• Journal of Nutrition and Health
• /
• v.28 no.4
• /
• pp.268-281
• /
• 1995

This study was undertaken to elucidate the effect of DHA-rich fish oil (DHA-rich oil) added to different dietary fats on lipid metabolism. Rats were fed perilla oil, sesame oil and beef tallow with or without DHA-rich oil for 12 weeks. The weight gain was higher in groups with DHA-rich oil than that of groups without DHA-rich oil, with DHA-rich oil, while weight of epididymal fat pad was lower in perilla oil and beef tallow groups with DHA-rich oil. The contents of total lipid and triglyceride in plasma were not affected by dietary fat types, but that of total and HDL cholesterol in plasma were higher in sesame oil group than perilla oil and beef tallow groups without DHA-rich oil. The contents of total lipid, triglyceride, total cholesterol, HDL cholestrol and LDL cholesterol in plasma were decreased by DHL-rich oil addition. The contents of total lipid, total cholesterol and triglyceride in the liver were not affected by dietary fat type. The contents of total cholesterol and triglyceride in the liver were not affected by dietary fat type. The contents of total lipid and TG in liver were not affected by DHA-rich oil addition while hepatic cholesterol increased by DHA-rich oil addition. The activities of glucose 6-phosphate dehydrogenase and malic enzyme were highest in beef tallow group without DHA-rich oil and decreased by DHA-rich oil addition. Peroxisomal ${\beta}$-oxidation had an inverse relationship against the activities of lipogenic enzymes. In conclusion, dietary DHA-rich oil decreased fat accumulation and had hypolipidemic effect, especially in beef tallow group. Also groups with DHA-rich oil showed more hypolipidemic effect than perilla oil group. And DHA-rich oil addition to diets resulted in increasing dietary n-3/n-6 ratio. Therefore increase in n-3/n-6 ratio as well as dietary DHA were considered to be responsible for the hypolipidemic effect resulted from DHA-rich oil addition.

• Journal of Nutrition and Health
• /
• v.28 no.11
• /
• pp.1078-1090
• /
• 1995

This study was undertaken to elucidate the effect of DHA rich fish oil(DHA rich oil) added to different dietary fats on thrombosis and lipid peroxidation. Rats were fed perilla oil, sesame oil and beef tallow with or without DHA rich oil for 12 weeks. Bleeding time was the longest in Perilla oil groups with or without DHA rich oil. The productions of thromboxane B2(TX B2) and 6-keto Prostaglandin F1$\alpha$(6-keto PG F1$\alpha$) were the highest in Esame oil group without DHA rich oil. Bleeding time tended to be extened and group showed the most antithrombotic effect among three oil groups when DHA rich oil added. The antithrombotic effect by DHA rich oil addition seemed to be resulted from the increase of dietary n-3 fatty acid rather than DHA. And there was not the difference in antithrombotic effect between DHA and $\alpha$-linolinic acid. The level of TBARS(thiobarbituric acid reactive substances) in plasma and liver, and the activities of lipid peroxide metabolizing enzymes(catalase, superoxide dismutase and gluthathion peroxidase) in erythrocyte and liver were not affected by the dietry fat type and DHA rich oil addition, except that activity of hepatic catalase was increased by DHA rich oil addition. Therefore it revealed the DHA level added in this study seldom affected lipid peroxidation. However, it dose not conclude that DHA level of this study make low production of lipid peroxide because the peroid of our study was short.

