Docosahexaenoic and arachidonic acid prevent a decrease in dopaminergic and serotoninergic neurotransmitters in frontal cortex caused by a linoleic and alpha-linolenic acid deficient diet in formula-fed piglets.

This study examined the effects of diets deficient (D) in linoleic [18:2(n-6)] and linolenic acid [18:3(n-3)] at 0.8 and 0.05% energy, respectively, or adequate (C) in 18:2(n-6) and 18:3(n-3) at 8.3 and 0.8% energy, respectively, without (-) or with (+) 0.2% energy arachidonic [20:4(n-6)] and 0.16% energy docosahexaenoic [22:6(n-3)] acid in piglets fed from birth to 18 d. Frontal cortex dopaminergic and serotoninergic neurotransmitters and phospholipid fatty acids were measured. Piglets fed the D- diet had significantly lower frontal cortex dopamine, 3,4-dihydroxyphenylacetic (DOPAC), homovanillic acid (HVA), serotonin and 5-hydroxyindoleacetic acid (5-HIAA) concentrations than did piglets fed the C- diets. Frontal cortex dopamine, norepinephrine, DOPAC, HVA, serotonin and 5-HIAA were higher in piglets fed the D+ compared to those fed the D- diet (P < 0.05) and not different between piglets fed the D+ and those fed the C- diets or the C- and C+ diets. Piglets fed the D- diet had lower frontal cortex phosphatidylcholine (PC) and phosphatidylinositol (PI) 20:4(n-6) and PC and phosphatidylethanolamine (PE) 22:6(n-3) than did piglets fed the C- diet (P < 0.05). Piglets fed the D+ diet had higher frontal cortex PC and PI 20:4(n-6) and PC, PE, PS and PI 22:6(n-3) than did piglets fed the D- diet. These studies show that dietary essential fatty acid deficiency fed for 18 d from birth affects frontal cortex neurotransmitters in rapidly growing piglets and that these changes are specifically due to 20:4(n-6) and/or 22:6(n-3).

Pure linoleate deficiency in the rat: influence on growth, accumulation of n-6 polyunsaturates, and [1-14C]linoleate oxidation.

Essential fatty acid deficiency has been widely studied but the extent to which its effects are attributable specifically to deficiency of linoleate as opposed to deficiency of all unsaturated fatty acids is unknown. Our objective was to evaluate the effect of pure linoleate deficiency on growth as well as changes in the metabolism and oxidation of n-6 polyunsaturates. The diets contained 20 energy % fat blended from 3 energy % pure oleate, 2 energy % linoleate (0.01 energy % in the linoleate-deficient group), 0.3 energy % pure alpha-linolenate, and the balance as palmitate and stearate from fully hydrogenated soybean oil. Thirty-five-day-old rats consumed the two diets for 84 days, after which the linoleate-deficient rats weighed 15% less than the controls (P < 0.05), had mild scaling on the paws, and visible hair loss (in a few rats). Compared with the controls, the ratio of eicosatrienoate to arachidonate after 84 days was elevated in liver (170-fold) and serum (520-fold) phospholipids of the linoleate-deficient group. In total, linoleate-deficient rats consumed 122 mg of linoleate and had a net whole body loss of 479 mg n-6 polyunsaturates compared with an intake of 24,130 mg and a net whole body gain of 7206 mg n-6 polyunsaturates in the control group. Linoleate-deficient rats oxidized 1% of an oral bolus of [1-14C]linoleate over 8 h compared with 34% in the control rats (P < 0.05). We conclude that pure linoleate deficiency has marked effects on accumulation of n-6 polyunsaturates but induces milder gross symptoms, particularly growth retardation, than classical essential fatty acid deficiency. alpha-Linolenate and possibly oleate may have a sparing effect on linoleate oxidation from body stores during linoleate deficiency.

Zinc deficiency and the desaturation of linoleic acid in rats force-fed fat-free diets.

