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1.
The purpose of this study was to examine the influence of long-term feeding of dietary fat rich in either n−3 or n−6 fatty
acids on the availability of arachidonic acid (20∶4n−6) in major phospholipids of gastric mucosa in rats. Three groups of
male Wistar rats were fed either a standard diet, a cod liver oil-enriched diet (10% by weight), or a corn oil-enriched diet
(10% by weight) for 8 mon. Dietary cod liver oil significantly reduced the level of 20∶4n−6 in phosphatidylcholine (PC) and
in phosphatidylethanolamine (PE) of gastric mucosa. The loss of 20∶4n−6 was compensated for by eicosapentaenoic acid (20∶5n−3)
in PC, whereas the decrease in 20∶4n−6 in PE corresponded to the increase in three n−3 fatty acids: 20∶5n−3, docosapentaenoic
acid (22∶5n−3), and docosahexaenoic acid (22∶6n−3). The level of 20∶5n−3 was higher than the level of 22∶6n−3 both in PC and
PE of mucosa in rats fed cod liver oil. Diets supplemented with corn oil increased the level of 18∶2n−6 but decreased the
monoene fatty acids 16∶1 and 18∶1n−7 in PC but not in PE of gastric mucosa. The 20∶4n−6 levels of both PC and PE were markedly
reduced by dietary cod liver oil, to about one-third of control levels. Similar changes were also observed in the stomach
wall. Gastric erosions were observed in all rats exposed to restriction stress, but this form of stress induced twice the
number of erosions in rats fed fish oil compared to control rats or rats fed corn oil. We conclude that a diet rich in fish
oil altered the balance between n−6 and n−3 fatty acids in major gastric mucosal phospholipids, markedly reduced the availability
of 20∶4n−6, and increased the incidence of gastric erosions induced by restriction or emotional stress. 相似文献
2.
A previous study has shown that the long and very long chain FA (VLCFA) content of the rat retina responds to changes in dietary
n−6/n−3 ratio of the fat fed (1). The present study tested whether similar changes in these FA are associated with alterations
in rhodopsin content and rhodopsin phosphorylation after light treatment. Weanling rats were fed diets containing 20% (w/w,
40% energy) fat with either high (4.8%, w/w) or low (1.2%, w/w) n−3 FA. After 6 wk of feeding, half of the animals in each
group were exposed to light for 48 h at 350 lx or were kept in complete darkness. In the rod outer segment, the high n−3 diet
treatment increased the level of 20∶5n−3 and 22∶6n−3 and reduced the levels of 20∶4n−6 and 24∶4n−6 in PC, PE, and PS. After
the feeding of a high n−3 FA diet, total n−3 pentaenoic VLCFA from C24 to C34 increased in PC, whereas the n−6 tetra- and pentaenoic VLCFA decreased. No changes occurred in n−3 hexaenoic VLCFA regardless
of the level of 22∶6n−3 in the diet. After light exposure, animals fed a high n−3 FA diet showed reduction in 22∶6n−3 as well
as in n−6 and n−3 VLCFA in PC. FFA and TG fractions contained increased levels of both 20∶4n−6 and 22∶6n−3 after light exposure.
Dark-adapted rhodopsin content and rhodopsin phosphorylation in the rod outer segment of rats fed the low n−3 FA diet were
higher than in animals fed a high n−3 FA diet. After light exposure, animals fed the low n−3 FA diet lost more rhodopsin compared
to animals fed the high n−3 FA diet, resulting in less phosphorylation of rhodopsin. Results indicate that the FA composition,
rhodopsin content, and phosphorylation in visual cells is influenced by the dietary n−3 FA fed as well as by light exposure.
The results also imply that 22∶6n−3 may not be the precursor for synthesis of hexaenoic VLCFA. 相似文献
3.
