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1.
The lipid and FA composition of the total lipids of the pearl oyster Pinctada fucata martensii, in different seasons and in different areas, were analyzed to clarify its lipid physiology and to estimate the possible
influence of its prey phytoplankton. TAG and sterols were the major components in the neutral lipids in all conditions, whereas
high levels of phospholipids (PE and PC) were found in the polar lipids. The major FA in the TAG in all samples were 14∶0,
16∶0, and 18∶0 as saturated FA (saturates); 16∶1n−7, 18∶1n−9, and 18∶1n−7 as monoenoic FA (monoenes); and 20∶4n−6 (arachidonic
acid: AA), 20∶5n−3 (EPA), and 22∶6n−3 (DHA) as PUFA. The major components found in the polar lipids were 16∶0 and 18∶0 as
saturates; 22∶2n−9, 15 and 22∶2n−7, 15 as non-methylene-interrupted dienes (NMID), and AA, 22∶3n−6, 9, 15, EPA, and DHA as
PUFA. Although it is a marine animal, characteristically high levels of AA were found in both the TAG and phospholipids. This
result suggests that lipids of P. fucata may be influenced by those of its phytoplanktonic prey. The increase in levels of NMID from TAG to PE with a decrease in
those of monoenes suggests that the tissues of this species are able to biosynthesize only the less unsaturated PUFA, such
as NMID. In particular, NMID derivatives are considered to be biosynthesized in the PE; thus, they might play a particular
role in the membrane, because NMID were characteristically localized only in the PE. 相似文献
2.
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
3.
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
4.
The effect of the water-soluble fraction (WSF) of crude oil on lipid contents, lipid classes, FA, and PC molecular species
was studied in high-phospholipid (hepatopancreas) and low-phospholipid (egg) tissues of a freshwater crustacean. After a 21-d
exposure to a sublethal concentration of WSF, a significant decrease in shrimp total lipids was observed, although no alterations
could be detected in the hepatopancreas or egg lipid contents. TAG/phospholipid ratios increased in the hepatopancreas and
decreased in the eggs, suggesting alterations either in the mobilization of TAG to phospholipid pools or in the energy balance.
The FA composition of phosphoglycerides in the hepatopancreas and eggs was dominated by PUFA, whereas the n−3/n−6 ratio was
not affected by WSF exposure, although there was a significant increase in hepatopancreas 18∶1n−9. Analysis of the PC molecular
species by HPLC-ELSD showed the presence of 15 species, with 16∶0/18∶1, 18∶1/18∶2, 16∶0/20∶5, and 16∶1/20∶5 being the major
species in the hepatopancreas. The PC molecular species in the eggs showed a different pattern, dominated by 16∶0/18∶1 and
18∶1/18∶2. Of the PC molecular species, 10 contained 22∶6n−3, 20∶5n−3, and 20∶4n−6. Small amounts of di-PUFA species were
also found. Exposure to WSF altered the PC molecular species in both tissues. The four major hepatopancreas molecular species
and most of the ones containing PUFA decreased. This was compensated for by an increase in 16∶1/18∶1 (152%) and 18∶1/18∶1
(50%). The two major egg PC molecular species decreased, whereas the PUFA-containing ones increased. The contrasting responses
of both tissues of WSF contamination suggests the presence of different homeostatic mechanisms. 相似文献
5.
