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1.
Male weanling rats were fed semi-synthetic diets high in saturated fat (beef tallow) vs high in linoleic acid (safflower oil)
with or without high levels of α-linolenic acid (linseed oil) for a period of 28 days. The effect of feeding these diets on
cholesterol content and fatty acid composition of serum and liver lipids was examined. Feeding linseed oil with beef tallow
or safflower oil had no significant effect on serum levels of cholesterol. Serum cholesterol concentration was higher in animals
fed the safflower oil diet than in animals fed the beef tallow diet without linseed oil. Feeding linseed oil lowered the cholesterol
content in liver tissue for all dietary treatments tested. Consumption of linseed oil reduced the arachidonic acid content
with concomitant increase in linoleic acid in serum and liver lipid fractions only when fed in combination with beef tallow,
but not when fed with safflower oil. Similarly, ω3 fatty acids (18∶3ω3, 20∶5ω3, 22∶5ω3, 22∶6ω3) replaced ω6 fatty acids (20∶4ω6,
22∶4ω6) in serum and liver lipid fractions to a greater extent when linseed oil was fed with beef tallow than with safflower
oil. The results suggest that the dietary ratio of linoleic acid to saturated fatty acids or of 18∶3ω3 to 18∶2ω6 may be important
to determine the cholesterol and arachidonic acid lowering effect of dietary α-linolenic acid. 相似文献
2.
Comparative effects of feeding dietary linoleic (safflower oil) and α-linolenic (linseed oil) acids on the cholesterol content
and fatty acid composition of plasma, liver, heart and epididymal fat pads of rats were examined. Animals fed hydrogenated
beef tallow were used as isocaloric controls. Plasma cholesterol concentration was lower and the cholesterol level in liver
increased in animals fed the safflower oil diet. Feeding the linseed oil diet was more effective in lowering plasma cholesterol
content and did not result in cholesterol accumulation in the liver. The cholesterol concentration in heart and the epididymal
fat pad was not affected by the type of dietary fatty acid fed. Arachidonic acid content of plasma lipids was significantly
elevated in animals fed the safflower oil diet and remained unchanged by feeding the linseed oil diet, when compared with
the isocaloric control animals fed hydrogenated beef tallow. Arachidonic acid content of liver and heart lipids was lower
in animals fed diets containing safflower oil or linseed oil. Replacement of 50% of the safflower oil in the diet with linseed
oil increased α-linolenic, docosapentaenoic and docosahexaenoic acids in plasma, liver, heart and epididymal fat pad lipids.
These results suggest that dietary 18∶2ω6 shifts cholesterol from plasma to liver pools followed by redistribution of 20∶4ω6
from tissue to plasma pools. This redistribution pattern was not apparent when 18∶3ω3 was included in the diet. 相似文献
3.
Rats were fed diets high in either saturated fat (beef tallow) or α-linolenic acid (linseed oil) or eicosapentaenoic and docosahexaenoic
acids (fish oil) with or without 2% cholesterol supplementation. Consumption of linseed oil and fish oil diets for 28 days
lowered arachidonic acid content of plasma, liver and heart phospholipids. Addition of 2% cholesterol to diets containing
beef tallow or linseed oil lowered 20∶4ω6 levels but failed to reduce 20∶4ω6 levels when fed in combination with fish oil.
Feeding ω3 fatty acids lowered plasma cholesterol levels. Addition of 2% cholesterol to the beef tallow or linseed oil diet
increased plasma cholesterol concentrations but not when fish oil was fed. Feeding the fish oil diet reduced the cholesterol
content of liver, whereas feeding the linseed oil diet did not. Dietary cholesterol supplementation elevated the cholesterol
concentration in liver in the order: linseed oil > beef tallow > fish oil (8.6-, 5.5-, 2.6-fold, respectively). Feeding fish
oil and cholesterol apparently reduced 20∶4ω6 levels in plasma and tissue lipids. Fish oil accentuates the 20∶4ω6 lowering
effect of dietary cholesterol and appears to prevent accumulation of cholesterol in plasma and tissue lipids under a high
dietary load of cholesterol. 相似文献
4.