Recent studies with rats force-fed zinc-deficient diets containing various types of fat failed to demonstrate a role of zinc in desaturation of linoleic acid. The present study was conducted to investigate the effect of zinc deficiency on desaturation of linoleic acid in rats that were initially force-fed fat-free diets to stimulate activity of desaturases. Therefore, rats were fed zinc-adequate and zinc-deficient fat-free diets for 6 d. After that period, the groups were divided and half of the rats continued feeding the fat-free diet for another 3.5 d whereas the other half was switched to a fat diet by supplementing the fat-free diet with 5% safflower oil. In order to assess desaturation of linoleic acid, fatty acid compositions of liver phosphatidylcholine, -ethanolamine, and -serine were considered, particularly levels of individual (n-6) polyunsaturated fatty acids (PUFA). Levels of total and individual (n-6) PUFA were similar in zinc-adequate and zinc-deficient rats fed the fat-free diet throughout the experiment. Addition of 5% safflower oil increased levels of total and individual (n-6) PUFA in both zinc-adequate and zinc-deficient rats. However, total (n-6) PUFA in all types of phospholipids were higher in zinc-adequate rats than in zinc-deficient rats. Additionally, in zinc-deficient rats there were changes of (n-6) PUFA levels typical for impaired delta 5 and delta 6 desaturation: linoleic acid and dihomo-gamma-linolenic acid were elevated; arachidonic acid, docosatetraenoic acid, and docosapentaenoic were lowered by zinc deficiency. Therefore, the study shows that zinc deficiency impairs desaturation of linoleic acid in rats force-fed fat-free diets and therefore supports results from former convential zinc deficiency experiments suggesting a role of zinc for desaturation of linoleic acid.

The Canadian Society for Nutritional Sciences 1995 Young Scientist Award Lecture. Recent studies on the synthesis, beta-oxidation, and deficiency of linoleate and alpha-linolenate: are essential fatty acids more aptly named indispensable or conditionally dispensable fatty acids?

Recent research on the synthesis, beta-oxidation, and deficiency of linoleate and alpha-linolenate raises questions about whether the term essential fatty acid is outdated. Linoleate and alpha-linolenate can be synthesized from their respective 16-carbon precursors, which are present in the human diet; whether the rate of conversion and dietary supply of the precursors are sufficient depends on the actual requirement for linoleate and alpha-linolenate. Pure deficiency of linoleate (diet excluding linoleate but including alpha-linolenate and oleate) has not been studied until recently, so it is unclear whether the recommended linoleate intake at 2% of energy, as based on classical essential fatty acid deficiency studies, is appropriate or too high. Despite marked whole-body depletion of linoleate and poor conservation of linoleate stores, pure linoleate deficiency has little effect on growth in rats, suggesting its requirement may be less than 2% of energy. Whole-body fatty acid balance studies indicate that the main route of linoleate and alpha-linolenate metabolism is oxidation, which increases sufficiently that accumulation of dietary linoleate and alpha-linolenate may actually be prevented in undernutrition and fasting refeeding. Part of the oxidized carbon from linoleate and alpha-linolenate is recycled and used for de novo synthesis of "non-essential" fatty acids and cholesterol, which in the brain of the suckling rat, can exceed conversion to longer chain polyunsaturates by as much as 10- to 40-fold. Given the capability to synthesize linoleate and alpha-linolenate, the imprecise knowledge of true linoleate requirement, and the absence of clear symptoms of their deficiency in healthy adults, it might be advantageous to consider using the terms indispensable and conditionally dispensable to clarify the conditional nature of the dietary requirement for linoleate and alpha-linolenate.

Nutritional modulation of guinea pig skin hyperproliferation by essential fatty acid deficiency is associated with selective down regulation of protein kinase C-beta.

In a previous study we demonstrated that 13-hydroxyoctadecadienoic acid (13-HODE), a 15-lipoxygenase metabolite of linoleic acid is incorporated into epidermal phosphatidyl 4,5-bisphosphate (PtdIns 4,5-P2) and released as 13-HODE-containing-diacylglycerol (13-HODE-DAG). In vitro, 13-HODE-DAG was shown to selectively inhibit epidermal total protein kinase C (PKC-beta) activity. To determine whether these observations are relevant in vivo, guinea pigs were made essential fatty acid deficient (EFAD) by feeding them a basal diet supplemented with 4% hydrogenated coconut oil for 8 wk. Tissue levels of putative 13-HODE-DAG, protein kinase C (PKC) isozymes and tissue hyperproliferation were determined in the epidermal preparations from skin of control safflower oil-fed guinea pigs, those fed EFAD diet and those fed EFAD diet followed by the control diet for 2 wk. Our data revealed that cutaneous 13-HODE and 13-HODE-DAG were significantly lower in EFAD animals than in safflower-fed controls. These reductions were associated with both elevated epidermal hyperproliferation and elevated expressions and activities of PKC-alpha and beta-isozymes. Refeeding the animals with safflower oil for 2 wk replenished tissue levels of 13-HODE-DAG, which inversely correlated with the selective down regulation of PKC-beta expression and activity and the reversal of hyperproliferation. In contrast, although, the expression and activity of PKC-alpha was elevated in the epidermis of the EFAD guinea pigs, this elevated PKC-alpha expression was not down regulated after refeeding the safflower oil diet to the animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Aspirin toxicity in chicks given diets deficient in linoleic acid.

