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1.
The effect of dietary n−3 fatty acids on prostaglandin E2 (PGE2) and leukotriene C4 (LTC4) levels in rat salivary glands and gingiva was examined in two separate nutritional studies. In the first set of experiments,
two groups of male weanling Sprague-Dawley rats were fed semipurified diets containing 10% corn oil (control group) or 10%
menhaden oil (experimental group). Rats were killed after 8 wk on the diets; the fatty acid composition of total phospholipids
and the concentrations of PGE2 and its precursor, arachidonic acid, were measured in gingiva and submandibular salivary glands (SMSG). Dietary n−3 fatty
acids were incorporated into the tissue phospholipids. Arachidonic acid levels were reduced by 56% in gingiva and SMSG of
rats fed menhaden oil compared with the control rats fed the diet containing corn oil. The concentrations of PGE2 in SMSG and gingiva of rats fed the diet containing menhaden oil were reduced by 74% and 83%, respectively. In a subsequent
nutritional study, we tested whether the diet-induced reduction in tissue arachidonic acid levels would also result in a corresponding
decrease in LTC4 production. Three groups of rats were fed diets containing 5% corn oil (group 1), 4% ethyl ester concentrate of n−3 fatty
acids plus 1% corn oil (group 2), or 5% ethyl ester concentrate of n−3 fatty acids (group 3). After 6 wk of feeding, gingiva
and SMSG were analyzed for arachidonic acid content andin vitro production of LTC4. Arachidonic acid content of total phospholipids was about 60% lower in gingiva and 69% lower in SMSG of rats fed the ethyl
ester concentrate of n−3 fatty acids (groups 2 and 3) than those of the control group fed the corn oil diet (group 1). Upon
incubation with calcium ionophore, gingiva and SMSG from rats fed the n−3 fatty acids rich diet produced significantly less
TLC4 than those from rats of the control group. Because PGE2 and LTC4 are believed to be important biochemical mediators of periodontal disease, one may speculate that a diet-induced reduction
in their levels may have a beneficial effect upon the course of the disease. The function of salivary glands may also be altered
because of the role of these eicosanoids in salivary secretions.
Presented in part for the Hatton Award Competition at the American Association for Dental Research Meeting, San Francisco,
California, March 15–19, 1989, and at the International Association for Dental Research Meeting, Acapulco, Mexico, April 17–21,
1991. 相似文献
2.
This study evaluated the effects of conjugated linoleic acids (CLA) on tissue fatty acid composition and ex vivo prostaglandin E2 (PGE2) production in rats given diets varying in n-6 and n-3 fatty acids. Four groups of rats were given a basal semipurified diet
(AIN-93G) containing 70 g/kg of added fat for 42 d. The fat treatments were formulated to contain CLA (0 vs. 10 g/kg of diet)
and n-6 (soybean oil having an n-6/n-3 ratio of 7.3) and n-3 fatty acids (menhaden oil+safflower oil having an n-6/n-3 ratio
of 1.8) in different ratios in a 2×2 factorial design. Fatty acids in liver, serum, muscle, heart, brain, spleen, and bone
(cortical, marrow, and periosteum) were analyzed by capillary gas-liquid chromatography. The various dietary lipid treatments
did not affect growth; however, CLA improved feed efficiency. The CLA isomers were found in all rat tissues analyzed although
their concentrations varied. Dietary CLA decreased the concentrations of 16∶1n−7, 18∶1, total monounsaturates and n−6 fatty
acids, but increased the concentrations of n−3 fatty acids (22∶5n−3 and 22∶6n−3), and saturates in the tissues analyzed. Ex vivo PGE2 production in bone organ culture was decreased by n−3 fatty acids and CLA. We speculate that CLA reduced the concentration
of 18∶1 fatty acids by inhibiting liver Δ9-desaturase activity. The fact that CLA lowered ex vivo PGE2 production in bone organ culture suggests that these conjugated fatty acids have the potential to influence bone formation
and resorption. 相似文献
3.
