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1.
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
2.
During the 6 months of vitellogenesis, 3-year-old female trout (Salmo gairdneri) were fed either an enriched (E) or an (n−3) polyunsaturated fatty acid (PUFA)-deficient (D) diet; serum vitellogenin (VG)
and lipoproteins (d<1.21 g/ml) were analyzed at the third month of vitellogenesis (September) and at ovulation (December).
The serum content of high density lipoproteins (HDL), the major protein class, maintained a mean value of 1500 mg/dl at both
stages and with both diets. On the contrary, very low density lipoproteins (VLDL) were 90% higher during vitellogenesis than
at spawning time, whereas excess vitellogenin circulated at this period (6580 mg/dl serum with diet E). The diet deficient
in (n−3) lowered serum vitellogenin content by 16% in September and by 26% in December. The degree of (n−3) PUFA incorporation
moderately decreased in low density lipoproteins (LDL) and in HDL with the (n−3)-deficient diet. The effect was more pronounced
for 20∶5. On the other hand, essential 22∶6 was incorporated into vitellogenin at the same rate in September as in December
with diet E (23% and 25%, respectively), whereas after a 3-month deficiency, the percentage fell to 12%; this percentage rose
again to 19% at spawning time. These findings show that, although stored (n−3) PUFA were not exhausted after a 6-month dietary
deficiency, the incorporation of essential fatty acids (EFA) into vitellogenin during the early stages of oogenesis was low,
suggesting changes in egg composition that may influence hatching. 相似文献
3.
Cholesteryl ester hydrolase was assayed in adrenal homogenates from mature female rats fed a control (corn oil-containing)
or essential fatty acid (EFA)-deficient diet. Cholesteryl ester of 16∶0, 18∶0, 18∶1, 18∶2(n−6), 20∶4(n−6) and 22∶4(n−6) were
used as substrates. In control rats, the unsaturated esters were hydrolyzed more rapidly than the saturated esters and cholesteryl
arachidonate was the preferred substrate of the six investigated; cholesteryl oleate elicited the highest activity in the
deficient group. Polyunsaturated esters were hydrolyzed at a significantly lower rate by homogenates from EFA-deficient rats
than by those from control animals. The esters of 18∶1, 18∶2(n−6) and 20∶4(n−6) were hydrolyzed more extenstively in relation
to their concentrations in adrenal tissue than were cholesteryl esters of 16∶0, 18∶0 and 22∶4(n−6). This difference was more
pronounced in control than in EFA-deficient rats. No simple relationship of adrenal cholesteryl ester hydrolase activity to
ester fatty acid structure or to nutritional essentiality was evident. 相似文献
4.
The effect of essential fatty acid (EFA) deficiency on the lipid composition of basolateral plasma membranes (BPM) from intestinal
mucosal cells was investigated in weaning pigs fed control or EFA-deficient diets for 12 weeks. The phospholipid and cholesterol
contents relative to protein were similar in both groups, showing a cholesterol/phospholipid molar ratio of 0.6. The distribution
of phospholipid classes was also unaffected by the diet. In contrast, fatty acid profiles of the two phospholipid main classes,
phosphatidylcholine and phosphatidylethanolamine were altered by EFA deficiency. Linoleic acid (18∶2n−6) was largely reduced,
whereas arachidonic acid (20∶4n−6) only slightly decreased in EFA-deficient pigs. The unsaturation index was essentially maintained
by high levels of oleic acid (18∶1n−9) and by conversion of oleic acid to 5,8,11-eicosatrienoic acid (20∶3n−9). Finally, during
the period of EFA deficiency, the lipid composition of BPM of the intestinal mucosal cells was little affected, suggesting
a preferential uptake of 20∶4n−6 and (or) precursor mobilized from other tissues. However, an effect of dietary treatment
on the function of membrane-associated proteins cannot be ruled out. 相似文献
5.
