• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.6
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• pp.712-726
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• 1994

Feeding trials were conducted to determine the essentiality of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and to compare the efficiency between EPA and DHA for juvenile Korean rockfish. Fish averaging 2.1 g were fed experimental diets containing different levels of EPA or DHA, and different combinations of EPA and DHA in two separate experiments. Graded levels ($0.0{\sim}l.75\%$) of dietary EPA or DHA as ethyl esters were substituted for a part of the $8\%$ beef tallow in the basal diet. After 5 weeks of the experimental period, weight gain, chemical composition of whole body, protein and lipid retention efficiency, hepatosomatic index, and fatty acid composition of liver were measured. Daily growth rate and feed efficiency were the lowest in fish fed the diets without EPA arid DHA. These responses were effectively improved by increasing EPA or DHA in the diets up to $1.0\%$ levels, and then reached a plateau between 1.0 and $1.75\%$ levels of either EPA or DHA. Protein and lipid retention efficiency were also improved with the high levels of dietary EPA or DHA. DHA was superior to EPA at the same level of each in weight gain, feed efficiency, and protein and lipid retention efficiency. Hepatosomatic index tended to decrease with increase of the dietary EPA or DHA levels. Lipid contents of whole body were increased with levels of EPA or DHA in the diets. Dietary EPA and/or DHA levels affected directly the fatty acid composition of liver polar lipid. EPA or DHA in the liver polar lipid were increased with levels of dietary EPA or DHA, respectively, whereas those in nonpolar lipid were not affected by the dietary levels of EPA and/or DHA. These finding indicate that either of the EPA or DHA is essential for normal growth of Korean rockfish, and the essential fatty acid requirement is $1.0\%$ of EPA and/or DHA in the diet. DHA is superior to EPA as essential fatty acid, and the dietary EPA/DHA ratio of less than 1.0 may be adequate for normal growth of Korean rockfish fed a diet enough n-3HUFA (EPA and DHA).

• KSBB Journal
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• v.14 no.6
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• pp.655-660
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• 1999

Supercritical fractional extraction of DHA and EPA from the mixture of fatty acids composing the fish oil was performed. The compositions, extracted quantities, and cumulative extracted quantities of fatty acids in the extract and the raffinate were investigated according to the fractional steps. The temperature and pressure for the miximum concentration of DHA and EPA in the extract or the raffinate were 60$^{\circ}C$ and 101 bar respectively among the extraction conditions considered in this study. In this case, the weight percent of EPA in the extract was 50% and that of DHA in the raffinate was 40%. These values were two times higher than those in fish oil. THe same temperature and pressure were used to extract DHA and EPA from the mixture of fatty acids whose the initial weight percent of DHA was 34%. The weight percent of DHA in the raffinate after the fourth fractionation was 7-%. And the remaining weight of DHA in the raffinate was 80% of DHA initially loaded in the extraction vessel.

• Journal of Life Science
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• v.9 no.4
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• pp.493-495
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• 1999

Eicosapentaenoic (EPA, 20:5) and docosahexaenoic (DHA, 22:6) acids of gull eggs were analyzed and the results are summarized as follows: 1. EPA and DHA were 2.25% and 4.35% in the total fatty acid of gull eggs. 2. Triglyceride fractions in the fatty acids had 0.56% in EPA and 1.59% DHA. 3. Diglyceride fractions contained 1.10% EPA and 1.97% DHA. 4. Phospholipid fractions had the most abundant amounts of 4.26% EPA and 8.13% DHA.

• Korean Journal of Food Science and Technology
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• v.22 no.5
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• pp.520-525
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• 1990

A modified method of urea adduct formation, in which water and organic solvent were used as the wetting agent and the reaction medium. respectively, is suggested to obviate methanolysis and to ease recovery in the separation of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from fish oil. With the new method the fraction in which the total content of EPA. DHA and their precursors is more than 80% could be obtained. Although the total content of precursors in the concentrate was hardly affected by the kind of the wetting agent or the organic solvent, the content of EPA and DHA varied significantly depending on the organic solvent. This finding made it possible to selectively enrich the desired components. After DHA-enriched fraction (I)HA is 50%) was obtained by using pentane, EPA-enriched fraction ( EPA is 53%)) could be obtained from the residue of DHA-enriched fraction by using heptane.

