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Forty-eight Duroc-cross gilts (40 kg initial BW) were fed a control or a linseed diet containing 60 g of whole crushed linseed/kg. Both diets were supplemented with 150 mg of vitamin E/kg. Eight pigs from each dietary treatment were slaughtered at 20, 60, or 100 d after the start of the experiment. There was no effect (P > 0.05) of diet on growth, carcass characteristics, or foreloin tissue composition. Feeding the linseed diet increased (P < 0.05) the content of n-3 PUFA in plasma, muscle, and adipose tissue, but docosahexaenoic acid was not (P > 0.05) altered by diet. The proportions of n-3 PUFA were highest (P < 0.01) in pigs fed the linseed-diet for 60 d, regardless of tissue (plasma, muscle, or adipose tissue) or lipid (neutral lipids and phospholipids) class. The linseed diet produced a PUFA:saturated fatty acid ratio [greater than or equal to] 0.4 in all groups and tissues, which is close to the recommended value for the entire diet of humans, as well as a robust decrease in the n-6:n-3 ratio. The decrease (P < 0.01) in the percentage of oleic acid in adipose tissue of pigs fed the linseed diet for 60 d could be attributed to a 40% decrease (P < 0.001) in stearoyl-CoA-desaturase activity. Diet did not (P > 0.05) affect the activities of acetyl-CoA-carboxylase, malic enzyme, or glucose-6-phosphate-dehydrogenase in any tissues. Muscle vitamin E content was decreased (P < 0.001) 30% in pigs fed crushed linseed for 60 d, whereas lower (P < 0.001) concentrations of skatole in pork fat were observed in linseed-fed pigs at all slaughter times. Inclusion of linseed (flaxseed) in swine diets is a valid method of improving the nutritional value of pork without deleteriously affecting organoleptic characteristics, oxidation, or color stability. Key Words: Acyl-CoA desaturase, Fatty Acids, Linseed, Lipogenesis, Meat Quality, Pigs

Dietary [alpha]-linolenic acid (ALA) can be converted to long-chain (n-3) PUFA in humans and may potentially reproduce the beneficial effects of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids on risk factors for coronary heart disease (CHD). This study compared the effects of increased intakes of ALA with those of dietary EPA and DHA on blood coagulation and fibrinolytic factors in fasting subjects. A placebo-controlled, parallel study was conducted in 150 moderately hyperlipidemic subjects, age 25-72 y. Subjects were randomly assigned to one of five interventions and consumed a total intake of 0.8 or 1.7g/d EPA+DHA, 4.5 or 9.5g/d ALA or control (linoleic acid; LA) for 6 mo. Fatty acids were incorporated into 25 g of fat spread, which replaced the subject's normal spread and three capsules. Long-term supplementation with either dietary EPA+DHA or estimated biologically equivalent amounts of ALA did not affect factors VIIa, VIIc, VIIag, XIIa, XIIag, fibrinogen concentrations, plasminogen activator inhibitor-1 or tissue plasminogen activator activity compared with the control. (n-3) PUFA of plant or marine origin do not differ from one another or from LA in their effect on a range of blood coagulation and fibrinolytic factors. KEY WORDS: * [alpha]-linolenicacid * eicosapentaenoic acid * docosahexaenoic acid * Factor VIIc * Factor XII

In response to elicitors in the oral secretions of caterpillars, plants produce and release volatile chemicals that attract predators and parasitoids of the caterpillar while it feeds. The most prevalent elicitors are fatty acid amides consisting of 18-carbon polyunsaturated fatty acids coupled with L-glutamine. We demonstrate rapid CoA- and ATP-independent in vitro biosynthesis of the fatty acid amide elicitor, N-linolenoyl-L-glutamine, by microsomal fractions of several alimentary tissues in Manduca sexta. N-linolenoyI-L-glutamine is a structural analog of several other elicitors including volicitin, the first fatty acid amide elicitor identified in caterpillars. The enzyme(s) that catalyzed biosynthesis of N-linolenoyl-L-glutamine was localized within the integral membrane protein fraction extracted from microsomes by Triton X-114 detergent phase partitioning and had maximum activity at alkaline pH. We found no evidence suggesting microbial or tissue-independent biosynthesis of N-linolenoyl-L-glutamine in M. sexta. The in vitro biosynthesis of N-linolenoyl-L-glutamine by membrane-associated enzyme(s) in M. sexta represents direct evidence of fatty acid amide synthesis by caterpillar tissues. fatty acid amide | linolenic acid | plant-insect interactions

