Different edible oil beneficial effects (canola oil, fish oil, palm oil, olive oil, and soybean oil) on spontaneously hypertensive rat glomerular enlargement and glomeruli number

We have tested the different edible oil effects on the blood pressure (BP) control and the following glomerular protection. Six groups of 12-week-old male spontaneously hypertensive rats (SHR) (n = 5), have received different edible oils (fish, canola, palm, olive, and soybean) or a placebo by gavage for 13 weeks. Renal cortex was analyzed through light microscopy and stereology. Usual BP increase, glomerulosclerosis, glomerular enlargement, and glomeruli loss in SHR has been prevented (fish, canola and palm oils) or attenuated (olive and soybean oils) by these oil long-term administration. The most favorable effect has been seen in the fish oil administration (source of n-3 polyunsaturated fatty acids, PUFA, eicosapentaenoic and docosahexaenoic acids), followed by both canola and palm oils (source of n-3 PUFA plus n-9 monounsaturated, MUFA, and saturated fatty acid, respectively), and finally both olive and soybean oils (source of n-9 MUFA and n-6 PUFA, respectively).     

Nutritional evaluation of structured lipid containing omega 6 fatty acid synthesized from coconut oil in rats

Coconut oil is rich in medium chain fatty acids, but deficient in polyunsaturated fatty acids (PUFA). Structured lipids (SL) enriched with omega 6 PUFA were synthesized from coconut oil triglycerides by employing enzymatic acidolysis with free fatty acids obtained from safflower oil. Rats were fed a diet containing coconut oil, coconut oil-safflower oil blend (1:0.7 w/w) or structured lipid at 10% levels for a period of 60 days. The SL lowered serum cholesterol levels by 10.3 and 10.5% respectively in comparison with those fed coconut oil and blended oil. Similarly the liver cholesterol levels were also decreased by 35.9 and 26.6% respectively in animals fed structured lipids when compared to those fed on coconut oil or the blended oil. Most of the decrease observed in serum cholesterol levels of animals fed structured lipids was found in LDL fraction. The triglyceride levels in serum showed a decrease by 17.5 and 17.4% while in the liver it was reduced by 45.8 and 23.5% in the structured lipids fed animals as compared to those fed coconut oil or blended oil respectively. Differential scanning calorimetric studies indicated that structured lipids had lower melting points and solid fat content when compared to coconut oil or blended oils. These studies indicated that enrichment of coconut oil triglycerides with omega 6 fatty acids lowers its solid fat content. The omega 6 PUFA enriched structured lipids also exhibited hypolipidemic activity.     

Comparative effects of perilla and fish oils on the activity and gene expression of fatty acid oxidation enzymes in rat liver

The activity and mRNA level of hepatic enzymes in fatty acid oxidation and synthesis were compared in rats fed diets containing either 15% saturated fat (palm oil), safflower oil rich in linoleic acid, perilla oil rich in α-linolenic acid or fish oil rich in eicosapentaenoic (EPA) and docosahexaenoic acids (DHA) for 15 days. The mitochondrial fatty acid oxidation rate was 50% higher in rats fed perilla and fish oils than in the other groups. Perilla and fish oils compared to palm and safflower oils approximately doubled and more than tripled, respectively, peroxisomal fatty acid oxidation rate. Compared to palm and safflower oil, both perilla and fish oils caused a 50% increase in carnitine palmitoyltransferase I activity. Dietary fats rich in n-3 fatty acids also increased the activity of other fatty acid oxidation enzymes except for 3-hydroxyacyl-CoA dehydrogenase. The extent of the increase was greater with fish oil than with perilla oil. Interestingly, both perilla and fish oils decreased the activity of 3-hydroxyacyl-CoA dehydrogenase measured using short- and medium-chain substrates. Compared to palm and safflower oils, perilla and fish oils increased the mRNA level of many mitochondrial and peroxisomal enzymes. Increases were generally greater with fish oil than with perilla oil. Fatty acid synthase, glucose-6-phosphate dehydrogenase, and pyruvate kinase activity and mRNA level were higher in rats fed palm oil than in the other groups. Among rats fed polyunsaturated fats, activities and mRNA levels of these enzymes were lower in rats fed fish oil than in the animals fed perilla and safflower oils. The values were comparable between the latter two groups. Safflower and fish oils but not perilla oil, compared to palm oil, also decreased malic enzyme activity and mRNA level. Examination of the fatty acid composition of hepatic phospholipid indicated that dietary α-linolenic acid is effectively desaturated and elongated to form EPA and DHA. Dietary perilla oil and fish oil therefore exert similar physiological activity in modulating hepatic fatty acid oxidation, but these dietary fats considerably differ in affecting fatty acid synthesis.     

