Effect Of PUFA Research Articles

Effect of PUFA at sn‐2 position in dietary triacylglycerols on the fatty acid composition of adipose tissues in non‐ruminant farm animals

AbstractThe influence of the distribution of polyunsaturated fatty acids on the glycerol backbone of dietary triacylglycerols on the fatty acid profile of adipose tissue and muscle phospholipids was investigated in growing‐finishing pigs (48) and broiler chicken (84). The animals were fattened on barley/soybean meal diets supplemented with a blend of soybean oil and beef tallow, either in the ratio 3:1 w/w (high‐PUFA) or 1:3 w/w (low‐ PUFA). Part of the high‐ and low‐PUFA blends was chemically interesterified to randomly distribute all fatty acids over the three positions of the glycerol. Thus, two sets of diets of identical overall fatty acid composition, but differing in the distribution of fatty acids in the triacylglycerols, were fed. Growth performance and carcass composition were neither affected by fatty acid composition nor by randomisation of dietary fats in either animal species. Apparent digestibility of energy was slightly lower in pigs fed the low‐PUFA blends. Fatty acid profile of subcutaneous fat of pigs and broilers as well as of internal body fat (lamina subserosa) and muscle phospholipids of pigs varied according to the dietary fatty acid composition but was not affected by randomisation of dietary fats. These findings are explained in terms of the hydrolysis of TAG during transport of lipids from enterocytes to adipose tissue cells and the continuous lipolysis and re‐esterification of fatty acids that take place in adipose tissue cells.

The cholesterolaemic effects of dietary fats in cholesteryl ester transfer protein transgenic mice.

In order to investigate the role of cholesteryl ester transfer protein (CETP) in the cholesterolaemic response to dietary fats, we analysed plasma lipid profiles of CETP-transgenic and control C57BL/6 mice fed standard chow (AIN-93G; AIN), a low-fat diet, and diets high in butter (saturated fatty acids; SFA), high-oleic acid safflower oil (monounsaturated fatty acids; MUFA), and safflower oil (polyunsaturated fatty acids; PUFA) for 5 weeks. Each group contained four or five mice. There were significant diet and dietxgenotype effects on plasma total cholesterol (TC; and respectively), liver TC ( and respectively), and esterified cholesterol (EC; and respectively); diet effects on plasma triacylglycerol liver free cholesterol and body weight a genotype effect on body-weight gain and a dietxgenotype effect on energy intake In transgenic mice the SFA diet caused significantly higher plasma TC than the PUFA diet In control mice MUFA and PUFA diets, but not the SFA diet, caused significantly higher plasma TC than the low-fat and AIN diets Transgenic mice fed PUFA had lower plasma TC while transgenic mice fed MUFA had lower LDL+VLDL-cholesterol than controls in the same dietary groups. Transgenic mice fed MUFA and PUFA diets also had significantly higher liver TC and respectively) and EC and respectively) than controls fed the same diets. In the present study we showed that: (1) CETP transgenic mice had a cholesterolaemic response to dietary fats similar to that in human subjects; (2) CETP transgenic mice fed PUFA showed significantly lower plasma TC, while those fed MUFA had lower LDL+VLDL-cholesterol than controls; (3) hepatic accumulation of cholesterol, possibly resulting from the combination of the enhanced cholesteryl ester transfer to apolipoprotein B-containing lipoproteins and increased hepatic uptake of cholesterol, may contribute to the cholesterol-lowering effect of MUFA and PUFA in CETP-transgenic mice; (4) CETP may play a role in appetite and/or energy regulation.

Effect of PUFA at sn-2 position in dietary triacylglycerols on fatty acid composition of adipose tissue in growing-finishing pigs

A potential effect of the specific composition of plant oil triacylglycerols, with PUFAs predominantly esterified at the sn-2 position, on the fatty acid composition of adipose tissues of pigs was investigated. Two blends with a ratio of 1/3 and 3/1 of soybean oil and beef tallow were randomised or left unmodified and fed at 4% of a conventional diet to 4 * 12 pigs. The randomisation of fatty acids at sn-1, 2 and 3 positions did not affect the fatty acid composition of pig adipose tissues. It is concluded that the position of PUFA in dietary triacylglycerols is of minor relevance for the composition of depot fat in growing-finishing pigs

Suppression of tumor growth and metastasis by dietary fish oil combined with vitamins E and C and cisplatin.

