• Journal of the Korean Applied Science and Technology
• /
• v.13 no.3
• /
• pp.15-24
• /
• 1996

Essentiality was proposed in the field of lipid by Burr and Burr in 1929. When rats were raised on the fat-free diet, their growth retarded and their skin and tails showed the characteristic deficient symptoms, which were relieved by the addition of ${\omega}6(n-6)$ polyunsaturated fatty acids as linoleic(LA) and arachidonic(AA) acids to the basal diet. LA is dehydrogenated to ${\gamma}-linolenic$ acid(GLNA) by ${\Delta}6$ desaturase, then GLNA is 2 carbon chain elongated by elongase to $dihomo-{\gamma}-linolenic$ acid(DGLNA), which is desaturated by ${\Delta}5$ desaturase to AA. These acids are called LA family or ${\omega}6(n-6)$ polyunsaturated fatty acids(PUFA). ${\alpha}-Linolenic$ acid(ALNA) is converted through the series of desaturation and elongation steps to docosahexaenic acid(DHA) via eicosapentaenoic acid(EPA). These acids belong to ALNA family or ${\omega}3(n-3)$PUFA. Human who consume large amounts of EPA and DHA, which are present in fatty fish and fish oils, have increased levels of these two fatty acids in their plasma and tissue lipids at the expense of LA and AA. Alternately, vegetarians, whose intake of LA in high, have more elevated levels of LA and AA and lower levels of EPA and DHA in plasma lipids and in cell membranes than omnivores. AA and EPA are metabolized to substances called eicosanoids. Those derived form AA are known as prostanocids(prostaglandins and prostacyclins) of the 2-types and leukotrienes of the 4-series, whereas those derived from EPA are known as prostanoids of the 3-types and leukotrienes of the 5-series. DGLNA is a precursor of the 1-types of prostaglandins. The metabolites of AA and EPA have competitive functions. Ingestion of EPA from fish or fish oil replaces AA from membrane phospholipids in practically all cells. So this leads to a more physiological state characterized by the production of proatanoids and leukotrienes that have antithrombic, antichemotactic, antivasoconstrictive and antiinflammatory properties. It is evident that ${\omega}3$ fatty acids can affect a number of chronic diseases through eicosanoids alone.

• Proceedings of the Korean Society of Fisheries Technology Conference
• /
• 2000.05a
• /
• pp.381-381
• /
• 2000

Lectin binding assay was conducted on 3 A. tamarense isolates (AT-A, AT-2 and AT-6). Fatty acid composition of all 3 isolates was analyzed, and total carotenoid content and $\beta$-carotene were also determined. AT-A and AT-2 treated with different lectins in this study showed the positive response, whereas potentially toxic AT-6 did not bind DBA lectin, regardless of different growth phase, but conjugated ConA, PNA, RCA, SBA, UEA and WGA. It is possible that DBA is a desirable method for rapid and easy discrimination of highly toxic A. tamarense. AT-A, AT-2 and AT-6 comprised saturated fatty acids (49.0-61.9%), monounsaturated fatty acids (8.0-20.5%) and polyunsaturated fatty acids (23.2-30.5%). In particular, 22:6 (n-3) polyunsaturated fatty acid in AT-6 had a high abundance, compared with AT-A and AT-2. However, carotenoid content and $\beta$-carotene were not contributed to discriminate each isolate. Due to variability in biochemical composition at different isolates, possibly DBA and 22:6 (n-3) polyunsaturate fatty acid provide a good information for discrimination of AT-6.

• Journal of Microbiology and Biotechnology
• /
• v.9 no.5
• /
• pp.624-630
• /
• 1999

In order to investigate the position of various fatty acids attached to glycerol and the specificity of Lipolase-100T, hydrolysis of fish oil was carried out with Lipolase-100T derived from Aspergillus oryzae. The amounts of free fatty acids produced from triglyceride, 1,2(2,3)-diglyceride, 1,3-diglyceride, and 2-monoglyceride and conversion rates of 1,2(2,3)-diglyceride to 1,3-diglyceride and 2-monoglyceride to 1(3)-monoglyceride were also calculated. The ratio of 1,2-diglyceride content to 1,3-diglyceride was higher than 70 in the early period of hydrolysis. The fatty acid content of the glyceride mixture after 72 h of hydrolysis was compared with that of fish oil, and it was found that polyunsaturated fatty acids such as C16:4, C20:4 n-3, C20:5 n-3, C21:5 n-3, C22:5 n-3 and C22:6 n-3 were located in the 2-position of glycerol. Material balance of each component in the hydrolysis system was written to obtain a set of simultaneous linear equations. The theoretical quantity of free fatty acids produced from triglyceride, 1,2-diglyceride, 1,3-diglyceride, and monoglyceride, respectively, were calculated by solving the linear equation system. The conversion rate of 1,2(2,3)-diglyceride to 1,3-diglyceride and that of 2-monoglyceride to 1(3)-monoglyceride were also obtained. The results showed that the migration rate of 1,2(2,3)-diglyceride to 1,3-diglyceride was higher than the hydrolysis rate of 1,2(2,3)-diglyceride to 2-monoglyceride and the conversion rate of 2-monoglyceride to 1(3)-monoglyceride was extremely low.

