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1.
Hepatic lipid characteristics and histopathology of laying hens fed CLA or n−3 fatty acids 总被引:2,自引:0,他引:2
The effect of dietary CLA and n−3 PUFA on hepatic TAG accumulation, histopathology, and FA incorporation in lipid classes
by laying chickens was investigated. One hundred twenty 30-wk-old single-comb white leghorn laying hens were distributed randomly
to four treatments (3 replications of 10 birds) and were fed diets containing CLA and animal fat (Diet I), 18∶3n−3 (Diet II),
or long-chain n−3 FA (Diet III). A sunflower oil (n−6 FA)-based diet was the control. Feeding Diet I resulted in an increase
in hepatic total lipids (P<0.05). The liver TAG content was 32.2, 18.9, 29.4, and 18.7 mg/g for hens fed Diet I, Diet II, Diet III, and the control
diet, respectively (P<0.05). The serum TAG was lowest in bilds fed Diet II (P<0.05). Diet I resulted in an increase in the total number of fat vacuoles and lipid infiltration in hepatocytes (P<0.05). The number of cells with 75% or higher lipid vacuolation was observed only in birds fed Diet I. Feeding diets containing
CLA resulted in an increase in the content of the c9,t11 CLA isomer in liver TAG and PC (P<0.05). No difference was observed in the CLA concentration of hepatic PE fractions. The content of DHA (22∶6n−3) was higher
in the TAG, PC, and PE of hens fed Diet II and Diet III than Diet I and the control (P<0.05). Feeding CLA resulted in an increase in total saturated FA in the TAG and PC fractions (P<0.05). Long-term feeding of CLA in laying birds leads to an increase in liver TAG and may predispose birds to fatty liver
hemorrhagic syndrome. 相似文献
2.
To examine whether dietary fat alters membrane lipid composition and peroxidation of polyunsaturated fatty acids in “non-proliferative”
and “proliferative” cells in the large intestine, Sprague-Dawley rats were fed diets providing a polyunsaturated-to-saturated
fatty acid ratio of 1.2 or 0.3 at a high or low level of fat intake for a 25-day period. Cell populations were isolated and
the effect of dietary fat on membrane polyunsaturated fatty acid content and peroxide levels was determined. Neither fat level
nor fatty acid composition of diet influenced total cholesterol, total phospholipids, and percentage of phospholipid classes
in membrane phospholipids. Feeding the high fat and/or high polyunsaturated-to-saturated fatty acid ratio diet increased polyunsaturated
fatty acid content of mucosal cell phospholipids. Increase in polyunsaturated fatty acid content was paralleled by a decrease
in the monounsaturated fatty acid content of mucosal cell phospholipids. Membrane content of total saturated fatty acids was
not significantly affected by diet. Variation in phospholipid fatty acid composition between “non-proliferative” and ”proliferative”
cells was observed. Lipid peroxide levels in mucosal cell lipid fractions were altered by dietary fat treatment. Animals fed
high fat diets, compared to groups fed low fat diets, exhibited higher membrane peroxide levels when results are expressed
as nmol/mg protein. Higher peroxide levels were observed in mucosal cells for rats fed high polyunsaturated-to-saturated fatty
acid ratio diets when results were expressed per nmol of phospholipid. It is concluded that changes in fat level and fatty
acid composition of the diet alters the mucosal cell membrane lipid composition in the rat large intestine and influences
susceptibility of mucosal cell lipid to peroxidation. Further research is required to delineate which dietary factors—fat
level, polyunsaturated-to-saturated fatty acid ratio, or both—have a primary influence on the degree of lipid peroxidation. 相似文献
3.
This study was designed to test the hypotheses that digestibility and post-absorption metabolism of fish oil are influenced
by impaired lipolysis and by the stereospecific composition of its triacylglycerols. Male Wistar rats were fed nonpurified
diets containing one of the following fat sources: 9% native fish oil (NFO), 9% autorandomized fish oil (RFO), 8.1% fish oil-derived
free fatty acids (FO-FFA) plus 0.9% glycerol, or 9% soybean oil (SO) as a reference fat. In a 24-day balance study, apparent
digestibility of total dietary fat averaged 93.1% in the SO, NFO and RFO groups, and 90.9% in the FO-FFA group. Randomization
of fish oil had no effect on apparent digestibility of individual fatty acids. In rats fed FO-FFA, apparent absorption of
saturated and monounsaturated fatty acids was lower when compared to the NFO and RFO groups. Feeding the FO-FFA diet tended
to increase plasma triglyceride content. The hypocholesterolemic effect of polyunsaturated n−3 fatty acids was not influenced
by the dietary source. Similar effects on fatty acid profiles of plasma and liver phospholipids were caused by the NFO, RFO
and the FO-FFA diets. We conclude that once polyunsaturated n−3 fatty acids are absorbed, their effect on lipid metabolism
is not determined by the dietary source. 相似文献
4.