The effect of a long-term adaptation of rainbow trout to 8 and 18°C combined with a corn oil-or a fish oil-supplemented diet
on the characteristics of the spermatozoan plasma membrane was investigated. The experiment lasted up to 22 mon during which
spermatozoa were collected from the mature males. Spermatozoan plasma membranes were isolated by nitrogen cavitation, and
the cholesterol content, phospholipid composition and fatty acid pattern were investigated. Membrane viscosity was assessed
on whole cells by electron spin resonance using spin-labeled phospholipids. Neither diet nor rearing temperature influenced
the cholesterol content of the plasma membrane nor the phospholipid class distribution. The rearing temperature of the broodstock
only slightly affected the phospholipid fatty acids. A minor decrease in 18∶0 and increase in monounsaturated fatty acids
was observed for the cold-adapted fish. These modifications were not sufficient to affect membrane fluidity, and we conclude
that trout spermatozoa do not display any homeoviscous adaptations in these conditions. On the contrary, the dietary fatty
acid intake greatly modified the fatty acid profile of plasma membrane phospholipids. The fish oil-fed trout displayed a much
higher n−3/n−6 fatty acid ratio than did the corn oil-fed ones, but the 22∶6n−3 levels remained unchanged. Modifications in
plasma membrane composition by the diet were obtained although neither of the two diets was deficient in essential fatty acids.
The enrichment in n−3 fatty acids, however, did not affect plasma membrane fluidity which was unchanged by the diets. 相似文献
4.
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
5.
Robin A. Henderson Robert G. Jensen Carol J. Lammi-Keefe Ann M. Ferris Kenneth R. Dardick 《Lipids》1992,27(11):863-869
To examine the effect of fish oil supplementation on the fatty acid (FA) composition of human milk and maternal and infant
erythrocytes, five lactating women were supplemented with 6 g of fish oil daily for 21d. Usual maternal diets contained 1,147
mg of total n−3 FA, with 120 mg from very long-chain (>C18) n−3 FA. Supplementation increased dietary levels to 3,092 mg of total n−3 FA and 2,006 mg of very long-chain n−3 FA. Milk
samples were collected daily, prior to fish oil ingestion, and at 4-h intervals on days 1, 7, 14 and 21. Milk n−3 FA content
increased within 8 h and reached steady state levels within one week. The n−6 fatty acid content decreased. Erythrocyte eicosapentaenoic
acid content increased from 0.24% to 1.4% (P<0.01) in mothers and from 0.11% to 0.70% (P<0.05) in infants. Docosapentaenoic acid increased from 1.4% to 2.2% (P<0.05) in mothers and from 0.30% to 0.78% (P<0.01) in infants. There was no significant change in docosahexaenoic acid or n−6 fatty acid content. Maternal platelet aggregation
responses were variable. No differences in milk or plasma tocopherol levels were noted.
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
6.
John K. G. Kramer Frank D. Sauer Edward R. Farnworth Mark S. Wolynetz Gwynn Jones Gail A. Rock 《Lipids》1994,29(12):859-868
To test if linolenic acid (18∶3n−3) from vegetable oils would affect bleeding times and platelet counts in new-borns, piglets
were used as a model fed milk replacer diets containing 25% (by wt) vegetable oils or oil mixtures for 28 d and compared to
sow-reared piglets. The oils tested included soybean, canola, olive, high oleic sunflower (HOAS), a canola/coconut mixture
and a mixture of oils mimicking canola in fatty acid composition. All piglets fed the milk replacer diets showed normal growth.