Ghafoorunissa 《Lipids》1990,25(11):763-766
Cereals and pulses alone provide nearly two-thirds of the daily linoleic acid requirement in habitual Indian diets. Two-thirds
of the lipids present in cereals is in bound form. To investigate to what extent the essential fatty acids (EFA) present in
cereals and pulses are biologically available, weanling rats were fed rice-pulse based diets either without supplementation
or supplemented with one of three vegetable oils—coconut, palmolein or groundnut oil. Plasma phospholipid fatty acid composition
was used to assess the EFA status, with ratios of eicosatrienoic/arachidonic acids (20∶3n−9/20∶4n−6) above 0.2, indicating
linoleic acid deficiency. In the unsupplemented group, the levels of linoleic and arachidonic acids were low as compared to
the groundnut oil fed group. However, the ratio of 20∶3n−9/20∶4n−6 was less than 0.2, indicating that there was no linoleic
acid deficiency. This shows that the linoleic acid present in rice and pulse may be readily available. 相似文献
6.
An essential fatty acid (EFA) deficiency-like profile of fatty acids has been observed in HF-1 human skin fibro-blasts cultured
at clonal densities in MCDB 110 and 0.4% fetal bovine serum (FBS). The profile was characterized by an accumulation of 16∶1n−7,
18∶1n−9, 20∶3n−9 and 22∶3n−9, a reduction of n−6 fatty acids and a reduction in total polyunsaturated fatty acids (PUFA).
The fatty acid composition of sphingomyelin (SPH), phosphatidylcholine (PC), phosphatidylserine (PS), phosphatidylinositol
(PI) and phosphatidylethanolamine (PE) was determined and, except for SPH, each displayed an EFA deficiency-like profile.
The triene to tetraene ratio (20∶3n−9/20∶4n−6) ranged from 5.3 in PI to 0.9 in PE. In addition, the highest percentage of
20∶3n−9 was present in the PI and the highest percentage of 22∶3n−9, in PE. Other human fibroblasts (normal, transformed and
at different population doubling number levels [PDL] were grown under the same conditions and were found to display triene
to tetraene ratios (20∶3n−9/20∶4n−6) in total cellular lipids ranging from 0.7 to 4.5. The accumulation of 20∶3n−9 and 22∶3n−9
is due primarily to the existence of a basal nutrient medium (MCDB 110) that allows for the rapid clonal growth of human fibroblasts
at reduced serum levels (0.4%). This culture procedure can be exploited to further elucidate various aspects of lipid metabolism
in human fibroblasts.
Fatty acids are abbreviated as number of carbon atoms: number of double bonds, followed by an n-number to designate the position
of the first double bond with respect to the methyl carbon. Thus, Mead acid is 20∶3n−9 and its elongation product is 22∶3n−9. 相似文献
7.
Effects of dietary vegetable oil on atlantic salmon hepatocyte fatty acid desaturation and liver fatty acid compositions 总被引:5,自引:0,他引:5
Fatty acyl desaturase activities, involved in the conversion of the C18 EFA 18∶2n−6 and 18∶3n−3 to the highly unsaturated fatty acids (HUFA) 20∶4n−6, 20∶5n−3, and 22∶6n−3, are known to be under
nutritional regulation. Specifically, the activity of the desaturation/elongation pathway is depressed when animals, including
fish, are fed fish oils rich in n−3 HUFA compared to animals fed, vegetable oils rich in C18 FFA. The primary aims of the present study were (i) to establish the relative importance of product inhibition (n−3 HUFA)
vs. increased substrate concentration (C18 EFA) and (ii) to determine whether 18∶2n−6 and 18∶3n−3 differ in their effects on the hepatic fatty acyl desaturation/elongation
pathway in Atlantic salmon (Salmo salar). Smolts were fed 10 experimental diets containing blends of two vegetable oils, linseed (IO), and rapeseed oil (RO), and
fish oil (FO) in a triangular mixture design for 50 wk. Fish were sampled after 32 and 50 wk, lipid and FA composition of
liver determined, fatty acyl desaturation/elongation activity estimated in hepatocytes using [1-14C]18∶3n−3 as substrate, and the data subjected to regression analyses. Dietary 18∶2n−6 was positively correlated, and n−3
HUFA negatively correlated, with lipid content of liver. Dietary 20∶5n−3 and 22∶6n−3 were positively correlated with liver
FA with a slope greater than unity suggesting relative retention and deposition of these HUFA. In contrast, dietary 18∶2n−6
and 18∶3n−3 were positively correlated with liver FA with a slope of less than unity suggesting metabolism via β-oxidation and/or desaturation/elongation. Consistent with this, fatty acyl desaturation/elongation in hepatocytes was significantly
increased by feeding diets containing vegetable oils. Dietary 20∶5n−3 and 22∶6n−3 levels were negatively correlated with hepatocyte
fatty acyl desaturation. At 32 wk, 18∶2n−6 but not 18∶3n−3 was positively correlated with hepatocyte fatty acyl desaturation,
wheres the reverse was true at 50 wk. The data indicate that both feedback inhibition through increased n−3 HUFA and decreased
C18 fatty acyl substrate concentration are probably important in determining the level of hepatocyte fatty acyl desaturation
and that 18∶2n−6 and 18∶3n−3 may differ in their effects on this pathway. 相似文献
8.