Masaharu Kamei Sumiko Ohgaki Tamotsu Kanbe Mitsuru Shimizu Shigeru Morita Isao Niiya Isao Matsui-Yuasa Shuzo Otani 《Lipids》1996,31(11):1151-1156
The effects of dietary highly hydrogenated soybean oil (HSO) upon the changes caused by dietary polychlorinated biphenyls
(PCBs) were examined in rats. Six groups of rats were fed the following diets for 30 d: a 20% soybean oil-containing diet
(control diet), a diet in which a half of soybean oil was substituted with HSO (HSO-A diet), a diet in which cellulose powder
was replaced with HSO (HSO-B diet) and these diets supplemented with 100 ppm PCBs (control+PCBs, HSO-A+PCBs and HSO-B+PCBs
diets). Hepatic concentration of PCBs and relative liver weight were markedly decreased in rats fed with the HSO-A+PCBs diet
compared with those fed with the other diets containing PCBs. Liver lipids and liver cholesterol were considerably decreased
with a reciprocal increase in fecal sterol excretion by rats fed the HSO-A+PCBs and the HSO-B+PCBs diets compared with those
fed with the control+PCBs diet. The fatty acid composition in hepatic phospholipids showed an independent increase of the
saturated fatty acid content induced by dietary HSO and PCBs. Dietary PCBs also caused decreases in the amounts of monounsaturated
and n-3 polyunsaturated fatty acids. These results suggest that dietary HSO prevents accumulation of PCBs in the liver and
promotes the excretion of lipids stimulated by PCBs, accompanied by a change in fatty acid metabolism. 相似文献
5.
Ramesh Kumar Selvaraj Gita Cherian 《European Journal of Lipid Science and Technology》2004,106(1):3-10
The splenocyte fatty acid profile and immune response of broiler chickens were investigated. One hundred and twenty day‐old broiler chicks were fed diets containing conjugated linoleic acid (CLA) (Diet I), sunflower oil (Diet II), flaxseed oil (Diet III) or fish oil (Diet IV). The total lipid content of the diets was 3.5%. Body weight and feed intake was higher (P <0.05) in Diet IV compared to Diets I, II and III. Birds fed Diet III and IV had a higher content of n‐3 fatty acids in splenocytes than those fed Diets I and II. Serum anti‐BSA immunoglobulin content was higher (P <0.05) in birds fed Diets III and IV, compared to those fed Diets I and II. Delayed type hypersensitivity response, measured as the wing web skin swelling reaction (thickness) to Mycobacterium butyricum injection (s.c.), increased (P <0.05) from 0.71 and 0.98 mm in Diets IV and III, respectively, to 1.19 and 1.41 mm in Diets I and II, respectively. The number of CD4+ and CD8+ blood lymphocytes and CD4+, CD8+ and IgM+ splenocytes did not differ (P >0.05) between treatment groups. N‐3 fatty acids increased production performances and antibody mediated responses, while n‐6 fatty acids and conjugated linoleic acid increased cell mediated responses in broiler birds. 相似文献
6.
Essential fatty acid deficiency consistently depresses eicosanoid (prostaglandin E2, F2, and I2 and thromboxane) biosynthesis independent of sampling protocols. Tissue fatty acid analyses support the hypothesis that the
decrease is due in part to depression of arachidonate and accumulation of eicosatrienoate (n−9). Research on the alteration
of eicosanoid biosynthesis by dietary linoleate supplementation is reviewed extensively. Responses of whole blood, lung, liver
and heart eicosanoid synthesis to feeding eight concentrations of dietary linoleate between 0 and 27 energy percent are reported.