The total lipid and fatty acid compositions of tissues and the stomach contents of three subtropical marine fish species,
subfamily Caesioninae, Caesio diagramma and C. tile, and family Siganidae Siganus canaliculatus, were investigated to clarify the differences between these species. Triacylglycerols (TAG) were the dominant depot lipids
of the three species, whereas wax esters were found as a minor component. In particular, muscle lipids were found to contain
mainly glycerol derivatives such as TAG and phospholipids. The major fatty acids identified in the three species were 16∶0,
18∶0, 18∶1n−9, and 22∶6n−3 (docosahexaenoic acid, DHA). In addition, noticeable levels of 16∶1n−7, 18∶1n−7, 20∶4n−6 (arachidonic
acid, AA), and 20∶5n−3 (eicosapentaenoic acid) were found. DHA was the most abundant polyunsaturated fatty acid (PUFA) in
the muscle and viscera lipids of the three species. The high DHA levels in the lipids of all the organs were found to be higher
than those of the lipid extracted from the stomach contents of the three fishes. In addition, the specimens of S. canaliculatus contained significantly higher levels of AA in its tissues than did the other two species. A high AA content is unusual since
such high levels of n−6 PUFA are rarely found in higher marine organisms. These levels may be due to its characteristic feeding
pattern, because S. canaliculatus prefer and mainly feed on seaweed, which often contains high amounts of n−6 PUFA, such as linoleic acid (18∶2n−6) and AA. 相似文献
6.
The FA composition of Fasciola hepatica 12 kDA purified native FA-binding protein (nFh12), a candidate vaccine against fascioliasis, is described. The FA chain lengths ranged between 12 and 24 carbons. The
principal FA were 16∶0 18∶1n−9, 18∶0, 20∶4n−6, and 20∶1n−9. The acids 16∶0, 18∶1n−9, and 18∶0 comprised over half the FA that
were bound to the whole FA-binding protein. Small amounts (1.0–2.8%) of isoanteiso methyl-branched FA also were characterized. Forty-one different FA were identified in extracts of the adult flukes, with
the three most abundant FA also being 16∶0, 18∶1n−9, and 18∶0. A similar proportion of saturated vs. unsaturated FA was observed
between the whole extract from F. hepatica and the nFh12 protein. However, the n−3/n−6 ratio of PUFA was significantly different, being 1.2 in the whole extract vs. 9.6 in the
nFh12 protein complex. The nFh12 protein binds more n−5, n−6, and n−7 PUFA and less n−3 and n−9 PUFA than the whole extract. In addition, cholesterol
(56%), sitosterol (36%), and fucosterol (8%) also were bound to the nFh12 protein complex. 相似文献
7.
Supercritical fluid extracts of New Zealand green-lipped mussels (NZGLM) have been suggested to have therapeutic properties
related to their oil components. The large number of minor FA in NZGLM extract was characterized by a GC-CIMS/MS method that
excels at identification of double-bond positions in FAME. The extract contained five major lipid classes: sterol esters,
TAG, FFA, sterols, and polar lipids. The total FA content of the lipid extract was 0.664 g/mL. Fifty-three unsaturated FA
(UFA) were fully identified, of which 37 were PUFA, and a further 21 UFA were detected for which concentrations were too low
for assignment of double-bond positions. There were 17 saturated FA, with 14∶0, 16∶0, and 18∶0 present in the greatest concentration.
The 10 n−3 PUFA detected included 20∶5n−3 and 22∶6n−3, the two main n−3 FA; n−3 PUFA at low concentrations were 18∶3, 18∶4,
20∶3, 20∶4, 21∶5, 22∶5, 24∶6, and 28∶8. There were 43 UFA from the n−4, n−5, n−6, n−7, n−8, n−9, n−10, n−11 families, with
16∶2n−4, 16∶1n−5, 18∶1n−5, 18∶2n−6, 20∶4n−6, 16∶1n−7, 20∶1n−7, 16∶1n−9, 18∶1n−9, and 20∶1n−9 being the most abundant. In general,
we estimated that FAME concentrations greater than 0.05% (w/w) were sufficient to assign double-bond positions. In total,
91 FA were detected in an extract of the NZGLM, whereas previous studies of fresh flesh from the NZGLM had reported identification
of 42 FA. These data demonstrate a remarkable diversity of NZGLM FA. 相似文献
8.
The effects of season, geographic source (Lake Geneva, Rhine River), and rearing system (extensive, semiextensive, and intensive
systems) on the lipid content and FA composition of fillets of Perca fluviatilis were studied. Significant differences in the total lipid content were found between fish coming from the Rhine River and
Lake Geneva (1.21 and 1.48%, respectively). Seasonal effects were investigated quarterly for perch sampled in the Rhine River.