Klaus Eder 《Lipids》1999,34(7):717-725
This study was carried out to investigate the effects of a dietary oxidized oil on lipid metabolism in rats, particularly
the desaturation of fatty acids. Two groups of rats were fed initially for a period of 35 d diets containing 10% of either
fresh oil or thermally treated oil (150°C, 6d). The dietary fats used were markedly different for lipid peroxidation products
(peroxide value: 94.5 vs. 3.1 meq O2/kg; thiobarbituric acid-reactive substances: 230 vs. 7 μmol/kg) but were equalized for their fatty acid composition by using
different mixtures of lard and safflower oil and for tocopherol concentrations by individual supplementation with dl-α-tocopherol acetate. In the second period which lasted 16 d, the same diets were supplemented with 10% linseed oil to study
the effect of the oxidized oil on the desaturation of α-linolenic acid. During the whole period, all the rats were fed identical
quantities of diet by a restrictive feeding system in order to avoid a reduced food intake in the rats fed the oxidized oil.
Body weight gains and food conversion rates were only slightly lower in the rats fed the oxidized oil compared to the rats
fed the fresh oil. Hence, the effects of lipid peroxidation products could be studied without a distortion by a marked reduced
food intake and growth. To assess the rate of fatty acid desaturation, the fatty acid composition of liver and heart total
lipids and phospholipids was determined and ratios between product and precursor of individual desaturation reactions were
calculated. Rats fed the oxidized oil had reduced ratios of 20∶4n−6/18∶2n−6, 20∶5n−3/18∶3n−3, 20∶4n−6/20∶3n−6, and 22∶6n−3/22∶5n−3
in liver phospholipids and reduced ratios of 20∶4n−6/18∶2n−6, 22∶5n−3/18∶3n−3, and 22∶6n−3/18∶3n−3 in heart phospholipids.
Those results suggest a reduced rate of desaturation of linoleic acid and α-linolenic acid by microsomal Δ4-, Δ5-, and Δ6-desaturases.
Furthermore, liver total lipids of rats fed the oxidized oil exhibited a reduced ratio between total monounsaturated fatty
acids and total saturated fatty acids, suggesting a reduced Δ9-desaturation. Besides those effects, the study observed a slightly
increased liver weight, markedly reduced tocopherol concentrations in liver and plasma, reduced lipid concentrations in plasma,
and an increased ratio between phospholipids and cholesterol in the liver. Thus, the study demonstrates that feeding an oxidized
oil causes several alterations of lipid and fatty acid metabolism which might be of great physiologic relevance. 相似文献
9.
Duplicate groups of Atlantic salmon (Salmo salar) post smolts were given diets in which the lipid component was either fish oil or a mixture of corn oil and lard. This difference
in the dietary lipid did not significantly affect growth over a period of sixteen weeks.
