Changes in lipids in liver and serum of rats fed a histidine-excess diet or cholesterol-supplemented diets

The influence of dietary excess (5%) L-histidine on serum and liver lipids was examined in rats. Feeding a histidine-excess diet for 3, 6, 14 or 30 days caused growth retardation, hepatomegaly and decreased liver lipids throughout the period of the experiment. Hypercholesterolemia was observed after feeding a histidine-excess diet for 6 days; then serum cholesterol continuously increased for 30 days. Serum triglyceride on day 30 in rats fed the histidine-excess diet showed a significant decrease compared to rats fed the basal diet. Serum phospholipids of rats fed the histidine-excess diet for 7 or 14 days showed a significant increase compared to rats fed the basal diet. When rats were fed a basal, histidine-excess or cholesterol-supplemented diet (0.5% and 1.0% cholesterol) for 6 days, the distribution of serum high density (HDL), low density (LDL) and very low density lipoprotein cholesterol in rats fed the histidine-excess diet was similar to that of rats fed the basal diet, whereas LDL-cholesterol increased and HDL-cholesterol decreased in rats fed the cholesterol-supplemented diet.     

Dietary fiber supplements: Effects on serum and liver lipids and on liver phospholipid composition in rats

Rats (6 per group) were fed semipurified diets containing either particulate fibers (alfalfa, 10%; cellulose, 10%; bran, 10%), a soluble ionic fiber (pectin 5%), soluble, nonionic fibers (guar gum, 5%; Metamucil, 10%), a mixed fiber preparation (Fibyrax, 10%, or an insoluble, ionic bile acid-binding resin (cholestyramine, 2%). The control group was fed the unsupplemented diet. The feeding period, during which diet and water were provided ad libitum, was 28 days. Compared with the control group, serum total cholesterol levels were increased by more than 10% in rats fed alfalfa and decreased by more than 10% in rats fed cellulose, guar gum, Fibyrax and cholestyramine. There were no significant differences in percentage of plasma HDL cholesterol. Serum triglycerides were elevated in the groups fed alfalfa, pectin, guar gum or Fibyrax and reduced in the group fed Metamucil. Plasma phospholipids were elevated in rats fed alfalfa or bran, unaffected in rats fed pectin or Metamucil and reduced in the other groups. Liver total cholesterol was elevated in all groups but those fed wheat bran and cholestyramine. The percentage of liver cholesterol present as ester was elevated in every group except that fed cholestyramine. Liver triglycerides were reduced in rats fed guar gum or Metamucil and elevated in those fed alfalfa. Liver phospho-lipids were lowered in the group fed cellulose. Liver phospholipids were fractionated by thin layer chromatography to give phosphatidylcholine (PC), phosphatidylethanolamine (PE), sphingomyelin (Sph), lysophosphatidylcholine (LPC) and phosphatidylinositol plus phosphatidylserine (PI+PS). PC was elevated in all test groups (7–25%); PE levels ranged from 14% below to 0.3% above controls; Sph levels were sharply lower (20–53%) in all groups. LPC and PI+PS levels were close to the control value in all test groups. The results demonstrate that different dietary fibers can affect liver phospholipid composition. In view of the critical roles of phospholipids in many biological reactions, it will be interesting to survey the influence of dietary fiber on phospholipid spectra of other tissues. Deceased.     

Novel biodegradable form stable phase change materials: Blends of poly(ethylene oxide) and gelatinized potato starch

Novel biodegradable form stable phase change materials were obtained in a process involving potato starch gelatinization in water/poly(ethylene oxide) (PEO) solution. DSC and microscopic investigations revealed that the presence of the starch considerably changes PEO phase transition behavior–in the blends solid–solid phase transition for PEO/starch 1 : 3 and 1 : 1 w/w has been observed; for PEO/starch blend 3 : 1 w/w solid–solid phase transition with a partial melting of PEO unbounded through hydrogen bonds with starch has been detected. The heat of phase transition depends on the strength of hydrogen bonds between PEO and starch. The intermolecular interactions were evidenced by FTIR analysis, which showed considerably shift of the stretching vibration bands of both the O? H group (proton‐donor group) from starch and PEO. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Susceptibility of serum lipids to copper-induced peroxidation correlates with the level of high density lipoprotein cholesterol