Bleeding times increased after birth from 4–6 min to 7–10 min by week 4 (P<0.001), and were higher in pigs fed diets containing 18∶3n−3, as well as in sowreared piglets receiving n−3 polyunsaturated
fatty acids (PUFA) in the milk, as compared to diets low in 18∶3n−3. Platelet numbers increased within the first week in newborn
piglets from 300 to 550×109/L, and remained high thereafter. Milk replacer diets, containing vegetable oils, generally showed a transient delay in the
rise of platelet numbers, which was partially associated with an increased platelet volume. The oils showed differences in
the length of delay, but by the third week of age, all platelet counts were >500×109/L. The delay in rise in platelet counts appeared to be related to the fatty acid composition of the oil, as the effect was
reproduced by a mixture of oils with a certain fatty acid profile, and disappeared upon the addition of saturated fatty acids
to the vegetable oil. There were no alterations in the coagulation factors due to the dietary oils. Blood plasma, platelets
and red blood cell membranes showed increased levels of 18∶3n−3 and long-chain n−3 PUFA in response to dietary 18∶3n−3. The
level of saturated fatty acids in blood lipids was generally lower in canola and HOAS oil-fed piglets as compared to piglets
fed soybean oil or reared with the sow. The results suggest that consumption of milk replacer diets containing vegetable oils
rich in 18∶3n−3 does not represent a bleeding risk, and that the transient lower platelet count can be counterbalanced by
the addition of saturated fatty acids to the vegetable oils. 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.
The effects of dietary stearidonic acid (18∶4n−3) on inflammatory mediator release in whole blood and splenocytes was investigated
in Balb/c mice, and the effects were compared with those of two other n−3 PUFA: α-linolenic acid (18∶3n−3) and EPA (20∶5n−3).
TAG mixtures containing 10% of 18∶4n−3, 18∶3n−3, or 20∶5n−3 as the respective sole n−3 PUFA were enzymatically synthesized.
Diets containing synthesized TAG mixtures were fed to Balb/c mice for 3 wk. The release of prostaglandin E2 (PGE2) and tumor necrosis factor (TNF) were measured in whole blood and splenocytes stimulated with lipopolysaccharide. In whole
blood, the production of INF was suppressed by all dietary n−3 PUFA (18∶3n−3, 18∶4n−3, and 20∶5n−3) as compared with the control
diet, which contained TAG prepared from safflower oil. PGE2 production was not significantly changed. Differences among the n−3 PUFA (18∶3n−3), 18∶4n−3, and 20∶5n−3) were not observed.
In splenocytes, PGE2 production was suppressed by dietary n−3 PUFA, but TNF production was not. GC analysis of plasma and splenocyte FA profiles
showed an increase in the levels of 20∶4n−3, 20∶5n−3, and 22∶6n−3 in mice fed the diet containing 18∶4n−3. 相似文献
9.
Svend G. Kaasgaard Gunhild Hølmer Carl-Erik Høy Willy A. Behrens Joyce L. Beare-Rogers 《Lipids》1992,27(10):740-745
Diets rich in linoleic acid (CO) from corn oil, or in linoleic acid and either α-linolenic acid (LO) based on linseed oil
or n−3 fatty acids (MO) from menhaden oil were fed to male and female Cynomolgus monkeys for 15 wk. In the liver a 40% reduction
of α-tocopherol occurred in the MO group relative to the CO and LO groups followed by increased formation of lipofuscinin vivo. A four-fold increase of α-tocopherol in the MO diet (MO+E) brought the level in the liver to that found with CO and LO.
The increased peroxidation in the MO group in the liver phospholipids was associated with the replacement of 60% of the n−6
fatty acids by n−3 fatty acids from menhaden oil. Similar fatty acid profiles were found in groups fed MO and MO+E, respectively.