Effects of diets high in saturated fat and cholesterol on the lipid composition of canine platelets 总被引:1,自引:0,他引:1
The phospholipid composition of platelets from dogs on various experimental diets was determined. Thyroidectomized foxhounds
were fed a control diet or the control diet supplemented with (1) beef tallow, (2) beef tallow and cholesterol, or (3) beef
tallow, cholesterol, and safflower oil for 23 weeks prior to isolation of platelets. Platelets from animals fed the control
diet contained 36.7% phosphatidylcholine (PC), 22.8% phosphatidylethanolamine (PE), 18.4% sphingomyelin (Sph), 11.8% phosphatidylserine
(PS), 6.3% phosphatidylinositol (PI), and 2.2% lysophosphatidylcholine. The PE was 77.6% in the plasmalogen form. No highly
significant changes in the phospholipid class composition resulted from the experimental diets. Cholesterol supplementation
of the diets, however, caused consistent alterations in the fatty acid compositions of the platelet phospholipids including
increases in the percentages of 18∶1ω9 (oleic acid), 18∶2ω6 (linoleic acid), and 20∶3ω6 (homo-gamma linolenic acid) and a
decrease in the percentage of 20∶4ω6 (arachidonic acid). Addition of safflower oil to the tallow-cholesterol diet partially
reversed these effects. These cholesterol-induced alterations in fatty acid composition could be due to exchange with plasma
lipids, de novo synthesis, or altered platelet metabolism. The mechanism remains to be determined.
Der. Nelson’s current affiliation is the Lipid Metabolism Branch, Division of Heart and Vascular Diseases, National Heart,
Lung, and Blood Institute. 相似文献
5.
Diets rich in meat are claimed to contribute to the high tissue arachidonic acid (20∶4ω6) content in people in Westernized
societies, but there are very few direct data to substantiate this assertion. Because meat contains a variety of long-chain
polyunsaturated fatty acids (PUFA) that are susceptible to oxidation, we initially examined the effect of cooking on the long-chain
PUFA content of beef, and then determined the effect of ingestion of lean beef on the concentration of long-chain PUFA in
plasma phospholipids (PL). First, we examined the effect of grilling (5–15 min) and frying (10 min) different cuts of fat-trimmed
lean beef on the long-chain PUFA content. Second, we investigated the effect of including 500 g lean beef daily (raw weight)
for 4 wk on the fatty acid content and composition of plasma PL in 33 healthy volunteers. This study was part of a larger
trial investigating the effect of lean beef on plasma cholesterol levels. In the first two weeks, the subjects ate a very
low-fat diet (10% energy) followed by an increase in the dietary fat by 10% each week for the next 2 wk. The added fat consisted
of beef fat, or olive oil (as the oil or a margarine) or safflower oil (as the oil or a margarine). This quantity of beef
provided 60, 230, 125, 140 and 20 mg/d, respectively, of eicosatrienoic acid (20∶3ω6), 20∶4ω6, eicosapentaenoic acid (20∶5ω3),
docosapentaenoic acid (22∶5ω3) and docosahexaenoic acid (22∶6ω3). Grilling for 10–15 min, but not frying, of the fat-trimmed
lean beef resulted in 20–30% losses of the 20 and 22 carbon PUFA. The consumption of the lean beef during the first two-week
period, when there was a very low level of dietary fat, was associated with significant increases in the proportion and concentration
of 20∶3ω6, 20∶4ω6, 20∶5ω3 and 22∶5ω3 in the plasma PL and a significant decrease in the proportion and content of 18∶2ω6.
The addition of beef fat or olive oil to the diets containing lean beef did not alter the plasma PL fatty acid profile compared
with the very low-fat diet, whereas the addition of safflower oil maintained the significant increases in 20∶4ω6 and 22∶5ω3
but led to decreases in 18∶3ω3 and 20∶5ω3 compared with the very lowfat diet. The results showed that diets rich in lean beef
increased the 20∶3ω6, 20∶4ω6 and the long-chain ω3 PUFA levels in the plasma PL. A high level of linoleic acid in diets rich
in lean beef prevented the rise in the plasma level of 20∶3ω6 and 20∶5ω3, two fatty acids known to antagonize the effects
of 20∶4ω6 on platelet aggregation. 相似文献
6.