As a first step in evaluating the significance of our recently developed method of monitoring the kinetics of copper-induced oxidation in unfractionated serum, we recorded the kinetics of lipid oxidation in the sera of 62 hyperlipidemic patients and analyzed the correlation between oxidation and lipid composition of the sera [high density lipoprotein (HDL) cholesterol, low density lipoprotein (LDL) cholesterol, and triglycerides]. We used six factors to characterize the kinetics of oxidation, namely, the maximal absorbance of oxidation products (OD_max), the maximal rate of their production (V _max), and the time at which the rate was maximal (t _max) at two wave-lengths (245 nm, where 7-ketocholesterol and conjugated dienic hydroperoxides absorb intensely, and 268 nm, where the absorbance is mostly due to dienals). The major conclusions of our analyses are that: (i) Both OD_max and V _max correlate positively with the sum of concentrations of the major oxidizable lipids, cholesterol, and cholesteryl esters. (ii). The value of t _max, which is a measure of the lag preceding oxidation and therefore reflects the resistance of the serum lipids to copper-induced oxidation, exhibits a negative correlation with HDL cholesterol. Although this finding accords with the observation of shorter lags for HDL than for LDL, it is apparently inconsistent with the role of HDL as an antirisk factor in coronary heart diseases.     

高浓度马铃薯淀粉废水处理工艺研究现状及发展

分析了高浓度马铃薯淀粉废水的水质特性及污染因子,介绍了目前国内外对高浓度马铃薯淀粉废水的传统处理工艺及可行性分析。通过对北方气候和马铃薯淀粉生产特点的分析,提出适合此特点的膜酵母反应器处理淀粉废水新工艺。结果表明,膜酵母反应器处理工艺适合北方马铃薯淀粉废水的高效处理。     

Studies on in vitro peroxidation of liver lipids in ethanol-treated rats

It has been confirmed that lipid peroxidation of liver homogenates is increased following acute ethanol intoxication. Studies with recombined fractions of the liver suggest that the cause for the ethanol-induced increase in malonic dialdehyde production is located in the soluble fraction. Reduced glutathione content of the liver supernatant is decreased following ethanol intoxication. The decrement, however, occurs after the increase in malonic dialdehyde production takes place. Glutathione reductase and glutathione peroxidase activities of the liver are unaffected by ethanol administration. It is suggested that the decrease in reduced glutathione content may reflect a condition of increased peroxidation in vivo.     

Glyceryl ether containing lipids of whole brains from germ-free and conventional rats

The percentage alkyl and alk-1’-enyl glyceryl ethers of the polar lipids isolated from germ-free and conventional rat brain tissue has been determined. No difference could be detected in the quantity of the ether-containing lipids in these animals. Similarly, the composition of the aldehydic chain of the alk-1’-enyl glyceryl ethers from germ-free and conventional rat brain tissue was shown to be the same. The microbial flora, therefore, do not influence either the quantity of the ether-containing lipids or the composition of the aldehyde chain of the alk-1’-enyl glyceryl ethers in the rat brain.     

