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1.
Response of free and esterified plasma cholesterol levels in the mongolian gerbil to the fatty acid composition of dietary lipid 总被引:2,自引:0,他引:2
The present study was undertaken to investigate the potential suitability of the Mongolian gerbil as a useful animal model
to study the effects of dietary fats on plasma cholesterol levels. Semipurified diets containing either 20% lard, 20% safflower
oil, or 19.5% beef tallow +0.5% safflower oil were equalized to contain 0.01% cholesterol and 0.05% plant sterol and were
fed for a four week experimental period. The proportions of total calories contributed by fat, protein and carbohydrate (starch/sucrose
ratio of 2∶1) were 40, 14 and 46%, respectively, so as to approach the distribution of calories within the average North American
diet. Free, esterified, and total plasma cholesterol levels of male gerbils were determined weekly by gas liquid chromatography
after drawing blood via a serial sampling technique. After 1, 2, 3, and 4 weeks of feeding the experimental diets, total cholesterol
levels were lowest in the safflower oil fed animals; the corresponding values were 19–64% greater in gerbils fed lard and
68–91% greater in those consuming the beef tallow diet. Cholesterol in the free form generally responded more dramatically
to the type of dietary lipid than did cholesterol in the ester form. Irrespective of the type of dietary lipid or the length
of the feeding trial, 18–23% of the total plasma cholesterol was in the free form and 77–82% was present as the ester. In
view of the similarity to the human of the relative proportions of free versus esterified cholesterol, the type of cholesteryl
esters, and their response to dietary manipulation, the gerbil appears to be a useful animal model for studying the regulatory
effect of dietary lipid on plasma cholesterol levels.
Presented in part at the A.O.C.S. Annual Meeting, San Francisco, CA, May 1979. 相似文献
2.
Rats were fed diets high in either saturated fat (beef tallow) or α-linolenic acid (linseed oil) or eicosapentaenoic and docosahexaenoic
acids (fish oil) with or without 2% cholesterol supplementation. Consumption of linseed oil and fish oil diets for 28 days
lowered arachidonic acid content of plasma, liver and heart phospholipids. Addition of 2% cholesterol to diets containing
beef tallow or linseed oil lowered 20∶4ω6 levels but failed to reduce 20∶4ω6 levels when fed in combination with fish oil.
Feeding ω3 fatty acids lowered plasma cholesterol levels. Addition of 2% cholesterol to the beef tallow or linseed oil diet
increased plasma cholesterol concentrations but not when fish oil was fed. Feeding the fish oil diet reduced the cholesterol
content of liver, whereas feeding the linseed oil diet did not. Dietary cholesterol supplementation elevated the cholesterol
concentration in liver in the order: linseed oil > beef tallow > fish oil (8.6-, 5.5-, 2.6-fold, respectively). Feeding fish
oil and cholesterol apparently reduced 20∶4ω6 levels in plasma and tissue lipids. Fish oil accentuates the 20∶4ω6 lowering
effect of dietary cholesterol and appears to prevent accumulation of cholesterol in plasma and tissue lipids under a high
dietary load of cholesterol. 相似文献
3.
Male weanling rats were fed semi-synthetic diets high in saturated fat (beef tallow) vs high in linoleic acid (safflower oil)
with or without high levels of α-linolenic acid (linseed oil) for a period of 28 days. The effect of feeding these diets on
cholesterol content and fatty acid composition of serum and liver lipids was examined. Feeding linseed oil with beef tallow
or safflower oil had no significant effect on serum levels of cholesterol. Serum cholesterol concentration was higher in animals
fed the safflower oil diet than in animals fed the beef tallow diet without linseed oil. Feeding linseed oil lowered the cholesterol
content in liver tissue for all dietary treatments tested. Consumption of linseed oil reduced the arachidonic acid content
with concomitant increase in linoleic acid in serum and liver lipid fractions only when fed in combination with beef tallow,
but not when fed with safflower oil. Similarly, ω3 fatty acids (18∶3ω3, 20∶5ω3, 22∶5ω3, 22∶6ω3) replaced ω6 fatty acids (20∶4ω6,
22∶4ω6) in serum and liver lipid fractions to a greater extent when linseed oil was fed with beef tallow than with safflower
oil. The results suggest that the dietary ratio of linoleic acid to saturated fatty acids or of 18∶3ω3 to 18∶2ω6 may be important
to determine the cholesterol and arachidonic acid lowering effect of dietary α-linolenic acid. 相似文献
4.