The toxicity of dietary aspirin on growth rate and lipid metabolism was investigated under linoleic acid (LA; 18: 2n-6) deficient conditions. One-week-old chicks were given diets containing 0 or 2% LA with or without 0.4% aspirin, until 4 weeks of age. Growth was severely depressed by dietary aspirin when chicks were given the LA-free diet. The liver was enlarged by both the aspirin and LA deficiency. The aspirin treatment induced a significant increase of 18:0 and arachidonic acid (20: 4n-6) and a decrease of 18: 1n-9 in the liver. In chicks fed LA-free diets, the ratio of 20:3n-9/20: 4n-6, which was used as an indicator of LA deficiency, was suppressed by aspirin treatment. In conclusion, the present results suggest that aspirin toxicity is altered by dietary LA concentrations.

Inhibition of cholesterol and sphingolipid synthesis causes paradoxical effects on permeability barrier homeostasis.

Cholesterol, fatty acid, and sphingolipid synthesis are required for barrier homeostasis, as demonstrated by studies where synthesis of these species is stimulated in parallel with barrier repair. Moreover, blockade of synthesis of these lipids with inhibitors of two of the rate-limiting enzymes, HMGCoA reductase (lovastatin, fluvastatin) and serine palmitoyl transferase (beta-chloroalanine), alters the kinetics of barrier repair. Whereas these studies demonstrated a requirement for these lipids individually, we asked here whether these lipids are required in either an additive or cooperative fashion. We applied each class of inhibitor alone or the two classes of inhibitors together to acetone-treated skin, or each class separately to essential fatty acid deficient murine skin. When fluvastatin or beta-chloroalanine was applied individually to acetone-treated skin, each caused a delay in the early or late stages of barrier recovery, respectively (assessed as transepidermal water loss). However, when applied together they caused no further worsening at the early time point and a paradoxical improvement at the later time points. This improvement correlated with an accelerated return of sphingolipids, which was perhaps due to a global stimulation of lipid synthesis induced by HMGCoA reductase inhibitors. In essential fatty acid deficient animals, inhibition of HMGCoA reductase caused drastic worsening of both clinical appearance and barrier function, but beta-chloroalanine caused a paradoxical improvement, which correlated with a significant reduction in epidermal sphingolipids. These results are consistent with a requirement for both cholesterol and sphingolipids for barrier homeostasis, and also with the suggestion that both of these lipids must be present (with free fatty acids) for optimal barrier function.

[The use of native triticale in poultry. 3. Use in laying hens]. / Untersuchungen zum Einsatz von einheimischem Triticale bei Geflügel. 3. Mitteilung-Einsatz bei Legehennen.

In three trials with a total of 3240 white laying hybrids, 10 to 72% Triticale of the variety "Grado" was used as a substitute for maize and wheat. The feeding of Triticale had no influence on feed consumption, laying performance, feed efficiency, mortality or weight gain. In two of three trials the egg weight was lowered with an increasing amount of Triticale in the diet. After supplementation of 1 or 1.5% sunflower oil to the diets with 50 resp. 72% Triticale the egg weight increased again to the level of the control group. With the exception of one group, there was no correlation between breaking strength and deformation of the eggs. The colour intensity of the egg yolk was decreased with increasing amounts of Triticale in the diet. It can be concluded, that laying hen feed supplemented with oil may contain up to 50% Triticale, but in non-supplemented diets the highest amount of Triticale should be only 20% because of the risk of linoleic acid shortage.