Compared to the CO fed group, feeding α-linolenic acid only resulted in a slight incorporation of n−3 fatty acids in the liver
membranes mainly due to a direct incorporation of α-linolenic acid. However, in monkeys fed menhaden oil more than 30% of
the total fatty acids in the liver phospholipids were n−3 fatty acids. The various diets did not influence the activity of
liver catalase (EC 1.11.1.6) nor superoxide dismutase (EC 1.15.1.1), but glutathione-peroxidase activity (EC 1.11.1.9) was
higher in monkeys fed the MO diet. The catalase activity in females was 20% higher than in males. In anin vitro assay, liver microsomes from monkeys fed the MO diet or the MO diet supplemented with tocopherol produced similar amounts
of thiobarbituric acid reactive substances and at a much higher rate than microsomes from the CO and LO groups. It appeared
that α-tocopherol did not protect long-chain n−3 C20 and C22 fatty acids as well as n−6 fattya acids against peroxidation. The present data showed that monkeys were not fully able to
compensate for increased peroxidative stress but a four-fold supplement of vitamin E to the diets reduced the oxidation. 相似文献
10.
Three groups of male mice were fed a normal diet or a semisynthetic diet containing either 10% hydrogenated coconut oil (CO
group) or 10% menhaden oil (MO group) for two wk. The synthetic diet altered the fatty acid composition of lung microsomal
lipids. Mice ingesting menhaden oil contained greater amounts of eicosapentaenoic acid (20∶5 n−3), docosapentaenoic acid (22∶5
n−3) and docosahexaenoic acids (22∶6 n−3) and decreased amounts of n−6 fatty acids such as arachidonic and adrenic. Synthesis
of prostaglandin E2 and prostaglandin F2α from exogenous arachidonic acid was significantly depressed in n−3 fatty acid-enriched lung microsomes. These studies indicated
that dietary fish oil not only alters the fatty acid composition of lung microsomes but also lowers the capacity of lungs
to synthesize prostaglandins from arachidonic acid. 相似文献
11.
We investigated the effects of perilla oil containing a high level of α-linolenic acid onin vivo phospholipid metabolism, particularly three subclasses of choline glycerophospholipids (CGP) and ethanolamine glycerophospholipids
(EGP), in rat kidney. After three weeks of feeding, a significantly lower proportion (by 35%) of the alkylacyl subclass of
CGP was found in the perilla oil, as compared to corn oil-fed animals. The alkylacyl species of EGP was also higher in the
perilla oil than in the corn oil-fed animals. These alterations were accompanied by a remarkably lower proportion of arachidonic
acid and a higher level of eicosapentaenoic acid (EPA) in all six subclasses of CGP and EGP in the perilla oil-fed animals.
The levels of linoleic acid were even higher in the diacyl subclasses of CGP and EGP in the perilla oil group, suggesting
that desaturase and elongase enzymes prefer n−3 to n−6 fatty acids as substrates for diacyl species. These data are useful
in defining the effects of α-linolenic acid on the biosynthesis of renal phospholipids and on the replacement of n−6 with
n−3 fatty acids in the six CGP and EGP subclasses. 相似文献
12.
The nephrotic syndrome was induced in rats by intravenous adriamycin (3 mg/kg). The rats were then divided into four groups
which, for six weeks, were pair-fed diets containing beef tallow (BT), fish oil (FO), a source of n−3 fatty acids, evening
primrose oil (EPO), a source of n−6 fatty acids, or a combination of evening primrose oil and fish oil, 75∶25 (EPO:FO). The
fat content of the diets was 15%. Significant incorporation of the fatty acids into kidney phospholipids was demonstrated.
Diets containing FO, EPO and EPO:FO lowered plasma triglycerides and total cholesterol levels as compared with diets containing
BT. Only EPO:FO raised high density lipoprotein (HDL) cholesterol levels, as compared with BT. The combination EPO:FO prevented
the tenfold suppression of aortic 6-keto-PGF1α caused by FO. These changes in plasma lipids and eicosanoid production are potentially antiatherogenic and may prevent glomerular
sclerosis. The combination of EPO and FO, containing n−6 and n−3 fatty acids may offer advantages over either family of fatty
acids in this model of nephrotic syndrome. 相似文献
13.