A new canola strain capable of producing >30% [gamma]-linolenic acid [GLA, 18:3(n-6)] in the seed oil has been developed in our laboratories. This study compares the intestinal absorption and lymphatic transport of this newly developed high GLA content canola oil (HGCO) with traditional GLA-rich borage oil (BO) using a lymph fistula rat model. To assess the extent that 1 mL of GLA in the supplemented oil was absorbed and transported, the fatty acid compositions of triglycerides in mesenteric lymph were compared over a 24-h collection period. The digestion, uptake and lymphatic transport of HGCO and the normal physiologic changes associated with fat absorption (e.g., lymph flow and an increase in lymphatic endogenous lipids outputs, triglycerides, cholesterol and phospholipids) were similar in the HGCO-and the BO-fed rats. The original differences in [gamma]-linolenic acid content in HGCO and BO were preserved in the fatty acid composition of the rats' lymph lipid. We conclude that the HGCO derived from the genetically modified canola plant is absorbed and transported into lymph similarly to BO. J. Nutr. 132: 218-221, 2002. KEY WORDS: * [gamma]-linolenic acid * intestinal lipid absorption * genetically modified canola oil * lymphatic lipids * rats

In diabetes, the activity of [DELTA]-6 desaturase, which converts linoleic acid (LA) into [gamma]-linolenic acid (GLA), the first step of arachidonic acid (AA) synthesis, is decreased, leading to alterations in membrane phospholipid composition. On the other hand, 12 wk after the onset of diabetes, [Na.sup.+], [K.sup.+]-ATPase activity is reduced in many organs, including the kidney. The medullary thick ascending limb (MTAL) reduced [Na.sup.+], [K.sup.+]-ATPase activity, whereas the sodium load secondary to glomerular hyperfiltration was increased. The aim of our study was to examine whether the changes in membrane fatty acid composition resulting from the inhibition of [DELTA]-6 desaturase may be involved in the decreased [Na.sup.+], [K.sup.+]-ATPase activity observed in the outer MTAL after 12 wk of diabetes. GLA is a fatty acid that by-passes the [DELTA]-6 desaturase step. We measured the membrane fatty acid composition and the [Na.sup.+], [K.sup.+]-ATPase activity in the renal outer medulla of control and streptozotocin (STZ)-induced diabetic rats 12 wk after the induction of diabetes. Measurements were performed after supplementation of control rats with sunflower oil (SO) or GLA for 12 wk, and supplementation of 12 wk diabetic rats with SO for 12 wk or with GLA for 6 or 12 wk. Supplementation with GLA not only prevented the decrease in [Na.sup.+], [K.sup.+]-ATPase activity observed after 12 wk of diabetes but also time dependently stimulated [Na.sup.+], [K.sup.+]-ATPase activity in the outer medulla. The changes in [Na.sup.+], [K.sup.+]-ATPase activity were related to parallel changes in the amount of [Na.sup.+], [K.sup.+]-ATPase [[alpha].sub.1] subunit protein. In addition, in diabetic rats only, [Na.sup.+], [K.sup.+]-ATPase activity was positively correlated with the amount of AA present in cell membranes (r = 0.92, P < 0.05). Our results indicate that nutritional GLA supplementation increases [Na.sup.+], [K.sup.+]-ATPase activity and expression in diabetic rats. In addition, the positive correlation between AA content and [Na.sup.+], [K.sup.+]-ATPase activity suggests that in diabetic rats, alterations in membrane fatty acid composition contribute to the decreased [Na.sup.+], [K.sup.+]-ATPase activity in outer medulla. KEY WORDS: * arachidonic acid * [gamma]-linolenic acid * [Na.sup.+], [K.sup.+]-ATPase * rats * medullary thick ascending limb

The use of unhydrogenated oils, such as rapeseed and soybean oil, can increase alpha-linolenic acid intake. Other sources of alpha-linolenic acid include margarines and some other fats. Partially hydrogenated vegetable oils in margarines increase the share of poly-unsaturated fatty acids in the total fat intake. A study involving Dutch elderly men shows that a diet rich in alpha-linolenic acid can prove beneficial to heart patients.

