Fatty Acids In Rats Research Articles

Effect of Chemical Stimulation of the Dorsomedial Hypothalamic Nucleus on Blood Plasma Glucose, Triglycerides and Free Fatty Acids in Rats

The effects of chemical stimulation of the dorsomedial hypothalamic nucleus (DMH) on blood plasma concentration of glucose, triglycerides, insulin, and free fatty acids (FFA) were investigated in anesthetized adult Wistar rats. Microinjection of 12.5 nmol of norepinephrine into the DMH increased blood plasma concentration of glucose and FFA, decreased triglycerides, and did not change plasma insulin within 5 min; after 20 min, blood glucose and FFA reached control values. Microinjection of epinephrine (12.5 nmol) into the DMH also increased blood plasma glucose concentration and decreased triglycerides after 5 min. These effects are probably mediated by beta-adrenergic mechanisms, because they were prevented by beta-adrenergic antagonist propranolol, but not by alpha-adrenergic antagonist prazosin. Microinjection into the DMH of glutamate, dopamine, or acetylcholine failed to cause any change in those metabolic parameters, corroborating the hypothesis that the DMH is part of a beta-adrenergic pathway involved in short-term modulation of the availability of glucose and FFA.

Assessment of the possible adverse effects of oils enriched with n-3 fatty acids in rats: peroxisomal proliferation, mitochondrial dysfunctions and apoplexy

Possible adverse effects of excess intake of dietary n-3 fatty acids have been reevaluated in rats by measuring peroxisomal proliferation, mitochondrial enzyme activity and incidence of apoplexy. When Sprague-Dawley rats were fed diets containing either fish oil rich in docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) or perilla seed oil rich in α-linolenic acid for 4 or 12 weeks, DHA accumulated in phospholipids of liver and heart in the fish oil group, but not in the perilla oil group when compared with safflower and soybean oil groups. Feeding a diet containing 15 weight % of fish oil induced a significant proliferation of peroxisomes compared with safflower oil-diet, but the proliferating activity of perilla oil was much less. The peroxisomal β-oxidation activities were negatively correlated with neutral lipid contents in liver. Heart mitochondrial cytochrome c oxidase activity was not affected significantly by feeding fish oil or perilla oil in the presence of an essential amount of linoleic acid for up to 12 weeks, though the proportion of linoleic acid in heart cardiolipin decreased from >86% in the safflower and soybean oil groups to 81% in the perilla oil group and to 33% in the fish oil group. Feeding n-3-enriched fish oil and perilla oil in 10 weight % of the diets did not accelerate the onset of cerebral bleeding in stroke-prone spontaneously hypertensive rats (SHRSP). Although the proliferating activity of peroxisomes by excess intake of fish oils should be noticed, these results provide evidence that n-3-enriched oils are safe under conditions applicable to human nutrition, considering the levels fed the rats were several fold higher than the anticipated maximal intake in human.

Effect of Dietary Corn Oil, Butter and Beef Tallow on the Cecal Microflora and Short-Chain Fatty Acids in Rats

Effect of Dietary Corn Oil, Butter and Beef Tallow on the Cecal Microflora and Short-Chain Fatty Acids in Rats

Effect of high fat diets with and without cholesterol on erythrocyte and tissue fatty acids in rats.