The anticancer activity of omega-3 polyunsaturated fatty acids (omega-3 PUFA) has been shown in a large number of studies. This study was undertaken to analyze the combined effect of omega-3 PUFA and antioxidative vitamins on the level of spontaneous metastatic dissemination. The supportive effect of this dietary combination on chemotherapy with cisplatin (CP) was determined in parallel. C57BL/6J mice bearing the Lewis lung carcinoma 3LL were fed ad libitum one of three isocaloric diets containing 5% soybean oil supplemented with 40 mg/kg alpha-tocopherol acetate (SO diet), or 4% fish oil plus 1% corn oil, and basal amounts of vitamin E (FO diet) or FO diet supplemented with vitamins E and C (FO+E+C diet). These diets were tested in combination with the conventional cytotoxic agent CP in a series of regimens. Tumor growth, feed consumption, body weight, lung metastasis and lung histology were followed. Both the FO dietary groups showed significantly lower tumor development than the SO group in all examined parameters, indicating that omega-3 PUFA have anticancer activity. However, the FO diet, in comparison with the FO+E+C diet induced a significantly slower rate of tumor growth, and lower metastatic load, as reflected in lung weight. The decrease in the anticancer activity of FO by the addition of vitamins E and C suggests that in situ oxidation of omega-3 PUFA underlies their anticancer action. It is thus proposed that oxidized omega-3 PUFA accumulates in the membranes and the cytosol of tumor cells, reducing their vitality and eventually leading to their death. No signs of anorexia or cachexia were observed in either FO group, in contrast to the SO group. CP treatment with the SO diet had no apparent therapeutic effect, while with the FO diets it reduced the metastatic load. The best regimen of this combined treatment was FO diet followed by CP treatment with FO diet supplemented with vitamins E and C after resection of the primary growth. This regimen could be translated to a combined therapy for human cancer. Diets enriched with omega-3 PUFA may have beneficial anticancer effects in particular when containing only basal amounts of antioxidants such as vitamin E or C. Furthermore, the addition of drugs which promote oxidation of omega-3 PUFA, such as ferrous salts (e.g. as prescribed for the treatment of anemia), may further increase these effects. However, the supportive effect of omega-3 PUFA in chemotherapy (e.g. with CP) increases when vitamins E and C are also included.

Polyunsaturated fatty acid dietary supplementation: An adjuvant approach to treatment of Helicobacter pylori infection

Recent studies suggest that PUFAs may have a role in both duodenal ulcer incidence and H. pylori growth in vitro. This study investigated the effect of dietary PUFA supplementation on H. pylori in vivo. Fifteen H. pylori positive patients with mild functional dyspepsia were enrolled. H. pylori was histologically detected using both rapid urease test and histology by a blinded observer. Two grams of a dietary mixture of fish oil and blackcurrant seed oil (v/v) were fed daily for eight weeks and magnitude H. pylori infection determined both at the end of treatment and six months later. H. pylori clearance was obtained in eight out fifteen patients (53%). No migration of bacterium from antrum to fundus was observed. H. pylori eradication was obtained in 20% of these patients. The oil mixture used in this study produced good bacterial clearance, but poor H. pylori eradication. The effect of PUFA on H. pylori clearance may be due to modification of cellular membranes of both bacterium and host. These changes may reduce H. pylori virulence by interfering with bacterial adhesion to gastric epithelial cells or through a direct bactericidal effect on the micro-organism. If these data are confirmed, PUFA may be considered has adjuvant treatment for drugs usually employed for H. pylori eradication.