The effect of clofibrate on heart and plasma lipids in rats fed a diet containing rapeseed oil

The effect of clofibrate on heart and plasma lipids in rats fed a diet containing 30% of the calories as peanut oil (PO) or rapeseed oil (RSO) (42.7% erucic acid and 0.5% eicosenoic acid) was studied. A decrease of erucic acid content to one-third and concomitant increase in the content of 18∶1, 16∶1 and 16∶0 fatty acids in plasma triacylglycerols were observed after administration of clofibrate to rats fed the RSO-diet. It is suggested that these changes reflect the increased capacity of the liver to chainshorten very long chain length fatty acids. The extent of lipidosis in the heart of rats fed the RSO-diet was decreased by 50% by clofibrate. However, the concentration of erucic acid in heart triacylglycerols decreased much less (30%) than the concentration of all other fatty acids (50–65%). It is concluded that the clofibrate administration increased the oxidative capacity of the heart mitochondria and that the heart cell does not have an efficient system to handle very long chain length monounsaturated fatty acids as does the liver.     

Cardiac lipids in rats and gerbils fed oils containing C22 fatty acids

Docosenoic acid from rapeseed oil or herring oil in the diet of the young rat promoted an accumulation of cardiac lipid. The triglyceride fraction accounted for most of the deposited fat and contained a high concentration of the docosenoic acid. Liquid rapeseed oil, partially hydrogenated rapeseed oil or partially hydrogenated herring oil increased the amount of cardiac fatty acids at 1 week and led to the development of degenerative lesions at 16 weeks. Whale or seal oils low in C₂₂ fatty acids produced little effect on the amount of lipids in the heart of rats or gerbils. The latter species receiving 20% rapeseed oil in the diet showed a peak in cardiac lipid deposition at 4 days with similar levels of total fatty acids to that of rats, but with a lower concentration of erucic acid. Oil fromLimnanthes douglasii and hydrogenated herring oil also increased the amount of cardiac fatty acids in gerbils. A high intake of docosenoic acid was common to the animals displaying the cardiac alterations. Presented at the AOCS Meeting, Atlantic City, October 1971.     

Liver and serum lipids and lipoproteins of rats fed 5% L-lysine

Soybean protein and casein supplemented with 1% Arg were compared for their ability to prevent fatty livers caused by excess dietary Lys. The concentrations of serum lipids and lipoproteins of rats fed 5% Lys and having vatty livers were also compared with those of rats fed the identical diet but lacking fatty livers when killed. The total liver lipids, triglycerides and cholesterol of rats fed 15% casein +5% Lys were 3.9, 12.4 and 2 times control values, respectively. Rats fed 5% Lys +1% Arg or 5% Lys with 15% soybean protein had liver lipid concentrations similar to controls fed no supplemental Lys. Serum total lipids, triglycerides, cholesterol, phospholipids and free fatty acids also did not change, and serum ketone bodies were slightly elevated with Lys feeding whether the rats had fatty livers or not. The concentrations of circulating HDL were slightly depressed in all rats fed 5% Lys while LDL were significantly elevated, particularly in rats without fatty livers. Serum VLDL did not change with 5% dietary Lys. Overall, excessive dietary Lys caused fatty livers which were prevented by varying the diet or length of feeding. Excess Lys feeding altered lipoprotein metabolism shown by decreased serum HDL and a substantial elevation in LDL. The latter was more apparent when the fat accumulation in liver was less severe or absent. The data suggest that the fatty liver from Lys excess is probably unrelated to increased fat mobilization from storage, decreased fat oxidation or to a major block in the transport of triglycerides from the liver to the circulation.     

Interaction between dietary proteins and lipids in the regulation of serum and liver lipids in the rabbit. Effect of fish protein