Male Fischer rats were fed the AIN76A diet containing varying n−6/n−3 FA ratios using sunflower oil (SFO), soybean oil (SOY),
and SFO supplemented with EPA-50 and GLA-80 (GLA) as fat sources. Hepatocyte nodules, induced using diethylnitrosamine followed
by 2-acetylaminofluorene/partial hepatoctomy promotion, were harvested, with surrounding and respective dietary control tissues,
3 mon after partial hepatectomy. The altered growth pattern of hepatocyte nodules in rats fed SFO is associated with a distinct
lipid pattern entailing an increased concentration of PE, resulting in increased levels of 20∶4n−6. In addition, there is
an accumulation of 18∶1n−9 and 18∶2n−6 and a decrease in the end products of the n−3 metabolic pathway in PC, suggesting a
dysfunctional Δ-6-desaturase enzyme. The hepatocyte nodules of the SFO-fed rats exhibited a significantly reduced lipid peroxidation
level that was associated with an increaser in the glutathione (GSH) concentration. The low n−6/n−3 FA ratio diets significantly
decreased 20∶4n−6 in PC and PE phospholipid fractions with a concomitant increase in 20∶5n−3, 22∶5n−3, and 22∶6n−3. The resultant
changes in the 20∶4/20∶5 FA ratio and the 20∶3n−6 FA level in the case of the GLA diet suggest a reduction of prostaglandin
synthesis of the 2-series. The GLA diet also counteracted the increased level of 20∶4n−6 in PE by equalizing the nodule/surrounding
ratio. The low n−6/n−3 ratio diets significantly increased lipid peroxidation levels in hepatocyte nodules, mimicking the
level in the surrounding and control tissue while GSH was decreased. An increase in n−3 FA levels and oxidative status resulted
in a reduction in the number of glutathione-S-transferase positive foci in the liver of the GLA-fed rats. Modulation of cancer
development with low n−6/n−3 ratio diets containing specific dietary FA could be a promising tool in cancer intervention in
the liver. 相似文献
4.
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
5.
Fish oil-enriched diets increase n−3 FA in tissue phospholipids; however, a similar effect by plant-derived n−3 FA is poorly
defined. To address this question, we determined mass changes in phospholipid FA, individual phospholipid classes, and cholesterol
in the liver, heart, and brain of rats fed diets enriched in flax oil (rich in 18∶3n−3), fish oil (rich in 22∶6n−3 and 20∶5n−3),
or safflower oil (rich in 18∶2n−6) for 8 wk. In the heart and liver phospholipids, 22∶6n−3 levels increased only in the fish
oil group, although rats fed flax oil accumulated 20∶5n−3 and 22∶5n−3. However, in the brain, the flax and fish oil diets
increased the phospholipid 22∶6n−3 mass. In all tissues, these diets decreased the 20∶4n−6 mass, although the effect was more
marked in the fish oil than in the flax oil group. Although these data do not provide direct evidence for 18∶3n−3 elongation
and desaturation by the brain, they demonstrate that 18∶3n−3-enriched diets reduced tissue 20∶4n−6 levels and increased cellular
n−3 levels in a tissuedependent manner. We hypothesize, based on the lack of increased 22∶6n−3 but increased 18∶3n−3 in the
liver and heart, that the flax oil diet increased circulating 18∶3n−3, thereby presenting tissue with this EFA for further
elongation and desaturation. 相似文献
6.
Watkins SM Lin TY Davis RM Ching JR DePeters EJ Halpern GM Walzem RL German JB 《Lipids》2001,36(3):247-254
Diet and fatty acid metabolism interact in yet unknown ways to modulate membrane fatty acid composition and certain cellular
functions. For example, dietary precursors or metabolic products of n-3 fatty acid metabolism differ in their ability to modify
specific membrane components. In the present study, the effect of dietary 22∶6n−3 or its metabolic precursor, 18∶3n−3, on
the selective accumulation of 22∶6n−3 by heart was investigated. The mass and fatty acid compositions of individual phospholipids
(PL) in heart and liver were quantified in mice fed either 22∶6n−3 (from crocodile oil) or 18∶3n−3 (from soybean oil) for
13 wk. This study was conducted to determine if the selective accumulation of 22∶6n−3 in heart was due to the incorporation
of 22∶6n−3 into cardiolipin (CL), a PL most prevalent in heart and known to accumulate 22∶6n−3. Although heart was significantly
enriched with 22∶6n−3 relative to liver, the accumulation of 22∶6n−3 by CL in heart could not quantitatively account for this
difference. CL from heart did accumulate 22∶6n−3, but only in mice fed preformed 22∶6n−3. Diets rich in non-22∶6n−3 fatty
acids result in a fatty acid composition of phosphatidylcholine (PC) in heart that is unusually enriched with 22∶6n−3. In
this study, the mass of PC in heart was positively correlated with the enrichment of 22∶6n−3 into PC. The increased mass of
PC was coincident with a decrease in the mass of phosphatidylethanolamine, suggesting that 22∶6n−3 induced PC synthesis by
increasing phosphatidylethanolamine-N-methyltransferase activity in the heart. 相似文献
7.
