Lower Levels Of Polyunsaturated Fatty Acids Research Articles

Evaluation of Fatty Acid and the Composition of Six Different Species of Freshwater Fish in the North of Algeria


 
 
 Background: Few studies have been published about the quality of freshwater fish in Algeria. This study determined the chemical composition and the fatty acid of six species of freshwater fish cultivated in the North region of Algeria (Nile tilapia, red tilapia, common carp, Algerian barb, crucian carp, and mirror carp) as well as the nutritional quality of the lipids in these freshwater fish species.
 Methods: One hundred and ten freshwater fish were randomly caught in the spring of 2021 from Achor Ali farm (Jijel), Beni-Haroun Dam (Mila), and EL-Agrem Dam (Jijel) from Algeria. Moisture, ash, protein, lipid, and fatty acids were measured according to standard laboratory procedures and protocols of previous studies. Statistical analysis was performed using ANOVA (XLSTAT 2014), and the pair wise comparison of the means was done by Tukeys test at the 5% significance level (p<0.05).
 Results: Regarding freshwater fish species, fatty acid profiles were discovered to have 38.94 to 57.75% Saturated Fatty Acids (SFAs), 29.35 to 46.63% Monounsaturated Fatty Acids (MUFAs), and 6.79 to 26.55% Polyunsaturated Fatty Acids (PUFAs). Common carp was a rich resource of Eicosapentaenoic Acid and Docosahexaenoic Acid (EPA+DHA) (5.38%); the highest concentration of ω-3 was recorded in crusian carp (10.63%); and Nile tilapia contained significant levels of ω-6 PUFA. Results demonstrated that the examined freshwater fish species appeared to have a good nutritional value and be a source of important fatty acids with positive effects on consumer health. On the other hand, results revealed low levels of PUFAs.
 Conclusion: The examined freshwater fish species appeared to have a good nutritional value, but, it is important to provide diets rich in fatty acids, in particular PUFAs, to these freshwater fish to improve the nutritional quality of their lipids.
 
 

Low Docosahexaenoic Acid, Dihomo-Gamma-Linolenic Acid, and Arachidonic Acid Levels Associated with Long-Term Mortality in Patients with Acute Decompensated Heart Failure in Different Nutritional Statuses.

The clinical significance of polyunsaturated fatty acids (PUFAs) in acute decompensated heart failure (ADHF) in various nutritional statuses remains unclear. For this study, we enrolled 267 patients with ADHF admitted to the cardiac intensive care unit at Juntendo University hospital between April 2012 and March 2014. The association between long-term mortality, the geriatric nutritional risk index (GNRI), and levels of PUFAs, including eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), dihomo-gamma-linolenic acid (DGLA), and arachidonic acid (AA) was investigated. The median age was 73 (64–82) years, and mortality was 29% (62 patients). The event-free survival rates for all-cause death were higher in patients with high PUFA levels or GNRI than in those with low PUFA levels or GNRI (p < 0.05 for all). In particular, high DGLA in the low-GNRI group and high DHA or AA in the high-GNRI group were associated with high event-free survival (p < 0.05 for all). After accounting for confounding variables, DHA, DGLA, and AA, but not EPA, were associated with long-term mortality (p < 0.01 for all). This study concludes that in patients with ADHF, decreased levels of DHA, DGLA, and AA are independently associated with long-term mortality in the various nutritional statuses.

Rearing system and oleic acid supplementation effect on carcass and lipid characteristics of two muscles from an obese pig breed