Acute ingestion of different dietary fatty acid species modulates postprandial lipid responses in New Zealand white rabbits

Although several investigations have linked the degree of fatty acid saturation to plasma lipid responses in the postprandial state, further evaluation is necessary. In this study, we compared the effect of saturated (SFA), monounsaturated (MUFA), and polyunsaturated (PUFA) fatty acids on postprandial lipid metabolism using complementary in vivo and in vitro approaches. Fat (10 g) cholesterol (0.5 g) test meals that provided either lard (SFA), olive oil (MUFA), or sunflower oil (PUFA) were ingested by chow-fed New Zealand white rabbits ( n = 8). In addition, hepatic uptake of triglyceride-cholesterol-rich lipoproteins (TCRL) isolated from rabbits chronically ingesting SFA, MUFA, or PUFA diets was measured using freshly isolated chow-fed rabbit hepatocytes. Whatever dietary fatty acids ingested, postprandial triglyceridemia and occurrence of radiolabelled dietary lipids in plasma were not markedly different. Conversely, SFA induced higher postprandial cholesterolemia and phospholipemia than MUFA ( P < 0.05) whereas PUFA prevented postprandial cholesterol increase. TCRL disappearance from cultured liver cell media was delayed with SFA-rich TCRL and faster with PUFA whereas MUFA-rich TCRL showed an intermediate figure. From these data, we conclude that SFA, MUFA, and PUFA elicited different postprandial plasma and lipoprotein lipid responses. The fatty acid composition of TCRL had a major impact on their subsequent metabolism, especially uptake by cultured hepatocytes. The SFA-induced hypercholesterolemia could be related to an altered hepatic uptake whereas a faster clearance and hepatic uptake could explain the cholesterol-lowering effect of PUFA in rabbits. MUFA, like PUFA, accelerate uptake by hepatocytes but favor cholesterol ester enrichment of TCRL.

Antiarrhythmic Effects of Polyunsaturated Fatty Acids

The epidemiological studies of Kromann and Green1 on the low mortality rate of Greenland Inuits from ischemic heart disease led to the suggestion by Bang et al2 that despite the high total fat intake of the Eskimos, this low mortality rate was due to the abundance of n-3 fatty acids from seafood in their diet. This hypothesis initiated research by many investigators into possible antiatherogenic effects of n-3 PUFAs. Much has been learned regarding physiological and biochemical changes induced by this class of essential fatty acids that could have potential antiatherogenic effects; nevertheless, controversy persists in the current literature regarding the clinical evidence for beneficial effects from fish ingestion (the major dietary source of n-3 fatty acids) on the development of coronary heart disease.3 4 Studies seeking a resolution to the potential antiatherogenic effects of n-3 PUFA will undoubtedly continue.5 Meanwhile, on the basis of earlier sporadic suggestions that n-3 PUFA might possess antiarrhythmic effects,6 7 McLennan and coworkers8 9 pursued this possibility. They showed in feeding studies in rats that when saturated fats or olive oil is the major dietary fat, a high incidence of fatal, irreversible VF occurs from experimental coronary artery ligation, which was significantly reduced when the dietary fat was vegetable oil but was essentially abolished by fish oil. They have confirmed their basic finding in marmosets.10 It is not our purpose in this brief review to discuss possible antiatherogenic effects of n-3 PUFA or the role of coronary heart disease in causing malignant ventricular arrhythmias. Clearly, coronary heart disease is the major clinical setting in which malignant ventricular arrhythmias occur today, and myocardial ischemia is the most common trigger eliciting such arrhythmias. Rather, we will focus on our recent studies on the mechanism of the apparent antiarrhythmic actions …

Effect of (n-3) PUFA and vitamin A Artemia enrichment on pigmentation success of turbot, Scophthalmus maximus (L).

Emulsions with different content of (n-3) PUFA and vitamin A were used to enrich Artemia and examine the effect of these nutrients on pigmentation success in turbot, Scophthalmus maximus (L.). The best pigmentation rates were obtained using an overdose of vitamin A (500 000 IU L−1), but coincided with a high incidence of skeletal deformations. Higher growth and pigmentation rates were achieved by increasing the quantity of (n-3) PUFA oil in the emulsion. The use of (n-3) PUFA-deficient diet caused the highest occurrence of albinism as well as a cessation of metamorphosis.