It is concluded that stimulation, depression and no change in eicosanoid production could be equally well documented as a
response to linoleate supplementation. Evidence for the obvious mechanism that alterations in precursor fatty acid composition
are a possible explanation is fragmentary and inconsistent. The appropriate sampling techniques appear not to be established
at this time and most likely are species, gender and tissue specific. 相似文献
7.
CLA has been shown to induce or suppress excess liver lipid accumulation in various animal models. Interestingly, the state
of insulin resistance may be an important modulator of this effect. The objective of the current study was to determine how
feeding a dietary CLA mixture would affect liver lipid accumulation in insulin-resistant/obese and lean rats in relation to
liver function, lipidemia, liver TAG and phospholipid FA composition, and expression of hepatic markers of FA transport, oxidation,
and synthesis. Six-week-old fa/fa and lean Zucker rats (n=20/genotype) were fed either a 1.5% CLA mixture or a control diet for 8 wk. CLA supplementation reduced liver lipid concentration
of fa/fa rats by 62% in concurrence with improved liver function (lower serum alanine aminotransferase and alkaline phosphatase) and
favorable modification of the serum lipoprotein profile (reduced VLDL and LDL and elevated HDL) compared with control-fed
fa/fa rats. The fa/fa genotype had two-thirds the amount of CLA (as % total FA) incorporated into liver TAG and phospholipids compared with the
lean genotype. In both genotypes, CLA altered the hepatic FA profile (TAG greater than phospholipids) and these changes were
explained by a desaturase enzyme index. Liver-FA-binding protein and acyl CoA oxidase, markers of FA transport and oxidation,
respectively, were expressed at higher levels in CLA-fed fa/fa rats. In summary, these results illustrate a strong relationship between the state of insulin resistance and liver lipid
metabolism and suggest that CLA acts to favorably modify lipid metabolism in fa/fa Zucker rats. 相似文献
8.
Day-old male broiler chickens were fed semipurified diets containing 5% lipid from one of four different lipid sources: corn
oil (CO), partially hydrogenated soybean oil (HSBO), a spent restaurant grease (SRG) and a purified mixture of triolein, tripalmitin
and tristearin (OPS). Diets CO and HSBO contained adequate amounts of linoleic acid, but diets SRG and OPS were deficient
in linoleate. In addition, SRG and HSBO containedtrans isomers of 16∶1 and 18∶1. The diets were fed for 3 wk to determine the effects of low linoleate levels andtrans isomers on fatty acid profiles in liver microsomes, mitochondria and cytosol. Chicks fed HSBO had the highest body weights,
while those fed SRG and OPS had the lowest. The incidence and severity of dermatitis were similar for all treatments. The
proportions of linoleate and arachidonate in lipids from liver subcecullar fractions were reduced significantly in chicks
fed OPS and SRG; however levels of 20∶3ω9 were not increased. Feeding HSBO, which is high in both linoleate and linolenate,
resulted in higher levels of 18∶3ω3 and 20∶5ω3 in liver subcellular fractions and lower levels of 20∶4ω6 than those seen in
chicks fed CO. The isomeric forms of 18∶1 present in the partially hydrogenated fats (HSBO and SRG) appeared to be incorporated
into the lipids of liver fractions. The results of this study show that dietary lipids influence fatty acid, profiles of chick
liver microsomes, mitochondria and cytosol. Decreases in linoleate and arachidonate in these organelles occur before overt
essential fatty acid (EFA) deficiency signs in chicks fed EFA-deficient diets.
Published as Scientific Paper No. 7512, College of Agriculture and Home Economics Research Center, Project No. 4723, Washington
State University, Pullman, WA. 相似文献
9.