Effects of dietary n−6 and n−3 fatty acids (FAs) on blood pressure (BP) and tissue phospholipid (PL) FA composition in spontaneously
hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats were compared. Male weanling SHR and WKY were fed a fat-free semisynthetic
diet supplemented with 10% (w/w) fats containing (a) 78% 18∶2n−6 (LA-rich), (b) 20% LA and 55% 18∶3n−3 (LN-rich), or (c) 11%
LA and 3% LN (CON) for seven weeks. Dietary fats did not affect the BP elevation, but significantly altered the FA composition
of brain, adrenal gland, renal medulla and cortex PL in SHR. The LA-rich diet increased n−6 FA while it reduced n−3 FA levels.
The levels of 20∶4n−6 were not significantly different between animals fed the LA-rich and the CON diets. LN-rich diet increased
the levels of n−3 FAs, while it reduced those of n−6 FAs. However, the extent of change was significantly less in SHR than
in WKY. In all dietary groups, SHR, as compared to WKY, had a relatively higher level of the 2 series prostaglandin (PG) precursor,
20∶4n−6, and a relatively lower level of the 1 and 3 series PG precursors, 20∶3n−6 and 20∶5n−3. The possibility that the unbalanced
eicosanoid FA precursor levels might contribute to the development of hypertension in this animal model is discussed. 相似文献
8.
Skuladottir GV Olason PI Jonsson L Skarphedinsson JO Eriksdottir VH Atlason PT Franzson L Schiöth HB 《Lipids》2003,38(11):1127-1132
Hyperphagia was achieved by continuous intracerebroventricular infusion of a melanocortin receptor antagonist (HS024; Neosystem,
Strasbourg, France) in rats. The effects of hyperphagia on FA composition and concentration of plasma phospholipids (PL),
plasma FFA, and adipose tissue TAG were studied in rats for 8 d [short-term hyperphagia (STH); n=8], or 28 d [longterm hyperphagia (LTH); n=9]. The control rats were treated with artificial cerebrospinal fluid for 8 d (n=8) or 28 d (n=10). The rats were fed the same regular diet. In STH rats the plasma PL and fasting plasma FFA contained higher concentrations
of saturated FA (SFA) and monounsaturated FA (MUFA), and plasma FFA contained lower n−6 PUFA than in the control rats. In
LTH rats the plasma PL contained higher concentrations of SFA, MUFA, and n−3 PUFA and higher proportions of 16∶1n−7 and 18∶1n−9
at the expense of 18∶2n−6 than in the control rats. In LTH rats the abundant dietary intake of 18∶2n−6 did not enrich 18∶2n−6
of the plasma PL or adipose tissue TAG. In LTH rats the fasting plasma FFA contained more than twofold higher concentrations
of SFA and MUFA, and higher proportions of 16∶1n−7 and 18∶1n−9 at the expense of 18∶2n−6 than in the control rats. This animal
obesity model shows that LTH affects the FA composition and concentration of plasma PL, plasma FFA, and adipose tissue TAG,
a result consistent with changes associated with increased risk of various diseases in humans. These results also demonstrate
that LTH alters the FA composition of plasma PL and adipose tissue TAG in a way that does not reflect the FA composition of
dietary fat. 相似文献
9.