Male weanling wistar rats were fed synthetic diets containing 20% safflower oil (SFO) or palm oil (PO) with and without cholesterol for a period of six weeks. Erythrocyte membranes were isolated and their fatty acid composition were determined at the end of the experiment. Besides the fatty acid composition of the kidney and spleen lipids were also determined. Erythrocyte membrane, kidney fatty acids of rats fed safflower oil (SFO) had in the majority of variants a higher level of n-6 fatty acids when compared to palm oil group. However, in the spleen, the level of n-6 fatty acids in the palm oil groups were higher than in the safflower oil group. In general the arachidonic acid [20:4 (n-6)] levels were higher in the spleen and erythrocytes particularly in the cholesterol fed groups when compared to the kidney levels. Palm oil fed rats had a higher level of palmitic (16:0) and oleic [18:1 (n-9)] acids. Rats fed diets containing cholesterol significantly reduced the level of stearic (18:0) but increased the level of oleic [18:1 (n-9)], linoleic [18:2 (n-3)], and arachidonic acids [20:4 (n-6)]. The ratios such as 18:1 (n-9)/18:2 (n-6), 18:1 (n-9)/18:0, 18:2 (n-6)/20:4 (n-6) and 20:4 (n-6)/18:2 (n-6) are all indicative of the normal activity of enzymes involved in the desaturation and elongation. Thus these studies indicate that addition of cholesterol can modify the fatty acid composition in erythrocytes, kidney and spleen lipids.

Positional Distribution of Stearic Acid and Oleic Acid in a Triacylglycerol and Dietary Calcium Concentration Determines the Apparent Absorption of these Fatty Acids in Rats

In this study the effect of the positional distribution of stearic acid (18:0) and oleic acid (18:1) in a triacylglycerol on absorption of fat, energy and nutrients was investigated in young rats. In addition the effect of dietary calcium on these variables was studied. Forty rats were fed purified diets containing either a fat blend high in 2-oleoyl-distearate or a fat blend high in 1-oleoyl-distearate. Both diets were given at low (0.3 g/100 g) and high (1.0 g/100 g) dietary calcium concentrations. Total fat absorption, expressed as the percentage of fat intake, was significantly lower in rats fed 2-oleoyl-distearate compared with 1-oleoyl-distearate at both dietary calcium concentrations. When expressed as absolute figures, the lower fat absorption in rats fed 2-oleoyl-distearate compared with 1-oleoyl-distearate only reached statistical significance at the high dietary calcium concentration. The reduced absorption of total fat was mainly caused by the lower absorption of stearic acid. The percentage of, but not absolute, absorption of oleic acid and energy were lower in rats fed 2-oleoyl-distearate. Absolute and percentage of calcium absorption were lower in rats fed 2-oleoyl-distearate compared with 1-oleoyl-distearate. Absolute and percentage of magnesium absorption were not significantly affected by the positional distribution of stearic acid and oleic acid in the triacylglycerol, but were decreased at a high dietary calcium concentration. We concluded that the lowered stearic acid absorption from 2-oleoyl-distearate compared with 1-oleoyl-distearate might have been due to the greater formation of insoluble calcium and magnesium soaps in the intestine.

Effect of dietary calcium on the absorption of triglycerides esterified at 1,2 and 1,3 positions of glycerol with long chain saturated fatty acids in rats

We investigated the effect of dietary Ca on the absorption of 1,3-dipalmitoyl-2-oleoyl glycerol (POP), 1(3),2-dipalmitoyl-3-oleoyl glycerol (PPO), cocoa butter (CB) which contained 1-palmitoyl-2-oleoyl-3-stearoyl glycerol (POS) as major triglycerides, chocolate (Choco) made from cocoa butter and corn oil. Rats were fed the diets containing 10% of one of the above lipids for 7 days. The apparent absorption efficiency of nutrients, especially fat, were lower in rats fed CB+Ca or POP+Ca diet than those fed CB or PPO+Ca diet. The low apparent absorption efficiency of fat was due to the low absorption efficiency of palmitic and stearic acids. Absorbed fat energy was 10% lower in CB+Ca diet group than in CB diet group, and was 18% lower in Choco+Ca diet group than in corn oil diet group. Although the apparent absorption efficiency of energy was lower in Choco diet group than in corn oil diet group, the apparent absorption efficiency of palmitic and stearic acids in Choco were larger than those in cocoa butter even when Ca was fortified. The apparent absorption efficiency of Ca were lower in rats fed Ca-fortified diets than in Ca-non-fortified groups, however absolute amounts of absorbed Ca were not different among all the groups. The present results suggest that Ca-fortification decreased the apparent absorption efficiency of fat with long chain saturated fatty acids, particularly at 1,3 positions of glyceride, and the apparent absorption efficiency of saturated fatty acids in foodstuff such as chocolate were also decreased by Ca-fortification.