Proportions of docosahexaenoic acid [22∶6(n−3)] and total (n−3) fatty acids in the polar lipids of liver and white muscle
were unaffected by this difference in dietary lipid component over the time period used. Fish given the diet containing corn
oil and lard had significantly higher levels of 20∶2(n−6), 20∶3(n−6) and 20∶4(n−6) in the polar lipids of these tissues than
were present in the tissues of the fish given diets containing fish oil. There results suggest that linoleic acid [18∶2(n−6)]
undergoes elongation and desaturation to arachidonic acid [20∶4(n−6)] in post-smolt Atlantic salmon. 相似文献
10.
Analyses of lipids and fatty acids in ripe roes of some Northwest European marine fish 总被引:7,自引:0,他引:7
Lipid class analyses and fatty acid analyses of neutral and polar lipids were carried out on ripe roes of herring, cod, haddock,
whiting, saithe, sand eel and capelin. Total lipid was 10–26% of roe dry weight. The species with the highest total lipid,
sand eel and capelin, also had the highest percentage of neutral lipid in total lipid, 77% and 49% respectively. In the other
species, phospholipids accounted for 62–77% of roe total lipid. Both the neutral lipids, and especially the phospholipids,
of all species were very unsaturated because of high concentrations of (n−3) polyunsaturated fatty acids (PUFA), frequently
amounting to 50% of the total egg lipid. Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) had similar fatty acid
compositions in all species, with an average ratio (n−3)/(n−6) of ca. 20∶1. Phosphatidylinositol (PI) consistently had high
concentrations of 18∶0 and 20∶4 (n−6) with an average ratio of (n−3)/(n−6) of 1.8∶1. Requirements for high levels of (n−3)
PUFA in the embryonic and early larval development stages of marine fish are suggested as is a special role for the 20∶4(n−6)
in PI. 相似文献
11.
Yung-Sheng Huang Dave E. Mills Ron P. Ward David F. Horrobin Valerie A. Simmons 《Lipids》1989,24(7):565-571
Weanling male spontaneously hypertensive (SHR) and normotensive (WKY) rats were maintained on a fat-free semisynthetic diet
and killed at various intervals. The effects of fat-depletion on the appearance of essential fatty acid (EFA) deficiency symptoms,
the progressive changes of major fatty acids in plasma, liver, heart, and kidney phospholipids (PL), and in skin total lipids
were compared between these two strains. After five weeks on the diet, the slower growth and the appearance of EFA deficiency
symptoms became evident in SHR. In general, fat-depletion reduced the levels of n−6 fatty acids, whereas it increased those
of 20∶3n−9. However, the fat-depletion induced reduction of 18∶2n−6 in heart PL and 20∶4n−6 in kidney, while the elevation
of 20∶3n−9 in plasma, heart, and kidney PL were greater in WKY than in SHR. As a result, the elevation of biochemical EFA
deficiency index—20∶3n−9/20∶4n−6 ratio—was greater in WKY than in SHR. In comparison with WKY, the concentrations of liver
triacylglycerols and the weights of adipose tissues in SHR were reduced to a greater extent, indicating an active catabolism
of triacylglycerols in SHR. This study suggests that the earlier appearance of morphological symptoms of EFA deficiency in
SHR was not associated with the reducing n−6 EFA levels or with an elevation of triene/tetraene ratio, but possibly to a reduced
supply of n−6 EFA for skin prostaglandin synthesis. 相似文献
12.
Differences in fatty acid composition of immature and mature articular cartilage in humans and sheep
Katherine A. Cleland Michael J. James Mark A. Neumann Robert A. Gibson Leslie G. Cleland 《Lipids》1995,30(10):949-953
Chondrocytes are imbedded in an avascular, highly charged extracellular matrix which could form a barrier to the transfer
of dietary essential fatty acids (EFA) to chondrocytes. A study was designed to assess the composition of immature and mature
joint cartilage with respect to essential and nonessential fatty acids relevant to EFA deficiency. Cartilage and muscle samples
were obtained from human fetus, infant and adult cadavers, and from fetal and mature sheep. Lipid extracts were prepared and
the fatty acid composition determined. In human and sheep joint cartilage, linoleic acid (LA; 18∶2n−6) content was lower,
and n−9 eicosatrienoic acid (ETrA; 20∶3n−9) and arachidonic acid (AA; 20∶4n−6) were higher in fetuses compared to mature subjects.