Biodiesel production from seed oil of Cleome viscosa L

Edible oil seed crops, such as rapeseed, sunflower, soyabean and safflower and non-edible seed oil plantation crops Jatropha and Pongamia have proved to be internationally viable commercial sources of vegetable oils for biodiesel production. Considering the paucity of edible oils and unsustainability of arable land under perennial plantation of Jatropha and Pongamia in countries such as India, the prospects of seed oil producing Cleome viscosa, an annual wild short duration plant species of the Indogangetic plains, were evaluated for it to serve as a resource for biodiesel. The seeds of C. viscosa resourced from its natural populations growing in Rajasthan, Haryana and Delhi areas of Aravali range were solvent extracted to obtain the seed oil. The oil was observed to be similar in fatty acid composition to the non-edible oils of rubber, Jatropha and Pongamia plantation crops and soybean, sunflower, safflower, linseed and rapeseed edible oil plants in richness of unsaturated fatty acids. The Cleome oil shared the properties of viscosity, density, saponification and calorific values with the Jatropha and Pongamia oils, except that it was comparatively acidic. The C. viscosa biodiesel had the properties of standard biodiesel specified by ASTM and Indian Standard Bureau, except that it had low oxidation stability. It proved to be similar to Jatropha biodiesel except in cloud point, pour point, cold filter plugging point and oxidation stability. In view of the annual habit of species and biodiesel quality, it can be concluded that C. viscosa has prospects to be developed into a short-duration biodiesel crop.     

The Fat-1 Mouse has Brain Docosahexaenoic Acid Levels Achievable Through Fish Oil Feeding

Fat-1 transgenic mice endogenously convert n-6 to n-3 polyunsaturated fatty acids (PUFA). The aims of this study were to test whether a) fish oil feeding can attain similar brain n-3 PUFA levels as the fat-1 mouse, and b) fat-1 mouse brain docosahexaenoic acid (22:6n-3; DHA) levels can be potentiated by fish oil feeding. Fat-1 mice and their wildtype littermates consumed either a 10% safflower oil (SO) or a 2% fish oil and 8% safflower oil chow (FO). Brain total lipid and phospholipid fraction fatty acids were analyzed using GC-FID. Wildtype mice fed FO chow had similar brain levels of DHA as fat-1 mice fed SO chow. Fat-1 mice fed FO chow had similar brain n-3 PUFA levels as fat-1 mice fed SO chow. In conclusion, brain levels of DHA in the fat-1 mouse can be obtained by and were not further augmented with fish oil feeding.     

Effects of Sunflower Oil on Tomato Powdery Mildew Caused by Oidium neolycopersici

When tomato leaves were sprayed with 0.1% emulsified canola oil, corn oil, grape seed oil, peanut oil, safflower oil, soya bean oil or sunflower oil, the severity of powdery mildew caused by Oidium neolycopersici was greatly reduced. Among these edible oils tested, sunflower oil was the most effective in the control of powdery mildew. When sprayed with 0.5% sunflower oil, powdery mildew on tomato leaves was reduced to a negligible level. Sunflower oil applied to halves of upper leaf surface did not induce resistance against the pathogen in the non‐treated halves. When applied to halves of lower leaf surface, it also failed to reduce the severity of powdery mildew on the upper leaf surface right above the treated area indicating that control of the powdery mildew by sunflower oil did not result from activation of host defence mechanisms. Scanning electron microscopy showed that control of powdery mildew with sunflower oil resulted mainly from the inhibition of conidial germination and suppression of mycelial growth of the pathogen.     