Intensively reared perch displayed a higher lipid content (1.48%) than the other farmed perch, i.e., 1.26% for a semiextensive
system and 1.16% for an extensive system. No significant difference in lipid content was found (i) between lacustrine fish
and intensively reared fish or (ii) among fish from the Rhine River and the semiextensive or extensive rearing systems. The
main FA were 22∶6n−3 (DHA, 21.3–37.1% of total FA), 16∶0 (17.7–20.2%), 20∶5n−3 (EPA, 9.2–13.2%), 18∶1 (8.0–11.5%), 20∶4n−6
[arachidonic acid (ARA), 1.9–10.7%], 16∶1 (4.3–6.0%), and 18∶2n−6 (2.1–6.0%). In comparison with perch coming from the Rhine
River, the lacustrine fish were characterized by higher total n−6 PUFA and a lower proportion of both total monounsaturated
FA (MUFA) and total n−3 PUFA. Among rearing systems, extensively farmed fish had higher n−6 PUFA and lower n−3 PUFA contents.
Wild fish showed higher ARA and 18∶2n−6 than farmed fish. They also had significantly more EPA (12.5–13.2%) than farmed perch
(9.2–10.9%). For DHA no difference existed between (i) the lacustrine fish (31.9% of total FA) and the intensively reared
fish (33.0%) and (ii) the Rhine (37.1%) and semiextensively reared fish (36%). Effects of size, diet composition, and environmental
conditions on the total lipid contents and FA composition are discussed. 相似文献
9.
It is widely reported that an association exists between dietary fat intake and the incidence of prostate cancer in humans.
To study this association, there is a need for an animal model where prostate carcinogenesis occurs spontaneously. The canine
prostate is considered a suitable experimental model for prostate cancer in humans since it is morphologically similar to
the human prostate and both humans and dogs have a predisposition to benign and malignant prostate disease. In this study,
the FA and lipids profiles of the normal canine prostate tissue from nine dogs were examined. The total lipid content of the
canine prostate tissue was 1.7±0.5% (wet weight). The lipid composition analysis using TLC-FID showed that the two major lipid
classes were phospholipids and TAG. Total FA, phospholipid, and TAG FA analysis showed that the major FA were palmitic acid
(16∶0), stearic acid (18∶0), oleic acid (18∶1), linoleic acid (18∶2n−6), and arachidonic acid (20∶4n−6), The n−3 FA were present
at <3% of total FA and included α-linolenic acid (18∶3n−3) (in total and TAG tissue FA), EPA (20∶5n−3) (not in TAG), and DHA
(22∶6n−3) (not in TAG). The n−3/n−6 ratio was 1∶11, 1∶13, and 1∶8 in total, phospholipid, and TAG FA, respectively. This study
shows the canine prostate has a low level of n−3 FA and a low n−3/n−6 ratio. This is perhaps due to low n−3 content of the
diet of the dogs. FA analysis of dogfoods available in Australia showed that the n−3 content in both supermarket and premium
bran dogfoods was <3% (wet weight), and the n−3/n−6 ratio was low. 相似文献
10.
To identify a stable resource of 20∶4 n−6 (arachidonic acid, AA) in marine fish tissues, the lipid profiles of Siganus fuscescens organs (muscle, liver, and other viscera) and stomach contents were examined throughout the year. Crude total lipid (TL)
contents in respective organs showed seasonal variations and were high in winter and low in summer. The main FA in TL were
16∶0, 18∶0, 16∶1n−7, 18∶1n−9, AA, and 22∶6n−3 (DHA). These FA were those generally observed in marine fish lipids, except
for comparatively high levels of AA. In TL of muscle and liver, AA showed relatively high values during the period from late
May to August (muscle, 4.6–13.1%; liver, 4.5–9.1%), compared with other seasons (muscle, 4.3–9.5%; liver, 3.6–8.4%). The AA
levels in TL of other viscera and stomach contents fluctuated (other viscera, 2.0–10.7%; stomach contents, 7.6–26.7%). Regardless
of the fishing season, each organ contained a higher level of AA in polar lipids (PL) than in neutral lipids. It was concluded
that the fish contain comparatively high levels of AA in their TL throughout the year, and they accumulate AA characteristically
in their tissue PL, probably from dietary food sources. Moreover, it was suggested that S. fuscescens has potential utility as a natural marine source of nutritional lipids, because the fish contain comparatively high levels
of DHA and AA. 相似文献
11.