• Ocean and Polar Research
• /
• v.21 no.2
• /
• pp.109-116
• /
• 1999

Total lipid content, lipid class and fatty acid composition of the Antarctic krill Euphausia superba collected from the water of King George Island, Antarctica during austral summer of 1997-1998, were investigated. The overall lipid content of 5. superba was 72 mg/g dry mass similar to the reported values for most temperate species. The neutral lipid of E. superba was 29% of the total lipid and that of phospholipid was 71%. The majority of neutral lipid was triacylglycerols(31.6% of neutral lipids) while phosphatidyl choline (44% of phospholipid) was the most abundunt in phospholipids. The quantitative composition of the fatty acid in E. superba show consisting mostly of the saturated 16:0 (16.6% -22.1%), along with the polyunsaturated 20:5(n-3) (20.6% -22.1%) and 22:6(n-3) (14.9% -16.9%) acids.

• Asian-Australasian Journal of Animal Sciences
• /
• v.16 no.9
• /
• pp.1320-1325
• /
• 2003

The purpose of present study was to assess the effect of polyunsaturated fatty acids (PUFA) on the immune responses of laying hens. Three hundred and sixty hens at the age of 60 weeks were randomly assigned to ten diets, which contained no oil (CK), 1%, 3%, 5% fish oil (FO); 2%, 4%, 6% linseed oil (LO) and 2%, 4%, 6% corn oil (CO). After 5 weeks of feeding experimental diets, humoral and cellular immune responses were assayed. Laying hens were injected with Sheep Red Blood Cell (SRBC) and Bovine Serum Albumin (BSA) and antibody titers, which were measured on d6, d10, d14 after primary challenge and on d5, d9, d13 after secondary challenge. Concanavalin (ConA) and lipopolysaccharide (LPS) -stimulated proliferation of peripheral blood and spleen lymphocytes were assessed by [$^3$H] thymidine incorporation at the week age of 5 and 10, respectively. The results showed that antibody titers in FO-fed and LO-fed laying hens were higher than that in laying hens fed CO. The proliferation response to ConA was lower in laying hens that fed oils rich in n-3 fatty acids than that in laying hens fed CO. Higher level n-3 fatty acids can improve immune functions of laying hens. In conclusion, dietary fat source and level had a significant impact on immune responses of laying hens.

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

• Journal of Nutrition and Health
• /
• v.28 no.5
• /
• pp.375-386
• /
• 1995

This study was designed to investigate the changes in energy substrates, glucose and non-esterified fatty acid(NEFA), and fatty acid compositions in serum, following physiolgical stress in rats fed diets containing various fatty acids. Forty two Sprague-Dawley strain male rats, weighing 108$\pm$2.1g, were fed 3 different experimental diets for 4 weeks. The diets were composed of 105 fat(w/w) of either corn oil(CO;18:2 n6:57%), plant perilla oil(PO;18:3 n3:59%), or tuna fish oil(FO;20:5 n3:17%%, 22:6 n3:19%). After 4 weeks of feeding, each group wa subdiveided into (a) control, (b) 2 min swim in ice-cold water. Animals wer decapitated 20min after commencing the swim; trunk blood, brain, liver and epididymal fat pad were obtained. The levels of serum corticosterone, glucose, NEFA, triglyceride, fatty acid compositions, brain serotonin and 5-hydroxyindoleacetic acid were determined. Basal levels of corticosterone na NEFA of serum were significantly lower in fish oil fed animals than those of any other oil fed animals. Compared to either perilla oil-fed or corn oil-fed rats, cold swim stress in fish oil fed rats produced significantly smaller NEFA and larger corticosterone responses. However, there was no significant difference in basal levels of serum glucose. Stress increased serum glucose levels slightly, and the amount of increment was larger in fish oil rats than those of any other oil fed rats than those of any other oil fed rats, although all the values were normal level. Dietary fats and stress did not affect serotonin metabolism. In additions, the composition of fatty acids in serum was significantly affected by the dietary compostion of fatty acids and stress. Stress induced decreases in monounsaturated fatty acid and non-polyunsaturated fatty acid concentration in either perilla oil fed or fish group, but did not in corn oil fed group. Stress resulted in changes in fatty acid metabolism similar to that associated with essential fatty acid(EFA) dificiency, when feeding animals n-3 fatty acids in diet. In conclusion, feeding fish oil was more effective to decrease NEFA in serum than feeding perilla oil or corn oil and improved lipid metabolism, when the rats were maintained in normal or exposed to stressful environment. However, the fact that feeding diet containing n-3 fatty acids decreased EFA status under stress suggests that the requirement of n-6 PUFA should be increased in these groups.