The esterification, desaturation, and elongation of [1-14C]18∶3n−3, [1-14C]18∶2n−6, and [1-14C]20∶5n−3 at 5 and at 12°C were studied using cultivated hepatocytes from Atlantic salmon. The salmon were fed diets, in which
0, 50, or 100% of the supplementary fish oil had been replaced by soybean oil, for 950 day-degrees at 5 and 12°C. The endogenous
percentage of 18∶2n−6 in hepatocyte lipids was 2% in cells from fish fed a diet with 100% of the supplemental lipid from fish
oil, and it was slightly less than 25% in cells from fish fed the diet with 100% of the supplemental lipid from soybean oil.
Furthermore, the percentages of 20∶3n−6 and 20∶4n−6 were significantly higher in hepatocytes from fish fed on soybean oil
than they were in those of fish fed on fish oil. The percentages of 20∶5n−3 and 22∶6n−3, on the other hand, were lower. The
endogenous levels of n−6 FA were not significantly correlated with the total amounts of radiolabeled FA esterified in hepatocyte
lipids. The main radiolabeled products formed from 18∶2n−6 were 20∶2n−6 and 20∶3n−6. The level of the important eicosanoid
precursor 20∶4n−6 was twice as high in hepatocyte phospholipids from fish fed the 100% soybean oil diet as it was in hepatocytes
from fish fed the diet with 100% of supplemental lipid from fish oil. The main products formed from 18∶3n−3 were 20∶4n−3,
20∶5n−3, and 22∶6n−3. High levels of dietary 18∶2n−6 do allow, or even seem to increase, the production of 22∶6n−3 from 18∶3n−3
in hepatocytes. The main products formed from 20∶5n−3 were 22∶5n−3 and 22∶6n−3. The production of 22∶6n−3 from 20∶5n−3 was
higher at 5°C than at 12°C. The percentage of 24∶5n−3 was higher at 5°C than it was at 12°C, as was the ratio of 24∶5 to 22∶5.
These results suggest that the elongation rate of 22∶5n−3 to 24∶5n−3 is higher at the lower temperature. 相似文献
10.
The effect that egg yolk or maternal n−3 FA have on the cardiac tissue long-chain n−3 FA status of chicks during growth was
investigated. Fggs with low, medium, and high levels of n−3 PUFA were obtained by feeding breeder hens a wheat/soybean meal-based
diet containing 5% sunflower oil (Low n−3), 2.5% sunflower oil plus 2.5% fish oil (Medium n−3), or 5% fish oil (High n−3).
The chicks hatched from Low, Medium, and High n−3 eggs were fed a diet containing 18∶3n−3, but devoid of long-chain n−3 FA.
The FA composition of cardiac tissue was determined on days 0, 14, 28, and 42. At day 0, the cardiac FA reflected maternal
diet. With time, the level of all the long-chain n−3 FA decreased compared with day 0, and this was true especially by day
14. These data show that dietary 18∶3n−3 fed to the chicks did not sustain high levels of EPA and DHA in cardiac tissue, despite
the high content of long-chain n−3 FA in the maternal diet. At days 0 and 14, the chicks hatched from High and Medium n−3
eggs had higher 20∶5n−3, 22∶5n−3, and 22∶6n−3 contents with a concomitant reduction in 20∶4n−6 in the cardiac tissue compared
with the Low n−3 egg group. Cardiac tissue of birds hatched from Medium n−3 eggs retained higher levels of 20∶5n−3 up to day
42 of growth when compared with other treatments (P<0.05). None of the treatments was effective in maintaining DHA levels after day 14 of growth. 相似文献
11.
The health benefits of long-chain n−3 PUFA (20∶5n−3 and 22∶6n−3) depend on the extent of incorporation of these FA into plasma
and tissue lipids. This study aimed to investigate the effect of the background dietary fat (saturated, monounsaturated, or
n−6 polyunsaturated) on the quantitative incorporation of dietary 18∶3n−3 and its elongated and desaturated products into
the plasma and the liver lipids of rats. Female weanling Wistar rats (n=54) were randomly assigned to six diet groups (n=9). The fat added to the semipurified diets was tallow (SFA), tallow plus linseed oil (SFA-LNA), sunola oil (MUFA), sunola
oil plus linseed oil (MUFA-LNA), sunflower oil (PUFA), or sunflower oil plus linseed oil (PUFA-LNA). At the completion of
the 4-wk feeding period, quantitative FA analysis of the liver and plasma was undertaken by GC. The inclusion of linseed oil
in the rat diets increased the level of 18∶3n−3, 20∶5n−3, and, to a smaller degree, 22∶6n−3 in plasma and liver lipids regardless
of the background dietary fat. The extent of incorporation of 18∶3n−3, 20∶5n−3, and 22∶5n−3 followed the order SFA-LNA>MUFA-LNA>PUFA-LNA.