Enteral diets containing borage and fish oils were fed to pigs with cardiopulmonary dysfunction following endotoxin-induced acute lung injury to determine if n-3 and gamma-linolenic acid (gamma-LA) can be used in the management of acute lung injury. The results show that dietary eicosapentaenoic acid and gamma-LA improved oxygen delivery and gas exchange, possibly by modifications of eicosanoid synthesis combined with an increase in cardiac output and reduction of pulmonary vascular resistance.

A mechanism in the livers of neonatal rats may which inhibits oxidation of linolic and linolenic n-3 and n-6 fatty acids and expresses them in triacylglycerol. Researchers compared the metabolism of fatty acids in the liver tissue of neonatal rats at various ages and adult rats. Livers of rats at ages 11 and 21 had two to four times higher secretions of triacylgycerol compared to cellular retention. Adult hepatocytes cultures incorporate greater ratios of each fatty acids species in to cellular triacylglycerol than phospholipid as compared to neonatal hepatocytes.

This study examined the effects of dietary [Alpha]-linolenic acid [18:3(n-3)] deficiency on dopaminergic and serotoninergic neurotransmission systems in 60-d-old male rats. Rats were fed semipurified diets containing either peanut oil [the (n-3)-deficient group] or peanut plus rapeseed oil (control group). We measured the densities of the serotonin-2 (5-HT2) receptors and the dopamine-2 (D2) receptors by autoradiography and membrane-binding assays in relation to the fatty acid composition and levels of endogenous monoamines in three cerebral regions: the frontal cortex, the striatum and the cerebellum. Long-term feeding of the (n-3)-deficient diet induced a significantly higher 5-HT2 receptor density in the frontal cortex compared with the control rats without any difference in the endogenous serotonin concentrations. The results also showed some modification of dopaminergic neurotransmission specifically in the frontal cortex in the rats deficient in [Alpha]-linolenic acid, with a significantly lower density of D2 receptors and a significantly lower concentration of endogenous dopamine than in control animals. Moreover, there were lower levels of (n-3) fatty acids in all the regions studied in the deficient rats, balanced by greater levels of (n-6) fatty acids. These results suggest that chronic consumption of an [Alpha]-linolenic acid-deficient diet could induce modifications of the neurotransmission pathways; this might induce the behavioral disturbances previously described in this fatty acid-deficient animal model. INDEXING KEY WORDS: dopaminergic; frontal cortex; serotoninergic; [Alpha]-linolenic acid deficiency; rats

We have previously determined the dietary Alpha-linolenic requirement for membrane synthesis in the developing animal. This study measures the dietary requirement for maintaining normal membrane composition in adult rats, as determined by 22:6(n-3) (docosahexaenoic acid) concentration. Sixty-day-old rats, previously fed a diet containing both linoleic and Alpha-linolenic acid, were divided into nine groups, each receiving different quantities of Alpha-linolenic acid but the same amount of linoleic acid. They were killed 4 wk after initiation of the new diet to determine the minimum quantity of Alpha-linolenic acid required in the diet for maintaining the 22:6 (n-3) tissue concentration in brain (whole tissue, myelin and nerve endings), liver and heart. The minimal amount of dietary Alpha-linolenic acid that maintained the maximal 22:6(n-3) level and minimal 22:5(n-6) level in tissues was considered to be the dietary requirement. The quantity was found to be 1.30 g/kg diet (0.26% of dietary energy). It was lower than that found for the developing animal (0.4% of energy). At lower quantities of dietary Alpha-linolenic acid, 22:6(n-3) was replaced by 22:5(n-6) in the organs examined, except in nervous tissue, in which 22:6(n-3) was highly preserved.

A study was done on the effect of dietary-linolenic acid on mouse peritoneal prostaglandin E1. It was shown that mouse peritoneal macrophages elongate dietary gamma-linolenic acid to dihomo-gamma-linolenic acid and converts it to prostaglandin E1 which is an anti-aggregatory, anti-inflammatory eicosanoid. Prostaglandin E1 inhibits platelet aggregation, superoxide anion generation, vascular smooth muscle cell proliferation and activation of the fibrinolytic system.

A study was done on the effects of polyunsaturated fatty acids on postnatal uterine development. It was shown that dietary alpha linolenic acid exert a significant effect on the phospholipid fatty acid composition of rat uterus. It was further shown that feeding rats a purified diet deficient in alpha linolenic acid for three generations significantly affected early sexual development especially the ponderant weight of the growing uterus.