Quality of pork depends on genotype, rearing and pre- and post-slaughter conditions. However, no information is available on rearing system changes and oleic acid supplementation on carcass characteristics and fatty acid (FA) profile of pork from the Alentejano (AL) pig, an obese breed. This study evaluates the effects of feeding low (LO) or high oleic acid diets (HO) to AL pigs reared in individual pens (IND) or outdoor (OUT) with access to pasture. Carcass composition was obtained and longissimus dorsi and semimembranosus samples were collected to analyse chemical composition and neutral and polar intramuscular lipids FA profile by gas chromatography. Statistical analysis was performed by a two-way ANOVA for rearing system and diet effects. OUT-reared pigs presented leaner carcasses than IND-reared ones. Both muscles presented lower intramuscular lipid content in OUT-reared pigs. Treatments affected the FA profile of muscles. Overall, OUT-reared pigs presented lower n-6/n-3 FA ratios, whereas pigs fed the HO diet exhibited lower saturated fatty acids (SFA), higher monounsaturated fatty acids (MUFA) levels and lower thrombogenic indexes on neutral intramuscular lipids than LO-fed pigs. On the polar fraction, OUT-reared pigs presented lower SAT and n-6/n-3 FA ratio, and higher polyunsaturated fatty acids (PUFA) levels on both muscles. Pigs fed the HO diet exhibited higher MUFA and lower PUFA levels on both muscles, and lower SAT levels on semimembranosus. This study shows rearing system and oleic acid supplementation have complementary effects and influence carcass composition and the nutritional quality of meat.

CARACTERÍSTICAS DE CANAL, CALIDAD DE CARNE Y COMPOSICIÓN QUÍMICA DE CARNE DE LLAMA: UNA REVISIÓN.

Llama meat has a high protein level and low cholesterol and lipid levels. The aminoacids profile is similar to other ruminants. The fatty acid profile is characterized by moderatelevels of saturated fatty acids and high levels of monounsaturated fatty acids and lowlevels of polyunsaturated fatty acids. The carcass of animals from 36 to 44 months of age is the most suitable for commercial cuts, while meat from older animals, based on theirtechnological characteristics, is more suitable for the manufacture of meat products.Carcasses of young llamas are characterized by low weight, poor conformation and littlefat cover. Feed supplementation in young animals helps improve carcass quality andperformance of commercial cuts, as well as meat quality.

A randomized placebo-controlled trial of an omega-3 fatty acid and vitamins E+C in schizophrenia

Membrane lipid metabolism and redox regulation may be disturbed in schizophrenia. We examined the clinical effect of adding an omega-3 fatty acid and/or vitamins E+C to antipsychotics. It was hypothesized that lower baseline levels of polyunsaturated fatty acids (PUFAs) would predict more benefit from the add-on treatment. The trial had a multicenter, randomized, double-blind, placebo-controlled 2 × 2 factorial design. Patients aged 18–39 years with schizophrenia or related psychoses were consecutively included at admission to psychiatric departments in Norway. They received active or placebo ethyl-eicosapentaenoate (EPA) 2 g day−1 and active or placebo vitamin E 364 mg day−1+vitamin C 1000 mg day−1 (vitamins) for 16 weeks. The main outcome measures were Positive and Negative Syndrome Scale (PANSS) total and subscales scores, analyzed by linear mixed models. Ninety-nine patients were included. At baseline, erythrocyte PUFA were measured in 97 subjects. Given separately, EPA and vitamins increased drop-out rates, whereas when combined they did not differ from placebo. In low PUFA patients, EPA alone impaired the course of total PANSS (Cohen's d=0.29; P=0.03) and psychotic symptoms (d=0.40; P=0.003), especially persecutory delusions (d=0.48; P=0.0004). Vitamins alone impaired the course of psychotic symptoms (d= 0.37; P=0.005), especially persecutory delusions (d=0.47; P=0.0005). Adding vitamins to EPA neutralized the detrimental effect on psychosis (interaction d=0.31; P=0.02). In high PUFA patients, there were no significant effects of trial drugs on PANSS scales. In conclusion, given separately during an acute episode, EPA and vitamins E+C induce psychotic symptoms in patients with low levels of PUFA. Combined, these agents seem safe.

Elevated lipogenesis and diminished cholesterol synthesis in patients with hepatitis C viral infection compared to healthy humans

