Dietary polyunsaturated fatty acids (C18:2 omega6 and C18:3 omega3) do not suppress hepatic lipogenesis

Omega 3 polyunsaturated fatty acids are promoted as beneficial in the prevention of metabolic and cardiovascular diseases. In general, dietary omega 3 fatty acids are derived from plant sources as linolenic acid (LNA, C18:3 omega3) the precursor to eicosapentaenoic acid (EPA, C20:5 omega3) and docosahexaenoic acid (DHA, C22:6 omega3). However, it remains unclear if the polyunsaturated fatty acid (PUFA) LNA can provide the same health benefits as the very long chain highly unsaturated fatty acids (HUFA) EPA and DHA generally derived from oily fish. In this study, mice were fed synthetic diets containing lard (low in PUFA and HUFA), canola oil (to supply PUFA), or a mixture of menhaden and arasco (fish and fungal) oils (to supply HUFA) for 8 weeks. The diets were neither high in calories nor fat, which was supplied at 6%. The lard and canola oil diets resulted in high levels of hepatic triglycerides and cholesterol and elevation of lipogenic gene expression. By comparison livers from mice fed the fish/fungal oil diet had low levels of lipid accumulation and more closely resembled livers from mice fed standard laboratory chow. SREBP1c and PPARgamma gene and protein expression were high in livers of animals fed diets containing lard or canola oil compared with fish/fungal oil. Hepatic fatty acid analyses indicated that dietary PUFA were efficiently converted to HUFA regardless of source. Therefore, differences in hepatic lipid levels and gene expression between dietary groups were due to exogenous fatty acid supplied rather than endogenous pools. These results have important implications for understanding the regulation of hepatic lipogenesis by dietary fatty acids.     

Influence of an increased intake of linoleic acid on the incorporation of dietary (n-3) fatty acids in phospholipids and on prostanoid synthesis in rat tissues.

We investigated whether the amount of dietary linoleic acid (LA) (as corn oil) influences the incorporation of dietary eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) in tissue phospholipids and the prostanoid biosynthesis. Rats were fed four different levels of corn oil (at a total dietary fat level of either 2.5%, 5%, 10% or 20%); at each corn oil level, two groups of rats were supplemented with either EPA and DHA (200 mg/day) during 6 weeks, and compared with a group receiving oleic acid. The phospholipid fatty acid composition of liver, kidney and aorta showed, as expected, that the incorporation of EPA was highly suppressed by increasing the content of dietary linoleic acid in the diets. On the other hand, DHA was almost unaffected by the amounts of (n - 6) fatty acids in the diets. These results indicate that EPA levels but not DHA levels in tissue phospholipids were influenced by the competing dietary (n - 6) fatty acids. The tissue arachidonate content was similar under the various dietary linoleic acid conditions, but feeding EPA or DHA lowers the AA content. Moreover, the amount of dietary linoleic acid did not significantly influence the prostaglandin E2 (PGE2) production in stimulated aortic rings. However, PGE2 synthesis was significantly decreased in the groups treated with either EPA or DHA. Thromboxane B2 levels in serum followed a similar pattern. It is suggested that an increase of dietary (n - 3) PUFAs is more efficient to reduce (n - 6) eicosanoid formation than a decrease of dietary (n - 6) fatty acids.     

碳源对粉核油球藻生长和脂肪酸组成特性的影响

研究了不同碳源类型（CO2、NaHCO3和葡萄糖）及其浓度对粉核油球藻（Pinguiococcus pyrenoidosus CCMP 2078）生长及脂肪酸组成的影响。结果表明：（1）培养液中适量添加碳源促进了粉核油球藻的生长,三种碳源的适宜添加浓度分别是0.5% CO2,5mmol/L NaHCO3和20g/L葡萄糖,对数生长末期的细胞密度分别是对照的3.10倍、1.47倍和2.78倍;（2）除了低浓度葡萄糖外,其他碳源类型和浓度均降低了TPUFA和EPA占总脂肪酸的比例,提高了TSFA的比例,胞内EPA和TSFA含量均下降;（3）低浓度碳源提高了TSFA和EPA产量。通入0.5% CO2培养的EPA和TSFA产量分别是对照的2.30倍和2.69倍,5mmol/L NaHCO3培养的TSFA产量是对照的1.85倍,5g/L和10g/L葡萄糖培养的EPA和TSFA产量最高分别可达对照的2.11倍和1.58倍。因此,通入低浓度CO2最有利于粉核油球藻的生长以及EPA和饱和脂肪酸的生产,EPA和饱和脂肪酸含量的提高主要是通过生物量的增大来实现的。     