Because lipoproteins and platelet aggregation have been implicated in atherogenesis, relative differences in the response
of these variables to dietary fat saturation were compared in three species of monkeys differing in their susceptibility to
atherosclerosis (cebus, rhesus, and squirrel monkeys). Both long-term (8–12 years) and short-term (8 weeks) responses to diets
containing 31% fat calories were examined in the same monkeys. As expected, long-term feeding of coconut oil by comparison
to corn oil produced significantly higher plasma concentrations of total cholesterol, LDL cholesterol, apoB, and triglycerides,
as well as higher ratios of LDL/HDL cholesterol and apo B/apo A-I. These responses were characteristic of all species with
cebus being most responsive and rhesus the least. The shortterm plasma cholesterol response to animal fats (butter, lard,
beef tallow) was significantly less than that to coconut oil. When fish oil was substituted for two-thirds of either corn
oil or coconut oil, exceptional decreases occurred in plasma cholesterol and triglycerides, as well as in HDL cholesterol
and apo A-I concentrations despite the fact that the fish oil diets contained more saturated fat and less polyenes than the
corn oil diet. Platelet aggregation tended to increase with saturated fat consumption and greatly decreased with fish oil
intake in all monkeys, although cebus monkeys were ten-fold more resistant to platelet aggregation than the other two species.
The molecular species of platelet phosphatidylcholine (PC) varied with both the dietary fat fed and species of monkey. An
inverse correlation (r=−0.60; p<0.001) was found between changes in one such PC molecular species (18∶0−20∶4) induced by diet
and the platelet aggregation threshold. These results demonstrate that the lipemic and platelet responses to dietary saturated
fat depend upon both the type of fat (i.e., the specific combination of dietary fatty acids, including the chain length of saturated fatty acids and the degree of polyunsaturation)
and the species of monkey (genetic component) in which the response is elicited. 相似文献
5.
Comparative effects of feeding dietary linoleic (safflower oil) and α-linolenic (linseed oil) acids on the cholesterol content
and fatty acid composition of plasma, liver, heart and epididymal fat pads of rats were examined. Animals fed hydrogenated
beef tallow were used as isocaloric controls. Plasma cholesterol concentration was lower and the cholesterol level in liver
increased in animals fed the safflower oil diet. Feeding the linseed oil diet was more effective in lowering plasma cholesterol
content and did not result in cholesterol accumulation in the liver. The cholesterol concentration in heart and the epididymal
fat pad was not affected by the type of dietary fatty acid fed. Arachidonic acid content of plasma lipids was significantly
elevated in animals fed the safflower oil diet and remained unchanged by feeding the linseed oil diet, when compared with
the isocaloric control animals fed hydrogenated beef tallow. Arachidonic acid content of liver and heart lipids was lower
in animals fed diets containing safflower oil or linseed oil. Replacement of 50% of the safflower oil in the diet with linseed
oil increased α-linolenic, docosapentaenoic and docosahexaenoic acids in plasma, liver, heart and epididymal fat pad lipids.
These results suggest that dietary 18∶2ω6 shifts cholesterol from plasma to liver pools followed by redistribution of 20∶4ω6
from tissue to plasma pools. This redistribution pattern was not apparent when 18∶3ω3 was included in the diet. 相似文献
6.
Male and female weanling rats were fed diets containing 2 or 42% of calories as corn oil or 40% as beef tallow plus 2% as
corn oil until they were 12 or 18 weeks of age. Incorporation of C14-acetate into lipids of serum and liver and concentration of lipids in serum, liver, and carcass at the end of these periods
were determined.