Reduction of linolenic acid content in soybean (Glycine max (L.) Merr.) oil is associated with improved odor and flavor characteristics. Germplasm with the lowest content of this fatty acid known in soybean (

Research discusses the bioconversion of alpha-linolenic acid by Clavibacter sp, strain ALA2 into tetrahydroxyfuranyl fatty acids (THFAs). Results describe identification of these THAFs, determination of their structure, their chemical characterization, and their production aspects.

Effects of gamma-linolenic acid and oleic acid on paclitaxel cytotoxicity in human breast cancer cells. Menendez JA, del Mar Barbacid M, Montero S, et al. Eur J Cancer 2001;37:402-413. It [...]

Previous studies have shown that supplementation with γ-linolenic acid (GLA, C18:3 n-6) reduces generation of lipid mediators of inflammation and attenuates clinical symptoms of chronic inflammatory disorders such as rheumatoid [...]

To study the influence on lipid metabolism and platelet aggregation of the fatty acid isomerization that occurs during heat treatment, weanling rats were fed for 8 wk a diet enriched with 5% isomerized (experimental group) or normal (control group) canola oil. Geometrical isomers of [Alpha]-linolenic acid representing 0.2 g/100 g of the experimental diet were incorporated into liver, platelets, aorta and heart, at the expense of their cis homologue and of 18:2(n-6). The major isomer, 9c,12c,15t-18:3, was also metabolized to 5c, 8c, 11c, 14c, 17t-20:5 and to an unknown compound, found in liver, platelets and aorta, which has been identified tentatively as 7c, 10c, 13c, 16c, 19t-22:5. The greater 20:4(n-6)/18:2(n-6) ratio in the liver, platelets and heart of the experimental group than the control group indicated an enhancement of desaturation activities. This induced a higher content of long-chain (n-6) fatty acids in the experimental group. Platelet aggregation tended to be slightly higher (P = 0.065) in the experimental group. We conclude that 0.2 g of trans isomers of [Alpha]-linolenic acid per 100 g of diet was sufficient to be incorporated and metabolized, thus altering the fatty acid profile of rat tissues. J. Nutr. 130: 2550-2555, 2000. KEY WORDS: * dietary trans [Alpha]-linolenic acid * trans 22:5 * platelet aggregation * rats

Bessesen, Daniel H., S. Holly Vensor, and Matthew R. Jackman. Trafficking of dietary oleic, linolenic, and stearic acids in fasted or fed lean rats. Am J Physiol Endocrinol Metab 278: E1124-E1132, 2000.--Increasing evidence supports the notion that there are significant differences in the health effects of diets enriched in saturated, as opposed to monounsaturated or polyunsaturated fat. However, the current understanding of how these types of fat differ in their handling by relevant tissues is incomplete. To examine the effects of fat type and nutritional status on the metabolic fate of dietary fat, we administered [sup.14]C-labeled oleic, linolenic, or stearic acid with a small liquid meal to male Sprague-Dawley rats previously fasted for 15 h (fasted) or previously fed ad libitum (fed). [sup.14][CO.sub.2] production was measured for 8 h after tracer administration. The [sup.14]C content of gastrointestinal tract, serum, liver, skeletal muscle (soleus, lateral, and medial gastrocnemius), and adipose tissue (omental, retroperitoneal, and epididymal) was measured at six time points (2, 4, 8, 24, and 48 h and 10 days) after tracer administration. Plasma levels of glucose, insulin, and triglyceride were also measured. Oxidation of stearic acid was significantly less than that of either linolenic or oleic acid in both the fed and fasted states. This reduction was in part explained by a greater retention of stearic acid within skeletal muscle and liver. Oxidation of oleate and stearate were significantly lower in the fed state than in the fasted state. In the fasted state, liver and skeletal muscle were quantitatively more important than adipose tissue in the uptake of dietary fat tracers during the immediate postprandial period. In contrast, adipose tissue was quantitatively more important than skeletal muscle or liver in the fed state. The movement of carbons derived from dietary fat between tissues is a complex time-dependent process, which varies in response to the type of fat ingested and the metabolic state of the organism. dietary fat; skeletal muscle; adipose tissue; fuel partitioning; triglyceride