• Asian-Australasian Journal of Animal Sciences
• /
• v.18 no.10
• /
• pp.1451-1456
• /
• 2005

To study the acute effect of dietary docosahexaenoic acid (DHA, $C_{22:6}$) on the expression of adipocyte determination and differentiation-dependent factor 1 (ADD1) mRNA in pig tissues, weaned, crossbred pigs (28 d of age) were fed with either 10% (on as-fed basis) tallow (high stearic acid), soybean oil (high linoleic acid), or high DHA algal oil for 2 d. The plasma and liver DHA reflected the composition of the diet. The adipose tissue and skeletal muscle DHA did not reflect the diet in the short term feeding. The results also showed that the diet containing 10% algal DHA oil significantly decreased the total plasma cholesterol (39%) and triacylglycerol (TG; 46%) in the pigs. Soybean oil significantly decreased plasma TG (13.7%; p<0.05), but did not have an effect on plasma cholesterol. The data indicate that different dietary fatty acid compositions have different effects on plasma lipids. The ADD1 mRNA was decreased (p<0.05) in the liver of DHA oil-treated pigs compared with the tallow-treated pigs. The diets did not have significant effect on the ADD1 mRNA in adipose tissue. Addition of algal DHA oil in the diet increased acyl CoA oxidase (ACO) mRNA concentration in the liver, suggesting that dietary DHA treatment increases peroxisomal fatty acid oxidation in the liver. However, dietary soybean oil supplementation did not affect mRNA concentrations of ADD1 or ACO in the tissues of pigs. Because ADD1 increases the expression of genes associated with lipogenesis, and ACO is able to promote fatty acid oxidation, feeding DHA oil may change the utilization of fatty acids through changing the expression of ADD1 and ACO. Therefore, feeding pigs with high DHA may lead to lower body fat deposition.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.30 no.6
• /
• pp.944-947
• /
• 1997

Docosahexaenoic acid (DHA) rich oil was obtained from blue fin tuna (Thunnus thynnus orientalis) orbital tissue with centrifugation of 12,000 rpm under vaccum $(10^{-1}\;Torr)\;at\;4^{\circ}C$. The effect of DHA rich oil (DHA content; $27.8\%$) on $CCl_4-induced$ acute injury was investigated biochemically and histopathologically. Dosage of DHA rich oil on 24h before $ CCl_4-administration$ prevented significantly the increase of glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GTP) values. No necrosis of hepatocytes was observed in rat livers treated with DHA oil on 24h prior to $CCl_4-administration$. These results suggested that DHA oil controls the accumulation of fat in the liver and prevented the liver injury.

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

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

• Journal of Nutrition and Health
• /
• v.29 no.1
• /
• pp.32-40
• /
• 1996

To investigate the effect of dietary docosahexaenoic acid(DHA) and environmental enrichment on brain fatty acid composition and acetylcholinesterase(AChE) activity, two groups of was fed isocaloric diets containing 10 or 12% dietary lipids for 7 weeks. A third group was fed 10% (w/w) dietary lipids with supplemented 2% DHA-rich fish oil. Each diet group was housed either in a stainless steel cage individually or in a large enriched cage with toys where 7 rats were kept together. The fatty acid composition of plasma and brain was significantly affected by dietary lipid composition but not by environmental enrichment. Fish oil supplementation significanlty decreased plasma levels of monounsaturated fatty acids(MUFA) and increased polyunsaturated fatty acids(PUFA). Fish oil supplemented groups also maintained lower plasma n-6 fatty acids and higher n-3 fatty acids levels than unsupplemented groups. The fish oil supplementation significantly decreased arachidonic acid and increased eicosapentaenic, docosapentaenoic acids, and DHA in brain fatty acid composition. In addition, brain DHA level in supplemented groups tended higher than the unsupplemented. Brain, AChE activity significantly increased by the environmental enrichment but not by the fish oil supplementation. These finding suggest that the 2% fish oil (0.57% DHA & 0.31% EPA, per diet weigth) supplementation is enough to accumulate n-3 fatty acids and to change the n-6 n-3 ratio in brain and environmental enrichment might promote the learning ability.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.26 no.6
• /
• pp.529-537
• /
• 1993