Purified diets varying in dietary protein, namely casein (CA), soy protein (SP), fish protein (FP), and lipid origin (corn oil (CN), coconut oil (CO)) were fed to rabbits to evaluate the effects of protein and fat source, as well as protein-lipid interactions, on serum total, lipoprotein and hepatic lipid levels. Dietary proteins and lipids exerted a separate effect on serum total cholesterol (C), very low-density lipoprotein cholesterol (VLDL-C), and low-density lipoprotein cholesterol to high density lipoprotein cholesterol (LDL-C/HDL-C) ratio. Hence, CA increased serum cholesterol compared to SP, while coconut oil enhanced serum and VLDL-C, and decreased LDL-C/HDL-C compared to corn oil. Dietary proteins interacted with dietary lipids to modulate HDL-C levels. Thus, FP maintained a high level of HDL-C regardless of lipid origin, compared to CA and SP whose HDL-C levels were decreased by corn oil, compared to coconut oil. A dietary protein-lipid interaction was also observed in the regulation of liver cholesterol levels. Coconut oil, compared to corn oil, decreased liver cholesterol in rabbits fed FP, whereas hepatic cholesterol concentration was unaltered by dietary lipid source in CA- and SP-fed rabbits. These results demonstrate that dietary proteins act synergistically with dietary lipids to regulate cholesterol metabolism in the rabbit. This work was presented in part at the 74th Annual FASEB meeting held in Washington, D.C., April 1–5, 1990.     

Fatty acid composition of liver lipids in rats fed brominated fatty acids

Feeding rats diets containing brominated corn oil or di- or tetrabromostearate as the monoglyceride produced changes in fatty acid composition of liver lipids. Those changes associated with the feeding of brominated corn oil or tetrabromosterates could be explained by the accumulation of triglyceride, and the changes associated with the feeding of dibromostearate could result from the proliferation of a membrane system. A unique response to the feeding of diets containing brominated corn oil is an increase in the level of γ-linolenic acid.     

The effects of original and randomized rapeseed oils containing high or very low levels of erucic acid on cardiac lipids and myocardial lesions in rats

The nutritional status of the very lowerucate rapeseed oil,Brassica napus var. ‘Tower,’ was compared with that of the high-erucate oil,Brassica napus var. ‘Target’, as well as with corn oil. The effect of randomization on the nutritional qualities of rapeseed oil was investigated as well. The feeding of diets containing the original and randomized ‘Tower” oil or the original ‘Target’ oil, at the 20% level by weight, gave growth rates which were not significantly different from that for corn oil. However, the randomized ‘Target’ oil gave growth rates which were significantly less than all other groups. The growth results could not be explained simply on the basis of food consumption. The level of triglycerides in the hearts of rats fed the very low-erucate oils was not significantly different from the corn oil group. Triglyceride concentrations in the hearts of animals given the high-erucate oils were 7–12 times greater than all other groups. The level of total fatty acids in tissue phospholipids was the same regardless of dietary treatment. Fatty acid compositions of the tissue lipids were the same in animals fed either the original or randomized rapeseed oils. A much higher incidence of focal myocardial necrosis was found in animals receiving high-erucate rapeseed oil relative to animals given the corn oil. The incidence in rats fed diets containing very low-erucate rapeseed oil was intermediate between these latter two extremes.     

Effect of ingestion of isomeric fatty acids on cholesterol and lipids of serum and liver

The effect of the ingestion of large amounts of thetrans, trans isomer of linolein upon the cholesterol and lipid levels of the blood and liver was investigated using hypercholesterolemic rats. The serum levels of esterified fatty acids and cholesterol of rats fed the diets containing 30% oftrans, trans linoleic acid glycerides and safflower oil were 15 and 25%, respectively, lower than those fed coconut oil. However, a weight loss associated with less intake of thetrans isomer as compared with a gain with the other two fats must be considered. The serum levels of labeled cholesterol of rats administered radioactive cholesterol along with thetrans isomer were intermediate in maximum value as compared to the levels obtained with coconut and safflower oils. These results suggest that thetrans isomers are not as effective as thecis isomers in lowering the cholesterol and lipids of the blood. The livers of the former group had a lower fat content than the latter which might be accounted for in part by the lower fat intake Presented at AOCS Meeting, Houston, Texas, 1965.     