Fatty acid profiles and relative mobilization during fasting in adipose tissue depots of the American marten (Martes americana) 总被引:2,自引:2,他引:0
The American marten (Martes americana) is a boreal forest marten with low body adiposity but high metabolic rate. The study describes the FA composition in white
adipose tissue depots of the species and the influence of food deprivation on them. American marten (n=8) were fasted for 2 d with 7 control animals. Fasting resulted in a 13.4% weight loss, while the relative fat mass was >25%
lower in the fasted animals. The FA composition of the fat depots of the trunk was quite similar to other previously studied
mustelids with 14∶0, 16∶0, 18∶0, 16∶1n−7, 18∶1n−9, and 18∶2n−6 as the most abundant FA. In the extremities, there were higher
proportions of monounsaturated FA (MUFA) and PUFA. Food deprivation decreased the proportions of 16∶0 and 16∶1n−7, while the
proportion of long-chain MUFA increased in the trunk. The mobilization of FA was selective, as 16∶1n−7, 18∶1n−9, and particular
n−3 PUFA were preferentially mobilized. Relative mobilization correlated negatively with the carbon chain length in saturated
FA (SFA) and n−9 MUFA. The Δ9 desaturation of SFA enhanced the mobilization of the corresponding MUFA, but the positional
isomerism of the first double bond did not correlate consistently with relative mobilization in MUFA or PUFA. In the marten,
the FA composition of the extremities was highly resistant to fasting, and the tail tip and the paws contained more long-chain
PUFA to prevent the solidification of lipids and to maintain cell membrane fluidity during cooling. 相似文献
12.
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
13.
Masaki Kaneniwa Song Miao Chunhong Yuan Haruka Lida Yutaka Fukuda 《Journal of the American Oil Chemists' Society》2000,77(8):825-831
The lipid and fatty acid composition of muscle of 10 species of freshwater fish obtained from a market of Shanghai City was
examined. Total lipids (TL) ranged over 0.9–4.7% of muscle for all samples. The content of triacylglycerol (TG) in muscle
ranged over 0.2–3.4% and that of polar lipids (PL) was 0.5–1.3%. Differences of TL content were dependent on TG contents.
The predominant important fatty acids (>10% of the total fatty acids in TL) were 16∶0 and 18∶1n−9 with some 16∶1n−7, 18∶2n−6,
and 22∶6n−3. The polyunsaturated fatty acids (PUFA) content was 10.2–43.4%, and especially Chinese sea bass contained above
20% of 22∶6n−3 in the total fatty acids. There were higher levels of PUFA such as 20∶5n−3 and 22∶6n−3 in PL than in neutral
lipids. Muscle of the silver carp was stored at 20°C, and changes of lipid classes during storage were examined. Free fatty
acids increased, and PL decreased during storage. This phenomenon was inhibited by heating the muscle, suggesting that lipid
hydrolysis by phospholipase occurred in silver carp muscle. 相似文献
14.
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
15.