Garlic supplementation enhances norepinephrine secretion, growth of brown adipose tissue, and triglyceride catabolism in rats

We investigated the effects of garlic supplementation on triglyceride metabolism, norepinephrine secretion, and growth of interscapular brown adipose tissue in rats. Rats were fed high-fat diets with or without a garlic powder (supplemented at 0.8%) for 10 or 28 days. After 28 days of feeding, body weights and the concentrations of plasma triglycerides and free fatty acids in rats fed a diet containing garlic powder were significantly lower than in rats given no garlic powder. Interscapular brown adipose tissue weights and the mitochondrial protein were significantly greater in rats given garlic powder as compared with rats fed no garlic powder for 28 days. Furthermore, plasma concentrations and urinary excretion of norepinephrine were significantly greater in rats fed a diet containing garlic powder than in those diets without garlic powder. The in situ effects of a major volatile sulfur-containing compound (diallyldisulfide) in garlic on norepinephrine secretion were also evaluated in anesthetized animals. The norepinephrine concentration of arterial blood was significantly increased by diallyldisulfide administration, and the increase was dose-dependent. These results suggest that garlic supplementation enhances the triglyceride catabolism and growth of interscapular brown adipose tissue by increasing norepinephrine secretion in rats.

Determination of portal short-chain fatty acids in rats fed various dietary fibers by capillary gas chromatography.

A simple, rapid and sensitive capillary gas chromatographic method was investigated to measure portal short-chain fatty acids (SCFAs). A 20-microliters sample of portal plasma was denatured with sulfosalicylic acid and then extracted with diethyl ether before the removal of protein precipitate. The resultant extract was concentrated by a transfer to 50 microliters of 0.2 M NaOH, thus avoiding tedious further concentration steps. This reduced the sample volume to one-fourth. Since the ratio of acetic acid, a major SCFA, to other acids varies widely, ranging from 10-fold to 100-fold, acrylic and methacrylic acids were used as internal standards to simultaneously measure SCFAs having a carbon number of 2-6. As a result, good recovery (90.38-103.17%) and reproducibility (coefficient of variation 0.83-8.85%) were observed over a wide range. Furthermore, portal SCFAs in rats fed various dietary fibers were determined by the present method. We showed that the amounts not only of the major acids such as acetic acid and propionic acid, but also of the minor fermented products such as n-valeric acid and n-caproic acid, could be significantly changed by dietary manipulation. Thus, the present method is simple and reliable, and requires only a small amount of sample.

Interaction of sesamin and eicosapentaenoic acid against delta 5 desaturation and n-6/n-3 ratio of essential fatty acids in rat.

Sesamin is a specific inhibitor of delta 5 desaturation, the conversion from dihomo-gamma-linolenic acid (20:3, n-6) to arachidonic acid (AA, 20:4, n-6). Previously, we reported that sesamin inhibited delta 5 desaturation of n-6 fatty acids in rat hepatocytes but not that of n-3 fatty acids, from 20:4 (n-3) to eicosapentaenoic acid (EPA, 20:5, n-3). In this study, we investigated the interaction of sesamin and EPA on delta 5 desaturation of both series and the n-6/n-3 fatty acids ratio by measuring actural fatty acid contents in vivo. Rats were fed three types of dietary oils; 1) linoleic acid (LA, 18:2, n-6): linolenic acid (LLA, 18:3, n-3) = 3:1, n-6/n-3 ratio of 3:1 (LA group), 2) LA:LLA = 1:3, n-6/n-3 ratio of 1:3 (LLA group), 3) LA:LLA:EPA = 1:0.5:3, n-6/n-3 ratio of 1:3.5 (EPA group) with or without sesamin (0.5% w/w) for 4 weeks. In all groups, sesamin administration increased the content of dihomo-gamma-linolenic acid (20:3, n-6) in the liver and decreased the delta 5 desaturation index of n-6 fatty acid, the ratio of 20:4/20:3 (n-6). On the contrary, the delta 5 desaturation index of n-3 fatty acid, the ratio of 20:5 + 22:5 + 22:6/20:4 (n-3), was increased by the administration of sesamin. These results suggest that sesamin inhibits the delta 5 desaturation of n-6 fatty acid, but not that of n-3 fatty acid in rat livers. Sesamin administration decreased incorporation of EPA (n-3) and simultaneously increased the AA (n-6) content in the liver. The n-6/n-3 ratio in the liver was increased by administering sesamin under n-3 rich conditions, i.e., the LLA and EPA groups.