脂肪肝与血脂、血糖的关系检测结果分析

目的研究脂肪肝病人的发病率及年龄分布情况,探讨脂肪肝的诊断、发病因素与血脂、血糖之间的关系。方法对我院2008年至2009两个年度内本地区健康查体抽样520人次,抽取空腹静脉血液检测分析血糖、血脂。结果 145例脂肪肝病人甘油三酯增高62例,胆固醇增高58例,两者均增高25例。血糖增高55例。结论脂肪肝与高甘油三酯及胆固醇、血糖增高有密切的关系。脂肪肝病人中甘油三酯升高尤为显著,是较好的观察指标之一。肥胖、嗜酒、职业特点及糖尿病等均为引起脂肪肝的因素。     

The influence of protein and carbohydrate type on serum and liver lipids and lipoprotein cholesterol in rabbits

The non-lipid portions of semi-synthetic diets appear to be important determinants of hypercholesterolemia and atherosclerosis in the rabbit. Serum and liver lipid concentrations were determined in rabbits which had been pair-fed various protein (casein or soy protein isolate) and carbohydrate (sucrose or dextrose) sources as part of low fat, low cholesterol, semi-synthetic diets. It was verified that caseincontaining diets render rabbits hypercholesterolemic, while soy protein caused a degree of hypocholesterolemia. Additionally, sucrose, when fed in conjunction with casein, appears to augment this hypercholesterolemic effect. The distribution of total cholesterol among lipoprotein subclasses was increased in both the intermediate density lipoprotein (IDL) (1.006–1.019 g/ml) and low density lipoprotein (LDL) (1.019–1.063 g/ml) fractions and decreased in the high density lipoprotein (HDL) (1.063–1.21 g/ml) fraction when casein is fed. Soy protein feeding caused relatively more cholesterol to appear only in the IDL fraction when compared with commercial chow fed rabbits. Reasons for these differences may involve the saturation or suppression of endogenous lipoprotein hepatic receptors.     

Comparison of a sports-hydration drink containing high amylose starch with usual hydration practice in Australian rules footballers during intense summer training

Background

Fluid deficits exceeding 1.6% can lead to physical and cognitive impairment in athletes. Sport drinks used by athletes are often hyper-osmolar but this is known to be suboptimal for rehydration in medical settings and does not utilize colonic absorptive capacity. Colonic absorption can be enhanced by fermentative production of short chain fatty acids (SCFA) from substrates such as high amylose maize starch (HAMS). This study therefore compared, in elite Australian Football League (AFL) players at the height of outdoor summer training, a novel dual-action sports oral rehydration strategy that contained HAMS as well as glucose, to their usual rehydration practices (Control). The primary outcome markers of hydration were hematocrit and body weight.

Methods

A randomized single-blind crossover study was undertaken in thirty-one AFL players; twenty-seven completed the study which was conducted on four days (two days in the Intervention arm and two in Control arm). The Intervention arm was comprised a 50-100 g evening preload of an acetylated HAMS (Ingredion Pty Ltd) followed by consumption of a specially formulated sports oral rehydration solution (SpORS) drink during intense training and recovery. Players followed their usual hydration routine in the Control arm. Quantitative assessments of body weight, hematocrit and urine specific gravity were made at three time-points on each day of training: pre-training, post-training (90 min), and at end of recovery (30–60 min later). GPS tracking monitored player exertion.

Results

Across the three time-points, hematocrit was significantly lower and body weight significantly higher in Intervention compared to Control arms (p <?0.02 and p =?0.001 respectively, mixed effects model). Weights were significantly heavier at all three assessment points for Intervention compared to Control arms (Δ =?0.30?±?0.13, p =?0.02 pre-training; Δ =?0.43?±?0.14, p =?0.002 post training; and Δ =?0.68?±?0.14, p <?0.001 for recovery). Between the pre-training and end-of-recovery assessments, the Control arm lost 0.80 kg overall compared with 0.12 kg in the Intervention arm, an 85% lower reduction of bodyweight across the assessment period.

Conclusion

The combination of the significantly lower hematocrit and increased body weight in the Intervention arm represents better hydration not only at the end of training as well as following a recovery period but also at its commencement. The magnitude of the benefit seems sufficient to have an impact on performance and further studies to test this possibility are now indicated.

