• Journal of Nutrition and Health
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• 제34권6호
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• pp.626-636
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• 2001

To compare the effect of three kinds of n-3 fatty acids-eicosapentaenoic acid(EPA), docosahexaenoic acid(DHA) and perilla oil (PO)-on serum and liver lipid levels and fatty acid composition of liver phospholipid(PL) at low fat level(5%, w/w), 4-weeks old Sprague-Dawley rats were fed with one of five different oil diets for 4 weeks. Beef tallow(BT) and corn oil(CO) was used as control for sturated or n-6 fatty acid respectively. Se겨m concentrations of cholesterol(TC) and phospholipid(PL) were lower in PO DHA and EPA groups than in BT and CO groups. HDL-cholesterol levels were higher in CO and PO groups than in EPA, DHA and BT groups. Liver PL concentrations were higher in DHA and EPA groups than in CO, PO and BT groups, but liver TC and heal PL and TC concentrations did not show any significant difference among groups. Hepatic fatty acid composition of phosphatidylcholine (PC) and phosphatidylethanolamine (PE), two major phospholipids in liver, reflected their dietary fatty acid composition. In PC and PE, total percentage own-6 series was higher in CO group than in any other groups, and that own-3 series was higher in DHA and PO groups than in EPA, CO and BT groups. Moreover, the ratio of 20 : 4/18 : 2 was lower in PO and DHA groups than in EPA, CO and BT groups. On the contrary, the percentage of C22 : 6 was lower in EPA, CO and BT groups than in PO and DHA groups. These results revealed that n-3 series(EPA, DHA and PO) were more effective in lowering um lipids than n-6 fatty acids or saturated fatty acid. Based on the results of fatty acid composition of hepatic phospholipid, we suggest that the dietary effect of PO and DHA on antiatherogenic characteristics seems to be similar extent. In addition, the effect of EPA might not be significantly different from that of BT or CO in the view of eicosanoids production from the precursor fatty acid. These difference of hepatic fatty acid composition might come from other characteristics of dietary oil as well as the type of unsaturation, not from the carbon chain length or the degree of unsaturation of n-3 fatty acid.

• Journal of Nutrition and Health
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• 제36권6호
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• pp.577-588
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• 2003

Severe protein-calorie malnutrition, common in patients with advanced liver disease, can seriously undermine the capacity for regeneration and functional restoration of liver. Nutritional supplementation for these patients can improve biochemical and hormonal abnormalities. However, these effects were not identified in patient with nonalcoholic liver cirrhosis. To determine effects of nutritional supplementation in patients with nonalcoholic liver cirrhosis, 77 subjects aged 29 to 69 years participated in this study for 12 weeks and were subdivided into three groups; normal diet group (Control group, n ＝ 16), branched-chain amino acid supplementation group (BCAA group, n ＝ 31), nutritional supplementation group (NS group, n ＝ 30). Anthropometric parameters, hemoglobin, hematocrit, blood cell counts, serum levels of lipids, vitamins, minerals and fatty acid composition, and plasma amino acids were examined. The mean values of age and height, and the initial values of weight and body mass index (BMI) were not different among all groups. After 12 weeks, there were no significant changes in these values in Control group. Only NS group showed significant increases in weight, lean body mass, midarm circumference, triceps skinfold thickness. Serum transferrins were increased both in BCAA and NS groups. Plasma levels of branched-chain amino acids, urea amino acids and glutamic acid were also significantly increased in these groups, but plasma levels of ammonia, serum LDL cholesterol and atherogenic index were decreased. However, there were no significant changes in serum levels of vitamin and mineral and composition of fatty acids in phospholipids in these groups. These results showed that the nutritional supplementation for patients with nonalcoholic liver cirrhosis can more improve nutritional status in these people together with increases of weight, body fat and lean body mass, compared to only BCAA supplementation. To ascertain and investigate the appropriate nutritional supplementation for patients with nonalcoholic liver cirrhosis, further studies are necessary.