Levels of 22∶6n−3 were increased to a similar extent regardless of the type of major fat in the rat diets. This indicates
that the background diet affects the incorporation in liver and plasma FA pools of the n−3 PUFA with the exception of 22∶6n−3
and therefore the background diet has the potential to influence the already established health benefits of long-chain n−3
fatty acids. 相似文献
12.
P. E. Wainwright Y. S. Huang B. Bulman-Fleming D. Dalby D. E. Mills P. Redden D. McCutcheon 《Lipids》1992,27(2):98-103
This study examines the effects of the ratio of n−3/n−6 fatty acids (FA) on brain development in mice when longchain n−3 FA
are supplied in the diet. From conception until 12 days after birth, B6D2F1 mice were fed liquid diets, each providing 10% of energy from olive oil, and a further 10% from different combinations of
free FA concentrates derived from safflower oil (18∶2n−6), and fish oil (20∶5n−3 and 22∶6n−3). The range of dietary n−3/n−6
ratios was 0,025, 0.5, 1.0, 2.0, and 4.0, with an n−6 content of greater than 1.5% of energy in all diets, and similar levels
of total polyunsaturated fatty acids (PUFA). In an additional group of ratio 0.5, 18∶2n−6 was partially replaced by its δ6
desaturation product, 18∶3n−6. Biochemical analyses were conducted on 12-day-old pup brains, as well as on samples of maternal
milk. No obvious effects on overall pup growth and development were observed, apart from a smaller litter size at ratio 1.
Co-variance analysis indicated that increasing the n−3/n−6 ratio was associated with slightly smaller brains, relative to
body weight. We found that 18∶2n−6 and 20∶5n−3 were the predominant n−6 and n−3 FA in the milk; in the brain these were 20∶4n−6
and 22∶6n−3, respectively. Increasing dietary n−3/n−6 ratios generally resulted in an increase in n−3 FA, with a corresponding
decrease in n−6 FA. The n−3/n−6 ratio of the milk lipids showed a strong linear relationship with the diet, but in the brain
the rate of increase tended to decrease beyond 0.5 (phosphatidylcholine, PC) and 0.25 (phosphatidylethanolamine, PE), such
that there was a significant quadratic contribution to the relationship. The partial replacement of dietary 18∶2n−6 with 18∶3n−6
raised levels of 20∶4n−6 in milk, brain PC, and brain PE. These results indicate that the n−3/n−6 ratio of the phospholipids
in the developing mouse brain responds maximally to maternal dietary long-chain n−3/n−6 ratios of between 0.25 and 0.5. 相似文献
13.
Total lipid, phospholipid, and FA composition and distribution of FA between polar lipids (PL) and neutral lipids (NL) were
investigated in the boreal soft coral Gersemia rubiformis from the Bering Sea. The total lipids were mostly hydrocarbons and waxes (33.7%) and PL (33.1%). The content of monoalkyldiacylglycerols
(9.7%) exceeded the content of TAG (6.7%). PC and PE constituted 31.4% and 25.6% of total phospholipids, respectively. Principal
FA were 16∶0, 16∶1n−7, 18∶0, 18∶1n−9, 18∶1n−7, 20∶1n−7, 20∶4n−6, 20∶4n−3, 20∶5n−3 22∶5n−3, 22∶6n−3, 24∶5n−6, and 24∶6n−3.
Most n−6 PUFA (52% of total FA) were associated with the PL fraction; this was especially true for arachidonic and tetracosapentaenoic
acids. The NL were enriched with mono-, di-, trienoic, and n−3 PUFA. The variation in EPA levels in both NL and PL suggests
an origin of this acid from lipids of diatoms consumed by the corals. 相似文献
14.