Net synthesis of noncholesterol lipid was repressed by changing the diet from 2% to 42% of calories from either dietary fat
in both sexes and at both ages. Cholesterol net synthesis was enhanced 29-fold in males and 22-fold in females fed 42% corn
oil compared to 2% corn oil to the age of 12 weeks. It was enhanced only 2.6-fold for males and 3.4-fold for females by 40%
beef tallow plus 2% corn oil. At 18 weeks of age cholesterol synthesis in males fed 42% corn oil was 7.3 and in females 9.1
times the value for those fed 2% corn oil. At this age the values for rats fed 40% beef tallow plus 2% corn oil were 1.2 and
3.7 times those for 2% corn oil fed rats of the respective sexes. 相似文献
7.
Injections of [24-14C] chenodeoxycholate and3H-cholate were made by heart puncture into 300 g male rats that bore T-cannulas in their bile ducts. The animals had been
raised on diet A, containing glucose, cholesterol and cholate, or diet B, containing sucrose and cholesterol; each of the
diets contained 5% safflower oil or 5% beef tallow as variables. From analysis of bile samples collected from the T at intervals
over a 5 day period, it was observed that the safflower oil group fed diet B had a 17% shorter cholate half-life, a 29% larger
cholate pool size and 52% higher rate of cholate synthesis than those fed beef tallow in the same diet. The safflower group
fed diet A also had a larger cholate pool size, but synthesis and half-life were obscured by cholate feeding. Chenodeoxycholate
turnover data were not obtainable because the decay curves were bimodal for all treatments and hence did not conform to a
simple pool model. It is concluded that dietary safflower oil causes more rapid formation of cholate than does dietary beef
tallow in the cholesterol-fed rat.
Journal Paper No. 4952 AES, Purdue University. 相似文献
8.
This study was designed to examine the effects of dietary n−3 and n−6 polyunsaturated fatty acids (PUFA) on postprandial lipid
levels and fatty acid composition of hepatic membranes. Male Sprague-Dawley rats were trained for a 3−h feeding protocol and
fed one of five semipurified diets: one fat-free diet or one of four diets supplemented with 10% (by weight) each of corn
oil, beef tallow, perilla oil, and fish oil. Two separate experiments were performed, 4-wk long-term and 4-d short-term feeding
models, to compare the effects of feeding periods. Postprandial plasma lipid was affected by dietary fats. Triacylglycerol
(TG) and total cholesterol levels were decreased in rats fed perilla oil and fish oil diets compared with corn oil and beef
tallow diets. Hepatic TG and total cholesterol levels were also reduced by fish oil and perilla oil diets. Fatty acid composition
of hepatic microsomal fraction reflected dietary fatty acids and their metabolic conversion. The major fatty acids of rats
fed the beef tallow diet were palmitic, stearic, and oleic. Similarly, linoleic acid (LA) and arachidonic acid in the corn
oil group, α-linolenic acid (ALA) and eicosapentaenoic acid (EPA) in the perilla oil group, and palmitic acid and docosahexaenoic
acid (DHA) in the fish oil group were detected in high proportions. Both long- and short-term feeding experiments showed similar
results. In addition, microsomal DHA content was negatively correlated with plasma lipid levels. Hepatic lipid levels were
also negatively correlated with EPA and DHA contents. These results suggest that n−3 ALA has more of a hypolipidemic effect
than n−6 LA and that the hypolipidemic effect of n−3 PUFA may be partly related to the increase of EPA and DHA in hepatic
membrane. 相似文献
9.
Male Wistar rats were fed for 4 wk on diets containing 2% oxidized corn oil. Liver tissue was then studied to determine the
effect of feeding peroxidized oil on lipogenic enzymes. Although substances which reacted with thiobarbituric acid increased
in liver microsomes and mitochondria with increasing peroxide values of the dietary corn oil fed, the activities of glucose-6-phosphate
dehydrogenase, malic enzyme and acetyl-CoA carboxylase in liver were unchanged. However, when rats were fed for 2 wk on diets
containing 10% fat, of which 0.5, 5 or 10% was unoxidized corn oil and the remainder was hydrogenated beef tallow filler,
the lipogenic enzyme activities and also the liver triglyceride levels were observed to decrease with increasing amounts of
dietary corn oil. Therefore, although a synthetic diet containing corn oil was easy to oxidize spontaneously, the reductions
of lipogenic enzymes in rats fed the diet would not have been caused by lipid peroxides but by unsaturated fatty acids themselves. 相似文献
10.
