• Journal of Nutrition and Health
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• v.30 no.9
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• pp.1067-1072
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• 1997

One known effect of long chain n-3 polyunsaturated fatty acids is their ability to decrease plasma triglycerides. However, identification of the specific n-3 fatty acids and the underlying mechanisms responsible for this change remains uncertain. This present study was designed to evaluate the effects of moderate levels of dietary docosahexaenoic acid (22 :6(n-3)) on modulating plasma triglyderides. Male CD-1 mice were maintained for 15 days on identical diets containing either docosahexahexaenoic acid ethyl ester(1.5%, w/w) or linoleic acid(18 : 2(n-6)) ethyl ester (1.5%, w/w) . Plasma triglycerides were 40% lower in the docosahexaenoic acid group than in the linoleic acid group. Hepatic carnitine palmitoyltransferase activity (a key regulatory enzyme for mitocondria $\beta$-oxidation) was not significantly different between the dietary groups. However, plasma acid soluble acylcarnitine levels (which increase with increasing $\beta$-oxidation )were significantly higher in the decosahexaenoic acid group. This data suggests that plasma triglyceride levels are lower in mice fed diets containing moderate levels of docosahexaenoic acid compared to linoleic acid, but this effect on plasma triglycerides is not modulated through an augmentation of mitochondrial $\beta$-oxidation.

• Journal of Applied Biological Chemistry
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• v.42 no.2
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• pp.75-80
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• 1999

The effects of dietary n-3 fatty acids, ${\alpha}$-linolenic acid (18:3), eicosapentaenoic acid (EPA, 20:5), and docosahexaenoic acid (DHA, 22:6), on brain phospholipid content and fatty acid composition were compared in rats fed with a diet containing constant ratios of saturated fatty acid/monounsaturated fatty acid/polyunsaturated fatty acid (PUFA) and n-3/n-6. The dietary fat in each diet was added at the level of 10%. In each diet, n-3 PUFA comprised two-thirds of the PUFA and the remaining one-third was linoleic acid (18:2). Dietary fat containing linoleic acid as the sole source of PUFA was also given to the control group. The content of brain phospholipid in the three n-3 PUFA groups was significantly lower than that of the linoleic acid group. This reduction was greater in the EPA and DHA groups than in the ${\alpha}$-linolenic acid group. The decrease in phospholipid content in rats fed n-3 fatty acid-rich diets was largely due to the decrease in the phosphatidylethanolamine fraction. Each dietary n-3 PUFA was found to affect the fatty acid composition of brain phospholipids; the most pronounced alteration was observed in phosphatidylethanolamine fraction. Furthermore, the proportion of DHA in the phosphatidylethanolamine fraction tended to be higher in the DHA group than in other PUFA groups. In conclusion, dietary ${\alpha}$-linolenic acid, EPA and DHA can influence the phospholipid content, phospholipid subclass, and fatty acid composition in rat brain.

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

• Nutrition Research and Practice
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• v.13 no.4
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• pp.344-351
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• 2019

BACKGROUND/OBJECTIVES: Adequate dietary fatty acid intake is important for toddlers between 12-24 months of age, as this is a period of dietary transition in conjunction with rapid growth and development; however, actual fatty acid intake during this period seldom has been explored. This study was conducted to assess the intake status of n-3 and n-6 polyunsaturated fatty acids by toddlers during the 12-24-month period using 2010-2015 Korea National Health and Nutrition Examination Survey data. SUBJECTS/METHODS: Twenty-four-hour dietary recall data of 12-24-month-old toddlers (n = 544) was used to estimate the intakes of ${\alpha}$-linolenic acid (ALA; 18:3n-3), eicosapentaenoic acid (EPA; 20:5n-3), docosahexaenoic acid (DHA; 22:6n-3), linoleic acid (LA; 18:2n-6), and arachidonic acid (AA; 20:4n-6), as well as the major dietary sources of each. The results were compared with the expected intake for exclusively breastfed infants in the first 6 months of life and available dietary recommendations. RESULTS: Mean daily intakes of ALA, EPA, DHA, LA, and AA were 529.9, 22.4, 37.0, 3907.6, and 20.0 mg/day, respectively. Dietary intakes of these fatty acids fell below the expected intake for 0-5-month-old exclusively breastfed infants. In particular, DHA and AA intakes were 4 to 5 times lower. The dietary assessment indicated that the mean intake of essential fatty acids ALA and LA was below the European and the FAO/WHO dietary recommendations, particularly for DHA, which was approximately 30% and 14-16% lower, respectively. The key sources of the essential fatty acids, DHA, and AA were soy (28.2%), fish (97.3%), and animals (53.7%), respectively. CONCLUSIONS: Considering the prevailing view of DHA and AA requirements on early brain development, there remains considerable room for improvement in their intakes in the diets of Korean toddlers. Further studies are warranted to explore how increasing dietary intakes of DHA and AA could benefit brain development during infancy and early childhood.