This study examined the effect on the plasma lipids and plasma phospholipid and cholesteryl ester fatty acids of changing
from a typical western diet to a very low fat (VLF) vegetarian diet containing one egg/day. The effect of the addition of
saturated, monounsaturated or polyunsaturated fat (PUFA) to the VLF diet was also examined. Three groups of 10 subjects (6
women, 4 men) were fed the VLF diet (10% energy as fat) for two weeks, and then in the next two weeks the dietary fat in each
group was increased by 10% energy/week using butter, olive oil or safflower oil. The fat replaced dietary carbohydrate. The
VLF diet reduced both the low density lipoprotein (LDL)-and high density lipoprotein (HDL)-cholesterol levels; addition of
the monounsaturated fats and PUFA increased the HDL-cholesterol levels, whereas butter increased the cholesterol levels in
both the LDL- and HDL-fractions. The VLF diet led to significant reductions in the proportion of linoleic acid (18∶2ω6) and
eicosapentaenoic acid (20∶5ω3) and to increases in palmitoleic (16∶1), eicosatrienoic (20∶3ω6) and arachidonic acids (20∶4ω6)
in both phospholipids and cholesteryl esters. Addition of butter reversed the changes seen on the VLF diet, with the exception
of 16∶1, which remained elevated. Addition of olive oil resulted in a significant rise in the proportion of 18∶1 and significant
decreases in all ω3 PUFA except 22∶6 compared with the usual diet. The addition of safflower oil resulted in significant increases
in 18∶2 and 20∶4ω6 and significant decreases in 18∶1, 20∶5ω3 and 22∶5ω3. These results indicate that the reduction of saturated
fat content of the diet (<6% dietary energy), either by reducing the total fat content of the diet or by exchanging saturated
fat with unsaturated fat, reduced the total plasma cholesterol levels by approximately 12% in normocholesterolemic subjects.
Although the VLF vegetarian diet reduced both LDL- and HDL-cholesterol levels, the long-term effects of VLF diets are unlikely
to be deteterious since populations which habitually consume these diets have low rates of coronary heart disease. The addition
of safflower oil or olive oil to a VLF diet produced favorable changes in the lipoprotein lipid profile compared with the
addition of butter. The VLF diets and diets rich in butter, olive oil or safflower oil had different effects on the 20 carbon
eicosanoid precursor fatty acids in the plasma. This suggests that advice on plasma lipid lowering should also take into account
the effect of the diet on the fatty acid profile of the plasma lipids. 相似文献
7.
The effect of diets high (15%) in saturated (beef tallow) or polyunsaturated (corn or cottonseed oil) fatty acids on the fatty
acid composition of sphingomyelin from canine erythrocytes and platelets and sphingomyelin and neutral glycosphingolipids
of swine erythrocytes was determined. Sphingolipids of platelets and erythrocytes from animals fed high levels of corn or
cottonseed oil exhibited a dramatic alteration in their fatty acid composition, most notable of which was a 50% reduction
in nervonic acid (24∶1ω9) as compared to levels observed in control or tallow fed animals. This decrease was compensated for
by a quantitatively similar increase in a C24 dienoic acid. The long chain dienoic acid was isolated by silver nitrate thin layer chromatography and determined by analysis
of its oxidation products to be Δ15, 18-tetracosadienoic acid (24∶2ω6). When the animals were fed the diets high in polyunsaturates,
the 24∶2ω6 represented 13, 20, and 9% of the sphingomyelin fatty acids from canine erythrocytes, platelets, and swine erythrocytes,
respectively, and 5% of the neutral glycosphingolipid fatty acids of swine erythrocytes. In contrast, the 24∶2ω6 represented
less than 4% of the total cellular sphingolipid fatty acids in animals fed the control or high beef tallow diets. The 24∶1ω9
in the sphingolipids of the animals fed the polyunsaturated diet was roughly equal to that of 24∶2ω6, whereas in the sphingolipids
of animals fed the control or saturated fat (beef tallow) diet, the 24∶1ω9 was twice these values. Since sphingomyelin is
a membrane component, the increase in unsaturation (24∶2ω6) in its fatty acid moiety induced by dietary polyunsaturates may
affect membrane fluidity and may alter membrane properties.
