma and BAL fluid, with DHA and EPA suppressing arachidonic acid–derived oxylipin production. DHA-derived oxylipins from the cytochrome P450 and 15-lipoxygenase pathways correlated significantly with BAL eosinophil levels. The proinflammatory effects of DHA suggest that the adverse effects of individual fatty acid formulations should be thoroughly considered before any use as therapeutic agents in asthma.
doi:10.1165/rcmb.2013-0136OC
PMCID: PMC4068931  PMID: 24134486
rodents; eosinophils; inflammation; lipid mediators
24.  A Transgenic Camelina sativa Seed Oil Effectively Replaces Fish Oil as a Dietary Source of Eicosapentaenoic Acid in Mice123 
The Journal of Nutrition  2016;146(2):227-235.
Background: Fish currently supplies only 40% of the eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) required to allow all individuals globally to meet the minimum intake recommendation of 500 mg/d. Therefore, alternative sustainable sources are needed.
Objective: The main objective was to investigate the ability of genetically engineered Camelina sativa (20% EPA) oil (CO) to enrich tissue EPA and DHA relative to an EPA-rich fish oil (FO) in mammals.
Methods: Six-week-old male C57BL/6J mice were fed for 10 wk either a palm oil–containing control (C) diet or diets supplemented with EPA-CO or FO, with the C, low-EPA CO (COL), high-EPA CO (COH), low-EPA FO (FOL), and high-EPA FO (FOH) diets providing 0, 0.4, 3.4, 0.3, and 2.9 g EPA/kg diet, respectively. Liver, muscle, and brain were collected for fatty acid analysis, and blood glucose and serum lipids were quantified. The expression of selected hepatic genes involved in EPA and DHA biosynthesis and in modulating their cellular impact was determined.
Results: The oils were well tolerated, with significantly greater weight gain in the COH and FOH groups relative to the C group (P < 0.001). Significantly lower (36–38%) blood glucose concentrations were evident in the FOH and COH mice relative to C mice (P < 0.01). Hepatic EPA concentrations were higher in all EPA groups relative to the C group (P < 0.001), with concentrations of 0.0, 0.4, 2.9, 0.2, and 3.6 g/100 g liver total lipids in the C, COL, COH, FOL, and FOH groups, respectively. Comparable dose-independent enrichments of liver DHA were observed in mice fed CO and FO diets (P < 0.001). Relative to the C group, lower fatty acid desaturase 1 (Fads1) expression (P < 0.005) was observed in the COH and FOH groups. Higher fatty acid desaturase 2 (Fads2), peroxisome proliferator–activated receptor α (Ppara), and peroxisome proliferator–activated receptor γ (Pparg) (P < 0.005) expressions were induced by CO. No impact of treatment on liver X receptor α (Lxra) or sterol regulatory element-binding protein 1c (Srebp1c) was evident.
Conclusions: Oil from transgenic Camelina is a bioavailable source of EPA in mice. These data provide support for the future assessment of this oil in a human feeding trial.
doi:10.3945/jn.115.223941
PMCID: PMC4725436  PMID: 26791554
n–3 PUFA; EPA; DHA; Camelina oil; fish oil; sustainability; desaturation; Fads; transgenic; TG sn-2
25.  Fish, Fish-Derived n-3 Fatty Acids, and Risk of Incident Atrial Fibrillation in the Atherosclerosis Risk in Communities (ARIC) Study 
PLoS ONE  2012;7(5):e36686.
Background
Results of observational and experimental studies investigating the association between intake of long-chain n-3 polyunsaturated fatty acids (PUFAs) and risk of atrial fibrillation (AF) have been inconsistent.
Methods
We studied the association of fish and the fish-derived n-3 PUFAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) with the risk of incident AF in individuals aged 45–64 from the Atherosclerosis Risk in Communities (ARIC) cohort (n = 14,222, 27% African Americans). Intake of fish and of DHA and EPA were measured via food frequency questionnaire. Plasma levels of DHA and EPA were measured in phospholipids in a subset of participants (n = 3,757). Incident AF was identified through the end of 2008 using ECGs, hospital discharge codes and death certificates. Cox proportional hazards regression was used to estimate hazard ratios of AF by quartiles of n-3 PUFAs or by fish intake.
Results
During the average follow-up of 17.6 years, 1,604 AF events were identified. In multivariable analyses, total fish intake and dietary DHA and EPA were not associated with AF risk. Higher intake of oily fish and canned tuna was associated with a nonsignificant lower risk of AF (p for trend = 0.09). Phospholipid levels of DHA+EPA were not related to incident AF. However, DHA and EPA showed differential associations with AF risk when analyzed separately, with lower risk of AF in those with higher levels of DHA but no association between EPA levels and AF risk.
Conclusions
In this racially diverse sample, dietary intake of fish and fish-derived n-3 fatty acids, as well as plasma biomarkers of fish intake, were not associated with AF risk.
doi:10.1371/journal.pone.0036686
PMCID: PMC3343018  PMID: 22570739

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