Effects of ω3 Polyunsaturated Fatty Acids on Growth and Tissue Fatty Acid Compositions of Maternal Rats and Their Progeny

The effects of ω3 polyunsaturated fatty acids [PUFA; mainly eicosapentaenoic acid (20: 5, ω3) and docosahexaenoic acid (22:6, ω3)] on the growth, tissue weights and fatty acid compositions of tissue total lipids in female rats and their progeny were investigated. Female rats of the Wistar strain, weighing 77~94g, were fed a 25% casein diet containing 5% of either corn oil (control), sardine oil or PUFA ethyl ester for 8 ~ 9 weeks prior to mating, and during gestation and lactation, and then for a further 2 weeks. The progeny were weaned to the maternal diet and then the latter was administered for a further 2 weeks. Dietary changes in the body weights of the dams were not generally seen, but the body weights at birth and growth of the offspring from the females supplied with the PUFA diet were inferior compared to those of the other groups. The fertility did not differ among the dietary groups. The weights of several tissues in the dams and the progeny increased in proportion to their body weights but not that of the progeny brain, which remained ' almost unchanged by the dietary fats. As to the fatty acid compositions of total lipids in the tissues, on the whole, decreased levels of ωβ fatty acids and increased percentages of ω3 fatty acids were found in the sardine and PUFA groups, the changes being greater in the PUFA group than in the sardine one. Such findings due to the feeding of PUFA were more remarkable in the progeny compared with in the dams. Eicosatrienoic acid (20: 3, ω9) was almost completely undetectable in the tissue total lipids of all the dietary groups.     

Dietary fat and cholesterol and serum cholesterol in the gerbil

Groups of gerbils were fed purified diets containing either 10 or 20% of safflower, olive, or coconut oil. Each diet was fed without cholesterol and with 0.1 and 0.2% of added cholesterol. The animals were bled after 2, 4, and 8 wk for the determination of the level of serum cholesterol. The major factors affecting the level of serum cholesterol were the kind of dietary oil, the amount of dietary cholesterol, and the length of time the diet was fed. The level of safflower oil had a statistically significant effect but the level of olive or coconut oil had no significant effect. Various other statistically significant interactions were observed which make simple interpretations of the data difficult. The levels of serum cholesterol achieved in the gerbils fed the different oils with no or very low levels of dietary cholesterol were similar to those seen in men fed the same oils. Although the gerbil is apparently resistant to the development of atherosclerosis, it may be a useful model for studying the effect of dietary fats upon cholesterol metabolism.     

Comparative hypocholesterolemic effects of five animal oils in cholesterol-fed rats

The hypocholesterolemic efficacy of various animal oils was compared in rats given a cholesterol-enriched diet. After acclimatization for one week, male F344 DuCrj rats (8 weeks of age) that had been fed with a conventional diet were assigned to diets containing 5% of oil from emu (Dromaius), Japanese Sika deer (Cervus nippon yesoensis, Heude), sardine, beef tallow, or lard with 0.5% cholesterol for 6 weeks. After this feeding period, the concentrations of serum total cholesterol and of very-low-density lipoprotein + intermediate-density lipoprotein + low-density lipoprotein-cholesterol in the sardine oil group were significantly lower than those in the other groups. The serum high-density lipoprotein-cholesterol concentration in the Japanese Sika deer oil group was significantly higher than that in the other groups. The atherosclerotic index and liver cholesterol concentration in the sardine oil and Japanese Sika deer oil groups were significantly lower than those in the other groups. The fecal cholesterol excretion by the Japanese Sika deer oil group was significantly higher than that of the other groups, except for the sardine oil group, and the fecal bile acid excretion by the sardine oil group was significantly higher than that of the other groups, except for the lard group. These results suggest that Japanese Sika deer oil reduced the atherosclerotic index and liver cholesterol concentration in the presence of excess cholesterol in the diet as well as sardine oil did by increasing the excretion of cholesterol from the intestines of rats.     

Chemical composition and oxidative stability of flax, safflower and poppy seed and seed oils

Three seeds of Turkish origin, flax, poppy and safflower were analyzed for their proximate, fatty acids, tocols (tocopherols and tocotrienols) and total phenolic composition, and oxidative stability of their oil. The major fatty acid in the flax oil was alpha-linolenic acid, comprising 58.3% of total fatty acids, whereas poppy and safflower oils were rich in linoleic acid at 74.5% and 70.5% level, respectively. The amount of total tocols was 14.6 mg/100g flax, 11.0mg/100g poppy and 12.1mg/100g safflower seed. Flax and poppy oil were rich in gamma-tocopherol as 79.4 mg/100g oil and 30.9 mg/100g oil, respectively, while alpha-tocopherol (44.1g/100g oil) was dominant in safflower oil. Only alpha- and gamma-tocotrienol were found in the oils. Oxidative stability of oils was measured at 110 degrees C at the rate of 20 L/h air flow rate, and poppy oil (5.56 h) was most stabile oil followed by safflower oil (2.87 h) and flax oil (1.57). There were no correlation between oxidative stability and unsaturation degree of fatty acids and tocol levels of the oils. All of the seeds investigated provide a healthy oil profile and may have potential as a source of specialty oils on a commercial scale.     