Dr. Nelson’s current affiliation is with the Lipid Metabolism Branch, Division of Heart and Vascular Diseases, National Heart,
Lung, and Blood Institute. 相似文献
8.
The fatty acid composition of testicular lipids has been determined and related to fertility data from groups of dubbed White
Leghorn cockerels after a 50-week feeding period on rations containing 10% safflower oil or coconut oil. Supplements of ethoxyquin
ord-α-tocopherol acetate maintained fertility in birds raised on rations containing safflower oils. This response was associated
with higher proportions of 22∶4 ω6 and lower proportions of 18∶2 ω6 in testicular lipids. Testes size was quite variable in
the unsupplemented group with changes in fatty acid composition being more pronounced in the smaller testes. A multiple regression
was calculated using data from those birds on the safflower oil ration. With a correlation ratio of 0.90 fertility was expressed
as a function of testes size, semen concentration and the proportions of 18∶2 ω6, 20∶4 ω6 and 22∶4 ω6 in testicular lipids.
Despite the low intake of linoleate significant levels of polyunsaturated fatty acids were maintained in testicular lipids
of birds fed the coconut oil rations. The major changes in fatty acid composition of testicular lipids produced by this variable
was a decrease in the proportion of 18∶2 ω6 and an increase in the proportion of 18∶1.
Paper No. 3050, Oregon Agricultural Experiment Station. 相似文献
9.
P. E. Wainwright Y. S. Huang D. E. Mills G. R. Ward R. P. Ward D. McCutcheon 《Lipids》1989,24(12):989-997
This study assesses the combined effects on brain and behavioral development of ethanol administration and supplementation
of the maternal diet with long chain n−3 polyunsaturated fatty acids. From day 7 to 17 of gestation, pregnant mice were fed
equivalent daily amounts of isocaloric liquid diets; 20% of the energy was provided by either ethanol or maltose-dextrin,
and a further 20% by either safflower oil (rich in linoleic acid, 18∶2n−6), or a combination of safflower oil with a fish
oil concentrate (rich in eicosapentaenoic acid, 20∶5n−3, and docosahexaenoic acid, 22∶6n−3). On day 18 the liquid diets were
replaced by lab chow; a fifth group was maintained on lab chow throughout the experiment. Measures on the pups included brain
weight and the fatty acid composition of the brain phospholipids on days 22 and 32 post-conception (birth=day 19), as well
as behavioral development. Maternal weight gain during gestation was decreased by ethanol relative to maltose-dextrin, and
increased by fish relative to safflower oil. On day 32, the brain weight of ethanoltreated animals fed fish oil was greater
than their safflower oil controls, whereas the reverse was true in the two maltose-dextrin groups; a similar trend was apparent
on day 22. The brain phospholipid content of the longer chain fatty acids (20∶4n−6, 22∶4n−6, 22∶5n−6, 20∶5n−3, 22∶5n−3, 22∶6n−3)
on day 22 reflected that of the prenatal diet, with the proportion of n−3 compounds being higher and that of n−6 floer in
the fish oil than safflower oil groups. Prenatal dietary effects were absent by day 32, with the exception of lower 22∶5n−6
in fish oil groups. Dietary supplementation with n−3 fatty acids increased the ratio of 20∶3n−6 to 20∶4n−6, which is consistent
with a blockade of the activity of Δ-5 desaturase. On day 22 the incorporation of dietary long chain n−3 fatty acids into
the brain phosphatidylcholine fraction was enhanced in the ethanol-treated animals; by day 32 the animals treated prenatally
with ethanol also showed increased levels of long chain n−6 compounds. Behavioral development was retarded by ethanol, but
there was no effect of the dietary oils. These results support the hypothesis that effects of ethanol on the developing brain
may be modified by the availability of an exogenous supply of long chain fatty acids. 相似文献
10.