Downstream processing and purification of eicosapentaenoic (20:5n-3) and arachidonic acids (20:4n-6) from the microalga Porphyridium cruentum

Eicosapentaenoic acid (FPA, 20:5n-3) and arachidonic acid (AA, 20:4n-3)were obtained from the microalga Porphyridium cruentum by a three-stepprocess: fatty acid extraction by direct saponification of biomass,polyunsaturated fatty acid (PUFA) concentration by urea inclusion complexingand EPA isolation by high-performance liquid chromatography (HPLC). Twosolvents were tested for direct saponification of lipids in biomass. Themost efficient solvent, ethanol (96% v/v), extracted 75% ofthe fatty acids. PUFAs concentration by urea inclusion employed a urea/fattyacid ratio of 4:1 wt/wt at the crystallization temperatures of 4°C and28°C. Concentration factors were similar at both temperatures, but theEPA and AA recoveries were higher at 28°C (67.7% and 61.8%for the two acids, respectively). EPA and AA were purified from this PUFAconcentrate using analytical scale HPLC and the best results of thisseparation were scaled up to preparative level (4.7 i. d. × 30 cmcompression radial cartridge). A 94.3% pure EPA fraction and a81.4% pure AA fraction were obtained. Suitability of severalmicroalgae (Porphyridium cruentum, Phaeodactylum tricornutum and Isochrysisgalbana) and cod liver oil as sources of highly pure PUFAs, mainly EPA, wascompared.     

不同脂肪源对泥鳅稚鱼生长性能及脂肪酸组成的影响

为研究饲料不同脂肪源对泥鳅稚鱼生长性能及鱼体脂肪酸组成的影响, 实验选择初始体重为(10.002.00) mg的健康泥鳅稚鱼1500尾, 随机分为5组, 每组3个重复, 每个水箱100尾鱼, 分别投喂5种含有鱼油(FO)、大豆油(SO)、玉米油(CO)、花生油(PeO)和棕榈油(PaO)的配合饲料, 每种饲料3个重复, 饲养期为40d。结果显示, 摄食不同脂肪源饲料的泥鳅稚鱼在增重率、成活率、饲料系数等生长性能指标和体成分上没有显著差异(P0.05), 但是, 摄食FO组鱼体极性脂肪含量显著高于其他植物油组(P0.05)。鱼油组鱼体中性和极性脂肪中总n-3系脂肪酸含量和EPA+DHA含量显著高于其他植物油组(P0.05)。植物油组鱼体极性脂肪中20:4n-6含量显著高于鱼油组(P0.05), 表明泥鳅稚鱼具有将C18转换为C20的能力。研究表明, 在饲料中添加足量磷脂, 鱼油、大豆油、玉米油、花生油、棕榈油都可以用作泥鳅稚鱼期专用饲料脂肪源。     

Increase of eicosapentaenoic acid in thraustochytrids through thraustochytrid ubiquitin promoter-driven expression of a fatty acid {delta}5 desaturase gene

Thraustochytrids, marine protists known to accumulate polyunsaturated fatty acids (PUFAs) in lipid droplets, are considered an alternative to fish oils as a source of PUFAs. The major fatty acids produced in thraustochytrids are palmitic acid (C(16:0)), n - 6 docosapentaenoic acid (DPA) (C(22:5)(n) (- 6)), and docosahexaenoic acid (DHA) (C(22:6)(n) (- 3)), with eicosapentaenoic acid (EPA) (C(20:5)(n) (- 3)) and arachidonic acid (AA) (C(20:4)(n) (- 6)) as minor constituents. We attempted here to alter the fatty acid composition of thraustochytrids through the expression of a fatty acid Δ5 desaturase gene driven by the thraustochytrid ubiquitin promoter. The gene was functionally expressed in Aurantiochytrium limacinum mh0186, increasing the amount of EPA converted from eicosatetraenoic acid (ETA) (C(20:4)(n) (- 3)) by the Δ5 desaturase. The levels of EPA and AA were also increased by 4.6- and 13.2-fold in the transgenic thraustochytrids compared to levels in the mock transfectants when ETA and dihomo-γ-linolenic acid (DGLA) (C(20:3)(n) (- 6)) were added to the culture at 0.1 mM. Interestingly, the amount of EPA in the transgenic thraustochytrids increased in proportion to the amount of ETA added to the culture up to 0.4 mM. The rates of conversion and accumulation of EPA were much higher in the thraustochytrids than in baker's yeasts when the desaturase gene was expressed with the respective promoters. This report describes for the first time the finding that an increase of EPA could be accomplished by introducing the Δ5 desaturase gene into thraustochytrids and indicates that molecular breeding of thraustochytrids is a promising strategy for generating beneficial PUFAs.     