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

• Nutrition Research and Practice
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• v.16 no.sup1
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• pp.47-56
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• 2022

This paper examines the process and evidence used to create the Dietary Reference Intake (DRI) of alpha-linolenic acid (ALA) and eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) for Koreans. ALA (18:3n3) is an essential fatty acid, and EPA and DHA are known to have beneficial effects on cardiovascular disease risk and reduction of triglyceride levels. Various international organizations have suggested dietary recommendations for n-3 polyunsaturated fatty acids (PUFAs), including ALA, EPA, and DHA. A DRI for Koreans was established for the first time in 2020, specifically for the adequate intake (AI) of ALA and EPA + DHA. This recommendation was based on the average intake of ALA and EPA + DHA from the Korea National Health and Nutrition Examination Survey 2013-2017. For Korean infants, the AI of ALA and DHA was based on the fatty acid composition of maternal milk. Estimated average requirement and a tolerable upper intake level have not been set for n-3 PUFA due to insufficient evidence. In addition, the intake level of n-3 PUFA for prevention of chronic disease has also not been determined. Future studies and randomized controlled trials are required to establish the UL and to define the level for disease prevention.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.5
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• pp.768-774
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• 2007

To study the effect of dietary docosahexaenoic acid (DHA) enrichment on the expression of hepatic genes in pigs, weaned, crossbred pigs (30 d old) were fed diets supplemented with either 2% tallow or DHA oil for 18 d. Hepatic mRNA was extracted. Suppression subtractive hybridization was used to explore the hepatic genes that were specifically regulated by dietary DHA enrichment. After subtraction, we observed 288 cDNA fragments differentially expressed in livers from pigs fed either 2% DHA oil or 2% tallow for 18 d. After differential screening, 7 genes were found to be differentially expressed. Serum amyloid A protein 2 (SAA2) was further investigated because of its role in lipid metabolism. Northern analysis indicated that hepatic SAA2 was upregulated by dietary DHA enrichment (p<0.05). In a second experiment, feeding 10% DHA oil for 2d significantly increased the expression of SAA2 (compared to the 10% tallow group; p<0.05). The porcine SAA2 full length cDNA sequence was cloned and the sequence was compared to the human and mouse sequences. The homology of the SAA2 amino acid sequence between pig and human was 73% and between pig and mouse was 62%. There was a considerable difference in SAA2 sequences among these species. Of particular note was a deletion of 8 amino acids, in the pig compared to the human. This fragment is a specific characteristic for the SAA subtype that involved in acute inflammation reaction. Similar to human and mouse, porcine SAA2 was highly expressed in the liver of pigs. It was not detectable in the skeletal muscle, heart muscle, spleen, kidney, lung, and adipose tissue. These data suggest that SAA2 may be involved in mediation of the function of dietary DHA in the liver of the pig, however, the mechanism is not yet clear.