Several methods were examined for purification of docosahexaenoic acid (DHA, 22:6n-3) from skipjack Euthynnus pelamis orbital tissue oil, a marine by-product, and a modified method for isolation of a high purity DHA was proposed. Skipjack orbital tissue contained $55.4\%$ of total lipid(TL), and DHA accounted for $23.7\%$ of the TL. Application of low-temperature crystallization and urea inclusion compound methods to the orbital fatty acid mixture resulted in increases of DHA concentrations to approximately $46\%\;and\;61\%$, respectively. These methods were suitable for large production of DHA with relative low purity because of the simple purification procedure. DHA of approximately $74\%$ in purity was obtained by silver nitrate aqueous solution method, but the method gave a very low recovery($<10\%$). Silver nitrate-impregnated silica column chromatography was suitable for purification of a high purity DHA(purity, $>98\%$ and recovery, $>90\%$) A modified method, silver nitrate-impregnated silica column chromatography combined with low-temperature crystallization(two step purication method) was proposed as the most effective method to obtain DHA with high purity($99.9\%$) from the skipjack orbital oil.

• Asian-Australasian Journal of Animal Sciences
• /
• v.19 no.7
• /
• pp.1047-1053
• /
• 2006

The current study was designed to determine the effects of dietary docosahexaenoic acid (DHA) on fatty acid deposition in egg yolk and various tissues of laying Tsaiya ducks, and on the mRNA concentrations of hepatic lipogenesis-related transcription factors. Thirty laying ducks were randomly assigned to three treatments with diets based on corn-soybean meal (ME: 2803 kcal/kg; CP: 17.1%; Ca: 3.4%) supplemented with 0% (control diet), 0.5% or 2% algal DHA oil. The DHA content in egg yolks of the ducks was elevated significantly (p<0.01) with the supplementation of dietary DHA. The DHA percentage of the total fatty acids in the egg yolk of laying ducks was 0.5%, 1.3% and 3.4% for 0%, 0.5% and 2% algal DHA oil treatments, respectively, for the $1^{st}$ week, and 0.5%, 1.5% and 3.3% for the $2^{nd}$ week. Therefore, algal DHA oil can be utilized by laying Tsaiya ducks to enhance the egg-yolk DHA content. The concentrations of triacylglycerol (TG) and cholesterol in plasma of laying Tsaiya ducks were not affected by dietary DHA treatments (p>0.05). The DHA concentration in plasma, liver, and skeletal muscle was increased with the addition of dietary algal DHA oil (p<0.05). The mRNA abundance of sterol regulatory element binding protein 1 (SREBP1) and SREBP2 in the livers of laying Tsaiya ducks was not affected by dietary DHA, suggesting that the expression of these transcription factors is tightly controlled and not sensitive to DHA treatments.

• Journal of Nutrition and Health
• /
• v.27 no.9
• /
• pp.901-909
• /
• 1994

The effects of sardine oil(high in eicosapentaenoic acid : EPA) and tuna oil(high in docosahexaenoic acid : DHA, also high in EPA) on fatty acid composition of brain and learning ability were evaluated in male weanling Sprague-Dawley rats and compared with the effects of corn oil and beef tallow. Animals assigned by randomized block design to one of the four experimental diet groups containing dietary lipid at 15%(w/w) level were given ad libitum for 7 weeks. Food intake and body weight gain of the fish oil groups were significantly lower than those of the corn oil and beef tallow groups. However, brain weights of the groups were not significantly different. In the brain fatty acid composition, the corn oil group showed high concentrations of n-6 fatty acids, the fish oil groups of n-3 fatty acids, and the beef tallow group of saturated fatty acids. Brain EPA and DHA contents of the fish oil groups showed significantly higher than the other groups while the brain ratio of saturated/monounsaturated/polyunsaturated fatty acid was controlled in a narrow range. In a maze test, the fish oil groups appeared to arrive at the goal faster than the corn oil and beef tallow groups. It explained that EPA in diets might efficiently convert to DHA resulting in DHA accumulation in brain tissue and might increase the learning performance as DHA did.