Existence of a dietary maximal level or threshold for incorporation of ω3 fatty acids into membrane phospholipids is of interest
as it may further define understanding of the dietary requirement for ω3 fatty acids. To test whether feeding increasing levels
of dietary ω3 fatty acids continues to increase membrane ω3 fatty acid content, weanling rats were fed a nutritionally adequate
semipurified diet which provided increasing amounts of C20 and C22 ω3 fatty acids, such as 20∶5ω3 and 22∶6ω3. Dietary 20∶5ω3 and 22∶6ω3 were provided by substituting a purified shark oil concentrate
of high 22∶6ω3 content for safflower oil high in 18∶2ω6. After four weeks of feeding, nuclear envelopes from four animals
in each diet group were prepared, lipid was extracted and phospholipids separated. Arachidonic acid content in membrane phosphatidylcholine,
phosphatidylethanolamine, phosphatidylinositol and phosphatidylserine was significantly reduced by feeding increased dietary
levels of ω3 fatty acids. Decline of 20∶4ω6 level in phospholipid tended to stabilize when the dietary content of total ω3
fatty acids reached 4–5% of total fatty acids. Above this level, dietary ω3 fatty acids did not result in a further decrease
in membrane content of 20∶4nω6. Increase in membrane phospholipid content of 20∶5ω3 occurred as the dietary intake of ω3 fatty
acids increased from 1.1% to 5% of total fatty acids. A dietary ω3 fatty acid level of 2.2–3% was sufficient to result in
maximum incorporation of 22∶6ω3 into membrane phosphatidylcholine and phosphatidylethanolamine, but not into phosphatidylinositol
or phosphatidylserine. 相似文献
11.
Cynomolgus monkeys were fed oils high in linoleic acid or with half of the linoleic acid replaced by either (n−3) linolenic
acid or marine fatty acids. When the diet contained similar quantities of linoleic and (n−3) linolenic acid, erythrocyte fatty
acids maintained a ratio of (n−6) to (n−3) fatty acids of approximately 2∶4. Fatty acids from menhaden oil enhanced the incorporation
of eicosapentaenoic and docosahexaenoic acids into the monkey erythrocytes, the composition of which was not altered by additional
α-tocopherol. 相似文献
12.
Donald L. Smith Anthony L. Willis Ngoc Nguyen Debra Conner Shaye Zahedi Judy Fulks 《Lipids》1989,24(1):70-75
Studies in man and laboratory animals suggest that ω3 polyunsaturated fatty acid consituents of fish oils have antiatherosclerotic
properties. We have studied the effects of several such polyunsaturated fatty acids for ability to modify the in vitro release
of mitogens from human platelets. Such mitogens may produce the fibroproliferative component of atherosclerotic plaques. Both
5,8,11,14,17-eicosapentaenoic acid (20∶5ω3) and 4,7,10,13,-16,19-docosahexaenoic acid (22∶6ω3), major constituents of fish
oils, inhibited adenosine diphosphate-induced aggregation of platelets and the accompanying release of mitogens. These effects
are dose dependent. Linolenic acid (18∶3ω3), the biosynthetic precursor of eicosapentaenoic acid, also inhibited platelet
aggregation and mitogen release. Eicosapentaenoic acid also inhibited mitogen release from human monocyte-derived macrophages,
which, in vivo, are an additional source of mitogens during atherogenesis.
Potent inhibition of human platelet aggregation and mitogen release was also seen with dihomo-γ-linolenic acid (8,11,14-eicosatrienoic
acid 20∶3ω6), whose levels are reportedly elevated in Eskimos subsisting on marine diets.
We conclude that diets that elevate plasma and/or tissue levels of eicosapentaenoic acid, docosahexaenoic acid and dihomo-γ-linolenic
acid precursor γ-linolenic acid (18∶3ω6) may exert antiatherosclerotic effects by inhibiting the release of mitogens from
platelets and other cells. 相似文献
13.
Nine healthy male volunteers were given 15 Max EPA fish oil capsules providing 2.67 g of eicosapentaenoic acid (EPA, 20∶5ω3)
and 1.72 g of docosahexaenoic acid (DHA, 22∶6ω3) daily for 3 wk. Measurements were taken at baseline, at the end of the fish-oil
period, and at 2 and 6 wk postsupplementation. The effect of fish oil on plasma lipids and the fatty acid composition of individual
platelet phospholipids was studied. In general, the proportions of 20∶5ω3 and 22∶6ω3 in platelet phosphoglycerides were substantially
increased mainly at the expense of arachidonic acid (AA, 20∶4ω6). A large and significant increase in the relative EPA content
of phosphatidylcholine (PC) (P<0.001) and phosphatidylethanolamine (PE) (P<0.001) was noted at the end of the 3 wk supplementation.