Hepatitis C virus (HCV) exerts a profound influence on host lipid metabolism. It has been suggested that the synthesis of both fatty acids (FA) and cholesterol is dysregulated in HCV but this has not been directly quantified in humans. The purpose of this study was to measure lipogenesis and cholesterol synthesis using stable isotopes in patients with HCV (n = 5) and healthy control (n = 9) subjects recruited from the University of Alberta hospital. Blood samples were taken at fasting (0 and 24 hours) and after meals over the day to mimic typical food consumption and postprandial metabolism. Isolation of free cholesterol (FC), cholesteryl ester (CE), and triglyceride (TG) from plasma and very low-density lipoproteins (VLDL) was used to measure FA and cholesterol synthesis using deuterium uptake and isotope ratio mass spectrometry. FA composition was analyzed by gas chromatography. VLDL-TG levels of polyunsaturated fatty acids (PUFA), including linoleic and linolenic acid, were lower in HCV compared to control (P < 0.05 for both). Fasting hepatic lipogenesis was significantly higher in HCV (2.80 ± 0.55%) compared to control (1.19 ± 0.27%; P = 0.03). Conversely, fasting whole-body synthesis of FC (HCV 1.64 ± 0.28% versus control 8.78 ± 1.59%) and CE (HCV 0.26 ± 0.08% versus control 1.92 ± 0.25%), as well as hepatic FC synthesis (HCV 1.68 ± 0.26% versus control 8.12 ± 0.77%) was lower in HCV (P < 0.001 for all). These data provide evidence that lipogenesis is elevated while cholesterol synthesis is impaired in HCV, supporting previous findings from cellular and animal models. Low PUFA levels combined with elevated lipogenesis suggests a role for dietary PUFA supplementation in HCV patients.

Organic and Conventional Chicken Meat Produced In Uruguay: Colour, Ph, Fatty Acids Composition and Oxidative Status

The organic chicken meat is present in the market and accepted by consumers in Uruguay. However, no information about its quality is available. The study of organic meat showed a higher lightness (L*) and lower yellowness (b*) than conventional chicken meat. For redness (a*), the results were inconclusive. Haem iron content was higher in organic meat and the lipids content was not different between organic and conventional meat. The fatty acids composition showed that the organic meat presented 31-34 %, 49-53 % and 12-14 % of saturated, monounsaturated and polyunsaturated fatty acids (PUFA), respectively. The limited uses of corn and soybean to fed organic chickens, probably explain the unexpected low level of PUFA in organic meat. The organic meat also showed a lower TBARs level and a similar level of protein carbonyl in comparison to the conventional one. Catalase presented a higher activity in organic meat compared to the conventional one. No differences were observed for superoxide dismutase and glutathione peroxidase.

Changes in diet, body mass and fatty acid composition during pre-hibernation in a subtropical bat in relation to NPY and AgRP expression

Prior to hibernation, mammals accumulate large amounts of fat in their bodies. In temperate mammalian species, hibernation is improved by increasing the levels of poly-unsaturated fatty acids (PUFA) in the body. The saturation of fatty acids (FA) in both white adipose tissue (WAT) and membrane phospholipids of mammals often reflects their diet composition. We found that the greater mouse-tailed bat (Rhinopoma microphyllum) accumulates large amounts of fat at the end of summer by gradually shifting to a fat-rich diet (queen carpenter ants, Camponotus felah). PUFA are almost absent in this diet (<1 % of total FA), which contains a high fraction of saturated (SFA) and mono-unsaturated (MUFA) fatty acids. We found similar low levels of PUFA in mouse-tailed bat WAT, but not in their heart total lipids. The expression of two appetite-stimulating (orexigenic) hypothalamic neuropeptides, AgRP and NPY, increased in parallel to the shift in diet and with fat gain in these bats. To the best of our knowledge, this is the only documented example of specific pre-hibernation diet in bats, and one which reveals the most saturated FA composition ever documented in a mammal. We suggest that the increase in expression levels of NPY and AgRP may contribute to the observed diet shift and mass gain, and that the FA composition of the bat's specialized diet is adaptive in the relatively high temperatures we recorded in both their winter and summer roosts.