Effects of replacing palm oil with maize oil and Curcuma longa supplementation on the performance, carcass characteristics, meat quality and fatty acid profile of the perirenal fat and muscle of growing rabbits

An experiment has been conducted to study the effects of the inclusion of plant oil in rabbit diets. This study was aimed at evaluating the beneficial effects of the inclusion of maize oil (MO), rich in unsaturated fatty acids (UFAs), compared to palm oil (PO) containing saturated fatty acids (SFAs), on the meat fatty acid (FA) profile. As UFAs are susceptible to rancidity, Curcuma longa (CL), which is known for its antioxidant properties, was also added (3 g/kg) to the diet with two plant oils. CL contains curcuminoids, volatile oils, sugars, proteins, resins and polyunsaturated fatty acids (PUFAs). We also evaluated the influence of CL inclusion in the diet on the FA profile of the meat. Furthermore, the possibility of using these oil-enriched diets and the ability to assimilate CL in rabbits was evaluated by analysing the performance, carcass characteristics and meat quality. At the end of the experiment, there were no significant differences between the groups concerning the live weight, live weight gain, feed consumption, feed efficiency, carcass yield or the percentages of edible organs. The hind legs, forelegs, loins and abdominal wall, breast and ribs, skin and limbs and head were not affected by the oil type or by the inclusion of CL. The chemical composition, pH and oxidative status of the Longissimus dorsi muscle of the rabbits fed the experimental diets were not affected by the oil source or by the CL supplementation. Conversely, it has been shown that it is possible to modify the FA profile of rabbit meat and fat by dietary means. The SFA/PUFA ratio significantly decreased from -18% to -16% in the meat and from -25% to -23% in the perirenal fat of the rabbits fed diets containing MO without or with CL supplementation, respectively, compared to same tissues of the rabbits fed diets containing PO without or with CL supplementation, respectively. Similar trends were found for the atherogenic index, which decreased from -20% to -17% in the meat and from -26% to -23% in the perirenal fat, respectively, and the thrombogenic index, which decreased from -19% to -24% in the meat and from -24% to -23% in the perirenal fat, respectively. CL increased the α-Linolenic acid and PUFA n-3 contents and reduced the vaccenic acid content and the n-6/n-3 ratio in the meat of the rabbits fed the PO or MO diets.     

The adaptive effects of dietary fish and safflower oil on lipid and lipoprotein metabolism in perfused rat liver

To elucidate the mechanisms underlying the plasma triacylglycerol-lowering effects of certain fish oils, livers from male rats fed either a standard commercial diet (controls) or diets supplemented with 15% (w/w) fish or safflower oils were perfused with undiluted rat blood. Rates of hepatic lipogenesis, measured by the incorporation of 3H2O into fatty acids, followed the order: control greater than safflower oil greater than fish oil. Secretion of newly synthesized fatty acids in very-low-density lipoproteins was also inhibited by the feeding of both oil-supplemented diets with the greater suppression being seen in livers from animals fed fish oil. The hepatic release of very-low-density lipoprotein triacylglycerol mass was also significantly depressed in animals fed the fish oil-supplemented diet but not in those fed safflower oil. Ketogenesis did not differ between livers from rats fed the control and safflower oil diets but was significantly raised in the fish oil group. Increased ketogenesis with fish oil was paralleled by a decrease in the sensitivity of carnitine palmitoyl transferase of isolated mitochondria to inhibition by malonyl-CoA. The inhibitory effect of malonyl-CoA in the safflower oil group was intermediate between that in the fish oil and control groups. Activities of glycerophosphate acyltransferase with either palmitoyl-CoA or oleyl-CoA were increased by feeding oil-supplemented diets. Activity with palmitoyl-CoA that was suppressible by N-ethylmaleimide was also considerably diminished in both groups. The results indicate that the lowering of plasma triacylglycerols by fish oil reflects: (a) diminished lipogenesis; (b) increased fatty acid oxidation possibly in peroxisomes; and (c) diminished secretion of triacylglycerols by the liver.     