• 대한수의학회지
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• 제36권3호
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• pp.577-598
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• 1996

This study was conducted to identify the effects of caffeine or combinations of caffeine and iron or vitamin E on the lipid and protein components or blood chemistry levels of the serum as well as the total homogenate, mitochondrial and microsomal fraction of the rat(Sprague-Dawley, female) liver. Chronic test were conducted to determine those effects. The chronic test was conducted by dividing rats into 5 groups according to the type of drugs and dosages administrated as follows; the control(group A), and group B was given 25mg/kg caffeine orally once daily for 30 days, group C was given 50mg/kg caffeine orally once daily for 30 days, group D was given 25mg/kg caffeine and orally ferric chloride once daily for 30 days and group E was given 25mg/kg caffeine and 25mg/kg vitamin E once daily for 30 days. The concentrations of glucose, urea nitrogen, uric acid, creatinine, total protein, albumin, A/G ratio, triglyceride, total cholesterol, HDL-cholesterol, free fatty acid, phospholipid as well as the activities of alanine aminotransferase(ALT), aspartate aminotransferase(AST) and alkaline phosphatase(ALP) were measured in the serum of each experimental groups. The concentrations of the carbonyl group and malondiaidehyde(MDA) and the patterns of the SDS-PAGE(Sodium Dodecyl Sulfate - Polyacrylamide Gel Electrophoresis) and fatty acid compositions in free fatty acids and phospholipids were analyzed to determine the oxidative damages and metabolic changes on the lipid and protein components in the serum, and total homogenate, mitochondrial and microsomal fractions of the rat liver. The results obtained from this study were summarized as follows; 1. Body weights of groups B, C, D and E were significantly decreased(p < 0.01) in comparison with that of the control in the chronic test. 2. The concentrations of serum glucose in groups B(124.5mg/dl), C(130.1mg/dl), D(122.1mg/dl), E(119.3mg/dl) were significantly higher(p < 0.01) in comparison to that of the control(101.5mg/dl). But, there were no significant differences in the concentrations of urea nitrogen, uric acid, creatinine, total protein, albumin and A/G ratio in comparison to that of the control. 3. The concentrations of total cholesterol and HDL-cholesterol in serum of groups B(69.6, 53.4mg/dl), C(73.0, 56.3mg/dl), D(68.9, 51.1mg/dl) and E(68.2, 51.3mg/dl) were significantly higher(p < 0.01) in comparison to that of the control(52.6, 38.8mg/dl). On the other hand, the concentrations of triglyceride in serum of groups B(45.0mg/dl), C(40.4mg/dl), D(33.8mg/dl) and E(47.2mg/dl) were significantly lower(p < 0.01) in comparison to that of the control(66.2mg/dl). There were no significant differences in the activities of ALT, AST and ALP in comparison to that of the control. 4. The concentrations of free fatty acid and phospholipid in serum of groups B(45.7, 154.4mg/dl), C(50.0, 167.2mg/dl), D(52.5, 148.4mg/dl) and E(41.1, 159.2mg/dl) were higher(p < 0.01) in comparison to that of the control(35.2, 125.3mg/dl). And the concentrations of the carbonyl group and malondialdehyde in serum of group D(1.82, 0.52nM/mg protein) were significantly higher(p < 0.01) in comparison to the control(1.53nM/mg protein). 5. The concentrations of carbonyl group in total homogenate, mitochondrial and microsomal fraction of group D(1.45, 0.94, 1.67nM/mg protein) were significantly higher (p < 0.01) in comparison to the control(1.16, 0.66, 1.27nM/mg protein). And the concentrations of malondialdehyde in the total homogenate, mitochondrial and microsomal fraction of group D(6.70, 6.10, 1.36nM/mg protein) were significantly higher(p < 0.01) in comparison to the control(5.17, 3.64, 0.68nM/mg protein). 6. As the analytical results of the fatty acid compositions of free fatty acid in serum, the proportions of stearic acid and arachidonic acid of groups B(16.52, 12.62%), C(17.52, 15.18%), D(19.73, 13.47%) and E(17.62, 13.28%) were significantly higher(p < 0.01) in comparison to the control(14.75, 7.88%), but the proportions of oleic acid and linoleic acid of groups B(12.97, 32.59%), C(10.88, 31.23%), D(12.37, 30.66%) and E(11.95, 32.41%) were significantly lower(p < 0.01) in comparison to the control(16.44, 35.12%). Otherwise, as the results of the fatty acid compositions of phospholipid in serum, the proportions of stearic acid and arachidonic acid of groups B(39.37, 16.39%), C(40.63, 17.83%), D(42.73, 15.39%) and E(39.16, 15.70%) were significantly higher(p < 0.01) in comparison to the control(37.74, 14.24%), but the proportions of oleic acid and linoleic acid of groups B(4.03, 14.38%), C(3.54, 12.38%), D(4.52, 11.68%) and E(4.29, 13.64%) were significantly lower(p < 0.01) in comparison to the control(5.53, 16.14%). 7. As the analytical results of the fatty acid compositions of free fatty acid in total homogenate, mitochondrial and microsomal fraction of liver, the proportions of oleic acid of groups B(7.8**, 8.73**, 6.88%) and C(6.89**, 7.75**, 6.58%) were lower(**:p < 0.01) in comparison to the control(8.67, 10.08, 7.81%), but the proportions of arachidonic acid of group C(22.62, 19.79, 23.71%) were significantly higher(p < 0.01) in comparison to the control(20.93, 18.47, 22.24%). And the proportions of palmitic acid of group D(25.95**, 26.16, 26.34**%) were significantly higher(**:p < 0.01) in comparison to the control(24.43, 25.42, 23.34%). In addition, the proportions of linoleic acid of group D(23.43, 25.02, 23.95%) were also significantly higher(p < 0.01) in comparison to the control(22.17, 23.75, 21.26%). The proportions of stearic acid of group D(19.87, 19.76**%) in mitochondrial and microsomal fraction were lower(**:p < 0.01) in comparison to the control(21.01, 24.18%), and the proportions of stearic acid of group E(16.71*, 19.65**%) in mitochondrial and microsomal fraction were significantly lower(**:p < 0.01, *:p < 0.05) in comparison to the control(21.01, 24.18%), and the proportions of linoleic acid of group E(25.04, 29.20, 26.48%) in total homogenate, mitochondria and microsome were significantly higher(p < 0.01) in comparison to the control(22.17, 23.75, 21.26%). 8. As the results of the fatty acid compositions of phospholipid in total homogenate, mitochondrial and microsomal fraction of liver, the proportions of palmitic acid of group D(17.58**, 18.78*, 18.23%**) were significantly higher(**:p < 0.01, *:p < 0.05) in comparison to the control(16.28, 17.22, 16.38%), and the proportions of stearic acid of group D(36.41, 37.23, 39.53%) were also significantly higher(p < 0.01) in comparison to the control(34.18, 34.16, 36.04%). But the proportions of oleic acid(3.41*, 3.11**, 3.12**%) and linoleic acid (18.03**, 15.79**, 14.74**%) of group D were significantly lower(**:p < 0.01, *:p < 0.05) in comparison to the control(oleic : 3.63, 3.72, 3.79%, linoleic : 20.03, 18.71, 18.48%). 9. In order to determine the oxidative damages to the protein in serum, mitochondrial and microsomal fraction of the rat liver, the patterns of the SDS-PAGE were identified, but the results of SDS-PAGE were not significantly different between the control and experimental groups.