Reducción del ácido docosahexaenoico: DHA, 22:6w3, durante el período de rápido desarrollo del cerebro de ratas: I. Efecto de la dieta materna deficiente en ácido alfa linolénico y alta en ácido linolénico / Reduction of docosahexaenoic acid: DHA, 22:6w3, during the period of rapid development of rat brain: I. Effect of maternal deficient in alpha linolenic acid and high in linolenic acid diet

Uno de los ácidos grasos piliinsaturados más abundantes en los lípidos del cerebro es el ácido docosahexaenoico (DHA, C22:6w3). Este se incorpora al tejido nervioso principalmente durante la visa uterina y en los primeros días de vida en la rata. Con el propósito de diseñar un modelo experimental que provoque una severa deficiencia de DHA en cerebro fetal y postnatal sometimos por generaciones sucesivas a ratas preñadas y nodrizas al consumo de una dieta deficiente en ácido alfa linolénico (18:3w3) y alta en ácido linolénico (18:2w6). La dieta deficiente se preparó con aceite de girasol al 10% y proporcionó 7,2 g de 18:2w6 y 10 mg de 18:3w3/100 g dieta. La dieta control se preparó con aceite de soya al 10% la que proporcionó 5,6 g de 18:2w6 y 740 mg de 18:3w3/100 g dieta. El análisis de los ácidos grasos de los fosfolípidos de cerebro de fetos de 20 días de edad gestacional de 2ª generación y el de crías con 18 días de vida postnatal de primera y segunda generación mostraron una significativa disminución del 22:6w3 y una elevación del 22:5w6 en el cerebro de la progenie de madres que consumieron la dieta con aceite de girasol con respecto a las alimentadas con dieta con aceite de soya. Esta compensación no fue cuantitativa pues la instauración total permaneció baja. No se observaron disminuciones progresivas en el contenido de 22:6w3 del cerebro en el período de lactancia con respecto a la disminución observada en el período prenatal. Se sugiere que el desarrollo prenatal del cerebro es el período de mayor vulnerabilidad a una deficiencia de ácidos grasos omega 3 dietéticos. Se propone este diseño nutricional experimental, en donde podría evaluarse la potencialidad de los aceites vegetales o marinos, fuentes de 18:3w3 ó 22:6w3 en su capacidad para revertir la deficiencia de 22:6w3 tisular

Fatty acid composition of serum lipids of mothers and their babies after normal and hypertensive pregnancies.

The biochemical essential fatty acid (EFA) status of neonates born after normal and hypertensive pregnancies (PIH) and that of their mothers was assessed by measuring the fatty acid composition of phospholipids (PL), triglycerides (TG) and cholesterol esters (CE) of umbilical cord serum and maternal serum, respectively. Relative contents of linoleic acid of serum PL and CE were significantly lower in mothers with PIH compared to normal pregnancies. Most other (n-6) polyenes in PL tended to be higher under hypertensive conditions. Total maternal (n-3) polyenes of serum PL were significantly higher in PIH, mainly due to clupanodonic acid, 22:5 (n-3), and cervonic acid, 22:6 (n-3). Total maternal (n-7) and (n-9) fatty acids were also significantly higher in PIH (PL and CE). The results indicate that PIH is associated with a relative increased unsaturation of maternal serum PL, which might facilitate the placental transfer of long-chain, polyunsaturated fatty acids. As a result, the neonatal EFA status after PIH only slightly differs from normal.

Membrane structures in normal and essential fatty acid-deficient stratum corneum: characterization by ruthenium tetroxide staining and x-ray diffraction.

Despite the importance of intercellular lamellar bilayers for stratum corneum (SC) barrier function, knowledge about the structure of these bilayers is limited due to their poor visualization and/or retention. Whereas substitution of ruthenium tetroxide (RuO4) for osmium tetroxide fixation provides clear images of these bilayers, the usefulness of RuO4 has been limited by its slow penetration and cytotoxicity. Utilizing a new fixation protocol for RuO4, we obtained clear images of lamellar domains at all levels of murine SC. Computer-aided image reconstructions demonstrated a lamellar spacing of 129 +/- 2 A, which agreed with x-ray diffraction data from parallel, unfixed samples (131 +/- 2 A), a spacing not affected by hydration. Furthermore, novel structures were seen in the intercellular spaces of normal SC. Finally, in murine essential fatty acid deficiency (EFAD), the overall lamellar spacing is comparable to normal [127 +/- 7 A by computer transform vs. 131.9 +/- 2 A (hydrated) and 129.6 +/- 2.2 A (dry) by x-ray diffraction]. Yet, these domains are structurally abnormal, displaying regions with either an excess or absence of lamellae. The new RuO4 protocol provides quantitative information about SC lamellar dimensions and morphologic abnormalities in bilayer distribution and substructure in EFAD stratum corneum that are not detected by either x-ray diffraction or computer-aided image reconstruction. Thus, the barrier abnormality in EFAD stratum corneum can be ascribed either to focal depletion of lamellae or abnormalities in lamellar substructure.