A line of mice was developed which exhibited spontaneous obesity when fed commercial laboratory ration low in fat content.
Obese mice were compared to a nonobese related line to determine whether energy source in the diet would affect onset of obesity.
Experimental diets-beef tallow (38% of calories as beef fat and 2% as corn oil), corn oil (40% corn oil) or low-fat (2% corn
oil)-were instituted ad libitum at the time of weaning. When the mice reached 6 months of age, lipogenesis was investigated
by injecting intravenously3H2O and glucose-U-14C.3H2O and glucose-U-14C incorporation into fatty acids of fed mice was greater for obese than for lean mice. Fatty acid synthesis was inhibited
by high-fat diets compared to low-fat diet in both lines. Of the 2 high-fat diets, the corn oil diet inhibited fatty acid
synthesis about twice as much as beef tallow diet. There was no line effect on tritium incorporation into cholesterol. Cholesterol
synthesis from glucose-U-14C was greater in obese than lean mice. Diets had no effect on tritium and glucose-U-14C incorporation into cholesterol. Fasting reduced fatty acid synthesis in all mice, but total body fatty acid synthesis was
not affected by lines or dietary treatment under fasted conditions. These data suggest that degree of lipogenesis, in part,
explains obesity. A failure of inhibition of lipogenesis or an enhanced efficiency in fat deposition by feeding beef tallow
compared to corn oil diet may explain the fact that lean mice fed the beef tallow diet tended to be more obese that lean mice
fed corn oil or low-fat diets. 相似文献
11.
Omega-3 fatty acids influence the function of the intestinal brush border membrane. For example, the omega-3 fatty acid eicosapentaenoic
acid (20∶5ω3) has an antiabsorptive effect on jejunal uptake of glucose. This study was undertaken to determine whether the
effect of feeding α-linolenic acid (18∶3ω3) or EPA plus docosahexaenoic acid (22∶6ω3) on intestinal absorption of nutrients
was influenced by the major source of dietary lipid, hydrogenated beef tallow or safflower oil. Thein vitro intestinal uptake of glucose, fatty acids and cholesterol was examined in rats fed isocaloric diets for 2 weeks: beef tallow,
beef tallow + linolenic acid, beef tallow + eicosapentaenoic acid/docosahexaenoic acid, safflower oil, safflower oil + linolenic
acid, or safflower oil + eicosapentaenic acid/docosahexaenoic acid. Eicosapentaenoic acid/docosahexaenoic acid reduced jejunal
uptake of 10 and 20 mM glucose only when fed with beef tallow, and not when fed with safflower oil. Linolenic acid had no
effect on glucose uptake, regardless of whether it was fed with beef tallow or safflower oil. The jejunal uptake a long-chain
fatty acids (18∶0, 18∶2ω6, 18∶3ω3, 20∶4ω6, 20∶5ω3 and 22∶6ω3) and cholesterol was lower in salfflower oil than with beef tallow.
When eicosapentaenoic acid/docosahexaenoic acid was given with beef tallow (but not with safflower oil), there was lower uptake
of 18∶0, 20∶5ω3 and cholesterol. The demonstration of the inhibitory effect of linolenic acid or eicosapentaenoic acid/docosahexaenoic
acid on cholesterol uptake required the feeding of a saturated fatty acid diet (beef tallow). These changes in uptake were
not explained by differences in the animals’ food intake, body weight gain or intestinal weight. Feeding safflower oil was
associated with an approximately 25% increase in the jejunal and ileal mucosal surface area, but this increase was prevented
by combining linolenic acid or eicosapentaenoic acid/docosahexaenoic acid with safflower oil. Different inhibitory patterns
were observed when mixtures of fatty acids were present together in the incubation medium, rather than in the diet: for example,
when 18∶0 was in the incubation medium with 20∶4ω6, the uptake of 20∶4ω6 was reduced, whereas the uptake was unaffected by
18∶2ω6 or 20∶5ω3. Thus, (1) the inhibitory effect of eicosapentaenoic acid/docosahexaenoic acid on jejunal uptake of glucose,
fatty acids and cholesterol was influenced by the major dietary lipid, saturated (beef tallow) or polyunsaturated fatty acid
(safflower oil); and (2) different omega-3 fatty acids (linolenic acid versus eicosapentaenoic acid/docosahexaenoic acid)
have a variable influence on the intestinal absorption of nutrients. 相似文献
12.