Dietary Linseed Oil Reduces Growth While Differentially Impacting LC-PUFA Synthesis and Accretion into Tissues in Eurasian Perch (Perca fluviatilis)
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F. Geay D. Wenon J. Mellery E. Tinti S. N. M. Mandiki D. R. Tocher C. Debier Y. Larondelle P. Kestemont 《Lipids》2015,50(12):1219-1232
The aim of this study was to evaluate the impact of replacing dietary fish oil (FO) with linseed oil (LO) on growth, fatty acid composition and regulation of lipid metabolism in Eurasian perch (Perca fluviatilis) juveniles. Fish (17.5 g initial body weight) were fed isoproteic and isoenergetic diets containing 116 g/kg of lipid for 10 weeks. Fish fed the LO diet displayed lower growth rates and lower levels of DHA in the liver and muscle than fish fed the FO diet, while mortality was not affected by dietary treatment. However, DHA content recorded in the liver and muscle of fish fed the LO diet remained relatively high, despite a weight gain of 134 % and a reduced dietary level of long‐chain polyunsaturated fatty acids (LC‐PUFA), suggesting endogenous LC‐PUFA biosynthesis. This was supported by the higher amounts of pathway intermediates, including 18:4n‐3, 20:3n‐3, 20:4n‐3, 18:3n‐6 and 20:3n‐6, recorded in the liver of fish fed the LO diet in comparison with those fed the FO diet. However, fads2 and elovl5 gene expression and FADS2 enzyme activity were comparable between the two groups. Similarly, the expression of genes involved in eicosanoid synthesis was not modulated by dietary LO. Thus, the present study demonstrated that in fish fed LO for 10 weeks, growth was reduced but DHA levels in tissues were largely maintained compared to fish fed FO, suggesting a physiologically relevant rate of endogenous LC‐PUFA biosynthesis capacity. 相似文献
10.
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
11.
Diets supplemented with high levels of saturated fatty acids derived from sheep kidney (perirenal) fat or unsaturated fatty
acids derived from sunflowerseed oil were fed to marmoset monkeys for 22 wk. The effect of such diets on plasma, red blood
cell phospholipids, and liver, heart, kidney and brain mitochondrial phospholipid fatty acids was determined. Despite large
differences in the level and type of lipid present in the experimental diets, there was little effect on the proportion of
saturated to unsaturated fatty acids in the phospholipids of the membranes examined. The diets did, however, alter the proportion
of the various classes of polyunsaturated fatty acids in the membrane phospholipids, with the sunflower-seed oil diet elevating
and the sheep kidney fat diet reducing the n−6/n−3 unsaturated fatty acid ratio, relative to a low (mixed fat) reference diet.
This change occurred in all membranes except brain, in which only a small response to altered dietary lipid intake was observed.
Elevation of dietary linoleic acid led to an increase in membrane linoleic acid and a marked decrease in membrane arachidonic
acid, such that the membranes from animals fed the sunflowerseed oil diet exhibited the lowest proportion of arachidonic acid.
In this latter respect, the response of the marmoset monkey to dietary lipid supplementation differs markedly from the rat.
Our inability to alter significantly membrane lipid saturation/unsaturation supports the notion that a homeostatic mechanism
is in some way responsible for buffering membranes from the effects of significant changes in the nature of the dietary lipid
intake. 相似文献
12.
Effects of dietary conjugated linoleic acids on hepatic and muscle lipids in hybrid striped bass 总被引:9,自引:0,他引:9
Conjugated linoleic acids (CLA) are the focus of numerous studies, yet the effects of these isomers of octadecadienoic acids
have not been evaluated in many species of fish. In this study, graded amounts of CLA-0,0.5, 0.75, or 1.0% of the diet—were
fed to juvenile hybrid striped bass for 8 wk. Dietary treatments were fed to apparent satiation twice daily to triplicate
groups of fish initially weighing 13.4 g/fish. Feed intake and weight gain of fish fed 1.0% CLA were significantly reduced
compared to fish fed no CLA. Fish fed 0.5 and 0.75% CLA exhibited reduced feed intake similar to fish fed 1.0% CLA, but had
growth rates that were not significantly different from those of fish fed no CLA. Feed efficiency improved significantly in
fish as dietary CLA concentrations increased. Total liver lipid concentrations were significantly reduced in fish fed the
diets containing CLA compared to those of fish fed the control diet, and intraperitoneal fat ratio was significantly lower
in fish fed 1.0% CLA compared to fish fed no CLA. Fish fed dietary CLA exhibited significant increases in hepatosomatic index
and moisture content of muscle and carcass. The CLA isomers were detected in liver and muscle of fish fed the diets containing
CLA, while a low concentration of one isomer was detected in liver and muscle of fish fed the control diet. Dietary CLA resulted
in a significant increase in 18∶2(c-9,c-12) concentration in liver and muscle, but a significant reduction in 18∶1n−7 in these tissues. Furthermore, feeding CLA
resulted in a significant increase in the concentration of 20∶5n−3 and 22∶6n−3 in liver, but a reduction of these fatty acids
in muscle. This study showed that feeding CLA elevated tissue concentrations of these fatty acid isomers, reduced tissue lipid
contents, improved feed efficiency, and altered fatty acid concentrations in liver and muscle of fish. 相似文献
13.
