Fish Oil Docosahexaenoic Acid Research Articles

Effects of a Fish Oil Rich in Docosahexaenoic Acid on Cardiometabolic Risk Factors and Oxidative Stress in Healthy Rats.

Omega-3 polyunsaturated fatty acids are associated with a lower risk of cardiometabolic diseases. However, docosahexaenoic acid (DHA) is easily oxidized, leading to cellular damage. The present study examined the effects of an increased concentration of DHA in fish oil (80% of total fatty acids) on cardiometabolic risk factors and oxidative stress compared to coconut oil, soybean oil, and fish oil containing eicosapentaenoic acid (EPA) and DHA in a balanced ratio. Forty healthy male Sprague–Dawley rats were supplemented with corresponding oil for 10 weeks. Supplementation with the fish oil containing 80% DHA decreased plasma fat, plasma total cholesterol and muscle fat compared to the coconut oil and the soybean oil. Increasing concentrations of DHA induced incorporation of DHA and EPA in cell membranes and tissues along with a decrease in ω-6 arachidonic acid. The increase in DHA promoted lipid peroxidation, protein carbonylation and antioxidant response. Taken together, the increased concentration of DHA in fish oil reduced fat accumulation compared to the coconut oil and the soybean oil. This benefit was accompanied by high lipid peroxidation and subsequent protein carbonylation in plasma and in liver. In our healthy framework, the slightly higher carbonylation found after receiving fish oil containing 80% DHA might be a protecting mechanism, which fit with the general improvement of antioxidant defense observed in those rats.

1H NMR Quantification of DHA and EPA in Fish Oil

Fish oil is a popular nutritional product consumed in China. The beneficial effects of fish oil have been attributed to docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Hence, it is crucial to develop a rapid and precise method to determine the contents of EPA and DHA in fish oil. In this study, a rapid and accurate proton nuclear magnetic resonance method for the quantification of DHA and EPA was developed. Dimethyl terephthalate was selected as an internal standard, and the signals at 2.391 ppm for DHA and at 1.697 ppm for EPA were chosen for the quantification. Validation of the method was performed in terms of specificity, precision, and stability. The results indicated that the method was precise and in line with the China Food and Drug Administration guidance. The method has been successfully applied to characterize fish oil capsules obtained from four pharmaceutical companies. This study indicated that the rapid 1H NMR method is suitable for the quality control of fish oil.

Purification and characterization of an extracellular lipase from Trichosporon sp. and its application in enrichment of omega-3 polyunsaturated fatty acids

Lipase catalysis has become the most promising technique for enrichment of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) due to its mild and green conditions. In this study, Trichosporon sp. F1-2 was newly isolated from oil-contaminated sludge, and its extracellular lipase was purified using ammonium sulfate precipitation and DEAE-Sepharose chromatography. The molecular weight of the lipase was estimated to be 32.6 kDa. The optimal temperature and pH for lipase activity were 50 °C and 8.0, respectively, and the optimal storage conditions were found to be temperatures below 45 °C and pH 7.0–9.0. The lipase did not require metal ions as cofactors and was significantly inhibited by Zn2+. It was stable in various organic solvents with different log P values, and n-hexane, toluene, dichloromethane, diethyl ether and glycerol even enhanced its activity. It had sn-1,3 regioselectivity and the highest activity towards a medium-chain fatty acid (C8) ester. This study demonstrated the lipase has good potential as a catalyst in enrichment of EPA and DHA in fish oil. The content of EPA and DHA reached 22.9 and 25.4 mol%, respectively, using 100 U of the lipase within 24 h, and the enrichment efficiency of DHA was higher than that of EPA.

Distinct Analgesic Actions of DHA and DHA-Derived Specialized Pro-Resolving Mediators on Post-operative Pain After Bone Fracture in Mice.