• Journal of Nutrition and Health
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• v.34 no.2
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• pp.132-140
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• 2001

The effects of various dietary docosahexaenoix acid(DHA) levels on the brain phospholipids and serum and liver lipid compositions were studied in rats using DHA concentrated oil and corn oil as a control for 4 weeks. Serum total cholesterol and HDL cholesterol levels tended to be the lowest by adding 20% DHA to corn oil. Serum triglyceride levels significantly decreased by adding 30% DHA. Liver cholesterol and triglyceride levels were apparently decreased in the groups added above 20% DHA, especially, the lowest at adding 30% DHA. Brain weight and phospholipid content were not different among groups. The ratios of arachidonic to linoleic acids in serum and liver phosphatidylcholine(PC) were significantly decreased by adding dietary DHA and showed a flat form above 20% of dietary DHA. DHA levels of serum PC were gradually increased according to dietary DHA level. The fatty acid compositions of the brain PC and phosphatidylethanolamine(PE) did not appear any changes with accordance of the dietary DHA levels. However, compared with those of serum and liver in general, linoleic and arachidonic acid levels were very low. Oleic acids were apparently higher than those in the other tissues. DHA were higher than those in the other tissues rigardless of the dietary DHA, especially in brain PE. The ratios of arachidonic to linoleic acid were not apparent tendency in brain PC and PE. However, the ratios of brain PE were above 2 times higher than those of brain PC. As the results, the hypolipidemic effects of dietary DNA were remarkable in liver. Especially in regard to tendency of liver lipid levels and desaturation indices in serum and liver PC, the effects indicated significantly higher by adding 20-30% DHA to diet(n-6/n-3 ratio, about 4-7). Thus, in this study, these dietary DHA levels seemed to be appropriate, at least in these lipid paramenters.(Korean J Nutrition 34(2) : 132∼140, 2001)

• Biomolecules & Therapeutics
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• v.20 no.2
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• pp.152-157
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• 2012

Docosahexaenoic acid (DHA) is the major polyunsaturated fatty acid (PUFA) in the brain and a structural component of neuronal membranes. Changes in DHA content of neuronal membranes lead to functional changes in the activity of receptors and other proteins which might be associated with synaptic function. Accumulating evidence suggests the beneficial effects of dietary DHA supplementation on neurotransmission. This article reviews the beneficial effects of DHA on the brain; uptake, incorporation and release of DHA at synapses, effects of DHA on synapses, effects of DHA on neurotransmitters, DHA metabolites, and changes in DHA with age. Further studies to better understand the metabolome of DHA could result in more effective use of this molecule for treatment of neurodegenerative or neuropsychiatric diseases.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.5
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• pp.712-720
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• 2018

Objective: The aim of this experiment was to evaluate the effect of dietary supplementation with the docosahexaenoic acid (DHA)-rich microalgae, Aurantiochytrium limacinum (AURA) on pig performance, carcass traits, and the fatty acid composition of pork Longissimus lumborum (LL) and backfat. Methods: A total of 144 Pig Improvement Company (PIC)${\times}$Goland finishing pigs (72 females and 72 castrated males) of mean weight 117.1 (${\pm}13.1$) kg were blocked by sex and body weight and provided with 0% or 1% AURA in isonutritive and isocaloric diets. A total of 24 pens provided 12 replicates per treatment. Animals were weighed on day 0 and 28 with feed and water intake recorded per pen. After 31 days supplementation (28 days of study and 3 days until the slaughtering date) three animals per pen (n = 72) were slaughtered and the LL and backfat thickness, lean meat content and dressing percentage were recorded for the carcasses. The fatty acid (FA) profile of the LL and backfat was established by direct FA methyl ester synthesis. Results: No differences were observed for any performance parameters or carcass traits. Supplementation with AURA resulted in significant changes to the FA profiles of both the LL and backfat with male and female pigs responding differently to supplementation in terms of particular FAs. Overall, pork LL samples had significantly higher eicosapentaenoic acid (p<0.001) and DHA concentrations (p<0.001), and higher omega-3 (n-3) FAs (p<0.001), as well as an increased omega3:omega6 (n-3:n-6) ratio (p = 0.001). For backfat, supplementation resulted in significantly higher amounts of DHA (p<0.001) and n-3 FAs (p<0.001). Conclusion: These results indicate that dietary supplementation with 1% AURA over a 31 day period can increase the FA composition of pork LL and backfat, specifically the DHA, with no major impact on growth performance and carcass traits.