Low breast milk levels of long‐chain n‐3 fatty acids in allergic women, despite frequent fish intake

BackgroundLong-chain n-3 polyunsaturated fatty acids (PUFAs) have immune regulating and anti-inflammatory effects. However, their role in allergic disease is unclear. Allergic diseases are immunologically heterogeneous, and we hypothesized that n-3 fatty acid composition in serum and breast milk may vary according to clinical manifestations. Further, animal studies have shown reduction of serum-PUFA levels during allergic inflammation.ObjectiveTo investigate fatty acid composition in breast milk and serum from women with different atopic disease manifestations. Secondly, to determine whether low PUFA levels reflected insufficient intakes.MethodsFatty acids were analysed in breast milk and serum of women with atopic eczema and respiratory allergy (n=16), only respiratory allergy (n=7), as well as healthy women (n=22). Dietary intake of foods expected to affect long-chain n-3 PUFA levels were estimated by food-frequency questionnaire. The fatty acid pattern was related to diagnostic group and intake of relevant food items using a multivariate pattern recognition method (partial least squares projections to latent structures and discriminant analysis).ResultsWomen with a combination of eczema and respiratory allergy had lower breast milk levels of several PUFAs (arachidonic acid, eicosapentaenoic acid, EPA, docosahexaenoic acid, DHA, and docosapentaenoic acid, DPA), and a lower ratio of long-chain n-3 PUFAs/n-6 PUFAs. Their PUFA levels differed not only from that of healthy women, but also from that of women with only respiratory allergy. The latter had a fatty acid pattern similar to that of healthy women. Despite low EPA, DHA and DPA levels women with eczema and respiratory allergy consumed no less fish than did healthy women.Conclusion & Clinical RelevanceOur data suggest that reduced levels of long-chain n-3 fatty acids in serum and breast milk characterize women with extensive allergic disease including eczema, and are not related to low fish intake. Consumption of PUFAs during the allergic process may explain these findings.

Long chain‐polyunsaturated fatty acids modulate membrane phospholipid composition and protein localization in lipid rafts of neural stem cell cultures

Rat neural stem cells/neural progenitors (NSC/NP) are generally grown in serum-free medium. In this study, NSC/NP were supplemented with the main long-chain polyunsaturated fatty acids (PUFAs) present in the brain, arachidonic acid (AA), or docosahexaenoic acid (DHA), and were monitored for their growth. Lipid and fatty acid contents of the cells were also determined. Under standard conditions, the cells were characterized by phospholipids displaying a highly saturated profile, and very low levels of PUFAs. When cultured in the presence of PUFAs, the cells easily incorporated them into the phospholipid fraction. We also compared the presence of three membrane proteins in the lipid raft fractions: GFR and connexin 43 contents in the rafts were increased by DHA supplementation, whereas Gbeta subunit content was not significantly modified. The restoration of DHA levels in the phospholipids could profoundly affect protein localization and, consequently, their functionalities.

Lipid compounds of the umbilical cord artery and their alterations in preeclampsia

The lipid composition of arterial walls changes during development, ageing and pathological processes. Preeclampsia is the most common pregnancy-associated pathological syndrome. It is accompanied by significant remodelling of the extracellular matrix, both in the umbilical cord vessels and in the surrounding Wharton's jelly. Lipids of the umbilical cord have not been extensively studied. Here we evaluate the lipid composition of the umbilical cord artery (UCA) and its alteration in preeclampsia. Thin layer chromatography and high-performance liquid chromatography were employed for these analyses. It was found that the UCA wall, as with most human tissues, contains free fatty acids, mono-, di- and triacylglycerols, free cholesterol and its esters. The characteristic feature of the UCA wall is the presence of high amounts of long chain polyunsaturated fatty acids (PUFA), including eicosapentaenoic acid (C20:5) and docosahexaenoic acid (C22:6), which are rather minor lipid components of most human tissues. They exist both in a free form and in a form of acylglycerols and cholesterol esters. Preeclampsia is associated with a marked decrease in most free fatty acids and acylglycerols. The total amount of long chain PUFA: C18:2, C:18:3, C20:4, C20:5 and C22:6 in these lipid fractions is decreased by half, with a concomitant increase in free cholesterol and its esters. We propose that these lower levels of PUFA may reduce prostaglandin synthesis in the arterial wall and thereby impair blood flow in the foetal vascular system, leading to preeclamptic symptoms.