Mechanisms of pain resolution are largely unclear. Increasing evidence suggests that specialized pro-resolving mediators (SPMs), derived from fish oil docosahexaenoic acid (DHA), promote the resolution of acute inflammation and potently inhibit inflammatory and neuropathic pain. In this study, we examined the analgesic impact of DHA and DHA-derived SPMs in a mouse model of post-operative pain induced by tibial bone fracture (fPOP). Intravenous perioperative treatment with DHA (500 μg), resolvin D1 (RvD1, 500 ng) and maresin 1 (MaR1, 500 ng), 10 min and 24 h after the surgery, delayed the development of fPOP (mechanical allodynia and cold allodynia). In contrast, post-operative intrathecal (IT) administration of DHA (500 μg) 2 weeks after the surgery had no effects on established mechanical and cold allodynia. However, by direct comparison, IT post-operative treatment (500 ng) with neuroprotectin D1 (NPD1), MaR1, and D-resolvins, RvD1 and RvD5, but not RvD3 and RvD4, effectively reduced mechanical and cold allodynia. ELISA analysis showed that perioperative DHA treatment increased RvD1 levels in serum and spinal cord samples after bone fracture. Interestingly, sham surgery resulted in transient allodynia and increased RvD1 levels, suggesting a correlation of enhanced SPM levels with acute pain resolution after sham surgery. Our findings suggest that (1) perioperative treatment with DHA is effective in preventing and delaying the development of fPOP and (2) post-treatment with some SPMs can attenuate established fPOP. Our data also indicate that orthopedic surgery impairs SPM production. Thus, DHA and DHA-derived SPMs should be differentially supplemented for treating fPOP and improving recovery.

Changes in Tissue Lipid and Fatty Acid Composition of Farmed Rainbow Trout in Response to Dietary Camelina Oil as a Replacement of Fish Oil

Camelina oil (CO) replaced 50 and 100% of fish oil (FO) in diets for farmed rainbow trout (initial weight 44±3gfish(-1)). The oilseed is particularly unique due to its high lipid content (40%) and high amount of 18:3n-3 (α-linolenic acid, ALA) (30%). Replacing 100% of fish oil with camelina oil did not negatively affect growth of rainbow trout after a 12-week feeding trial (FO=168±32gfish(-1); CO=184±35gfish(-1)). Lipid and fatty acid profiles of muscle, viscera and skin were significantly affected by the addition of CO after 12weeks of feeding. However, final 22:6n-3 [docosahexaenoic acid (DHA)] and 20:5n-3 [eicosapentaenoic acid (EPA)] amounts (563mg) in a 75g fillet (1 serving) were enough to satisfy daily DHA and EPA requirements (250mg) set by the World Health Organization. Other health benefits include lower SFA and higher MUFA in filets fed CO versus FO. Compound-specific stable isotope analysis (CSIA) confirmed that the δ(13)C isotopic signature of DHA in CO fed trout shifted significantly compared to DHA in FO fed trout. The shift in DHA δ(13)C indicates mixing of a terrestrial isotopic signature compared to the isotopic signature of DHA in fish oil-fed tissue. These results suggest that~27% of DHA was synthesized from the terrestrial and isotopically lighter ALA in the CO diet rather than incorporation of DHA from fish meal in the CO diet. This was the first study to use CSIA in a feeding experiment to demonstrate synthesis of DHA in fish.

Efficient Display of Active Geotrichum sp. Lipase on Pichia pastoris Cell Wall and Its Application as a Whole-Cell Biocatalyst To Enrich EPA and DHA in Fish Oil

Geotrichum sp. lipase (GSL) was first displayed on the cell wall of Pichia pastoris on the basis of the a-agglutinin anchor system developed in Saccharomyces cerevisiae . Surface display levels were monitored using Western blotting, immunofluorescence miscroscopy, and fluorescence-activated cell sorting analysis. Lipase activity of the yeast whole cells reached a maximum at 273 ± 2.4 U/g of dry cells toward olive oil after 96 h of culture at 30 °C, with optimal pH and temperature at 7.5 and 45 °C, respectively. Displayed GSL exhibited relatively high stability between pH 6.0 and 8.0 and retained >70% of the maximum activity. The surface-displayed lipase retained 80% of its original activity after incubation at 45 °C for 4 h. Moreover, the GSL-displaying yeast whole cells were then used as a biocatalyst to enrich eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from fish oil on the basis of selective hydrolysis. As a result, EPA and DHA increased from 1.53 and 24.1% in the original fish oil to 1.85 and 30.86%, which were increases of 1.21- and 1.29-fold, respectively. The total yield of EPA and DHA reached 46.62%.