Changes in tissue composition in Brazilian mojarra Eugerres brasilianus (Cuvier, 1830) females at different stages of gonadal development as a starting point for development of broodstock diets

Thie study evaluated the changes in proximate composition and fatty acid profile in the muscle, liver and ovarian tissues of wild‐caught Brazilian mojarra Eugerres brasilianus females during sexual maturation as a starting point for the development of broodstock diets. A total of 114 females captured in the Santa Cruz Canal, Itapissuma, PE, north‐eastern Brazil, from August 2012 to April 2013, were classified into four stages of gonadal development by histological analyses. Ovarian protein and total lipid levels increased with maturation, and a simultaneous decrease in liver protein and lipid levels was observed. The levels of arachidonic acid (ARA, 20:4n‐6), eicosapentaenoic acid (EPA, 20:5n‐3), docosapentaenoic acid (DPA, 22:5n‐3) and docosahexaenoic acid (DHA, 22:6n‐3) also increased in the ovary as the gonadal development proceeded; they represented 96.4% of the total highly unsaturated fatty acids (HUFA) in the ovaries of fully mature females. These findings highlight the need to include protein and lipid‐rich sources containing n‐6 HUFA, particularly ARA, and n‐3 HUFA (EPA, DPA and DHA) in the diets of Brazilian mojarra breeders.     

Dietary n-3 polyunsaturated fatty acids modify fatty acid composition in hepatic and abdominal adipose tissue of sucrose-induced obese rats

The fatty acid profile of hepatocytes and adipocytes is determined by the composition of the dietary lipids. It remains unclear which fatty acid components contribute to the development or reduction of insulin resistance. The present work examined the fatty acid composition of both tissues in sucrose-induced obese rats receiving fish oil to determine whether the effect of dietary (n-3) polyunsaturated fatty acids (PUFAs) on the reversion of metabolic syndrome in these rats is associated to changes in the fatty acid composition of hepatocyte and adipocyte membrane lipids. Animals with metabolic syndrome were divided into a corn–canola oil diet group and a fish oil diet group, and tissues fatty acids composition were analyzed after 6 weeks of dietary treatment. Fatty acid profiles of the total membrane lipids were modified by the fatty acid composition of the diets fed to rats. N-3 PUFAs levels in animals receiving the fish oil diet plus sucrose in drinking water were significantly higher than in animals under corn–canola oil diets. It is concluded that in sucrose-induced obese rats, consumption of dietary fish oil had beneficial effects on the metabolic syndrome and that such effects would be conditioned by the changes in the n-3 PUFAs composition in hepatic and adipose tissues because they alter membrane properties and modify the type of substrates available for the production of active lipid metabolites acting on insulin resistance and obesity.     

Dietary supplementation with docosahexaenoic acid, but not eicosapentaenoic acid, dramatically alters cardiac mitochondrial phospholipid fatty acid composition and prevents permeability transition