• 한국독성학회:학술대회논문집
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• 한국독성학회 2002년도 국제심포지움
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• pp.20-45
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• 2002

In this study, we demonstrated the in vitro and in vivo formation of carcinogen-lipid adduct and its correlation with DNA or protein adducts. The lipids from serum or hepatocyte membranes of Spragu-Dawley rats. human serum, and standard major lipids were in vitro reacted with benzo[a]pyrene(BP) and BP metabolites. 7,8-Dihydroxy-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]-pyrene(BPDE-I), an ultimate carcinogenic form of BP, was covalently bound to triglyceride(TG). BPDE-I-TG adducts isolated by thin-layer chromatography (TLC) were further detected by high performance liquid chromatography(HPLC). TGs, including triolein, tripalmitin and tristearin, showed positive reactions with BPDE-I. However, cholesterol, phospholipids(Phosphatidylcholine, phosphatidyl-ethanolamine, phosphatidyl-inositol and sphingomyelin) and nonesterified fatty acids(palmitic acid, oleic acid, linoleic acid and stearic acid) did not react with BPDE-I. In addition, other BP metabolites (BP-phenols and -diols) did not react with TG, which TG appeared to be the most reactive lipid yet studied with respect to its ability to form an adduct with BPDE-I. There was a clear-cut dose-respect to its ability to form an adduct with BPDE-I-lipid adduct in vitro between TG and [1,3-3H]BPDE-I. In an animal study, BPDE-I-TG was also formed in the serum of rats orally treated with BP(25 mg/rat). Also, obvious correlations between [3H]BP related-biomolecule adducts (DNA, protein) or lipid damage and the BPDE-I-TG adduct were obtained in various tissues of mice i.p. treated with [3H]BP. These data suggest that TG can form an adduct with BPDE-I, as do other macromolecules (DNA, RNA, and protein). Therefore, a carcinogen-lipid adduct would be a useful biomarker for chemical carcinogenesis research and cancer risk assessment.