• Applied Biological Chemistry
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• v.41 no.6
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• pp.414-420
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• 1998

We studied the difference effects of dietary ${\alpha}-linolenic\;acid\;({\alpha}-LA,\;18:3\;n-3)$, eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic acid (DHA, 22:6 n-3) on the lowering of triacylglycerol in the liver and serum on lipid metabolism in rats. Rats were fed semipurified diets containing 10% fat with constant polyunsaturated/monounsaturated/saturated fatty acids (1:1:1) and n-6/n-3 ratio (1:2). EPA (98%) and DHA (98%) were added in diets as the ethyl esters. The concentration of liver triacylglycerol was significantly lower in rats fed both EPA and DHA than in those fed ${\alpha}-LA$. The concentration of liver phospholipid was significantly higher in rats fed DHA than in those fed ${\alpha}-LA$ and EPA. Both EPA and DHA reduced serum triacylglycerol concentration compared with ${\alpha}-LA$, but this effect was more pronounced in the EPA diet. The activity of phophatidate phosphohydrolase in the liver microsome was significantly lower in rats fed both EPA and DHA than in those fed ${\alpha}-LA$. but, there was no significant difference on the activities of diacylglycerol acyltransferase among the three groups. The concentration of liver triacylglycerol were correlated with changes in the microsomal phosphatidate phosphohydrolase activity (r=0.84). Hepatic NADPH generating enzyme, glucose-6-phosphate dehydrogenase was more effective to reduce the activity in rats fed both EPA and DHA than in those fed ${\alpha}-LA$. In conclusion, EPA or DHA reduced the hepatic triacylglycerol concentration by inhibiting microsomal phosphatidate phosphohydrolase, thereby inhibiting synthesis of triacylglycerol in the liver.

• Fisheries and Aquatic Sciences
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• v.17 no.1
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• pp.95-103
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• 2014

This study was carried out to investigate the influences of dietary levels, ratios and sources of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on the growth and fatty acid compositions of juvenile olive flounder Paralichthys olivaceus. Sixteen diets containing five levels of EPA (0.5%, 1.0%, 1.5%, 2.0%, and 4.0%), five levels of DHA (0.5%, 1.0%, 1.5%, 2.0% and 4.0%), three ratios of EPA/DHA (75/25, 50/50 and 25/75), two levels of squid liver oil (5% and 10%) and a control diet containing 5% soybean oil were hand-fed to triplicate groups of fish (average weight, $9.7{\pm}0.3g$) for 8 weeks. Survival, specific growth rate, feed efficiency and protein efficiency ratio of fish were not affected by dietary EPA and DHA levels or ratios. Also, the dietary treatment had no significant effect on the lipid and protein contents of muscle and whole body of fish. A corresponding increase in the EPA and DHA contents of fish occurred with increasing EPA and DHA levels in their diets. Our results suggest that juvenile olive flounder require a dietary EPA level of approximately 0.32% in the presence of 0.74% DHA for suitable survival and growth, and that EPA and DHA levels in fish muscle can increase to as much as 32% and 53%, respectively, of the total fatty acid content.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.1
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• pp.68-72
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• 1994

Six brands of encapsulated fishoil products and five fishes were analyzed for their contents of eicosapentaenoic acid (EPA 20 :5 n-3) , docosahexaenoic acid(DHA 22: 6 n-3) and tocopherols. In both of the fish oil products and the fishes, major fatty acids were palmitic acid, oleic acid, eicosapentaeoic acid and docosahexaenoic acid and fatty acid compositions were also similar pattern each other. EPA showed variable amounts from 19.2 to 50.3% in the oil products whereas DHA were 13.2% to 28.3% inthe fishes. Tocopherols were studied in relation to the oxidative stability of fish products no relation was observed. However the amount of tocopherols in fish oil proudcts were higher than that of fishes. Contents of EPA, DHA and tocopherols in encapsulated fishoil products oil products were variable comparing with manufactures' claimed contents.