We have also shown for the first time a small but significant (P<0.001) incorporation of EPA in phosphatidylserine (PS). Incorporation
of DHA was also detected in PC, PE and PS, whereas the relative AA content of these phospholipids was significantly reduced.
Fish oil supplementation led to a significant increase of 22∶5ω3 in PS and decreases of 20∶3ω6 in PC and 22∶4ω6 in PE. Postsupplementation
measurements showed a gradual return of all fatty acids to baseline levels. The fatty acid composition of the phosphatidylinositol
(PI) fraction remained unchanged throughout the trial period. We conclude that in humans ω3 fatty acids are incorporated into
platelet membrane phospholipid subclasses with a high degree of specificity. 相似文献
14.
Pre-term infants, that are not breast-fed, are deprived of vital intrauterine fat accretion during late pregnancy and must
rely on formula to obtain fatty acids essential for normal development, particularly of the visual system. Preterm infants
(30 wk postconception) receiving human milk were compared to infants given one of the following formulae: Formula A was a
commercial preterm formula with predominantly 18∶2ω6 (24.2%) and low (0.5%) 18∶3ω3; Formula B was based on soy oil and contained
similar 18∶2ω6 levels (20%) and high 18∶3ω3 (2.7%); Formula C was also a soy oil-based formula (20% 18∶2, 1.4% 18∶3) but was
supplemented with marine oil to provide ω3 long-chain polyunsaturated fatty acids (LCP) at a level (docosahexaenoic acid,
DHA, 0.35%) equivalent to human milk. At entry (10 days of age), the fatty acid composition of plasma and red blood cell (RBC)
membrane lipids of the formula groups were identical. By 36 wk postconception, the DHA content in lipids of group A was significantly
reduced compared to that in the human milk and marine oil formula groups. Omega-3 LCP results were further amplified by 57
wk with compensatory increases in 22∶5ω6 in both plasma and RBC lipids. Provision of 2.7% α-linolenic acid in formula group
B was sufficient to maintain 22∶6ω3 levels equivalent to those in human milk-fed infants at 36 wk but not at 57 wk. Effects
on the production of thiobarbituric acid reactive substances and fragility of RBC attributable to the marine oil supplementation
were negligible. The results support the essentiality of ω3 fatty acids for preterm infants to obtain fatty acid profiles
comparable to infants receiving human milk. Formula for preterm infants should be supplemented with ω3 fatty acids including
LCP.
Based on a paper presented at the Symposium on Milk Lipids held at the AOCS Annual Meeting, Baltimore, MD, April 1990. 相似文献
15.
J. T. Venkatraman D. Pehowich B. Singh R. V. Rajotte A. B. R. Thomson M. T. Clandinin 《Lipids》1991,26(6):441-444
Experimental diabetes may manifest itself in a defect in liver microsomal fatty acid desaturation and increased activity of
glucose-6-phosphatase (G-6-Pase). The present study was designed to determine whether these changes could be normalized by
a change in the dietary fat consumed. Control and streptozotocin-induced diabetic rats were fed nutritionally adequate diets
which varied in fatty acid composition. Fatty acid analysis of liver microsomal phospholipids revealed that non-diabetic control
animals fed saturated fat (beef tallow) or a diet high in ω3 fatty acids (fish oil) exhibited a significantly higher level
of 18∶2ω6 and a lower level of 20∶4ω6 in the phosphatidylcholine and phosphatidylethanolamine fractions compared with diabetic
animals. Control and diabetic animals fed the high linoleic acid diet had similar levels of 18∶2ω6 in the microsomal phosphatidylcholine
and phosphatidylserine fractions. Microsomal G-6-Pase activity was higher in diabetic than in control animals. Activity of
G-6-Pase was lower in microsomes of control animals fed the soybean oil or the fish oil diet, but was not significantly reduced
in diabetic animals fed high polyunsaturated fats. Blood glucose levels were similar in control groups fed the different diets,
but the plasma hemoglobin A1c level was lower in diabetic animals fed the soybean oil diet. Cholesterol and triglyceride levels
were lower in diabetic animals fed the fish oil-based diet. The results suggest that dietary fat manipulation has the potential
to change at least some of the abnormalities in the microsomal membrane in experimental diabetes. 相似文献
16.