J. K. G. Kramer F. D. Sauer M. S. Wolynetz E. R. Farnworth K. M. Johnston 《Lipids》1992,27(8):619-623
Male Sprague-Dawley rats were fed for one week diets containing 20% by weight fat/oil mixtures with different levels of erucic
acid (22∶1n−9) (∼2.5 or 9%) and total saturated fatty acids (∼8 or 35%). Corn oil and high erucic acid rapeseed (HEAR) oil
were fed as controls. The same hearts were evaluated histologically using oil red O staining and chemically for cardiac triacylglycerol
(TAG) and 22∶1n−9 content in cardiac TAG to compare the three methods for assessing lipid accumulation in rat hearts. Rats
fed corn oil showed trace myocardial lipidosis by staining, and a cardiac TAG content of 3.6 mg/g wet weight in the absence
of dietary 22∶1n−9. An increase in dietary 22∶1n−9 resulted in significantly increased myocardial lipidosis as assessed histologically
and by an accumulation of 22∶1n−9 in heart lipids; there was no increase in cardiac TAG except when HEAR oil was fed. An increase
in saturated fatty acids showed no changes in myocardial lipid content assessed histologically, the content of cardiac TAG
or the 22∶1n−9 content of TAG at either 2.5 or 9% dietary 22∶1n−9. The histological staining method was more significantly
correlated to 22∶1n−9 in cardiac TAG (r=0.49;P<0.001) than to total cardiac TAG (r=0.40;P<0.05). The 22∶1n−9 content was highest in cardiac TAG and free fatty acids. Among the cardiac phospholipids, the highest
incorporation was observed into phosphatidylserine, followed by sphingomyelin. With the addition of saturated fat, the fatty
acid composition showed decreased accumulation of 22∶1n−9 and increased levels of arachidonic and docosahexaenoic acids in
most cardiac phospholipids, despite decreased dietary concentrations of their precursor fatty acids, linoleic and linolenic
acids. 相似文献
16.
Lipid and fatty acid composition and energy partitioning during embryo development in the shrimp Macrobrachium borellii 总被引:2,自引:0,他引:2
Energy partitioning, composition of lipids and fatty acids, and their utilization by embryos were determined in the lecithotrophic
shrimp Macrobrachium borellii during seven development stages. The biochemical composition at stage I is represented by lipids, proteins, and carbohydrates,
with 29.3, 28.7, and 0.2% dry weight, respectively. The former two were identified as the major energy-providing components,
contributing 131 and 60 cal/100 mg egg, dry weight, respectively. The overall conversion efficiency (CE) was 45.0% (calculated
as percentage of vitelline energy transformed into embryonic tissues). Lipids were the most important energy reserve (CE 39.3%),
followed by proteins (CE 57.1%), both being simultaneously utilized during development while carbohydrates were synthesized
de novo (CE 587.5%). Variation in the lipid class composition of embryos and vitellus showed an accumulation of triacylglycerols
(TAG) and phospholipids (PL) up to stage IV, a more active accumulation and selective utilization phase (stages V and VI),
and a consumption and de novo synthesis period until hatching. Structural lipids (PL and cholesterol) and pigment astaxanthin were selectively conserved
in embryos, but TAG, hydrocarbons, and esterified sterols were preferentially depleted. Monounsaturated fatty acids (FA) were
the major group in TAG, whereas polyunsaturated FA (PUFA) were the major group in PL after organogenesis. Certain PUFA such
as 22∶6n−3 and 20∶5n−3 were selectively accumulated in PL. 相似文献
17.
The influence of the linoleic acid levels of diets containing partially hydrogenated marine, oils (HMO) rich in isomeric 16∶1,
18∶1, 20∶1 and 22∶1 fatty acids on the fatty acid profiles of lipids from rat liver, heart and adipose tissue was examined.
Five groups of rats were fed diets containing 20 wt% fat−16% HMO+4% vegetable oils. In these diets, the linoleic acid contents
varied between 1.9% and 14.5% of the dietary fatty acids, whereas the contents oftrans fatty acids were 33% in all groups. A sixth group was fed a partially hydrogenated soybean oil (HSOY) diet containing 8%
linoleic acid plus 32%trans fatty acids, mainly 18∶1, and a seventh group, 20% palm oil (PALM), with 10% linoleic acid and notrans fatty acids.