• Journal of Life Science
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• v.10 no.2
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• pp.115-124
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• 2000

The present study was undertaken to separate the available components effectively, such as tetrodotoxin(TTX), docosahexaenoic acid(DHA, C22:6,ω-3) and eicosapentaenoic acid (EPA, C20:5,ω -3) from pufferfish liver waste, which are known to have high values as bioactive materials. By using ultrafiltration, it was possible to separate high contents of 68mg TTX from pufferfish liver waste. In contrast, by activated charcoal column, it was to obtain about 54mg TTX. The recovering ratios were 65.3% and 45.0% in the two different methods of ultrafiltration and activated charcoal column, respectively. From the results of HPLC and gas chromatography-mass spectrometry(GC-MS), the obtained toxins were identified to be TTX and its derivatives. In addition, it was also possible to obtain 72.3g DHA and 11.4g EPA from 1kg of pufferfish liver by high performance liquid chromatography (HPLC). These amounts of DHA and EPA were also 17.70% and 1.04% in the total lipid of pufferfish liver oil from analysis of gas chromatography(GC), respectively.

• BMB Reports
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• v.54 no.5
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• pp.278-283
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• 2021

Our understanding of the differential effects between specific omega-3 fatty acids is incomplete. Here, we aimed to evaluate the effects of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) on T-helper type 1 (Th1) cell responses and identify the pathways associated with these responses. Naïve CD4⁺ T cells were co-cultured with bone marrow-derived dendritic cells (DCs) in the presence or absence of palmitate (PA), DHA, or EPA. DHA or EPA treatment lowered the number of differentiated IFN-γ-positive cells and inhibited the secretion of IFN-γ, whereas only DHA increased IL-2 and reduced TNF-α secretion. There was reduced expression of MHC II on DCs after DHA or EPA treatment. In the DC-independent model, DHA and EPA reduced Th1 cell differentiation and lowered the cell number. DHA and EPA markedly inhibited IFN-γ secretion, while only EPA reduced TNF-α secretion. Microarray analysis identified pathways involved in inflammation, immunity, metabolism, and cell proliferation. Moreover, DHA and EPA inhibited Th1 cells through the regulation of diverse pathways and genes, including Igf1 and Cpt1a. Our results showed that DHA and EPA had largely comparable inhibitory effects on Th1 cell differentiation. However, each of the fatty acids also had distinct effects on specific cytokine secretion, particularly according to the presence of DCs.

• The Korean Journal of Food And Nutrition
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• v.8 no.2
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• pp.59-69
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• 1995

This study designed to compare the hypolipidemic e(feats of n6 linoleic acid (LA), n3 w-linolenic acid(LL) and n3 eicosapentaenoic acid(EPA) and docosahexaenoic acid(DHA) In rats fed high fat (40% Cal) diet. Male Sprague-Dawley rats fed experimental diets for 6 weeks, which were different only in fatty acid composition. The dietary fats were beef tallow (BT) as a source of saturated fatty acid (SFA), corn oil(CO) for n6 LA, perilla oil (PO) for n3 a-LL and fish oil (FO) for n3 EPA+DHA. Plasma total cholesterol (T-chol) level was increased by n6 LA but decreased by n3 LL and n3 EPA+DHA and most effectively reduced by n3 EPA+DHA. Plasma triglyceride(TG ) level was reduced by n6 LA, but lipogenesis in liver was not affected by n6 LA. However, plasma TG level was lowered by n3 LL and EPA+DHA. Both lipogenic enzyme activity and liver TG level were also decreased by n3 PUFA. PO and FO groups were significantly higher in the relative Proportions of C20:5 and C22:6 of plasma and liver and lower in those of C20:4/C20:5 ratio. Overall, the lipid-lowering effect was in the order of n3 EPA+DHA >n3 LL > n6 LA and fish oil and perilla oil rich in n3 PUFA may have important nutritional applications in the prevention and treatment of hyperlipidemia.