Distribution of liposomes containing mannobiose esters of fatty acid in rats.

The biodistribution of liposomes modified by mannobiose residues was studied in rat. The purpose of the modification was to target the liposomes to macrophages. Mannobiose mono arachidic acid esters (MAEs) were synthesized and used to modify the surface of liposomes. It was shown by gel permeation chromatography that the MAE was preferentially incorporated into the membrane of the liposomes. After intravenous administration, mannobiose-modified liposomes were eliminated from the systemic circulation more rapidly than control liposomes without the modification. Whilst the modification did not affect the distribution of liposomes to kidney, lung, or thymus, it increased the distribution to liver and spleen. The uptake in the hepatic parenchymal cell fraction was not influenced by MAE incorporation. Taking into account the fact that endothelial cells do not take up particles whose size is > 100 nm, the increase in the distribution to liver were ascribed to an increase in uptake by Kupffer cells. These results suggest that mannobiose mono fatty acid esters are useful in the targeting of liposomes to Kupffer cells and other macrophages.

P1-318 - Age-related change in anti-platelet aggregation in feeding of a high fat diet and ω-3 fatty acid in rats

P1-318 - Age-related change in anti-platelet aggregation in feeding of a high fat diet and ω-3 fatty acid in rats

Comparative changes of fat digestibility and fat accumulation by the carbon chain length of dietary glycerol tri-homogenous fatty acids in rats

The present study was undertaken to investigate the influence of the carbon chain length of dietary glycerol tri-homogenous fatty acid on fat digestibility and body fat accumulation in rats. Thirty-six Wistar male rats were divided into six groups and fed the semipurified C8, C10, C12, C14, C16, C18 triglyceride diets, respectively. Body weight was significantly lower (p<0.05) in rats fed the C14, C16 and C18 diets than in rats fed the C8, C10 and C12 diets. Weights of adipose tissues and apparent fat digestibility were markedly low in the C16 and C18 fed rats. In these groups, fat content of whole-body carcass was significantly lower (p<0.05), but moisture, ash and protein contents were significantly greater (p<0.05) than those of the other groups. Fatty acid profile of epididymal adipose tissue revealed that dietary C8:0 was not directly incorporated into adipose tissues, and only a small amount of dietary C10:0 was directly deposited as body triglycerides. Meanwhile, dietary C12:0 was extensively incorporated into adipose tissues when compared to those of C8 and C10 rats. The present study indicated that apparent fat and energy digestibilities of dietary glycerol tripalmitin and glycerol tristearin were remarkably lower than the glycerol tricaprylin, tricaprin, trilaurin and trimyristin, which results in lower fat accumulation in the C16 and C18 fed rats.

Effects of high dietary cellulose on the large intestinal microflora and short-chain fatty acids in rats

Wistar rats fed diets containing different contents of cellulose or 5% transgalactosylated oligosaccharides (TOS) for 7 weeks were examined for faecal microflora and caecal short-chain fatty acids. High (15 %) cellulose diet showed remarkable increases in concentrations of faecal bifidobacteria and caecal butyrate with a reduced concentration of propionate as compared with the other diets. TOS-fed rats showed strikingly increased concentrations of bifidobacteria and acetate. A comparison of pH values between the caecal contents and faeces suggested more fermentation of cellulose in the distal than proximal part of the large bowel of rats