Randall Wood 《Lipids》1982,17(11):763-770
Groups of rats were fed a fat-free diet supplemented with 0.5% safflower oil (control) or the control diet containing 0.5%
of 5,8,11,14-eicosatetraynoic acid (TYA). Blood was collected weekly and plasma lipids analyzed. After 4 weeks, the animals
were killed and the liver lipids were analyzed in detail. The acetylenic fatty acid perturbed plasma neutral lipid and phospholipid
class concentrations and reduced growth rates. Liver triglyceride concentrations were reduced dramatically in the TYA fed
animals, suggesting interference with complex lipid synthesis. Plasma and liver triglycerides were shifted to higher molecular
weight species suggesting that TYA affected fatty acid metabolism. The phospholipids showed an accumulation of 18∶2 and a
fall in 20∶4 percentages indicating an inhibition in the conversion of linoleate to arachidonate. All major lipid classes
exhibited an increase in 18∶1 levels. Analysis of the octadecenoate positional isomers indicated the proportion of oleate
increased substantually in all lipid classes whereas vaccenate proportions had fallen dramatically. All of the data collectively
suggest that TYA inhibits the elongation of unsaturated fatty acids. A group of rats bearing hepatoma 7288CTC were also fed
the TYA diet. Host liver lipids were affected by TYA similar to normal TYA fed animals, but the effects on hepatoma lipids
were marginal. 相似文献
14.
A study was made of the influence of semisynthetic diets of low and high unsaturation on the fatty acid composition and desaturation-chain
elongation enzymatic activity of the liver microsomal fractions of male Sprague-Dawley rats of different ages. Groups of rats
were fed 5 or 20% coconut oil (CO), or a 5 or 20% mixture of corn and menhaden oils (3∶7) (CME) from weaning to 100 wk of
age. Growth rate and food consumption were measured during this period in which animals were sacrificed at 36, 57, 77 and
100 wk of age. Both the level and composition of the dietary fat supplements produced marked effects on the fatty acid composition
of the liver microsomal lipids. In general, the fatty acid composition of the microsomal fractions reflected that of the dietary
fat and was more unsaturated with the higher level of fat fed. The rate of conversion of linoleic to arachidonic acid in assays
performed in vitro with liver microsomal preparations from animals of the different groups also showed marked differences.
The 6-desaturase-chain elongation activity was higher in the 5% than 20% group and corresponded to the essential fatty acid
(EFA) status of the animals in these groups as represented by the triene-tetraene ratio of the microsomal lipid. The relationship
of the 6-desaturase activity to fatty acid composition of the microsomal lipid indicated that if varied directly with the
level of 20∶3ω9, 18∶1 and 16∶1 and was inhibited by arachidonic acid. The activity of the 6-desaturase enzyme system was lowest
in the liver microsomal fraction obtained from the animals fed the CME diets and appeared to be suppressed by the high levels
of 20∶5 and 22∶6 that accumulated in the microsomal lipid. Accordingly, the levels of arachidonic acid were lower in the microsomal
lipid of these groups than those of the corresponding CO groups in spite of a greater abundance of linoleic acid in the diet.
The data suggest that the activity of the 6-desaturase-chain elongation system is regulated by the fatty acid composition
of the microsomal lipid as influenced by the composition of the dietary fat. 相似文献
15.
Groups of rats were fed from weaning with diets containing 5% by wt of hydrogenated coconut oil (HCO), safflower oil, or a
concentrate of ethyl elaidate and linolelaidate (TRANS) as the sole source of dietary fat. Fatty acid composition of the lipid
classes from serum, liver, heart, and kidney was determined, and the serum lecithin: cholesterol acyl transferase (LCAT) activities
were assayed for each animal. Serum LCAT activity was increased by both the HCO and TRANS diets in the early stages of the
development of an essential fatty acid (EFA) deficiency but was suppressed in the animals of the TRANS group as they became
older. The HCO and TRANS groups exhibited changes in tissue lipid fatty acid composition, as well as reduced growth, characteristic
of an EFA deficiency. Conversion of oleic acid to eicosatrienoic acid was impaired in the animals fed the TRANS diet, greatly
increasing the octadecenoic acid content of the tissue lipids at the expense of eicosatrienoic acid. The TRANS diet also suppressed
incorporation of eicosatrienoic acid into cholesteryl esters of tissue and serum, indicating that, when fed as the sole source
of unsaturated fat,trans fatty acids influenced the metabolism of unsaturated fatty acids and cholesterol. 相似文献
16.