• Journal of Nutrition and Health
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• 제47권6호
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• pp.385-393
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• 2014

Purpose: The aim of this study is to examine the effects of egg consumption and suggest proper guidelines for consumption of eggs by determining the relationship between eggs and cholesterol. Methods: Literature review was conducted on the relationship between nutritional, functional properties of eggs and serum cholesterol, as well as cardiovascular disease. Results: Eggs, which are a good protein food with complete amino acid composition, contain vitamin A, riboflavin, vitamin $B1_2$, folic acid, vitamin D, vitamin E, vitamin K, calcium, iron, choline, selenium, ${\beta}$-carotene, lutein, zeaxanthin, etc. However the egg yolk has a high cholesterol content, which is associated with chronic diseases, including heart disease and hypertension. As a result, its intake is subject to regulation. Outbreak of heart disease by yolk intake can show different results depending on the characteristics of the subjects, amount of egg intake, and the implications of other foods eaten. It is difficult to determine whether eggs are beneficial, as they are the main supplying source for other major nutritive elements as well. Several research studies insist that when cholesterol intake increases by 100 mg, the level of serum cholesterol increases by 2.2~4.5 mg/dL and when serum cholesterol increases by 1%, the risk of heart disease increases by 2%. This indicates that a large intake of eggs can increase the risk of heart disease. Although the cholesterol of egg yolk and serum cholesterol are correlated, it is insufficient to conclude that only cholesterol and not other components are related to heart disease. In fact, other components in egg such as various unsaturated fatty acids and phospholipids could be related as well. Rather than concluding egg as a 'good' or 'bad' food according to its cholesterol content, it is important to define egg as a part of dietary patterns. Conclusion: Generalizing an indiscriminate and uniform amount of egg intake for all seems inadequate. However, patients with diabetes or heart disease should pay particular attention to the amount of egg intake. As for the norm, eating egg with vegetables as a substitute for other animal products seems beneficial.

• Journal of Ginseng Research
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• 제12권1호
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• pp.76-86
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• 1988

쥐에게 물대신 12% 에탄올(대조군) 또는 인삼사포닌 분획을 포함한 12% 에탄올(시험군)을 6일간 투여한 후 간과 혈청에서의 acetaldehyde 농도와 간의 [$NAD^+$]/ [NADH] 및 [$NADP^+$]/[NADPH] 비율을 조사하였다. 대조군의 간과 혈청의 acetaldehyde 농도는 물로 사육한 정상군에 비해 훨씬 높았으나 물대신 인삼사포닌을 포함한 에탄올을 투여한 시험군의 경우는 정상군에 비해 약간 높았을 뿐이었으며 [$NAD^+$]/ [NADH] 비의 감소율도 대조군보다는 시험군이 훨씬 작았다. l-$^{l4}C$]-ethanol을 함유한 10% ethanol을 1ml 복강으로 투여하고 30분 후의 간의 지방질의 방사능을 분석한 결과 시험군의 간 지방질의 전체 방사능은 대조군보다 훨씬 낮았고 인산지방질, 콜레스테롤, 지방산, 중성지방과 같은 지방질의 분석결과는 에탄올 투여로 인한 인산지방질 생합성 저하와 지방산 및 중성지방의 생합성 증가현상이 인삼사포닌의 투여로 개선되는 것으로 관찰되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제9권1호
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• pp.1-25
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• 1996