Occurrence of 5c,8c,11c,15t‐eicosatetraenoic acid and other unusual polyunsaturated fatty acids in rats fed partially hydrogenated calola oil

Uncommon cis and trans fatty acids can be desaturated and elongated to produce unusual C18 and C20 polyunsaturated fatty acids in animal tissues. In the present study we examined the formation of such metabolites derived from cis and trans isomers of oleic and linoleic acids of partially hydrogenated vegetable oil origin in rats. For two months, adult male rats were fed a partially hydrogenated canola oil diet containing moderately high levels of trans fatty acids (9.6 energy%) and an adequate level of linoleic acid (1.46 energy%). Analysis of the phospholipid (PL) fatty acids of liver, heart, serum and brain showed no new C18 polyunsaturated fatty acids, except for those uncommon 18:2 isomers originating from the diet. However, minor levels (each < 0.3% PL fatty acids) of six unusual C20 polyunsaturated fatty acids were detected in the tissues examined, except in brain PL. Identification of their structures indicated that the dietary 9c,13t-18:2 isomer, which is the major trans polyunsaturated fatty acid in partially hydrogenated vegetable oils, was desaturated and elongated to 5c,8c,11c,15t-20:4, possibly by the same pathway that is operative for linoleic acid. Furthermore, dietary 12c-18:1 was converted to 8c,14c-20:2 and 5c,8c,14c-20:3; dietary 9c,12t-18:2 metabolized to 11c,14t-20:2 and 5c,8c,11c14t-20:4, and dietary 9t,12c to 11t,14c-20:2. These results suggested that of all the possible isomers of oleic and linoleic acids in partially hydrogenated vegetable oils, 12c-18:1, 9c,13t-18:2, 9c,12t-18:2 and 9t,12c-18:2 are the preferred substrates for desaturation and elongation in rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Modulation of plasma and hepatic oxidative status and changes in plasma lipid profile by n-3 (EPA and DHA), n-6 (corn oil) and a 3-thia fatty acids in rats

This manuscript describes changes in plasma lipid profiles and parameters of oxidative status in the plasma and liver of rats fed 5 different fatty acids: 95% eicosapentaenoic acid, 92% docosahexaenoic acid (DHA), corn oil (n-6), 1-mono-(carboxymethylthio)-tetradecane (CMTTD) and palmitic acid (controls) for 3 months. At the given doses both EPA and the 3-thia fatty acid, CMTTD, caused a significant decrease in plasma triglycerides, phospholipids, free fatty acids and cholesterol. DHA decreased plasma free fatty acids and cholesterol, while corn oil feeding reduced only plasma free fatty acids. Plasma and hepatic vitamin E levels were significantly decreased in EPA, DHA and CMTTD fed rats, but remained unchanged in corn oil fed rats. Plasma glutathione was noted to decrease after EPA and DHA feeding but remained unchanged in other groups. However, hepatic glutathione content was increased in EPA, DHA and CMTTD fed rats, whereas cysteine levels were noted to decrease. As hepatic levels of cysteinylglycine remained unchanged, increased rate of cellular glutathione synthesis rather than its decreased degradation is likely to contribute to the increased hepatic glutathione content in EPA, DHA and CMTTD fed rats. Except for reduction in the levels of plasma lipid peroxidation caused by CMTTD, no significant changes were noted between the different treatment groups. Hepatic lipid peroxidation was elevated only in rats given DHA. Furthermore, our results show that EPA and DHA cause minimal imbalance of the peroxisomal H 2O 2 metabolising enzymes as compared to CMTTD. In addition, contrary to the potent peroxisome proliferator compound CMTTD which decreased the activities of glutathione transferase and glutathione peroxidase, EPA and DHA increased the activities of these detoxification enzymes.