Diets in which both the lipid content and composition (polyunsaturated to saturated fatty acid ratio) were varied were fed
to rats for 20 weeks, and the effects on the tissue lipid profiles were determined. The fatty acid profile of the plasma lipids,
and the phospholipid fatty acids of the mitochondrial and microsomal fractions of liver, heart, kidney and brain, as well
as erythrocyte membranes were determined. Despite large differences in the level and type of lipid present in the experimental
diets and in the proportion of saturated fatty acids in the plasma lipids in response to the various diets, there was little
effect on the proportion of saturated to unsaturated fatty acids in the phospholipids of the various membranes examined. The
major effect of altering the dietary level of polyunsaturated to saturated fatty acids was on the ratio of the ω6/ω3 series
of unsaturated fatty acids in the membrane lipids. This change occurred in all tissues except the brain, in which only a small
response to altered dietary lipid intake was observed. The ω6/ω3 ratio was elevated upon feeding a diet rich in ω6 polyunsaturated
fatty acids, but decreased when a diet rich in saturated fatty acids was fed. The failure to significantly alter membrane
lipid saturation/unsaturation in the tissues examined would suggest that a homeostatic mechanism is operative in biological
membranes and may act to buffer membranes from the effects of changes in the nature of the dietary lipid intake. 相似文献
17.
L. G. Cleland M. A. Neumann R. A. Gibson T. Hamazaki K. Akimoto M. J. James 《Lipids》1996,31(8):829-837
n-9 Eicosatrienoic acid (ETrA), also known as Mead acid, is a minor fatty acid in essential fatty acid (EFA)-sufficient healthy
subjects but is found at increased levels in EFA deficiency. This study examined the influence of dietary ETrA from a biological
source on plasma and tissue ETrA. A synthetic fat-free diet was prepared to which was added Mut 48 oil which contains 19%
ETrA (wt%) as well as other n-9 fatty acids. Blends of vegetable oils were used to achieve overall diets with 5% fat (wt%)
and varying amounts of ETrA at two different dietary levels of linoleic acid (LA), approximately 4.4 and 19% of total fatty
acids. These diets were fed to 5-week-old Dark Agouti rats for four weeks. Plasma lipid fractions and liver, spleen, and peritoneal
exudate (PE) cells were analyzed for fatty acid composition. ETrA was present at up to 20% total fatty acids in plasma triglyceride,
cholesterol ester, and phospholipid fractions. ETrA also accumulated to substantial levels in phospholipids of liver and spleen
(up to 15% of total fatty acids) and PE cells (up to 11%). ETrA was found in plasma and tissue phospholipids in proportion
to the amount of ETrA present in the diet. The incorporation was reduced in diets with higher LA content compared to diets
containing similar amounts of ETrA but lower LA. All rats remained apparently healthy, and histological survey of major organs
revealed no abnormality. While the long-term implications for health of ingestion of diets rich in ETrA remain to be established,
rats appear to tolerate high levels of dietary ETrA without adverse effects. Dietary enrichment with ETrA warrants further
investigation for possible beneficial effects in models of inflammation and autoimmunity, as well as in other conditions in
which mediators derived from n-6 fatty acids can affect homeostasis adversely. 相似文献
18.
trans-10,cis-12 (t10c12) Conjugated linoleic acid (CLA) reduced body lipid deposition in various experimental animals, but the mechanisms involved were still emerging. Carnitine palmitoyltransferase I (CPT I) catalyzes an important regulatory step in lipid metabolism. At present, no studies, to our knowledge, have evaluated the kinetic constants influenced by dietary CLA in fish. In the present study, we tested the hypothesis that changes in body lipid content in fish as a response to dietary t10c12 CLA was related to the change of CPT I kinetic constants [Michaelis constant (K m), maximal velocity and catalytic efficiency for carnitine and palmitoyl-CoA]. Juvenile Synechogobius hasta were fed three experimental diets with fish oil replaced with 0 (control), 1, or 2 % t10c12 CLA for 8 weeks. Weight gain, specific growth rate and protein efficiency rate increased with dietary t10c12 CLA level. Dietary t10c12 CLA addition significantly reduced lipid contents both in liver and muscle. Dietary CLA addition also improved CPT I activities in muscle but did not significantly influence hepatic CPT I activity. CPT I kinetic parameters (K m, V max and catalytic efficiency) were significantly influenced by t10c12 CLA. CPT I catalytic efficiencies with carnitine and palmitoyl-CoA as substrates were higher in muscle and liver of fish fed increasing t10c12 CLA. For the first time, the findings demonstrated effect of dietary CLA addition on CPT I kinetics in fish and supported our starting hypothesis that dietary t10c12 CLA addition induced alterations in CPT I kinetic constants of muscle and liver. Increased CPT I catalytic efficiency might be the main reason for reduced lipid deposition in these tissues by dietary t10c12 CLA supplementation. 相似文献
19.