The objective of the present studies was to examine the effect of dietary fat on the lipid composition of rat colonocytes
and their utilization of short-chain fatty acids (SCFA). Rats were fed 14% beef fat, fish oil or safflower oil plus 2% corn
oil in a semi-synthetic base diet for 4 wk. Colonocytes were isolated and their lipid composition was examined. Feeding beef
fat and fish oil resulted in an increase in monounsaturated fatty acids and a reduction in ω-6 fatty acids. Feeding fish oil
resulted in an enrichment with ω-3 fatty acids. These was no dietary influence on the amount of either cholesterol or phospholipids
of colonocytes. Fish oil feeding resulted in significant increase in colonocyte free fatty acids (FFA) as compared to other
diets. Dietary fat was found to have no effect on SCFA utilization by colonocytes. Colonocytes were found to utilize SCFA
in the order of butyrate ≥acetate ≥propionate. The presence of acetate and propionate in the medium had no effect on the rate
of butyrate utilization. 相似文献
13.
Jacqueline Dupont 《Journal of the American Oil Chemists' Society》1965,42(11):903-907
Young adult female rats were fed diets containing 2% of calories from corn oil plus 20, 40, 60 or 80% of calories as beef
tallow or diets containing 2% corn oil and the calorie allowance restricted to 80, 60, 40 or 20% of ad libitum consumption.
Incorporation of C14-acetate into cholesterol and total fat was determined as an indication of rate of synthesis.
As dietary fat was increased there was a linear increase in cholesterol radioactivity, as measured in serum, liver and carcass.
As calories were decreased there were small but significant increases in cholesterol radioactivity. There was a highly significant
decrease in incorporation of acetate into total fat as dietary fat increased, and a decrease in total fat radioactivity when
calorie intake was restricted. The differences in rate of cholesterol biosynthesis were not accompanied by differences in
total quantity of cholesterol. The conclusion reached was that utilization of fat for energy results in accelerated cholesterol
biosynthesis.
Presented in part at the annual meeting of the Federation of American Societies for Experimental Biology, Chicago, 1964. 相似文献
14.
Interaction between dietary protein and fat in triglyceride metabolism in the rat: Effects of soy protein and menhaden oil 总被引:4,自引:0,他引:4
The objective of the present study was to determine the mechanisms by which dietary proteins interact with dietary lipids
in the regulation of triglyceridemia in rats. Male Sprague-Dawley rats (n=56) were subjected to 28-d experimental diets containing different combinations of proteins (20% w/w) and lipid sources (14%
w/w): (i) casein-menhaden oil, (ii) casein-beef tallow, (iii) soy protein-menhaden oil, and (iv) soy protein-beef tallow.
Significant protein-lipid interactions were observed on triglyceridemia and hepatic cholesterol in fasted rats. The combination
of casein and beef tallow was associated with high plasma TG and hepatic cholesterol concentrations, which were reduced by
substitution either of soy for casein or of menhaden oil for beef tallow. Therefore, triglyceridemia and liver cholesterol
remained low with soy protein feeding, independently of the lipid source, as well as with menhaden oil feeding, regardless
of the protein source. The menhaden oil diets reduced plasma cholesterol, hepatic TG, and TG secretion compared with beef
tallow diets independently of the dietary protein source. Modifying the source of dietary proteins and lipids had no effect
on post-heparin plasma lipoprotein lipase activity. These results demonstrate that soy protein can lower rat triglyceridemia
relative to casein when associated with beef tallow consumption, whereas menhaden oil can attenuate hypertriglyceridemia when
rats are fed casein. The data further suggest that part of the hypotriglyceridemic effect of soy protein in the rat may be
mediated by reduced hepatic lipid synthesis, as is the case for menhaden oil. 相似文献
15.