Treatment with the ω-3 polyunsaturated fatty acids (PUFAs) docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) exerts cardioprotective effects, and suppresses Ca²⁺-induced opening of the mitochondrial permeability transition pore (MPTP). These effects are associated with increased DHA and EPA, and lower arachidonic acid (ARA) in cardiac phospholipids. While clinical studies suggest the triglyceride lowering effects of DHA and EPA are equivalent, little is known about the independent effects of DHA and EPA on mitochondria function. We compared the effects of dietary supplementation with the ω-3 PUFAs DHA and EPA on cardiac mitochondrial phospholipid fatty acid composition and Ca²⁺-induced MPTP opening. Rats were fed a standard lab diet with either normal low levels of ω-3 PUFA, or DHA or EPA at 2.5% of energy intake for 8 weeks, and cardiac mitochondria were isolated and analyzed for Ca²⁺-induced MPTP opening and phospholipid fatty acyl composition. DHA supplementation increased both DHA and EPA and decreased ARA in mitochondrial phospholipid, and significantly delayed MPTP opening as assessed by increased Ca²⁺ retention capacity and decreased Ca²⁺-induced mitochondria swelling. EPA supplementation increased EPA in mitochondrial phospholipids, but did not affect DHA, only modestly lowered ARA, and did not affect MPTP opening. In summary, dietary supplementation with DHA but not EPA, profoundly altered mitochondrial phospholipid fatty acid composition and delayed Ca²⁺-induced MPTP opening.     

Polyunsaturated fatty acids production with a solid-state column reactor

To investigate the potential production of polyunsaturated fatty acids (PUFAs), a solid-state column reactor of rice bran with Mortierella alpina was used. The optimal conditions for PUFAs production were rice bran supplementation with 3.75% (ww(-1)) nitrogen source at initial moisture content 57%, initial pH 6-7, aeration, and incubation at 20 degrees C for 5 days and then at 12 degrees C for 7 days. Each gram of substrate carbon yielded 127 mg of total PUFAs, 12 mg of eicosapentaenoic acid (EPA), 6 mg of arachidonic acid (AA), 5mg of alpha-linolenic acid (ALA), and 117 mg of linoleic acid (LA) after 12 days incubation. Aeration enhanced the productions of AA, EPA, and total PUFAs. Supplementation of the nitrogen source on the fourth day and then a shift to lower temperature on the fifth day increased EPA production.     

Fatty acid composition of the cold-water-inhabiting freshwater red alga Sirodotia Kylin

Four samples of freshwater alga Sirodotia (class Rhodophyceae) collected from two distinct streams in the Mahabaleshwar, Satara district (1,732 m a.s.l.) of the Western Ghats of Maharashtra (India) were analysed for their fatty acid content. The presence of 32 fatty acids was revealed, of which 13 were saturated (SFA), 8 were monounsaturated (MUFA) and 11 were polyunsaturated (PUFA) fatty acids. The major finding was the presence of three pharmaceutically and neutraceutically important PUFAs: arachidonic acid (AA), eicosapentanoeic acid (EPA), and docosahexanoiec acid (DHA). The major fatty acids identified were palmitic (16:0), cis-11,14 icodienoic (20:2), behenic (22:0), cis-8,11,14 eicosatrienoic(20:3n6), cis-4,7,10,13,16,19 docosahexanoeic (22:6n3), cis-13,16 docosadienoic (22:2), erucic (22:1n9), -5,8,11,14,17 eicosapentaenoic (20:5n3), trichosonoic (23:0), nervonic (24:0), arachidonic (20:4n6), cis-10 pentadecanoic (15:1), cis-11,14,17 eicosatrienoic (20:3n3), and myristic acid (14:0). The total PUFA contents ranged from 31.45 to 40.37%. The fatty acids were characterised by the relatively high abundance of PUFAs, while C20 unsaturated acids were appreciably more abundant than C18 unsaturated acids. This is the first report on fatty acid profiles of the genus Sirodotia.     

EFFECTS OF LOWERING TEMPERATURE DURING CULTURE ON THE PRODUCTION OF POLYUNSATURATED FATTY ACIDS IN THE MARINE DIATOM PHAEODACTYLUM TRICORNUTUM (BACILLARIOPHYCEAE)1

The composition of fatty acids and contents of eicosapentaenoic acid (EPA) and polyunsaturated fatty acids (PUFAs) of the economically important marine diatom, Phaeodactylum tricornutum (Bohlin), were investigated to see whether reducing the culture temperature enhances the production of EPA and PUFAs. The contents of EPA and PUFAs of P. tricornutum were found to be higher at lower temperature when cultured at 10, 15, 20, or 25°C. When the cells grown at 25°C were shifted to 20, 15, or 10°C, the contents per dry mass of PUFAs and EPA increased to the maximal values in 48, 24, and 12 h, respectively. The highest yields of PUFAs and EPA per unit dry mass (per unit volume of culture) were 4.9% and 2.6% (12.4 and 6.6 mg·L^?1), respectively, when temperature was shifted from 25 to 10°C for 12 h, both being raised by 120% compared with the control. The representative fatty acids in the total fatty acids, when temperature was lowered from 25 to 10°C, decreased proportionally by about 30% in C_16:0 and 20% in C_16:1(n?7) but increased about 85% in EPA. It was concluded that lowering culture temperature of P. tricornutum could significantly raise the yields of EPA and PUFAs.     