Dietary conjugated linoleic acid reciprocally modifies ketogenesis and lipid secretion by the rat liver 总被引:3,自引:0,他引:3
Sakono M Miyanaga F Kawahara S Yamauchi K Fukuda N Watanabe K Iwata T Sugano M 《Lipids》1999,34(9):997-1000
The effects of dietary conjugated linoleic acid (CLA) and linoleic acid (LA) on ketone body production and lipid secretion
were compared in isolated perfused rat liver. After feeding the 1% CLA diet for 2 wk, the concentration of post-perfused liver
cholesterol was significantly reduced by CLA feeding, whereas that of triacylglycerol remained unchanged. Livers from CLA-fed
rats produced significantly more ketone bodies; and the ratio of β-hydroxybutyrate to acetoacetate, an index of mitochondrial
redox potential, tended to be consistently higher in the liver perfusate. Conversely, cumulative secretions of triacylglycerol
and cholesterol were consistently lower in the livers of rats fed CLA, and the reduction in the latter was statistically significant.
Thus dietary CLA appeared to exert its hypolipidemic effect at least in part through an enhanced β-oxidation of fatty acids
at the expense of esterification of fatty acid in the liver. 相似文献
20.
Dietary fats which were protected from ruminal metabolism were fed to ruminants, and the constituent fatty acids subsequently
appeared in the glycerides of tissues and secretory products. These dietary fat induced alterations in tissue lipid composition
were particularly apparent when the fat source was enriched with linoleic acid. Similarly, when pigs were fed linoleic-enriched
fats, the linoleic acid was incorporated into the adipose tissue triglycerides. Stereospecific analyses were carried out on
triglycerides from various tissues and secretory products obtained from animals fed control or linoleate-enriched diets. The
analysis of adipose tissue triglycerides showed that linoleate and oleate were preferentially esterified to positions 2 and
3 (cattle and sheep), and positions 1 and 3 (pigs). Of the other major adipose tissue fatty acids, palmitate was preferentially
esterified at position 1 (ruminants) and position 2 (pigs), and stearate was preferentially esterified at positions 1 and
3 (ruminants), and position 1 (pigs). Stereospecific analysis of high mol wt milk triglycerides showed that linoleate was
either evenly distributed on all three positions (goats), or predominantly on position 3 (cows). Furthermore, the incorporation
of this linoleate did not markedly alter the positional specificity of the other major milk triglyceride fatty acids. Of these
fatty acids, the short and medium chain length acids (butyratelaurate) were mainly on position 3, myristate and palmitate
on positions 1 and 2, and stearate and oleate evenly distributed. Thoracic duct lymph triglycerides from sheep tended to show
preferential incorporation of linoleate at position 3, palmitate at position 2, and stearate at position 1 and 3; oleate,
on the other hand, tended to be evenly distributed on all three positions of the lymph triglyceride. The stereospecific arrangement
of fatty acids in sheep liver triglycerides was similar to that of lymph triglycerides, and this may reflect the uptake of
intact or partially hydrolysed chylomicron and/or very low density lipoprotein triglycerides by the liver. There were also
some analogies in the stereospecific arrangement of fatty acids on ruminant lymph and milk triglycerides and this may reflect
an incomplete hydrolysis of chylomicron and/or very low density lipoprotein triglycerides prior to uptake by the mammary gland.
An unusual feature of lymph from sheep fed linoleate was the presence of phospholipids which contained large amounts of linoleate
in ca. equal proportion at both positions 1 and 2 of the phospholipid molecule. 相似文献