This study was designed to examine the effects of dietary n−3 and n−6 polyunsaturated fatty acids (PUFA) on postprandial lipid
levels and fatty acid composition of hepatic membranes. Male Sprague-Dawley rats were trained for a 3−h feeding protocol and
fed one of five semipurified diets: one fat-free diet or one of four diets supplemented with 10% (by weight) each of corn
oil, beef tallow, perilla oil, and fish oil. Two separate experiments were performed, 4-wk long-term and 4-d short-term feeding
models, to compare the effects of feeding periods. Postprandial plasma lipid was affected by dietary fats. Triacylglycerol
(TG) and total cholesterol levels were decreased in rats fed perilla oil and fish oil diets compared with corn oil and beef
tallow diets. Hepatic TG and total cholesterol levels were also reduced by fish oil and perilla oil diets. Fatty acid composition
of hepatic microsomal fraction reflected dietary fatty acids and their metabolic conversion. The major fatty acids of rats
fed the beef tallow diet were palmitic, stearic, and oleic. Similarly, linoleic acid (LA) and arachidonic acid in the corn
oil group, α-linolenic acid (ALA) and eicosapentaenoic acid (EPA) in the perilla oil group, and palmitic acid and docosahexaenoic
acid (DHA) in the fish oil group were detected in high proportions. Both long- and short-term feeding experiments showed similar
results. In addition, microsomal DHA content was negatively correlated with plasma lipid levels. Hepatic lipid levels were
also negatively correlated with EPA and DHA contents. These results suggest that n−3 ALA has more of a hypolipidemic effect
than n−6 LA and that the hypolipidemic effect of n−3 PUFA may be partly related to the increase of EPA and DHA in hepatic
membrane. 相似文献
17.
Changes in dietary lipid intake are known to alter the fatty acid composition of cardiac muscle of various animals. Because
changes in cardiac muscle membrane structure and function may be involved in the pathogenesis of arrythmia and ischemia, we
have examined the effects of dietary lipid supplements on the phospholipid distribution and fatty acid composition of rat
atria and ventricle following 20 weeks feeding of diets supplemented with either 12% sunflower-seed oil or sheep fat.
Neither lipid supplement produced significant changes in the proportions of cholesterol, total phospholipids or phosphatidylcholine,
phosphatidylethanolamine or diphosphatidylglycerol,—the phospholipid classes that together account for more than 90% of the
total phospholipids of rat cardiac muscle. Significant changes were found in the profiles of the unsaturated fatty acids of
all 3 phospholipid components of both atria and ventricle. Although similar, the changes between these tissues were not identical.
However, in general, feeding a linoleic acid-rich sunflower seed oil supplement resulted in an increase in the ω-6 family
of fatty acids, whereas feeding the relatively linoleic acid-poor sheep fat supplement decreased the level of ω-6 fatty acids
but increased the levels of the ω-3 family, resulting in major shifts in the proportions of these families of acids. In particular,
the ratio of arachidonic acid: docosahexaenoic acid (20∶4, ω-6/22∶6, ω-3), which is higher in all phospholipids of atria than
ventricle, is increased by feeding linoleic acid, primarily by increasing the level of arachidonic acid in the muscle membranes.
As dosahexaenoic acid does not occur in the diet, the increase in this acid which occurs after feeding animal fat, presumably
arises from increased conversion of the small amounts of linolenic acid in all diets when the amount of linoleic acid present
is reduced. 相似文献
18.
Guinea pigs were fed one of three diets containing 10% black currant seed oil (a source of gamma-linolenic (18∶3 n−6) and
stearidonic (18∶4 n−3) acids), walnut oil or lard for 40 days. The fatty acid composition of liver triglycerides, free fatty
acids, cholesteryl esters, phosphatidylinositol, phosphatidylserine, cardiolipin, phosphatidylcholine and phosphatidylethanolamine
were determined.