An intermediate pattern was seen in infant cartilage. n−3 Fatty acids tended to be higher in fetal than in mature cartilage
in humans and in sheep. In human muscle (and in other noncartilaginous comparison tissues), similar differences between fetuses
and adults were seen in LA and AA, but not in ETrA. In fetal sheep muscle, very low LA, reduced AA and raised ETrA levels
compared to mature sheep muscle were seen. However, although the pattern is characteristic of EFA deficiency, the abundance
of n−6 EFA in liver and spleen of human fetuses and of n−3 EFA in liver and spleen of fetal sheep suggests that placental
transfer of EFA is not likely to be limiting. During fetal development, the metabolism of fatty acids is distinctive and differs
between the species. ETrA appears to be a readily measurable component of some tissues at certain stages of development when
its presence in tissues does not indicate EFA deficiency. 相似文献
13.
Essential fatty acid (EFA)-deficient rats were fed highly purified methyl esters of docosahexaenoate (22∶6n−3), arachidonate
(20∶4n−6), alpha-linolenate (18∶3n−3) or oleate (18∶1n−9) (100 mg/day, tube fed for 3–10 days), and their plasma triacylglycerol
(TG) secretion rates were measured. Secretion rates of TG into plasma were reduced by tube-feeding 22∶6n−3, 20∶4n−6, 18∶3n−3,
but not 18∶1n−9, to EFA-deficient rats. A significant reduction occurred after feeding 22∶6n−3 for only three days. Feeding
22∶6n−3 or 18∶3n−3 to EFA-deficient rats for three days also reduced the activities of liver lipogenic enzymes and sharply
increased the proportions of 22∶6n−3 and 20∶5n−3 in liver phospholipid fractions. Mechanisms by which these EFA may reduce
lipogenesis are discussed. 相似文献
14.
The effects of dietary n−3 and n−6 polyunsaturated fatty acids on the fatty acid composition of phospholipid, Ca++· Mg++ ATPase and Ca++ transport activities of mouse sarcoplasmic reticulum were investigated. Mice were fed a 2 weight percent fat diet containing
either 0.5 weight percent ethyl esters of 18∶3n−3, 20∶5n−3 or 22∶6n−3 as a source of n−3 polyusaturated fatty acid or 0.5
weight percent safflower oil as a cource of n−6 polyunsaturated fatty acid for 10 days. Olive oil (2 weight percent) was used
as a control diet. Although feeding n−6 polyunsaturated fatty acid induced very little modifications of the phospholipid sarcoplasmic
reticulum fatty acid composition, feeding n−3 polyunsaturated fatty acid altered it markedly. Inclusion of 18∶−3, 20∶5n−3
or 22∶6n−3 in the diet caused an accumulation of 22∶6n−3, which replaced 20∶4n−6 and 18∶2n−6 in phospholipid sarcoplasmic
reticulum. The saturated fatty acids were significantly increased with a concurrent reduction of 18∶1n−9. These changes in
the fatty acid composition resulted in a decrease in the values of the n−6/n−3 polyunsaturated fatty acid ratio and a decrease
in the ratio of 20 carbon to 22 carbon fatty acids esterified in the phospholipid sarcoplasmic reticulum. This was associated
with a decrease in Ca++ uptake by n−3 polyunsaturated fatty acid enriched sarcoplasmic reticulum vesicles as compared with n−6 fatty acid and control
diet sarcoplasmic reticulum vesicles. However, neither the affinity for Ca++ nor the maximal velocity of ATP hydrolysis activity of Ca++·MG++ ATPase were altered by the different diets. The data suggest that the incorporation of 22∶6n−3 and/or the decrease of 20∶4n−6
plus 18∶2n−6 in the phospholipid sarcoplasmic reticulum may affect the membrane lipid bilayer structure and make it more permeable
to Ca++. 相似文献
15.