The effects of clofibrate on the content and composition of liver and plasma lipids were studied in mice fed for 4 wk on diets
enriched in n−6 or n−3 polyunsaturated fatty acids (PUFA) from sunflower oil (SO) or fish oil (FO), respectively; both oils
were fed at 9% of the diet (dry weight basis). Only FO was hypolipidemic. Both oil regimes led to slightly increased concentrations
of phospholipids (PL) and triacylglycerols (TG) in liver as compared with a standard chow diet containing 2% fat. Clofibrate
promoted hypolipidemia only in animals fed SO. Its main effect was to enlarge the liver, such growth increasing the amounts
of major glycerophospholipids while depleting the TG. SO and FO consumption changed the proportion of n−6 or n−3 PUFA in liver
and plasma lipids in opposite ways. After clofibrate action, the PUFA of liver PL were preserved better than in the absence
of oil supplementation. However, most of the drug-induced changes (e.g., increased 18∶1n−9 and 20∶3n−6, decreased 22∶6/20∶5
ratios) occurred inrrespective of lipids being rich in n−6 or n−3 PUFA. The concentration of sphingomyelin (SM), a minor liver
lipid that virtually lacks PUFA, increased with the dietary oils, decreased with clofibrate, and changed its fatty acid composition
in both situations. Thus. oil-increased SM had more 22∶0 and 24∶0 than clofibrate-decreased SM, which was significantly richer
in 22∶1 and 24∶1. 相似文献
15.
Eurasian perch, Perca fluviatilis, were fed a semipurified fat-free diet for 4 wk, followed by a 16% feeding supplementation of either olive oil (OO), safflower
oil (SO), linseed oil (LO), or cod liver oil (CLO) as the only lipid source in each diet for 10 wk. Significant reductions
in total lipid of tissues were observed (31.4% in viscera, 66.7% in muscle, and 74.1% in liver) after feeding the fat-free
diet. The SO-, LO-, and CLO-fed fish significantly increased lipid deposition in liver and viscera compared to fish fed the
OO diet; however, muscle lipid levels were not significantly affected. Large amounts of dietary 18∶1n−9 were incorporated
directly into tissue lipids when fish were fed the OO diet. The LO diet significantly elevated 18∶4n−3, 20∶5n−3, 22∶5n−3,
and 22∶6n−3 in the liver compared to fish fed OO or SO diets, and the n−3/n−6 ratio was 16 times that of the SO group, with
significantly high desaturation and elongation products of 18∶3n−3. These results suggest that Δ6 and Δ5 desaturases are highly
active in Eurasian perch, and that the enzymes at this dietary n−3/n−6 ratio favor 18∶3n−3 over 18∶2n−6 as substrate. The
SO diet significantly increased 18∶3n−6, 20∶3n−6, and 22∶5n−6 in the liver and significantly decreased EPA and DHA. This indicates
that desaturation enzymes were not specifically favoring n−3 over n−6 acids in perch lipid metabolism, and that these elongation
and desaturation enzymes were influenced by n−3 and n−6 FA content in the diet. The present study indicates that high tissue
content of DHA in the muscle of Eurasian perch was attributable to the greater ability for n−3 acid bioconversion. 相似文献
16.
Indian diets comprising staples such as cereals, millets, and pulses provide 4.8 energy % from linoleic acid (18∶2n−6) but
fail to deliver adequate amounts of n−3 FA. Consumption of long-chain n−3 PUFA such as EPA (20∶5n−3) and DHA (22∶6n−3) is
restricted to those who consume fish. The majority of the Indian population, however, are vegetarians needing additional dietary
sources of n−3 PUFA. The present work was designed to use n−3 FA-enriched spray-dired milk powder to provide n−3 FA. Whole
milk was supplemented with linseed oil to provide α-linolenic acid (LNA, 18∶3n−3), with fish oil to provide EPA and DHA, or
with groundnut oil (GNO), which is devoid of n−3 PUFA, and then spray-dired. Male Wistar rats were fed the spray-dired milk
formulations for 60 d. The rats given formulations containing n−3 FA showed significant increases (P<0.001) in the levels of LNA or EPA/DHA in the serum and in tissue as compared with those fed the GNO control formulation.