Enhancing pork flavor and fat quality with swine raised in sylvan systems: Potential niche-market application for the Ossabaw hog

Our global food supply becomes more vulnerable as we continue to lose diverse genetic resources. The Ossabaw hog is a feral breed that is unique to North America, a distant relative to the renowned Iberian hog and is considered an endangered swine breed. The objective of our farmer participatory project was to examine the meat and fat characteristics of Ossabaw hogs raised in alternative management systems for niche-market application. At one farm, eight Ossabaw pigs were randomly assigned to a grass pasture and fed a free choice corn–soy (CS) ration or placed in a mixed hardwood forest plot and provided free choice peanuts in the shells (P), alfalfa pellets (A) and mast from the mixed hardwoods (diet collectively referred to as PAM). The two diets had no effect on Ossabaw production data or pork quality characteristics; however, fat profiles were altered. Ossabaws weighed approximately 70 kg when harvested at 400 days and produced chops with small loin eyes (21–23 cm2) and minimal evidence of intramuscular fat deposits (1%). The unsaturated fatty acid (USFA) to saturated fatty acid (SFA) ratio improved from 1.6 to 2.6 (P&lt;0.01) as a result of feeding the PAM diet. Forest-finished Ossabaw pork was considered more flavorful by food critics and renowned chefs than that of conventionally fed animals. Mast from hardwoods offers the possibility of enhancing pork flavor for niche markets and using a renewable forest resource as a food source. For farm two, eight Ossabaw gilts and eight crossbred progeny (from European breeds) were randomly assigned to one of the two dirt-lots and fed free choice a CS ration or PA diet (same ration as mentioned above with no mast). Ossabaw hogs grew nearly one-third as fast as the crosses and weighed approximately 80% of the crosses' harvest weight at twice their age. Loin eye areas of the crosses were nearly twice as large as the Ossabaws while the subcutaneous back fat deposition was nearly half. Compared to the CS diet, the PA ration decreased SFA by 23% while polyunsaturated fatty acids (PUFA) increased by 60%. The USFA to SFA ratios improved from 1.5 to 2.2 (P&lt;0.01) when PA diets were fed. Differences (P&lt;0.05) in USFA profiles were observed for breed effects; Ossabaws had 8% higher levels of monounsaturated fatty acids and 18% lower PUFA levels than the crosses. When adjusted for breed effects, no differences in sensory characteristics for the CS versus PA diets were detected by a trained panel. Ossabaws were more flavorful than the crosses (2.3 versus 1.6); (P&lt;0.05).

Geographical and seasonal differences in lipid composition and relative weight of by-products from gadiform species

The amount of available lipids and the lipid composition from gadiform species caught during three seasons in the Barents Sea, the Icelandic Sea and off the south coast of Ireland were determined. The size of the liver, constituting 1.3–6.9% of round weight, was affected by fishing ground. The fishing ground affected the lipid content in liver (30–78%) and viscera (2.2–7.1%). No significant effect of season was found on the lipid content of cod liver, while seasonal differences were found for other species and fractions. Polyunsaturated fatty acids (PUFAs) made up 21–45% and 34–63% of the total fatty acids in liver and viscera. Overall, effect of fishing ground and season were found on groups of fatty acid, and lower levels of PUFA were found in the liver of Icelandic cod. Depending on species and fishing ground, 550–1700 kg lipids can be obtained from the by-products from an average daily production of fillets (10 000 kg). The amount of available lipids was higher from gadiform species from the Barents Sea compared to the two other fishing grounds. All lipids extracted contained significant amounts of health-beneficial PUFAs.

Fatty acid composition of phytoplankton, settling particulate matter and sediments at a sheltered bivalve aquaculture site

Fatty acid biomarkers were used to investigate the biogeochemistry of a former blue mussel ( Mytilus edulis ) aquaculture site in a shallow, sheltered cove in northeastern Newfoundland. High levels of polyunsaturated fatty acids (PUFA) in net-tow and sediment trap samples indicated a substantial phytoplankton source of organic matter, and fluctuations in specific fatty acid biomarkers reflected the changing abundances of diatoms and dinoflagellates . In comparison, sediments contained very low levels of PUFA (<15%) and were dominated by terrestrial and bacterial markers. In a separate study, blue mussels were grown at this closed site, providing the opportunity to examine the relationship between lipid supply, as recorded by net-tow and trap samples, and bivalve requirements. The average plankton fatty acid composition throughout the year agreed well with that of the adult blue mussels, suggesting that fatty acids were provided in proportions very similar to the bivalves' requirements. The fatty acid composition of the blue mussels was typical of those collected elsewhere, with PUFA proportions near 50%. However, examination of fatty acid data of plankton sampled in other areas revealed that the plankton in the current study may have been unusual in providing fatty acids at levels required by the bivalves.