Detection of lard and randomized lard as adulterants in refined-bleached-deodorized palm oil by differential scanning calorimetry 总被引:1,自引:0,他引:1
J. M. N. Marikkar O. M. Lai H. M. Ghazali Y. B. Che Man 《Journal of the American Oil Chemists' Society》2001,78(11):1113-1119
A study was conducted to assess the use of differential scanning calorimetry (DSC) for detecting the presence of lard/randomized
lard as adulterants in refined-bleached-deodorized (RBD) palm oil. Lard extracted from the adipose tissues of pig was chemically
interesterified using sodium methoxide as catalyst. DSC thermal profiles of both genuine lard and randomized lard were compared
with those of other common animal fats such as beef tallow, mutton tallow, and chicken fat. Lard and randomized lard were
then blended with RBD palm oil in two series, in proportions ranging from 0.2 to 20%, and DSC analyses were obtained. The
DSC cooling profiles of adulterated RBD palm oil samples showed an adulteration peak corresponding to lard/randomized lard
in the low-temperature region. This peak was confirmed as an indicator of the presence of lard in RBD palm oil since similar
experiments carried out using other common animal fats such as mutton tallow, beef tallow, and chicken fat showed that the
lard adulteration peak could be distinctly identified. Using this method, a detection limit of 1% lard/randomized lard was
reached (P<0.0001). 相似文献
16.
For four weeks, groups of eight male and eight female F344/N rats were fed diets containing 15.5, 20, 30 or 40% of energy
(en%) as fat. The fat was composed of corn oil and beef tallow with 9 en% from linoleate in all diets. Females had greater
mean hepatic α-tocopherol levels, whereas males had greater plasma α-tocopherol and cholesterol concentrations. In males,
the plasma ratio of α-tocopherol/cholesterol was significantly greater than in females (P<0.05). Plasma α-tocopherol increased with increasing en% fat (r=0.51,P<0.001) in both sexes, but dietary fat did not alter hepatic α-tocopherol levels. These results suggest that plasma α-tocopherol
may serve as a biomarker of total dietary fat intake and that in F344/N rats gender differences affect α-tocopherol and cholesterol
status. 相似文献
17.
The activity of lipoprotein lipase (LPL) in the adipose tissue and skeletal muscle of rats fed glucose- or fructose-based
diets containing fish oil, corn oil or tallow was examined. In addition, heart LPL activity was measured in rats fed a glucose-based
diet containing either corn oil or fish oil. Adipose tissue LPL activity was unaffected by dietary fat. In both heart and
skeletal muscle, LPL activity was higher in rats fed the fish oil diet. These results suggest that increased removal of triglyceride
by muscle may contribute to the blood triglyceride lowering effect of dietary fish oil. 相似文献
18.
Interrelationship of stearic acid content and triacylglycerol composition of lard,beef tallow and cocoa butter in rats 总被引:4,自引:0,他引:4
We investigated modes whereby stearic acid (18∶0) exerts a neutral or cholesterol-lowering effect using dietary fats which
provided graded levels of 18∶0 and distinct triacylglycerol (TAG) profiles. Male Sprague-Dawley rats (150–175 g) were fed
diets containing 0.2% cholesterol and 16% fat from corn oil, or from 1% corn oil plus 15% lard (13.2% 18∶0), beef tallow (19.2%
18∶0) or cocoa butter (34.7% 18∶0) for 3 wk, and then killed in a fasted or fed state. Chylomicron (CM) fatty acid profiles
suggested reduced absorption of 18∶0 with greater 18∶0 intake. CM TAG profiles indicated a reduction or loss of two TAG species
compared to the TAG profiles of the stearate-rich diets: 1-palmitoyl-2-oleoyl-3-stearoyl glycerol (POS) and 1,3-distearoyl-2-oleoyl
glycerol (SOS). Hepatic total cholesterol concentrations were 54–77% lower (P<0.01) in the cocoa butter-fed than the lard- and beef tallow-fed groups. The cocoa butter group showed a significantly lower
ratio of high-density lipoprotein esterified/free cholesterol than all other groups. Hepatic stearoyl-CoA and oleoyl-CoA concentrations,
the substrate and product for hepatic δ9 desaturase, were not significantly different for corn oil-fed and cocoa butter-fed
groups in spite of a large difference in 18∶0 intake. These data suggest that the neutral or cholesterol-lowering effect of
18∶0 is not due to hepatic conversion of stearic to oleic acid, and that POS and SOS are poorly absorbed from stearate-rich
dietary fats. 相似文献
19.