The pathogenesis of atherosclerosis can not be summarized as a single process. Lipid infiltration hypothesis and endothelial injury hypothesis have been proposed and investigated. Recent developments show that there are many points of potential interactions between them and that they can actually be regarded as two phases of a single, unifying hypothesis. Among the many risk factors of atherosclerosis, plasma homocysteine and lipoprotein(a) draw a considerable interest because they are independent indicators of atherogenicity. Triglyceride (TG)-rich lipoproteins (chylomicron and VLDL) are not considered to be atherogenic but they are related to the metabolism of HDL cholesterol and indirectly related to coronary heart disease (CHD). LDL can of itself be atherogenic but the oxidative products of this lipoprotein are more detrimental. HDL cholesterol has been considered to be a favorable cholesterol. The so-called 'causalist view' claims that HDL traps excess cholesterol from cellular membranes and transfers it to TG-rich lipoproteins that are subsequently removed by hepatic receptors. In the so-called 'noncausalist view', HDL does not interfere directly with cholesterol deposition in the arterial wall but instead reflects he metabolism of TG-rich lipoproteins and their conversion to atherogenic remnants. Approximately 70-80% of the human population shows an effective feedback control mechanism in cholesterol homeostasis. Type of dietary fat has a significant effect on the lipoprotein cholesterol metabolism and atherosclerosis. Generally, saturated fatty acids elevate and PUFA lower serum cholesterol, whereas MUFA have no specific effect. EPA and DHA inhibit the synthesis of TG, VLDL and LDL, and may have favourable effects on some of the risk factors. Phospholipids, particularly lecithin, have an antiatherosclerotic effect. Essential phospholipids (EPL) may enhance the formation of polyunsaturated cholesteryl ester (CE) which is less sclerotic and more easily dispersed via enhanced hydrolysis of CE in the arterial wall. Also, neutral fecal steroid elimination may be enhanced and cholesterol absorption reduced following EPL treatment. Antioxidants protect lipoproteins from oxidation, and cells from the injury of toxic, oxidized LDL. The rationale for lowering of serum cholesterol is the strong association between elevation of plasma or serum cholesterol and CHD. Cholesterol-lowing, especially LDL cholesterol, to the target level could be achieved using diet and combination of drug therapy. Information on the link between cholesterol and CHD has decreased egg consumption by 16-25%. Some clinical studies have indicated that dietary cholesterol and egg have a significant hypercholesterolemic effect, while others have indicated no effect. These studies differed in the use of purified cholesterol or cholesterol in eggs, in the range of baseline and challenge cholesterol levels, in the quality and quantity of concomitant dietary fat, in the study population demographics and initial serum cholesterol levels, and clinical settings. Cholesterol content of eggs varies to a certain extent depending on the age, breed and diet of hens. However, egg yolk cholesterol level is very resistant to change because of the particular mechanism involved in yolk formation. Egg yolk contains a factor of factors responsible for accelerated cholesterol metabolism and excretion compared with crystalline cholesterol. One of these factors could be egg lecithin. Egg lecithin may not be as effective as soybean lecithin in lowering serum cholesterol level due probably to the differences of fatty acid composition. However, egg lecithin may have positive effects in hypercholesterolemia by increasing serum HDL level and excretion of fecal cholesterol. The association of serum cholesterol with egg consumption has been widely studied. When the basal or control diet contained little or no cholesterol, consumption of 1 or 2 eggs daily increased the concentration of plasma cholesterol, whereas that of the normolipemic persons on a normal diet was not significantly influenced by consuming 2 to 3 eggs daily. At higher levels of egg consumption, the concentration of HDL tends to increase as well as LDL. There exist hyper-and hypo-responders to dietary (egg) cholesterol. Identifying individuals in both categories would be useful from the point of view of nutrition guidelines. Dietary modification of fatty acid composition has been pursued as a viable method of modifying fat composition of eggs and adding value to eggs. In many cases beneficial effects of PUFA enriched eggs have been demonstrated. Generally, consumption of n-3 fatty acids enriched eggs lowered the concentration of plasma TG and total cholesterol compared to the consumption of regular eggs. Due to the highly oxidative nature of PUFA, stability of this fat is essential. The implication of hepatic lipid accumulation which was observed in hens fed on fish oils should be explored. Nutritional manipulations, such as supplementation with iodine, inhibitors of cholesterol biosynthesis, garlic products, amino acids and high fibre ingredients, have met a limited success in lowering egg cholesterol.

• 한국식품영양과학회지
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• 제26권2호
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• pp.314-318
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• 1997