José L. Periago María L. Pita María A. Sanchez del Castillo Guillermo Caamaño María D. Suárez 《Lipids》1989,24(5):383-388
Changes in fatty acid composition, microsomal Δ9- and Δ6-desaturase activities and liver contents of cholesterol and phospholipids were studied in rats fed medium chain triglyceride-supplemented
diets. Weanling rats were divided into four groups and fed for three weeks a basal diet with different 10%-fat supplements:
corn oil, medium chain triglyceride-corn oil, olive oil and medium chain triglyceride-olive oil. The highest relative content
of saturated fatty acids corresponded to corn oil-fed animals. Both monounsaturated fatty acid content and Δ9-desaturase activity were higher in the animals fed olive oil diets than in corn oil-fed rats. The long chain polyunsaturated
fatty acids of the n−3 series were increased in the olive oil and medium chain triglyceride-olive oil-fed groups probably
due to the lower linoleic/α-linolenic ratios found in these two diets. The cholesterol/phospholipid molar ratio was unaffected
by diet and the unsaturation index was only slightly changed in the four groups. Thus, some mechanism may be operative under
these conditions to maintain the homeostasis of the membrane. 相似文献
14.
To investigate the effects of dietary fat quality on synthesis and esterification of cholesterol, Syrian hamsters were fed
diets containing corn, olive, coconut or menhaden oils (10% w/w) with added cholesterol (0.1% w/w). After 3 weeks, animals
were sacrificed 90 min following IP injection of3H2O. Synthesis of free cholesterol and movement of free cholesterol into ester pools were measured from3H-uptade rate in liver and duodenum. Plasma total cholesterol and triglycerides levels were highest in coconut oil-fed animals,
whereas hepatic total cholesterol and ester levels were elevated in olive oil-fed animals, as compared with all other groups.
No diet-related differences were seen in duodenal cholesterol or total fatty acid content. In duodenum, uptake of3H per g tissue into cholesterol was greater compared with liver; however, within each tissue,3H-uptake into cholesterol was similar across groups. Notably,3H-uptake into cholesterol ester in liver was highest in menhaden oil-fed animals. These data suggest that menhaden fish oil
consumption results in enhanced movement of newly synthesized cholesterol into ester as compared with other fat types. 相似文献
15.
Soad H. Abou-El-Ela Keith W. Prasse Richard Carroll Adelbert E. Wade Suniti Dharwadkar Opal R. Bunce 《Lipids》1988,23(10):948-954
The comparative effects of high-fat diets (20%, w/w) on eicosanoid synthesis during mammary tumor promotion in 7,12-dimethylbenz(a)anthracene
(DMBA)-induced rats were studied using diets containing 20% primrose oil (PO), 20% menhaden oil (MO) or 20% corn oil (CO).
Sprague-Dawley rats fed the PO or MO diet had 21% or 24% fewer adenocarcinomas, respectively, than rats fed the CO diet. Histologically
(i.e., mitotic figures, inflammatory cell infiltration and necrosis), the CO-fed rats exhibited the highest frequency of changes
within tumors. Plasma fatty acid composition was significantly altered by diet, reflecting the composition of the oils which
were being fed. Only the plasma of PO-fed rats contained detectable levels of gamma-linolenic acid (GLA). Arachidonic acid
(AA) levels were significantly higher (p<0.05) in PO-fed than in CO- or MO-fed rats. MO-fed rats had significantly higher
levels of plasma palmitic acid, while palmitoleic, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids were detected only
in MO-fed rats. As expected, linoleic acid (LA) and AA levels were lower (p<0.05) in the MO-fed rats than in PO- or CO-fed
groups. The plasma of the CO-fed rats contained significantly higher levels of oleic acid. Eicosanoid synthesis in mammary
carcinomas of rats fed the 20%-fat diets was 2–10 times higher than in mammary fat pads of control rats. The synthesis of
PGE1 and LTB4 was significantly (p<0.05) higher in PO-fed rats than in CO-fed or MO-fed rats, although PGE values were significantly (p<0.05)
higher in CO-fed rats than in Mo or PO groups. The synthesis of eicosanoids in both mammary fat pads and mammary carcinomas
of MO-fed rats was lower (p<0.05) than in tissues of rats fed either CO or PO diets due to less AA precursor being fed and/or
to competition between n−6 and n−3 fatty acids for cyclooxygenase and lipoxygenase. The ratios of monoenoic to dienoic eicosanoids
in both mammary fat pads and mammary carcinomas were higher in the PO group than in the MO or CO groups. These results suggest
that inclusion of GLA (PO feeding) or EPA and DHA (MO feeding) in the diet may decrease malignancy by altering eicosanoid
profiles. 相似文献
16.