[Essential fatty acid deficiency in enteral nutrition]. / Déficit de ácidos grasos esenciales durante nutrición enteral.

A case is presented of a 57-year-old patient who developed a clinical picture compatible with linoleic acid deficit while on a diet with 6.4 g of this fatty acid (2.8% of total calories). The factors involved in essential fatty acid requirements, and the need of some patients for up to 50 g of linoleic acid in order to reach normal serum levels are discussed. It was concluded that some commercial diets should be supplemented with additional linoleic acid.

Dietary linoleic acid deprivation: an experimental model of salt-sensitive hypertension.

The present study investigates arterial blood pressure (BP), renal arachidonic acid cyclooxygenase metabolism and excretory function in rats during dietary linoleic acid deprivation and a concomitant low and high NaCl-intake. Four groups of animals were fed isocaloric diets containing 10 energy (en) % saturated fat and either 5 en % linoleic acid (groups I and III) or 5 en % oleic acid (groups II and IV) over six weeks. In addition, groups I and II received a chronic high intake of sodium (5.4 mmol/24 h) while groups III and IV were NaCl-restricted (average NaCl intake of 0.7 mumol/24 h). Systolic BP significantly increased from 97.0 +/- 1.7 to 112.0 +/- 2.2 mmHg (p less than 0.01) in the salt loaded group II fed the diet deficient in linoleic acid and remained unchanged in the three other groups. Renal cyclooxygenase metabolism was significantly stimulated by sodium restriction and suppressed following dietary linoleic acid deprivation. During infusion of 0.45% saline to a stable increase in body weight of 10%, animals in the linoleic acid deprived groups II and IV excreted significantly less sodium, chloride, and potassium than animals in groups I and III. This impairment in renal excretory function occurred without concomitant changes in RPF, GFR, or UPhos V. It was associated, however, with marked decreases in fractional free water excretion (CH2O/GFR), distal delivery of solute [(CH2O + CCl)/GFR] and with an increase in "distal fractional chloride absorption" [CH2O/(CH2O + CCl)]. Furthermore, linoleic acid deprivation was associated with a significantly enhanced papillary osmolality and papillary sodium, chloride, and potassium concentrations in group II animals as compared to group I.(ABSTRACT TRUNCATED AT 250 WORDS)

Linoleic acid and coronary heart disease.

Low tissue concentrations of the essential fatty acid, linoleic acid, occur in communities with high rates of coronary disease and in patients with angina and myocardial infarction. This relationship is independent of lipids and blood pressure, but in smokers linoleic acid is particularly low because they eat less linoleic acid-containing foods.

Linoleic acid-deficient rat neutrophils show decreased bactericidal capacity, superoxide formation and membrane depolarization.

Essential fatty acid deficiency (EFAD) is associated with depressed inflammatory responses, e.g. neutrophil chemotaxis, which may be related to reduced generation of the arachidonate metabolite LTB4, a potent mediator for neutrophil activation. In this study we show that neutrophils from EFAD rats exhibited impairments of membrane depolarization and superoxide anion formation upon stimulation with a formylpeptide, FMLP, or when challenged with living Staphylococcus aureus (but not when activated with phorbol myristate acetate). Likewise, bactericidal capacity for S. aureus was depressed. However, ionomycin and FMLP stimulated intracellular Ca2+ elevations, phagocytic capacity, and conformational alterations as well as spreading were similar to control neutrophils. Thus, EFAD confers discrete functional abberations in neutrophils likely to be due to perturbation of arachidonate metabolism and/or membrane function.

Relation between essential fatty acid metabolism and gastrointestinal symptoms in cystic fibrosis.

Studies in our laboratory have supported the hypothesis, that the basic defect in cystic fibrosis increases the metabolism of essential fatty acids and thereby gradually gives rise to essential fatty acid deficiency, which is a well documented finding in most cases with this disease. Both the increased metabolism--giving high liberation of arachidonic acid and its metabolic products, i.e. different eicosanoids--and the subsequent essential fatty acid deficiency will cause gastrointestinal symptoms and the sequence of this development will mirror the natural history of the disease. Clinical data and results from animal research are discussed in relation to gastrointestinal symptoms and signs of cystic fibrosis.