Maternal Dietary Fat and Polyunsaturated Fatty Acids in the Developing Foetal Rat Brain

Abstract: Female rats were fed pursed diets containing 10% safflower oil, which is high in linoleic acid, from approximately 2 weeks prior to mating until the 14th day of gestation. They were then fed purified diets containing safflower oil, soybean oil (containing linoleic and linolenic acids), or hydrogenated coconut oil (essential fatty acid deficient). On days 16, 18, and 21 of gestation, foetuses were removed by caesarean section and the brains were subjected to fatty acid analysis. By day 16 of gestation, the ethanolamine glycerophospholipids and combined serine-inositol glycerophospholipids were rich in polyunsaturated fatty acids, particularly arachidonic acid. Between days 16 and 21 of gestation, there was a marked increase in the C₂₂-polyunsaturated acids in these glycerophospholipids, with 225n-6 deposited in foetuses from dams fed safflower or coconut oils and 22:6n-3 deposition occurring in the soybean oil group; the effects of essential fatty acid deficiency in this period were minimal. A similar pattern was evident in the choline glycerophospholipids but this fraction contained less of the polyunsaturated acids. The data are consistent with increased placental transfer of highly unsaturated fatty acids or increased foetal synthesis of these compounds during the last week of gestation, with the actual fatty acid pattern reflecting the dietary fat available to the dam.     

Development and Characterization of Multifunctional Gelatin-Lysozyme Films Via the Oligomeric Proanthocyanidins (OPCs) Crosslinking Approach

Herein, we report firstly the development of sustained antimicrobial and antioxidant gelatin-lysozyme films crosslinked by the oligomeric proanthocyanidins (OPCs), a duel-functional agent. Lysozyme release kinetic studies were performed at neutral and acidic pH, and they could be described as a biphasic process. OPCs crosslinking retarded lysozyme release at pH 7.0, in a dose dependent manner, and the inhibition zone tests confirmed that the sustained release of lysozyme was realized upon weak crosslinking with OPCs. OPCs crosslinking enhanced thermal stability of the gelatin films, and gave them the ability to barrier ultraviolet light. OPCs loadings endowed the films excellent antioxidant activities, the DPPH radical scavenging activity of the films increased linearly to 93.97% upon increasing OPCs loadings from 0 to 2.0%. Concomitantly, the reducing powder of the films increased linearly from 6.08 ± 0.09 to 45.53 ± 2.74 μmol Asc Acid/g film. Additionally, the antioxidant properties of gelatin films against lipid oxidation in edible oils were evaluated. Lipid hydroperoxides of algal oils in the gelatin bags were approximately a quarter of that in low-density polyethylene (LDPE)-based bags, and the malondialdehyde (MDA) values of algal oils were lower than that in LDPE-based bags by 1–2 orders of magnitude. Regrettably, the incorporation of OPCs did not enhance the antioxidant capability of gelatin films against lipid oxidation in wrapped edible oils, possibly due to the limited release toward algal oils in term of its oil-soluble attribute. This study opens a promising pathway for producing sustained antimicrobial and antioxidant gelatin films using a bi-functional agent.     

Rapid modulation of the n-3 docosahexaenoic acid levels in the brain and retina of the newly hatched chick

The newly hatched chick obtains its fatty acids almost completely from the lipids of the egg yolk as these are transferred to the developing embryo during its 21-day period of incubation. Since the diet of the laying hen greatly influences the fatty acid composition of the egg lipids, and presumably also the fatty acid composition of the resulting chick, we tested how quickly and to what extent varying the amount of n-3 fatty acids in the diet of the hen would modulate the level of n-3 fatty acids in the brain and retina of the newly hatched chick. White Leghorn hens were fed commercial or semi-purified diets supplemented with 10% fish oil, linseed oil, soy oil, or safflower oil. Eggs, together with the brain, retina, and serum of newly hatched chicks, were then analyzed for fatty acid composition. The fatty acids of egg yolk responded quickly to the hen's diet with most of the change occurring by 4 weeks. There was a linear relationship between the linolenic acid content of the diets and levels of this fatty acid in egg yolk and chick serum. In chicks from hens fed the fish oil diet, the total n-3 fatty acids, including 22:6(n-3), were elevated twofold in the brain and retina and sevenfold in serum relative to commercial diet controls. The safflower oil diet led to a very low n-3 fatty acid content in egg yolks and only 25% of the control n-3 fatty acid content in the brain and retina of chicks.(ABSTRACT TRUNCATED AT 250 WORDS)     