Dietary n−3 fatty acids found esterified in liver lipids had been desaturated and elongated to longer chain analogues, notably
docosapentaenoic acid (22∶5 n−3) and docosahexaenoic acid (22∶6 n−3). When the diet contained low amounts of n−6 fatty acids,
proportionately more of the n−3 fatty acids were transformed. Significantly more eicosapentaenoic acid (EPA) (20∶5 n−3) was
incorporated into triglycerides, cholesteryl esters, phosphatidylcholine and phosphatidylethanolamine of the black currant
seed oil group compared with the walnut oil group.
Feeding black currant seed oil resulted in significant increases of dihomogamma-linolenic acid (20∶3 n−6) in all liver lipid
classes examined, whereas the levels of arachidonic acid (20∶4 n−6) remained relatively stable. The ratio dihomo-gamma-linolenic
acid/arachidonic acid was significantly (2.5-fold in PI to 17-fold in cholesteryl esters) higher in all lipid classes from
the black currant seed oil fed group. 相似文献
19.
Chicks were fed isocaloric and isonitrogenous diets containing 6% (w/w) added fat consisting of various proportions of animal
tallow and flaxseed oil (FSO). No differences among treatments were seen in growth rate, muscular deposition of protein and
lipids nor in the muscle phospholipid (PL) and triglyceride (TG) contents. Prostaglandin (PG)E2 synthesis in isolated skeletal muscle was depressed significantly by feeding FSO or by treatment with naproxen (6-methoxy-α-methyl-2-napthaleneacetic
acid), an inhibitor of PG synthesis. The changes associated with diet may be related to differences in the fatty acid composition
of muscle lipids. Levels of saturated fatty acids in muscle PL and TG were relatively insensitive to dietary treatments. Monounsaturated
fatty acid levels were significantly lower in the FSO-fed groups. FSO diets caused significant depression in muscle PL 20∶4ω6
and almost completely inhibited 22∶5ω6 incorporation. FSO diets decreased ratios of ω6/ω3 fatty acids and increased the unsaturation
index of muscle PL. Muscles of chicks fed FSO showed increased levels of 18∶3ω3, and of its derivatives 20∶4ω3 and 22∶5ω3.
These results suggest that FSO inhibits PG synthesis and modifies the fatty acids of PL and TG of chick muscle. These changes
may have implications for PG-dependent and/or membrane-dependent processes in muscle metabolism. 相似文献
20.
Effects of parenteral nutrition with high doses of linoleate on the developing human liver and brain
The developmental changes in the fatty acid composition of ethanolamine phosphoglycerides (EPG) and choline phosphoglycerides
(CPG) were studied in the liver and brain of 18 newborn infants with gestational ages ranging from 20 to 44 wk. A small group
of five newborns receiving total parenteral nutrition (TPN) with high doses of linoleic acid (18∶2ω6) was also studied and
compared to controls of the same gestational age to look for effects on the developmental fatty acid patterns of liver and
brain EPG and CPG. TPN with Intralipid 20% was given for 4–12 days, the total fat intake being 14.7–90 g (mean ±S.D.=47.1±29.8
g). The main developmental changes in the liver and brain of the control group were an increase in 22∶6ω3 (docosahexaenoic
acid) at the end of gestation and a linear decrease in 20∶4ω6 (arachidonic acid) and 18∶1ω9 (oleic acid) in EPG and CPG. A
very good correlation in the percent values of these fatty acids in the brain and liver tissues was obtained. Very significant
changes in the fatty acid composition of liver EPG and CPG could be found in the infants receiving TPN with Intralipidmainly
an increase in 18∶2ω6, a decrease in the linoleate elongation/desaturation to longer members of the series and a decrease
in the 22∶6ω3 levels of liver EPG and CPG. In the brain, only an increase in the 18∶2ω6 value of CPG, not accompanied by any
increase in the longer ω6 fatty acids, could be detected. Possible adverse effects of high doses of 18∶2ω6 on the tissue levels
of long chain polyunsaturated fatty acids (PUFA), especially of 22∶6ω3, are discussed. 相似文献