Selective regulation of UGT1A1 and SREBP‐1c mRNA expression by docosahexaenoic,eicosapentaenoic, and arachidonic acids

We evaluated, in human cell line HepG2, the action of individual dietary polyunsaturated fatty acids (PUFAs) on the expression of several lipid metabolism genes. The effects of docosahexaenoic acid, 22:6, n‐3 (DHA), eicosapentaenoic acid, 20:5, n‐3 (EPA), and arachidonic acid, 20:4, n‐6 (AA) were studied alone and with vitamin E (Vit.E). DHA, EPA, and AA down‐regulated mRNAs and encoded proteins of stearoyl‐CoA desaturase (SCD) and sterol regulatory element binding protein (SREBP‐1c), two major factors involved in unsaturated fatty acids synthesis. DHA affected SREBP‐1c mRNA less markedly than EPA and AA. Vit.E did not affect these products, both when individually added or together with fatty acids. The expression of UDP‐glucuronosyl transferase 1A1 (UGT1A1) mRNA, an enzyme of phase II drug metabolism with relevant actions within lipid metabolism, resulted also differentially regulated. DHA did not essentially reduce UGT1A1 mRNA expression while EPA and AA produced a considerable decrease. Nevertheless, when these PUFAs were combined with Vit.E, which by itself did not produce any effect, the result was a reduction of UGT1A1 mRNA with DHA, an increase reverting to basal level with EPA and no variation with AA. Observed regulations did not result to be mediated by peroxisome proliferator‐activated receptor (PPAR). Our data indicate that major dietary PUFAs and Vit.E are differentially and selectively able to affect the expression of genes involved in lipid metabolism. The different actions of these slightly different molecules could be associated with their physiological role as relevant nutrient molecules. J. Cell. Physiol. 226: 187–193, 2010. © 2010 Wiley‐Liss, Inc.     

Preferential accumulation of fatty acids in the testis and ovary of cultured and wild sweet smelt Plecoglossus altivelis

The effect of dietary lipid on the fatty acid composition of muscle, testis and ovary of cultured sweet smelt, Plecoglossus altivelis, was investigated and compared with that of wild sweet smelt. Cultured fish were fed three different diets for 12 weeks: a control diet rich in docosahexaenoic acid (DHA, 22:6n-3) and eicosapentaenoic acid (EPA, 20:5n-3) (CO group); a diet deficient in DHA and EPA (DP group); and a diet rich in alpha-linolenic acid (ALA, 18:3n-3), but deficient in DHA and EPA (LP group). The fatty acid composition of muscle and gonad lipids was related with dietary fatty acids. Despite the difference in DHA and EPA content in the diets, muscles and gonads, respectively, contained almost equal levels of DHA and EPA in each CO and DP group. However, the muscle and gonad of the LP group showed a lower level of DHA than other groups, due to having the highest level of ALA. In the wild fish muscle, the DHA content was similar to that of CO and DP groups, but the EPA content showed the highest level in all groups. There was no difference in the muscle fatty acid proportions between male and female. On the other hand, the testes of cultured and wild fish were rich in DHA, EPA, docosapentaenoic acid and arachidonic acid, while ovaries were rich in oleic, palmitoleic, linoleic acids and ALA. Moreover, of all the groups, the fish fatty acid composition of the LP group was closest to that of wild fish. These results indicate that in the sweet smelt, tissue n-3 polyunsaturated fatty acids (PUFAs) greater than C20 can be synthesized from dietary precursors and special fatty acids are preferentially accumulated to the testis or ovary, respectively, to play different physiological functions.     