The effect of dietary polyunsaturated fatty acids (PUFA) on acute rejection and cardiac allograft blood flow in rats.

For six weeks, recipient (Lewis RT11) and donor rats (LBNF11/n) were fed three diets that varied only in their lipid content. Diet A (MO) contained 19.5% menhaden oil and 0.5% safflower oil and was rich in omega 3 PUFA; diet B (SO) was 20% safflower oil rich in omega 6 PUFA; and diet C (BT) was 20% beef tallow rich in omega 9 monounsaturated fatty acids and saturated fat. In the first set of graft survival studies a group fed laboratory chow was included (CHOW). Heterotopic cardiac transplantation from donor to recipient animals was performed after the six-week feeding period. The effect of these diets on cardiac allograft survival, mixed lymphocyte response, and blood flow in the rejecting grafts was investigated. The median graft survival in days was significantly prolonged in the rats maintained on either MO (12 days) or SO (14.5 days) compared with the BT (8 days)-or lab chow (7.5 days)-fed animals (P < 0.05). Cyclosporine (CsA) administered at subtherapeutic levels further increased the differences between the PUFA-fed animals and the BT-fed group. The myocardial blood flow of the rejecting allografts was measured using an 85Sr-labeled microsphere technique on the fifth posttransplant day. Flow was greatest in the MO-fed group, and both MO and SO groups had significantly higher myocardial blood flow than BT-fed rats (P < 0.05) or those bearing isografts. The allogenic mixed lymphocyte responses of peripheral blood mononuclear cells (PBMC) and splenic lymphocytes were suppressed in MO- and SO-fed groups compared with BT-fed animals. The immunosuppressive effect of dietary PUFA warrants further investigation, and their use as a possible adjunctive treatment in organ transplantation should be considered.

Effect of N-3 polyunsaturated fatty acid supplemented diet on neutrophil-mediated ileal permeability and neutrophil function in the rat.

Fish oil, rich in n-3 polyunsaturated fatty acids, can alter leukotriene production and hence neutrophil function, factors which may be important in the inflammation of Crohn's disease (CD). Therefore we studied the effect of dietary PUFA on neutrophil mediated ileal inflammation and neutrophil function in the rat. Animals were ad libitum-fed pellet diets containing 9.5% fish oil (menhaden oil, rich in n-3 PUFA) with 0.5% safflower oil, 10% safflower oil (rich in n-6 PUFA) or standard chow (6% fat) for 50 days prior to the study. Weight and circulating leukocyte and total neutrophil counts were identical in all three groups. Neutrophil mediated ileal inflammation induced by formyl-methionyl-leucyl-phenylalanine (fMLP) perfusion was evaluated by measuring macromolecular uptake of radiolabelled dextran (MW 70,000) and changes in mucosal neutrophil infiltration. The fish oil diet group showed no difference in fMLP-induced permeability changes relative to the Chow Control group. However, the Safflower Oil supplemented diet group had a reduced permeability response (p < 0.01). Mirroring the permeability changes, there was diminished mucosal neutrophil infiltration in the Safflower Oil group following ileal perfusion with fMLP (< .005). Chemotaxis and chemiluminescence, two important neutrophil functions, were also significantly suppressed in the Safflower Oil animals (p < 0.05). The failure of a n-3 PUFA enriched diet to diminish the ileal inflammatory response to a bacterial peptide and suppress neutrophil function in the rat suggests such therapy would not be expected to be highly successful in CD. However, it requires confirmation in man, especially under the more complicated inflammatory conditions found in CD. On the other hand, the decreased neutrophil mediated responses with a high linoleic acid (n-6 PUFA) diet warrant further investigation.

Studies on Peroxidative Hemolysis and Erythrocyte Fatty Acids in the Rabbit: Effect of Dietary PUFA and Vitamin E

Studies on Peroxidative Hemolysis and Erythrocyte Fatty Acids in the Rabbit: Effect of Dietary PUFA and Vitamin E