Trial registration

Trial is listed on the Australian New Zealand Clinical Trials Registry (ACTRN 12613001373763). 

     

Lung surfactant and fatty acid composition of lung tissue and lavage of rats fed diets containing different lipids

Two nutritional models, essential fatty acid (EFA) deficiency and the feeding of saturated vs unsaturated fats, were used to determine the effects of dietary lipids on the fatty acid composition of rat lung and lavage. Semipurified diets containing 7% corn oil, 7% hydrogenated coconut oil (EFA-deficient), 10% butter or 10% safflower oil were fed to dams during lactation and thereafter to their offspring for a total of 24 weeks. Lipids were extracted from the lung lavage and lung tissue and their fatty acid composition was determined. The content of dipalmitoylphosphatidylcholine (DPPC), the main surfactant in the lungs, was also determined. The results show that the levels of DPPC in the lungs of rats fed 10% butter decreased although the decrease in the EFA-deficient rats was greater. Comparing rats fed butter with those fed corn oil, there were also modifications in the fatty acid composition of the total lipids and phospholipids of lung tissue and lavage as well as in phosphatidylcholine, phosphatidylethanolamine and phosphatidylinositol +phosphatidylserine fractions isolated from the lung tissue. The changes in fatty acid composition were somewhat fewer in rats fed butter then in those fed an EFA-deficient diet. The results suggest that a marginal EFA deficiency produced in rats by long-term feeding of 10% butter may account for the reduction in DPPC levels and in the changes in fatty acid composition in the lung tissue and lavage.     

Identification of noveltrans isomers of 20∶5n−3 in liver lipids of rats fed a heated oil

Trans polyunsaturated n−3 fatty acids are formed as a result of the heat treatment of vegetable oils. It was demonstrated previously that the 18∶3 Δ9cis, 12cis, 15trans containing acis Δ9 ethylenic bond was converted to a geometrical isomer of 20∶5n−3, the 20∶5 Δ5cis, 8cis, 11cis, 14cis, 17trans. In the present study, we have identified two new isomers of eicosapentaenoic acid, the Δ11 monotrans and the Δ11, 17 ditrans isomers in liver of rats fed a heated oil. These are formed as a result of the conversion of two of the main isomers of linolenic acid which are present in refined and frying oils, the 18∶3 Δ9trans, 12cis, 15cis and the 18∶3 Δ9trans, 12cis, 15trans.     

Effect of age and α-linolenic acid deficiency on Δ6 desaturase activity and liver lipids in rats

The combined effects of age and of diet deficient in n−3 fatty acids on Δ6 desaturation of linoleic acid and on lipid fatty acid composition were studied in the liver of the rat at 2, 6, 12, 18 and 24 mon of age. The profiles of Δ6 desaturase activity and fatty acid composition were studied in the deficient rats refed, at these different ages either with 18∶3n−3 (mixture of peanut and rapeseed oils) or with 20∶5n−3+22∶6n−3 (fish oil) diets for 2, 4, 8 or 12 wk. Results showed that the liver Δ6 desaturation activity in the control rats remained high at 2 and 6 mon, decreased by 30% from 6 to 12 mon, and then remained stable from 12 to 24 mon. In the deficient rats, this activity remained high during the entire period studied. Thus, the profile of liver Δ6 desaturase activity after puberty was not related to age only; it also depended on the polyunsaturated fatty acid (PUFA) n−6 and n−3 balance in the diet. In the controls, in parallel with the Δ6 desaturase activity, PUFA metabolism could be divided into three periods: a “young” period, and “old age” period, separated by a period of transition between 6 and 12 mon. Recovery from PUFA n−3 deficiency occurred at all ages but in a different manner depending on whether the rats were “young” or “old”. Recovery was faster if long-chain n−3 PUFA rather than α-linolenic acid were supplied in the diet.