In order to ascertain whether the dermal lesions observed in male rats fed rapeseed oils are due to impaired prostaglandin
biosynthesis, endogenous levels of prostaglandin E2 (PGE2) in skin and the capacity of this tissue to synthesize PGE2 from arachidonic acid was investigated. Male Sprague-Dawley rats were fed from weaning for 8 weeks either a standard rat
diet (chow) or semisynthetic diets containing 20% by weight of the following fat sources: corn oil; commercial lard; commercial
lard to which was added 5.4% free erucic acid; rendered pig fat; or the following rapeseed oils:Brassica napus var. Zephyr;B. campestris var. Span;B. campestris var. Arlo (15%) and var. Echo (85%) designated HEAR (high erucic acid rapeseed). The long-chain monoene content (18∶1, 20∶1,
and 22∶1) of the diets fed ranged from 30 to 71 mole % and that of skin from 27 to 74 mole %. A significant (P<0.01) correlation
was found between the level of 18∶2n−6 in the diet and the endogenous PGE2 levels in skin and the capacity of this tissue to synthesize PGE2. No relationship was found between these two PGE2 parameters and the level of erucic acid in the diet. The rate of turnover of PGE2 appeared to be lower in rats fed rapeseed oil as evidenced by the relatively high endogenous PGE2 levels when these oils were fed (96 to 105 μg/g). On the other hand, the lowest capacity for PGE2 synthesis was found with skin from rats fed Zephyr rapeseed oil, rats which also had the most severe incidence of hair loss
and dermal lesions. Significant (P<0.01) negative correlations were observed between the level of monoenes and specifically
the level of oleic (18∶1n−9) acid in the diets and PGE2 synthesis capacity of skin, possibly confirming the known inhibitory effect of 18∶1n−9 on the prostaglandin synthesizing
enzyme system.
Contribution No. 687, Animal Research Institute. 相似文献
17.
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
18.
Maternally-supplied fish oil alters piglet immune cell fatty acid profile and eicosanoid production 总被引:5,自引:0,他引:5
This study was designed to examine the incorporation of omega-3 (n−3) fatty acids into the immune tissues of pigs nursing
fish oil-fed sows and to determine the effect of maternal dietary n−3 consumption onin vitro immune cell eicosanoid production. On day 107 of gestation, 12 sows were randomly allotted to a diet containing either 7%
menhaden fish oil (MFO) or lard (LRD). The fatty acid profile of serum, liver, thymus, splenocytes and alveolar macrophages
(AM) of 18–21-day-old pigs was significantly affected by the fat source provided to the sow. Arachidonic acid (20∶4n−6) content
was typically reduced by more than 50% in MFO as compared with LRD pigs. In MFO pigs, eicosapentaenoic acid (20∶5n−3) was
the major n−3 polyunsaturated fatty acid, and its levels matched or exceeded those of arachidonic acid. Basal release of prostaglandin
E, thromboxane B and leukotriene B by AM was 60–70% lower in MFOvs. LRD pigs. However, when these immune cells were stimulated with calcium ionophore A23187, release of leukotriene B was similar
in MFO and LRD pigs. In conclusion, substituting MFO for LRD in a sow's late-gestation and lactation diet greatly elevated
the content of n−3 fatty acids in the nursing pig immune cells and generally reducedin vitro eicosanoid release by pig immune cells.