본 연구에서는 in vivo에서 메주단백질이 콜레스테롤 대사에 미치는 효과를 검토하기 위해, 4주령의 Sprague-Dawley rats를 이용하여 0.5% 콜레스테롤을 함유한 식이에 증자대두분말, 메주분말을 단백질원으로 첨가하여 4주간 자유 급식한 후 혈청 및 간장 중의 지질농도와 분변 중 담즙산 함량을 분석하였다. 증자대두, 메주분말을 포함한 식이를 섭취시켰을 때 실험기간 동안 평균 식이 섭취량, 체중 증가량 및 간장의 무게는 실험군 간에 유의적인 차이는 없었다. 혈청 총콜레스테롤 농도는 메주분말 섭취군이 증자대두 섭취군에 비해 유의적으로 낮았으나(p＜0.05), 혈청 HDL-콜레스테롤 농도에 유의한 차이는 군간 관찰되지 않아, 메주분말 투여에 의한 혈청 콜레스테롤 농도의 감소는 VLDL-, LDL-콜레스테롤 농도 저하에 기인함을 보여 주었다. 혈청 중 인지질, 중성지질, 유리지방산 농도는 두 군간에 유의적인 차이를 보이지 않았다. 간장 중 중성지질, 인지질, 콜레스테롤 농도는 두 군간에 유의적인 차이는 없었다. 한편, 분변 중의 담즙산 함량은 메주분말 투여군이 대조군과 증자대두군에 비해 유의적으로 높은 수준을 보였다 (p＜0.05). 이러한 결과로부터 메주분말 투여에 의한 혈청 콜레스테롤 농도의 저하효과는 담즙산 배설량의 증가에 기인된것으로 판단되며, 미생물에 의해 발효된 대두단백질(메주)은 발효되지 않은 대두단백질에 비하여 강한 콜레스테롤 저하작용이 있음을 시사한다.

• Nutritional Sciences
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• 제7권4호
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• pp.208-213
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• 2004

In this study, we examined the effects of dietary 1,3-diacylglycerol (DG) compared to conventional triacylglycerol (TG) oil on the postprandial response of total and chylomicron TG, glucose, insulin, and free fatty acid (FFA). This study was conducted using a cross-over design. Ninety subjects participated in the high-fat meal tolerance test where they were randomly assigned to consume two experimental sandwiches containing mayonnaise with TG or DG oil with a seven-day interval. Blood samples were collected before ingestion and at 2, 3, 4 and 6 hr time point after ingestion and analyzed for total and chylomicron TG, glucose, insulin, FFA and phospholipid fatty acid composition. Both TG and DG ingestion had similar effects on postprandial TG response, but a different response from chylomicron TG. Compared with the TG group, TG levels were significantly lower only at 6 hr time point in the DG group. On the other hand, chylomicron TG rose steeply at 2 hr time point and decreased faster in this group. Also, the adjusted value to fasting levels was the same as the unadjusted level. Fasting levels and net differences in insulin were significantly lower at 3 hr time point where chylomicron TG levels were significantly lower in the DG group. But those of glucose and FFA in the TG and DG groups did not differ significantly. Fasting and postprandial levels of fatty acid composition in serum phospholipids in the two groups did not differ significantly. In conclusion, this study indicated that one could reduce the magnitude of postprandial lipemia without influencing glucose metabolism by consumning DG oil as a substitute for TG oil. Based on the correlation of coronary artery disease and postprandial lipemia, dietary DG ingestion might have a beneficial effect in treating such a disease. Further studies are required to clarify the long-tenn effects of dietary DG on blood lipid levels in humans.

• Asian-Australasian Journal of Animal Sciences
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• 제20권8호
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• pp.1215-1221
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• 2007

Three Holstein steers fitted with ruminal and duodenal cannulae were fed grass silage-based diets supplemented with potato pulp silage as a substitute for rolled corn at levels of 0%, 50% and 100% on a DM basis in a $3{\times}3$ Latin square design to investigate the effect of potato pulp silage on nitrogen (N) utilization in ruminants. Organic matter (OM) intake, and rumen and total tract digestibilities did not differ among treatment diets. Rumen and post-rumen starch digestibilities were similar among treatments, although starch intake decreased (p<0.01) with potato pulp supplementation. There were no significant differences (p>0.05) in ruminal N utilization and non-ammonia N supply to the duodenum of steers fed grass silage supplemented with potato pulp silage as a substitute for rolled corn. There were no treatment differences (p>0.05) in rumen pH, volatile fatty acid (VFA) concentration or the molar percentages of acetate and propionate. The ammonia-N concentration in rumen fluid tended to decrease (p<0.1) when rolled corn was substituted with potato pulp silage. Ether extract intake and post-ruminal digestibility significantly (p<0.01) decreased in steers fed diets containing potato pulp silage. Concentrations of total cholesterol and phospholipids in serum markedly decreased (p<0.01) with potato pulp silage supplementation without adversely affecting liver function. These data suggested that potato pulp silage has a similar value as rolled corn as an energy source for rumen microorganisms.