Rats fed formulations containing n−3 FA had 30–35% lower levels of serum total cholesterol and 25–30% lower levels of serum
TAG than control animals. Total cholesterol and TAG in the livers of rats fed the formulations containing n−3 FA were lower
by 18–30% and 11–18%, respectively, compared with control animals. This study showed that spray-dried milk formulations supplemented
with n−3 FA are an effective means of improving dietary n−3 FA intake, which may decrease the risk factors associated with
cardiovascular disease. 相似文献
17.
High levels of n−6 docosapentaenoic acid (22∶5n−6) have been reported in the retina of guinea pigs fed commercially-prepared
grain-based rations (commercial diet). In rats and monkeys, high levels of 22∶5n−6 are an indicator of n−3 polyunsaturated
fatty acid (PUFA) deficiency. We have examined the fatty acid composition of the retina and brain in guinea pigs fed a commercial
diet or one of three semi-purified diets containing three different levels of n−3 PUFA. The diets comprised a diet deficient
in n−3 PUFA (semi-purified diet containing safflower oil), two diets containing α-linolenic acid (standard commercial laboratory
diet and semi-purified diet containing canola oil), and a diet containing α-linolenic acid, eicosapentaenoic acid, and docosahexaenoic
acid (DHA) (semi-purified diet containing canola oil, safflower oil, and fish oil). Two groups of guinea pigs were given the
diets from day 1 to 4 wk or day 1 to 8 wk, when they were sacrificed and the retinal tissues were extracted and analyzed for
PUFA content by gas-liquid chromatography. Fatty acid analyses of the retinal phospholipids of the four-week-old animals revealed
that the group fed DHA (from the fish oil) had the highest level of DHA (32%), compared with values of 19 and 13% for the
groups fed canola oil diet and commercial diet, respectively, and 2% for the group fed the diet deficient in n−3 PUFA. The
levels of 22∶5n−6 in the retinal lipids were inversely related to the DHA values, being 0.6, 6.6, 11.4, and 20.6 for the fish
oil, canola oil, commercial diet, and safflower oil diet groups, respectively. The long-chain PUFA profiles in the brain phospholipids
of the four-week-old group were similar to those from the retina. The retinal PUFA values for the eight-week-old animals were
similar to the four-week-old group. The safflower oil diet induced a greater deficit of DHA in retinal lipids than has been
reported in rats and monkeys fed similar diets. The guinea pigs fed the commercial diet had retinal and brain PUFA patterns
similar to that produced by n−3 PUFA-deficient diets in rats and monkeys. Guinea pigs fed the canola oil diet had significantly
greater retinal DHA levels than those fed the commercial diet, but lower than those fed fish oil. The data suggest that the
guinea pig has a reduced capacity for DHA synthesis from α-linolenic acid as compared with other mammals. Supplementation
of guinea pig diets with fish oil produced high retinal and brain DHA levels and prevented the accumulation of 22∶5n−6. 相似文献
18.
The purpose of this study was to assess the FA composition of both cholesteryl esters (CE) and phospholipids (PL) in maternal
plasma during pregnancy and at delivery and in umbilical plasma at birth. A longitudinal study of 32 normal pregnant women
was carried out with three cutoff points during pregnancy (first, second, and third trimester) and at delivery. Few significant
differences occurred in the FA profile of maternal CE: 18∶1n−9 increased, 18∶2n−6 dropped slightly, and 18∶3n−3 decreased
with progressing gestation. In maternal PL, long-chain highly unsaturated FA concentrations dropped and were replaced by saturated
FA as gestation progressed. Additionally, changes in saturated FA in PL occurred: Shorter-chain 16∶0 was higher whereas longer-chain
18∶0 was lower at delivery compared to early pregnancy. The FA profile of umbilical venous plasma was strikingly different
from that of maternal plasma at delivery. Cord plasma CE contained more saturated and monounsaturated FA than maternal CE.