Adiponectin translation is increased by the PPARγ agonists pioglitazone and ω-3 fatty acids

Adiponectin, made exclusively by adipocytes, is a 30-kDa secretory protein assembled posttranslationally into low-molecular weight, middle-molecular weight, and high-molecular weight homo-oligomers. PPARgamma ligand thiozolidinediones, which are widely used in the treatment of type II diabetes, increase adiponectin levels. PPARgamma also has several putative ligands that include fatty acid derivatives. Overnight treatment of rat adipocytes with pioglitazone, docosahexaenoic acid (DHA), or eicosapentaenoic acid (EPA) triggered a twofold increase in the synthesis and secretion of HMW adiponectin, and this increase was blocked by the addition of PPARgamma inhibitor GW-9662. Inhibition of glycosylation using 2,2'-dipyridyl decreased the synthesis of high-molecular weight adiponectin by pioglitazone, EPA, and DHA, but there was increased secretion of trimeric adiponectin resulting from increased translation. Although pioglitazone, DHA, and EPA increased adiponectin synthesis by more than 60%, there was no increase in total protein synthesis and no corresponding change in adiponectin mRNA expression, indicating the upregulation of translation. We examined the possibility of transacting factors in the cytoplasmic extracts from adipocytes treated with pioglitazone or DHA. In vitro translation of adiponectin mRNA was inhibited by S-100 fraction of control adipocytes and increased by S-100 extracts from adipocytes treated with pioglitazone or DHA. Consistent with this observation, both pioglitazone and DHA treatments increased the association of adiponectin mRNA with the heavier polysome fractions. Together, these data suggest that pioglitazone and the fish oils DHA or EPA are PPARgamma agonists in adipocytes with regard to adiponectin expression, and the predominant mode of adiponectin stimulation is via an increase in translation.

Does maternal docosahexaenoic acid supplementation during pregnancy and lactation lower BMI in late infancy?

We compared growth of infants whose mothers either did or did not receive docosahexaenoic acid (DHA) supplements during pregnancy and lactation. At 21 weeks' gestation, 144 women were enrolled into a randomized, double-blind clinical trial receiving: (1) a basic supplement consisting of vitamins and minerals (BS), or (2) BS plus 4.5 g fructooligosaccharide (BSF), or (3) BSF plus fish oil DHA (200 mg) until the end of the third month of lactation. Infants' length, weight and head circumference were measured at birth and at 1, 3 and 21 months. A total of 51 mothers/infants were lost to follow-up by the third month and 24 at 21 months. The two groups not receiving DHA were combined into a control group. Analysis with mixed models adjusted for confounding factors showed a significant time dependent effect for the DHA group on the development of the body mass index (BMI) (P=0.037), and of weight (P=0.046), but no effect on the development of length (P=0.537), or of head circumference (P=0.267). At 21 months, weight of the DHA group was lower by -601 g (95% CI -171; -1030 g) and BMI was lower by -0.76 kg/m(2) (95% CI -0.07; -1.46) compared to controls. The results indicate that DHA taken by pregnant and lactating mothers may reduce BMI in late infancy.

Separation of eicosapentaenoic acid and docosahexaenoic acid in fish oil by kinetic resolution using lipase

AbstractThe objective of this study was to investigate the use of lipases as catalysts for separating eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in fish oil by kinetic resolution. Transesterification of various fish oil triglycerides with a stoichiometric amount of ethanol by immobilized Rhizomucor miehei lipase under anhydrous solvent‐free conditions resulted in a good separation. When free fatty acids from the various fish oils were directly esterified with ethanol under similar conditions, greatly improved results were obtained. By this modification, complications related to regioselectivity of the lipase and nonhomogeneous distribution of EPA and DHA into the various positions of the triglycerides were avoided. As an example, when tuna oil comprising 6% EPA and 23% DHA was transesterified with ethanol, 65% conversion into ethyl esters was obtained after 24 h. The residual glyceride mixture contained 49% DHA and 6% EPA (8:1), with 90% DHA recovery into the glyceride mixture and 60% EPA recovery into the ethyl ester product. When the corresponding tuna oil free fatty acids were directly esterified with ethanol, 68% conversion was obtained after only 8h. The residual free fatty acids comprised 74% DHA and only 3% EPA (25:1). The recovery of both DHA into the residual free fatty acid fraction and EPA into the ethyl ester product remained very high, 83 and 87%, respectively.