The emperor penguin (Aptenodytes forsteri) is an Antarctic seabird feeding mainly on fish and therefore has a high dietary intake of n-3 polyunsaturated fatty acids.
The yolk is accumulated in the developing oocyte while the females are fasting, and a large proportion of the fatty acid components
of the yolk lipids are derived by mobilization from the female's adipose tissue. The fatty acid composition of the total lipid
of the yolk was characterized by high levels of n-3 polyunsaturated fatty acids. However, it differed in several respects
from that of the maternal adipose tissue. For example, the proportions of 14∶0, 16∶1n−7, 20∶1n−9, 22∶1n−9, 20∶5n−3, and 22∶6n−3
were significantly greater in adipose tissue than in yolk. Thus adipose tissue lipids contained 7.6±0.3% and 8.0±0.3% (wt%
of total fatty acids; mean ±SE; n=5) of 20∶5n−3 and 22∶6n−3, respectively, whereas the yolk total lipid contained 1.6±0.1 and 5.5±0.3% of these respective
fatty acids. The proportions of 16∶0, 18∶0, 18∶1n−9, 18∶2n−6, and 20∶4n−6 were significantly lower in the adipose tissue than
in the yolk lipids. The proportions of triacylglycerol, phospholipid, free cholesterol, and cholesteryl ester in the yolk
lipid were, respectively, 67.0±0.2, 25.4±0.3, 5.3±0.2, and 1.8±0.2% (wt% of total yolk lipid). The proportions of 20∶4n−6,
20∶5n−3, 22∶5n−3, and 22∶6n−3 were, respectively, 5.7±0.3, 2.8±0.2, 1.4±0.1, and 11.7±0.5% in phospholipid and 0.4±0.0, 1.2±0.1,
0.8±0.1 and 3.6±0.3% in triacylglycerol. About 95% of the total vitamin E in the yolks was in the form of α-tocopherol with
γ-tocopherol forming the remainder. Two species of carotenoids, one identified as lutein, were present. 相似文献
16.
On day seven of gestation, Wistar rats were assigned to a high essential fatty acid (EFA), low EFA, or a fat free diet. The
same diets were continued during lactation. On weaning, the offspring were fed the same diets as their mother. Rats were killed
at 222 days, brain capillary endothelia isolated, and total lipids extracted from the purified capillaries. The composition
of the constituent fatty acids of ethanolamine glycerophospholipid (EGP), choline glycerophospholipid (CGP), and the alk-1-eny
EGP composition from each diet is reported. A decrease in dietary EFA led to reduced proportions of total saturated acyl groups
in EGP with no change observed in the total saturated acyl groups from CGP, and an increase in monoenoic fatty acids, particularly
18∶1n−9 for each phospholipid class. The proportions of 20∶4n−6 in alk-1-enyl EGP were reduced in fat-free fed animals. In
addition, the relationship between 20∶3n−9 and 20∶4n−6 fatty acids in brain capillary endothelia were markedly increased with
a reduction in dietary fat. Low EFA and fat deficient animals showed a tendency to sequester 22∶6n−3. 相似文献
17.
Cod (mean start weight of 26 g) were fed three diets for 15 months, each based on a dry pellet coated at a level of 9g/100
g with soybean oil, capelin oil or sardine oil. The fatty acid compositions of neutral lipids and four glycerophospholipids
of white muscle, liver, gills and heart were determined. The fatty acid composition of dietary lipids influenced the composition
of neutral lipids in all organs. Linoleic acid (18∶2n−6) from soybean oil was selectively incorporated into phosphatidylcholine
of the four tissues. Similar levels of 20∶5n−3 and 22∶6n−3 in phosphatidylcholine and phosphatidylethanolamine were found
in all organs from cod fed capelin oil and sardine oil in spite of highly differentiated feed fatty acid levels. The polyunsaturated
fatty acid (PUFA) composition of phosphatidylinositol was least influenced by dietary lipids. The preferred monoenic fatty
acid in phospholipids of cod was 18∶1n−9, independent of dietary intake, whereas the longer chain monoenoic acids seemed to
be preferentially catabolized. The results suggest that 20∶4n−6 as well as 20∶5n−3 and 22∶6n−3 fatty acids are essential for
cod. 相似文献
18.