As the level of linoleic acid in the HMO diets increased from 1.9% to 8.2%, the contents of (n−6) polyunsaturated fatty acids
(PUFA) in the phospholipids increased correspondingly. At this dietary level of linoleic acid, a plateau in (n−6) PUFA was
reached that was not affected by further increase in dietary 18∶2(n−6) up to 14.5%. Compared with the HSOY- or PALM-fed rats,
the plateau value of 20∶4(n−6) were considerably lower and the contents of 18∶2(n−6) higher in liver phosphatidylcholines
(PC) and heart PC. Heart phosphatidylethanolamines (PE) on the contrary, had elevated contents of 20∶4(n−6), but decreased
22∶5(n−6) compared with the PALM group.
All groups fed HMO had similar contents oftrans fatty acids, mainly 16∶1 and 18∶1, in their phospholipids, irrespective of the dietary 18∶2 levels, and these contents were
lower than in the HSOY group.
High levels of linoleic acid consistently found in triglycerides of liver, heart and adipose tissue of rats fed HMO indicated
that feeding HMO resulted in a reduction of the conversion of linoleic acid into long chain PUFA that could not be overcome
by increasing the dietary level of linoleic acid. 相似文献
18.
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
19.
The fresh-water green alga Parietochloris incisa is the richest plant source of the PUFA arachidonic acid (20∶4n−6, AA). To elucidate the biosynthesis of AA in this alga
we labeled cultures of P. incisa with radioactive precursors. Pulse chase labeling with acetate resulted in its incorporation via the de novo biosynthesis pathway of FA. However, labeled acetate was also utilized for the elongation of C16 and C18 PUFA. Labeling with [1-14C]oleic acid has shown that the first steps of the lipid-linked FA desaturations utilize cytoplasmic lipids. PC and diacylglyceryltrimethylhomoserine
are the major lipids involved as acyl carriers for the Δ12 and Δ6 desaturations of oleic acid, leading sequentially to linoleic
and γ-linolenic acids. The latter is released from its lipid carrier and elongated to 20∶3n−6, which is reincorporated primarily
into PF and PC and finally desaturated to AA. Galactolipids, mostly monogalctosyldiacylglycerol (MGDG), serve as substrates
for the chloroplastic Δ12 desaturase and, apparently, the ω3 desaturation, common to higher plants and many green algae. The
predominant sequence desaturates the 18∶1/16∶0 molecular species of MGDG stepwise to the 18∶3n−3/16∶3n−3 molecular species
similar to the prokaryotic pathway of higher plants and green algae. 相似文献
20.
Reena Rao Balaraman Manohar Kari Sambaiah Belur R. Lokesh 《Journal of the American Oil Chemists' Society》2002,79(9):885-890
Response surface methodology is a statistical design that helps one to determine optimal conditions for an enzyme-catalyzed
reaction by performing a minimal number of experiments. This methodology was adapted for modifying coconut oil TAG by using
lipase-catalyzed acidolysis in hexane to incorporate n−3 or n−6 PUFA. FFA obtained after hydrolysis of cod liver oil and safflower
oil were used as acyl donors. Immobilized lipase, Lipozyme IM60, from Rhizomucor miehei was used for catalyzing the reaction. The reaction conditions—substrate molar ratio, incubation time, and temperature—were
optimized. The experimental data were fitted to a response function based on the central composite rotatable design. The optimal
conditions generated from models indicated that maximal incorporation of n−3 PUFA occurred at a 1∶4 molar ratio of TAG/FFA
when incubation was carried out for 34 h at 54°C. Similarly, maximal incorporation of n−6 FA was predicted at a 1∶3 molar
ratio of TAG/FFA when incubated for 48.5 h at 39°C. Experiments conducted at optimized conditions predicted by the equation
obtained from response surface methodology yielded structured lipids with 13.65 and 45.5% of n−3 and n−6 FA, respectively.
These values agreed well with that predicted by the model. The reactions were also scaled up to 100 g levels in batch reactors
with the incorporation level of n−3 and n−6 fatty acids agreeing closely with that observed when the reactions were carried
out at lab scale (100 mg). These studies indicated that response surface methodology is a useful tool in predicting the conditions
for incorporating desired levels of specific FA during the synthesis of structured lipids. 相似文献