Differential distribution of DHA-phospholipids in rat brain after feeding: A lipidomic approach

On a per-weight basis, the brain is the organ richest in lipids, including a remarkable proportion of polyunsaturated fatty acids (PUFAs) of the omega 3 series, namely eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. The cerebral effects of exogenous DHA likely depend on its degree of incorporation into neuronal phospholipids and on its distribution among the various brain structures, after intake. Hence, because PUFAs are not evenly distributed among the brain phospholipid classes and because the existence of class-specific phospholipases that regulate their turnover, we sought to investigate the incorporation of omega 3 PUFAs in selected brain areas regions and specific phospholipid classes. Rats (n=7) were administered, by oral gavage, 100mg/kg/d of a commercially available fish oil (containing ～84% of long-chain omega 3 fatty acids, of which ～38% of DHA and ～46% of EPA). Control rats (n=7) received liquid paraffin. This treatment was continued for 30 days. Thereafter, we dissected three areas, namely the hippocampus, the striatum, and the cortex. Quantization of individual phospholipid classes and their molecular species was performed by ESI-MS/MS. Principal component analysis was used to examine the variation of the molecular lipid profiles (as percentage) induced by omega 3 supplementation. Our results show that provision of omega 3 fatty acids to rats results in their incorporation into brain phospholipids, the extent of which is lower in the striatum as compared with cortex and hippocampus. These data might in part explain the mixed therapeutic results obtained in neurological disorders, many of which are likely region-specific.     

Effect of polyunsaturated fatty acids on dexamethasone-induced gastric mucosal damage

BACKGROUND: Increased dietary intake of polyunsaturated fatty acids (PUFAs) is known to be associated with a decrease in the incidence of peptic ulcer disease possibly due to increase in the synthesis of prostaglandins. But, it is also likely that conversion of PUFAs to PGs may not always be required for gastric mucosal protection. Present study was designed to study the role of PUFAs in pathobiology of steroid induce gastric damage in rats. METHODS: Wistar rats were treated with 5 mg/kg bodyweight of dexamethasone to induce gastric mucosal ulcers. Effects of PUFAs was studied by supplementation of Fish oil (rich in n-3 EPA and DHA) and AA rich oil. Famotidine was used as a positive control. Generation of lipid peroxides, nitric oxide and the activity of anti-oxidant enzymes were also studied. RESULTS: Dexamethasone induced ulceration was associated with changes in the phospholipid fatty acid profile, levels of lipid peroxidation products, nitric oxide and activity of anti-oxidant enzymes. The fatty acid profile showed an increase in LA and a decrease in other PUFAs like GLA, AA, EPA and DHA. When PUFAs were supplemented in the form of Fish oil and AA rich oil or when the animals were treated with H2-blocker, famotidine, there was a decrease in the incidence of ulceration in the animals associated with near normalization of changes in the phospholipid fatty acid profile. The levels of lipid peroxides, nitric oxide, and anti-oxidant activity also reverted to control values. CONCLUSIONS: Dexamethasone induced gastric ulceration was prevented by PUFAs. This is supported by the results of our earlier study where in it was noted that in patients with DU plasma lipid peroxides, nitric oxide and phospholipid fatty acid pattern and red cell antioxidant activity were altered similar to those seen in dexamethasone treated group of the present study. These abnormalities, similar to the PUFA treated groups of the present study, reverted to normalcy following treatment of the patients with lansoprazole, a proton pump inhibitor. Further, PUFAs are known to inhibit the growth of Helicobacter pylori in vitro. Hence, it is concluded that PUFAs, free radicals, nitric oxide and anti-oxidants play a significant role in the pathobiology of peptic ulcer.     

Chemical synthesis and biological evaluation of ω-hydroxy polyunsaturated fatty acids

ω-Hydroxy polyunsaturated fatty acids (PUFAs), natural metabolites from arachidonic acid (ARA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were prepared via convergent synthesis approach using two key steps: Cu-mediated CC bond formation to construct methylene skipped poly-ynes and a partial alkyne hydrogenation where the presence of excess 2-methyl-2-butene as an additive that is proven to be critical for the success of partial reduction of the poly-ynes to the corresponding cis-alkenes without over-hydrogenation. The potential biological function of ω-hydroxy PUFAs in pain was evaluated in naive rats. Following intraplantar injection, 20-hydroxyeicosatetraenoic acid (20-HETE, ω-hydroxy ARA) generated an acute decrease in paw withdrawal thresholds in a mechanical nociceptive assay indicating pain, but no change was observed from rats which received either 20-hydroxyeicosapentaenoic acid (20-HEPE, ω-hydroxy EPA) or 22-hydroxydocosahexaenoic acid (22-HDoHE, ω-hydroxy DHA). We also found that both 20-HEPE and 22-HDoHE are more potent than 20-HETE to activate murine transient receptor potential vanilloid receptor1 (mTRPV1).     