The impact of a moderate Zn deficiency on growth and plasma and liver lipids was investigated in two 4-week experiments with
male weanling rats fed fat-enriched diets. Semisynthetic, approximately isocaloric diets containing 3% soybean oil were supplemented
with either 7 or 100 mg Zn/kg diet and with 22% beef tallow (BT) or sunflower oil (SF). In Experiment 1, which compared the
dietary fat level and the fat source in a factorial design of treatments, all diets were fed ad libitum to 6 × 8 animals,
whereas intake of the high-Zn BT and SF diets was restricted in Experiment 2 (5 × 6 rats) to the level of intake of the respective
low-Zn diets. The low-Zn SF diet consistently depressed food intake and final live weights of the animals to a greater extent
than the other low-Zn diets, while intake and growth were comparable among the animals fed the high-Zn diets. The marginal
Zn deficit per se did not alter plasma triglyceride and cholesterol concentrations nor hepatic concentrations of triglyceride,
cholesterol and phospholipids. The fatty acid pattern of liver phospholipids did not indicate that chain elongation and desaturation
of fatty acids was impaired by a lack of zinc. It was concluded that dietary energy and fat intake, and fat source have a
greater effect on plasma and liver lipids than a moderate Zn deficiency. Marginally Zn-deficient diets enriched with sunflower
oil as a major energy source cause a greater growth retardation than diets rich in carbohydrates or beef tallow. 相似文献
20.
The Mongolian gerbil,Meriones unguiculatus, may be a suitable animal model for the investigation of dietary lipid effects on cholesterol metabolism. The effects of
dietary cholesterol, and its possible interaction with the type of dietary fat, on the lipoprotein status of this animal have
not been examined previously. In the present research, the effects of adding 0.5% cholesterol to diets high in saturated (19.5%
beef tallow: 0.5% safflower oil) or polyunsaturated (20% safflower oil) fats on the lipoprotein status of the gerbil were
determined after 11 and 22 days of feeding. Lipoproteins (VLDL, LDL and HDL) were separated by sequential ultracentrifugation.
Their cholesterol, phospholipid and protein concentrations were determined colorimetrically. In the absence of 0.5% cholesterol,
safflower oil lowered the concentration (mg/100 ml) of cholesterol in each of the VLDL, LDL and HDL relative to beef tallow
(BT) without greatly influencing the cholesterol distribution amongst them. The HDL carried the majority of the serum cholesterol
and the VLDL transported the smallest amount. However, inclusion of 0.5% dietary cholesterol resulted in a redistribution
of cholesterol amongst the lipoproteins so that the VLDL and LDL became the major and the HDL the minor carriers. Dietary
cholesterol also brought about a rise in the VLDL and LDL concentrations (mg/100 ml) of cholesterol, phospholipid and protein
and altered the VLDL and LDL compositions. No such changes were observed in the HDL, indicating that the HDL are relatively
resistant to any of the possible effects of cholesterol feeding measured in this experiment. The specific mechanisms responsible
for the changes observed in the lipoprotein status of the gerbil remain to be elucidated.
Presented in part at the Triennial Joint Meeting of the AIN/ASCN/CSNS, July 1982 相似文献