Presented in part at the 1991 Midwest Animal Sciences meeting, Des Moines, Iowa. 相似文献
19.
We have studied the effect of various diets on the phospholipid fatty acid composition andin vitro Δ5 desaturase activity of hepatic microsomes derived either from the normal or streptozotocin-induced diabetic rat. The diets
studied were the standard rat chow diet and a basal fat-free diet supplemented either with 20 percent saturated fat, 20 percent
unsaturated fat, or 20 percent menhaden oil. Phospholipid fatty acid composition analysis revealed that the normal rat fed
the saturated fat or menhaden oil diet had significantly decreased arachidonate levels, consistent with decreased Δ5 desaturase
activities and decreased 18∶2n−6 intake. On the contrary, the unsaturated fat diet decreased dihomo-γ-linolenate and increased
arachidonate levels, without increased Δ5 desaturase activity. Streptozotocininduced diabetes resulted in decreased arachidonate
and Δ5 desaturase activity. The unsaturated fat diet fed to the diabetic rat also failed to correct this decreased Δ5 desaturase
activity. The unsaturated fatty acids in this diet also displaced a substantial amount of n−3 fatty acids in both normal and
diabetic microsomes, due to the competition between these two fatty acid families for incorporation into the membrane phospholipids.
Conversely, the menhaden oil diet fed to the normal and diabetic rats displaced n−6 fatty acids, reduced Δ5 desaturase activity,
and enhanced 22∶6n−3 incorporation into diabetic microsomes. 相似文献
20.
This investigation was carried out to characterize the effects of specific dietary marine oils on tissue and plasma fatty
acids and their capacity to generate metabolites (prostanoids, lipid peroxides). Young male guinea pigs were fed nonpurified
diet (NP), or NP supplemented (10%, w/w) with menhaden fish oil (MO), harp seal oil (SLO), or corn oil (CO, control diet)
for 23 to 28 d. Only the plasma showed significant n−3 polyunsaturated fatty acid (PUFA)-induced reductions in triacylglycerol
(TAG) or total cholesterol concentration. Proportions of total n−3 PUFA in organs and plasma were elevated significantly in
both MO and SLO dietary groups (relative to CO), and in all TAG fractions levels were significantly higher in MO-than SLO-fed
animals. The two marine oil groups differed in their patterns of incorporation of eicosapentaenoic acid (EPA). In guinea pigs
fed MO, the highest levels of EPA were in the plasma TAG, whereas in SLO-fed animals, maximal incorporation of EPA was in
the heart polar lipids (PL). In both marine oil groups, the greatest increases in both docosahexaenoic acid (22∶6n−3, DHA)
and docosapentaenoic acid (22∶5n−3, DPA) relative to the CO group, were in plasma TAG, although the highest proportions of
DHA and DPA were in liver PL and heart TAG, respectively. In comparing the MO and SLO groups, the greatest difference in levels
of DHA was in heart TAG (MO>SLO, P<0.005), and in levels of DPA was in heart PL (SLO>MO, P<0.0001). The only significant reduction in proportions of the major n−6 PUFA, arachidonic acid (AA), was in the heart PL
of the SLO group (SLO>MO=CO, P<0.005). Marine oil feeding altered ex vivo generation of several prostanoid metabolites of AA, significantly decreasing thromboxane A2 synthesis in homogenates of hearts and livers of guinea pigs fed MO and SLO, respectively (P<0.04 for both, relative to CO). Lipid peroxides were elevated to similar levels in MO- and SLO-fed animals in plasma, liver,
and adipose tissue, but not in heart preparations. This study has shown that guinea pigs respond to dietary marine oils with
increased organ and plasma n−3 PUFA, and changes in potential synthesis of metabolites. They also appear to respond to n−3
PUFA-enriched diets in a manner that is different from that of rats. 相似文献