The polyunsaturates 18∶2n−6 and 18∶3n−3 are lower in umbilical CE than in maternal CE whereas 20∶4n−6 and 22∶6n−3 are twice
as high in umbilical CE. Cord plasma PL have a higher content of long-chain highly unsaturated FA than maternal plasma PL
at delivery. In contrast to maternal plasma PL, 16∶0 was lower and longer-chain saturated FA were higher in cord plasma PL.
The FA profile of umbilical plasma at birth shows preferential accumulation of 20∶4n−6 and 22∶6n−3, with low concentrations
of 18∶2n−6 and 18∶3n−3 in CE and PL, indicating a preferential supply of the fetus with long-chain highly unsaturated FA needed
for fetal development. 相似文献
19.
Renée Grataroli Jeannie Léonardi Monique Charbonnier Raymond Lafont Huguette Lafont Gilles Nalbone 《Lipids》1988,23(7):666-670
Three groups of male rats were fed either a corn oilenriched diet (17%, w/w), a salmon oil-enriched diet (12.5%) supplemented
with corn oil (4.5%) or a low-fat diet (4.4%) for eight wk to investigate the possible relationships between dietary fatty
acids and lipid composition, and prostaglandin E2 level and phospholipase A2 activity in the rat gastric mucosa.
High-fat diets induced no important variation in total protein, phospholipid and cholesterol contents of gastric mucosa.
Compared with a low-fat diet, corn oil produced a higher n−6/n−3 ratio in mucosal lipids, whereas this ratio was markedly
lowered by a fish oil diet.
In comparison with the low-fat diet, the production of prostaglandin E2(PGE2) in gastric mucosa of rats fed salmon oil was significantly, decreased by a factor of 2.8. In the corn oil group, PGE2 production tended to decrease, but not significantly.
In comparison with the low-fat diet, both specific and total gastric mucosal phospholipase A2 activities were increased (+18 and 23%, respectively) in the salmon oil group; they were unchanged in the corn oil group.
It is suggested that the decrease of gastric PGE2 in rats fed fish oil is not provoked by a decrease in phospholipase A2 activity but may be the result of the substitution of arachidonic acid by n−3 PUFA or activation of PGE2 catabolism. 相似文献
20.
John K. G. Kramer Edward R. Farnworth Kathleen M. Johnston Mark S. Wolynetz H. Wayne Modler Frank D. Sauer 《Lipids》1990,25(11):729-737
This study was undertaken to determine whether the neonate was more susceptible to the effects of dietary erucic acid (22∶1n−9)
than the adult. Newborn piglets were used to assess the safety of different levels of 22∶1n−9 on lipid and histological changes
in the heart. Newborn piglets showed no myocardial lipidosis as assessed by oil red 0 staining, but lipidosis appeared with
consumption of sow milk and disappeared by seven days of age. Milk replacer diets containing soybean oil, or rapeseed oil
mixtures with up to 5% 22∶1n−9 in the oil, or 1.25% in the diet, gave trace myocardial lipidosis. Rapeseed oil mixtures with
7 to 42.9% 22∶1n−9 showed definite myocardial lipidosis in newborn piglets, which correlated to dietary 22∶1n−9, showing a
maximum after one week on diet. The severity of the lipidosis was greater than observed previously with weaned pigs. There
were no significant differences among diets in cardiac lipid classes except for triacylglycerol (TAG), which increased in
piglets fed a repeseed oil with 42.9% 22∶1n−9. TAG showed the highest incorporation of 22∶1n−9, the concentration of 22∶1n−9
in TAG was similar to that present in the dietary oil. Among the cardiac phospholipids, sphingomyelin and phosphatidylserine
had the highest, and diphosphatidylglycerol (DPG) the lowest level of 22∶1n−9. The low content of 22∶1n−9 in DPG of newborn
piglets is not observed in weaned pigs and rats fed high erucic acid rapeseed oil. The relative concentration of saturated
fatty acids was lowered in all cardiac phospholipids of piglets fed rapeseed oils, possibly due to the low content of saturated
fatty acids in rapeseed oils. The results suggest that piglets fed up to 750 mg 22∶1n−9/kg body weight/day showed no adverse
nutritional or cardiac effects. 相似文献