The sciatic nerve of rats fed sunflower oil (6 mg 18∶3n−3/100 g of diet) presented dramatic alterations in the long chain
polyunsaturated fatty acids in comparison with those fed soy oil (130 mg 18∶3n−3/100 g of diet). In both 15-day-old and 60-day-old
animals fed sunflower oil, 22∶6n−3 (cervonic acid) was fourfold less, 22∶5n−6 was 10-fold greater; adrenic acid (22∶4n−6)
was slightly greater and arachidonic acid (20∶4n−6) was close to that in rats fed soy oil. The percentage distribution of
total polyunsaturated fatty acids as well as the individual saturated and monounsaturated fatty acids were the same in both
groups.
When the sunflower oil-fed animals were switched to a soy oil-containing diet for either 15 or 60 days, the percentage distribution
of 22∶6n−3 increased slowly to reach the control value 2.5 months later. Conversely 22∶5n−6 decreased slowly. The decay of
22∶5n−6 was more rapid than the increase of 22∶6n−3. 相似文献
19.
The effects of dietary lipids on the fatty acid composition of hyaline cartilage, epiphyseal chondrocytes (EC) and matrix
vesicles (MV) were evaluated in chicks. A basal semipurified diet was fed to chicks containing one of the following lipid
sources at 70 g/kg: soybean oil, butter+corn oil, margarine+corn oil or menhaden oil+corn oil (MEC). Articular and epiphyseal
growth cartilage were isolated from the proximal tibiotarsus; EC and MV were subsequently released by trypsin (EC 3.4.21.4)
and collagenase (EC 3.4.24.3) digestion followed by ultracentrifugation. The fatty acid composition of polar lipids in chick
epiphyseal cartilage at three and six weeks, as well as articular cartilage, EC and MV at eight weeks of age revealed the
presence of high levels of saturated and monounsaturated fatty acids (up to 85.5%) but low levels of n−6 polyunsaturated fatty
acids (PUFA) (2.6–10.2%). Mead acid (20∶3n−9,>3%) was also present in cartilage, EC and MV lipids, and was unaffected by the
dietary lipid treatments. Total n−3 PUFA concentrations were the highest in cartilage, EC and MV of chicks consuming MEC.
Feeding MEC lowered the levels of 20∶4n−6 in cartilage, but increased 20∶5n−3 levels. The data are consistent with those reported
previously which showed that cartilage tissues are low in n−6 PUFA and that they contain 20∶3n−9. We furthermore demonstrated
that the PUFA composition of cartilage can be modified by dietary lipids. 相似文献
20.
We investigated the effect of oral supplementation with evening primrose oil, containing 72% linoleic acid (18∶2n−6) and 10%
γ-linolenic acid (18∶3n−6), on the epidermal and neutrophil phospholipid fatty acid composition in 15 patients with atopic
dermatitis (AD). Three different dose levels, 4, 8 and 12 capsules per day containing 0.5 g oil, were given to three groups
of patients. The only n−6 fatty acid showing a significant (p<0.05) dose-related increase was dihomo-γ-linolenic acid (20∶3n−6)
in neutrophil phospholipids. The highest dose increased dihomo-γ-linolenic acid by 45% in neutrophil phospholipids, by 46%
in lesion-free epidermal phosphatidylcholine, and by 15% in lesion-free epidermal phosphatidylethanolamine. In both lesional
and lesion-free epidermis, supplementation resulted in a rise in the ratio between n−6 and monounsaturated fatty acids, reaching
significance (p<0.05) in lesional epidermis. This study shows that moderate and favorable fatty acid changes can be obtained
in the epidermis of AD patients, when given 6 g per day of oil rich in n−6 fatty acids. The abnormal lipid and fatty acid
pattern of the atopic epidermis may be involved in the pathogenesis of the disease, and should therefore be the target for
future therapeutic approaches with fatty acid supplements. 相似文献