Failure of insulin to stimulate lipogenesis and triacylglycerol secretion in perfused livers from rats adapted to dietary fish oil

Livers from male rats fed a standard commercial diet supplemented with 8% (w/w) marine fish or safflower oils were perfused for 70 min with undiluted blood in the presence and absence of insulin. Lipogenesis, as measured by the incorporation of ³H₂O into liver and perfusate fatty acids, was inhibited by the feeding of fish oil. Net triacylglycerol secretion was also depressed by this dietary treatment. Infusion of insulin stimulated triacylglycerol secretion and the incorporation of newly synthesised fatty acids into liver and perfusate lipids with dietary safflower oil but not with fish oil. Hepatic cholesterol synthesis was also depressed by feeding fish oil. Net ketogenesis was raised by feeding fish oil and was depressed by insulin with both safflower and fish oil. Blood glucose was raised in the fish oil group but with both dietary oils the hormone exerted a significant hypoglycaemic effect. The data are discussed with respect to the observations that in vivo dietary fish oil (but not safflower oil) opposes the hypertriglyceridaemia arising from the hepatic overproduction of very-low-density lipoproteins.     

Teratogenic actions of thermally-stressed culinary oils in rats

Lipid oxidation products (LOPs), generated in culinary oils during episodes of thermal stressing can give rise to cellular damage. The aims of this study were to determine whether orally-administered, LOP-containing thermally-stressed safflower oil exerts teratogenic actions in rats, and whether this effect could be prevented by co-administration of alpha-tocopherol (alpha-TOH). Safflower oil was heated for a period of 20 min according to standard frying practices and stored at -20 degrees C under N2. Four experimental groups of pregnant Wistar rats were employed; two received 0.30 ml of pre-heated oil (HO), one of which was also supplemented with 150 mg of alpha-TOH (HOE), and two served as controls, one treated with the non-heated oil (O) and the other without any treatment (C). The oil was administered daily by gavage from day 1 of pregnancy to day 11.5, when the animals were killed and the embryos examined. LOPs and alpha-TOH were determined both in the heated and non-heated oils. The percentage of embryo malformations and reabsorptions were determined in the above four experimental groups. Heating the oil substantially increased its concentration of LOPs and decreased its alpha-TOH content. The percentage of embryo malformations in the HO group was 21.73%, compared with 5.6 and 7% in the O and C groups, respectively. Supplementation of the pre-heated oil with alpha-TOH was found to decrease the percentage of malformations to 7%. The results obtained from these investigations indicate that LOPs detectable at millimolar levels in the heated cooking oils administered (e.g. saturated and alpha,beta-unsaturated aldehydes, and/or their conjugated hydroperoxydiene precursors) exert potent teratogenic actions in experimental animals which are at least partially circumventable by co-administration of the chain-breaking antioxidant alpha-TOH. Plausible mechanisms for these processes and their health relevance to humans regarding diet and methods of frying/cooking are discussed.     

Antioxidant activity of vegetable oils with different omega-6/omega-3 fatty acids ratio

The antioxidant activity and the oxidative stability of flax, sesame, silybum oils and seed blend oils with different ω-6/ω-3 fatty acid ratios have been investigated. The antioxidant content (AO) in crude oils and their reactivity towards peroxyl radicals were studied using the kinetic method based on oil addition to the model reaction of cumene oxidation. There were correlations between the ratio polyunsaturated fatty acids (PUFA)/ω-9 and thermal stability (50°C); between the effect of γ-tocopherol content and oil resistance to oxidative changes during long-term storage at (10 ± 2)°C.     

Effect of age on the modification of rat plasma lipids by fish and soybean oil diets

The effects of sardine and soybean oils on plasma lipids have been studied in young and aged rats. Plasma cholesterol and bile acids of aged rats fed on a sardine oil diet decreased to a greater degree than those of young rats. Cholesterol, bile acids and phospholipids of the soybean oil diet group decreased only in aged rats. Increases in plasma eicosapentaenoic (sardine) and linoleic (soybean) acid levels of aged rats were observed to be greater than those of young rats. These results indicate that the age enhances the effects of fish and soybean oils on plasma lipids by suppressing their characteristic fatty acid metabolism.