• Fisheries and Aquatic Sciences
• /
• v.3 no.2
• /
• pp.118-125
• /
• 2000

Lipid classes and fatty acid compositions of eight species of wild and cultured seawater fish in Korea were investigated. Total lipid (TL) contents of wild and cultured fish were $2.64\pm1.88\%$ and $5.42\pm1.76\%$, respectively, except for rockfish and striped beakperch. Non-polar lipids (NL) in all fish samples comprised approximately $84\%$ of the TL content. The proportion equation of NL content to TL content was y=0.9296x-0.4468 $(R^2=0.98l2, p<0.001)$. The most abundant NL class was triglyceride. The prominent fatty acids in all fish samples were 16: 0, 18: 1(n-9), 22 : 6(n-3) (docosahexaenoic acid, DHA), 16: 1(n-7), 20 : 5 (n-3) (eicosapentaenoic acid, EPA), 18 : 0 and 18 : 1(n-7). The polyunsaturated fatty acid (PUFA) group was the richest among the total fatty acids (TFA). DHA and EPA were comprised of approximately $85\%$ of n-3 PUFA. There was a positive correlation between TFA content and n-3 PUFA content; y=0.292x-0.0055 $(R^2=0.9349, p<0.001)$. The n-3 PUFA content of the cultured fish was approximately twice as much as that of the wild fish. Therefore, cultured fish were proven to provide better sources of n-3 PUFA if compared to wild fish.

• Asian-Australasian Journal of Animal Sciences
• /
• v.13 no.2
• /
• pp.176-181
• /
• 2000

In order to clarify the inhibitory effects of orchardgrass (Dactylis glomerata L.) lipids on ruminal fermentation and digestion, two experiments were carried out in vitro. Experiment 1 was carried out using residues of grass hay from which the lipid fraction was removed by ether extraction. To ground grass samples were added 0, 1.5, 3.0, 4.5 and 6.0% lipids and incubated anaerobically at $39^{\circ}C$ for 24 h, with the mixtures of artificial saliva and rumen fluid. Increasing grass lipid levels remarkably reduced DM and NDF disappearances. Volatile fatty acid concentration was significantly reduced at 3.0, 4.5 and 6.0% lipid levels. Microbial nitrogen proportion to total nitrogen tended to decrease by the addition of the lipids. These results indicated that grass lipids have a marked inhibitory effect on ruminal fermentation and digestion, especially when to the substrate was added 3% or more grass lipids as ether extracts. Experiment 2 was conducted to study the relationship between changes in the free fatty acids and changes in the fermentation traits. Samples were incubated for 3, 6, 9, 12, 15, 18, 21 and 24 h as a sole substrate. The polyunsaturated fatty acids steadily decreased during incubation, whereas the saturated fatty acid ($C_{18:0}$) increased. It was suggested that the hydrogenation was extended during the initial stage of incubation. The unsaturated fatty acids ($C_{18:2}$, $C_{18:3}$) produced at the initial stage of incubation were negatively correlated with the amount of microbial N and DM disappearance, indicating that polyunsaturated fatty acids had the possibility to show an inhibiting effect on ruminal fermentation and digestion.

• Food Science of Animal Resources
• /
• v.36 no.2
• /
• pp.178-185
• /
• 2016

The influence of three cooking methods (stewing, microwaving and Aluminium (Al) foil-baking) was evaluated on the content of intramuscular lipid and the composition of intramuscular fatty acids of Hyla rabbit. The percentage of intramuscular lipid in cooked-longissimus dorsi (LD) (dry weight %) were in the order mentioned below: microwaving > foil-baking > stewing. All treated samples showed decrease in the proportion of polyunsaturated fatty acids (PUFA) and monounsaturated fatty acids (MUFA), whilst increase in the proportion of saturated (SFA) and n-6/n-3 value during processing. All of the cooked samples had the n-6/n-3 ratio within the recommended range (5-10). By the analysis of partial least squares regression (PLSR), the microwaving treatment was better to keep the stability of unsaturated fatty acids (UFA), whilst the long-time Al foil-baking did the most serious damage to UFA, especially the PUFA. In addition, the heating method showed greater influence on the samples than the processing time. The shorter processing time was better to retain the intramuscular PUFA of Hyla rabbit, especially the LC-PUFAs (C20-22). Considering all the factors, microwaving showed the superiority in reserving the composition of intramuscular fatty acids of Hyla rabbit.