Production of arachidonic and eicosapentaenoic acids in plants using bryophyte fatty acid Delta6-desaturase, Delta6-elongase, and Delta5-desaturase genes

The liverwort Marchantia polymorpha L. synthesizes arachidonic (ARA) and eicosapentaenoic acids (EPA) from linoleic and alpha-linolenic acids respectively by a series of reactions catalyzed by Delta6-desaturase, Delta6-elongase, and Delta5-desaturase. Overexpression of the M. polymorpha genes encoding these enzymes in transgenic M. polymorpha plants resulted in 3- and 2-fold accumulation of ARA and EPA respectively, as compared to those in the wild type. When these three genes were introduced and co-expressed in tobacco plants, in which long-chain polyunsaturated fatty acids (LCPUFAs) are not native cellular components, ARA and EPA represented up to 15.5% and 4.9% respectively of the total fatty acid in the leaves. Similarly in soybean, C20-LCPUFAs represented up to 19.5% of the total fatty acids in the seeds. These results suggest that M. polymorpha can provide genes crucial to the production of C20-LCPUFAs in transgenic plants.     

Fatty Acid Composition of Porcine Muscle and Adipose Tissue Lipids as Affected by Anatomical Location and Cod Liver Oil Supplementation of the Diet

In pigs fed a standard pig mash the contents of polyunsaturated fatty acids (PUFAs) of both the n-6 and n-3 series were significantly higher in the dark red mm adductores compared to the light coloured m longissimus lumborum. Perirenal fat had a higher concentration of saturated fatty acids (14:0,16:0, 18:0) than backfat, and a lower concentration of monounsaturated fatty acids, such as 16:ln-7 and 18:ln-9. Daily supplementation of 50 ml cod liver oil, rich in n-3 PUFAs, during the fourth and third week before slaughter led to a 1.4 to 1.7 times increase in the contents of n-3 PUFAs in muscles and fat depots. There was no difference between the incorporation of n-3 PUFAs in dark and light muscles. Perirenal fat contained more 20:5n-3 (EPA) and 22:6n-3 (DHA), but less 20:ln-9 (eicosenoic acid) than the backfat, after cod liver oil supplementation rich in these 3 fatty acids. Supplementation of cod liver oil reduced the n-6/n-3 fatty acid ratio in all anatomical locations examined.     

Effect of arachidonic, eicosapentaenoic and docosahexaenoic acids on the oxidative status of C6 glioma cells

n-3 polyunsaturated fatty acids (PUFAs) have been described to have beneficial effects on brain development and in the prevention and treatment of brain damage. C6 glioma cells were incubated with 100 microM of either C20:4n-6 (ARA), or C20:5n-3 (EPA), or C22:6n-3 (DHA) for different time periods to assess whether these acids altered the cellular oxidative state. The ARA and EPA were promptly metabolised to C22:4n-6 and C22:5n-3, respectively, whereas DHA treatment simply increased the amount of DHA in the cells. Cell viability was not affected by ARA, while a cytotoxic effect was observed 72 h after n-3 PUFAs supplementation. The levels of reactive oxygen species and thiobarbituric acid-reactive substances were significantly higher in DHA-treated cells than in EPA- and ARA-treated groups. This modification in the oxidative cellular status was also highlighted by a significant increase in catalase activity and a decrease in glutathione content in DHA-supplemented cells. Glucose-6-phosphate dehydrogenase activity, an enzyme involved in redox regulation, and O2*- release were significantly increased both in EPA and DHA groups. The effect of DHA was more severe than that of EPA. No significant changes were observed in the ARA group with respect to untreated cells. These data show that EPA and DHA induce alterations in the oxidative status that could affect the glial function.