Erratum to : Effects of 4'-Galactosyllactose on the Cecal Microflora and Short-Chain Fatty Acids in Rats and Mice

Erratum to : Effects of 4'-Galactosyllactose on the Cecal Microflora and Short-Chain Fatty Acids in Rats and Mice

Diversity in the Incorporation into Tissue Phospholipids and Effects on Eicosanoid Production oftrans-Monoene Fatty Acid in Rats Fed with Different Dietary Proteins

The incorporation into tissue phospholipids and the effects on eicosanoid production of trans-fatty acid were studied in rats fed different proteins, casein or soybean protein. After feeding partially hydrogenated corn oil containing 32% t-18:1 at the 10% level for 3 weeks, the incorporation of trans-fatty acid into liver phospholipids was species-specific. More trans-acid was incorporated into phosphatidylinositol than into phosphatidylcholine (PC) and phosphatidylethanolamine (PE), and there was apparently no incorporation into cardiolipin. The incorporation of trans-acid tended to be higher in the rats fed soybean protein than in those fed casein. In general the proportion of linoleic acid increased, but that of arachidonic acid tended to be decreased by trans-fat as compared with cis-fat, suggesting an interference with linoleic acid desaturation, but this was not the case for the spleen of rats fed vegetable protein. The concentration of plasma prostaglanidin E2 was not influenced by the type of diet...

Dietary Lipids from Marine Unicellular Algae Enhance the Amount of Liver and Blood Omega-3 Fatty Acids in Rats

The nutritional effect of omega-3 (omega 3) polyenoic fatty acids, originating from marine unicellular algae or from fish oil, on the liver and blood lipids was studied in weanling rats fed for 2 weeks on control or experimental diets. Isolipid experimental diets containing either 10% marine microalgae or algal lipids or fish (capelin) oil substituting part (40%) or all of the soybean oil of the control diet. The algae employed were Nannochloropsis sp. or Isochrysis galbana, which are rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), respectively. Cell disruption improved the digestibility of the Nannochloropsis biomass. Diets containing algal meal significantly reduced the relative abundance of arachidonic acid (AA) in the blood and liver lipids and caused a significant increase in the percentage of the omega 3 polyunsaturated fatty acids (PUFA). Feeding Nannochloropsis lipids resulted in a similar effect on the plasma and liver fatty acid pattern as that of a diet containing disrupted cells of Nannochloropsis biomass. In comparison, the response of the plasma and liver lipids to capelin oil was characterized by a further reduction in the abundance of AA and a significant elevation in the percentage of EPA and DHA. These differences are probably due to the variations in the fatty acid composition and not to the fact that omega 3 fatty acids are associated with different lipid classes in these lipid sources. Based on the present study, it is postulated that certain marine unicellular algae can be used as a nutritional source for omega 3 PUFA.

The effect of dietary mannitol on the caecal microflora and short-chain fatty acids in rats

Wistar rats fed 5%-mannitol diet showed significant decreases of viridans streptococci and bifidobacteria, and a remarkable increase of butyric acid concentration and a decrease of acetic acid in the caecal contents compared with the sucrose and basal diet groups. Stocky fusiform bacteria were increased in concentration in the rats on mannitol compared with the other groups.

Coconut Oil and Sesame Oil Affect Lymphatic Absorption of Cholesterol and Fatty Acids in Rats

Five groups of male Wistar rats weighing approximately 200 g consumed 12 or 24% sesame oil or coconut oil diets or a control diet (14% corn oil) ad libitum for 4 wk. The thoracic ducts of these rats were cannulated, and a lipid emulsion containing [3H]cholesterol and [14C]oleic acid was given through a duodenal catheter. Lymph was collected for 24 h and the isotopic tracers for cholesterol and fatty acid were measured. Rats fed the 24% sesame oil diet had significantly lower lymphatic cholesterol and fatty acid compared with the control group. Absorption of oleic acid in rats fed 24% coconut oil was significantly greater than in controls during 0-8 h but was not significantly different during 0-24 h. There were no differences among groups in the distribution of cholesterol and oleic acid either in the lymph lipoproteins or in the lipid classes. The significant reduction in lymph cholesterol and fatty acids due to sesame oil feeding may be an important factor in reducing hypercholesterolemia.