Evidence for the involvement of polyunsaturated fatty acids in the regulation of long-chain acyl CoA thioesterases and peroxisome proliferation in rat carcinosarcoma.

The feeding of high-fat diets rich in polyunsaturated fatty acids (PUFAs) caused a marked increase in the acyl CoA thioesterase activity of the Walker 256 tumour. Diets containing lower levels of PUFAs did not alter the activity of acyl CoA thioesterase and the exposure of LLC-WRC256 tumour cells, in culture, to PUFAs (150 microM) also was ineffective in altering activity. The tumours from n-3 PUFA-rich and control diets were analysed by transmission electron microscopy in order to compare peroxisomal content. The presence of PUFAs led to an almost 10-fold increase in the number of peroxisomes present in the tumour tissue. A common feature of the PUFA-treated tumour was the presence of many cells containing highly condensed heterochromatin at the periphery of the nucleus, indicative of apoptosis. The sparsity of endoplasmic reticulum and the lack of detection of mitochondrial acyl CoA thioesterase, MTE-I, led to the conclusion that the increase in tumour acyl CoA thioesterase activity may be due to an increase in the activity of the peroxisomal enzyme.

Wax esters versus triacylglycerols in myctophid fishes from the Southern Ocean

Five species of myctophid fishes were collected by trawl from the Elephant Island region of the Antarctic Peninsula between 60°30′–62°S and 55°–61°30′W. Two species, Gymnoscopelus braueri and Krefftichthyes anderssoni were lipid-rich (406–456 mg g−1 dry weight whole fish) with wax esters (WE) the major lipid class. In three species, G. opisthopterus, G. nicholsi, and Electrona carlsbergii, triacylglycerols (TAG) were the major lipid. All fish had oily bones, with values up to 471 mg g−1 dry weight in the vertebral centra of K. anderssoni. The principal fatty acids of the TAG-rich myctophids included the monoenes 18:1(n-9) and 20:1. There were lower levels of 16:0 and 18:0 saturated fatty acids. Polyunsaturated fatty acids (PUFA) were present at higher abundance in the TAG-rich E. carlsbergii and G. opisthopterus, with lower levels in G. nicholsi. In comparison, the WE-dominated species contained lower levels of PUFA than in the TAG-rich species. The principal fatty acids of the WE-rich myctophids included the monoenes 18:1(n-9), 16:1(n-7), and 18:1(n-7), with lower levels of the saturated acids 16:0 and 18:0. Fatty alcohols were dominated by 16:0 and 14:0 and the monounsaturated 18:1(n-9) with 16:1(n-7), 18:1(n-7), and 20:1(n-9). Based on the fatty acid profiles, the diet of G. opishtopterus and G. nicholsi, previously thought to be mainly Euphausia superba, is suggested to include copepods and other zooplankton with only a minor krill component, possibly consisting of other species than E. superba.

EFFECT OF NICKEL DEFICIENCY ON FATTY ACID COMPOSITION OF TOTAL LIPIDS AND INDIVIDUAL PHOSPHOLIPIDS IN BRAIN AND ERYTHROCYTES OF RATS

The present investigation was designed to examine the effect of nickel deficiency on fatty acid composition of total lipids and individual phospholipids in brain and erythrocyte membranes of rats. Therefore, a study over two generations was conducted feeding a nickel-deficient diet containing 13 μg/kg nickel or a nickel-adequate control diet supplemented with 1 mg/kg nickel. Male 7 week old rat pups from the second offspring were studied. The concentrations of individual brain phospholipids did not differ between the nickel-deficient and the nickel-adequate group, whereas in erythrocyte membranes the concentration of phosphatidylethanolamine (PE) diacyl was reduced in consequence of nickel depletion. Moreover, nickel deficiency slightly altered fatty acid composition of total lipids and individual phospholipids both in brain and erythrocytes. The changes in fatty acids were more marked in erythrocytes than in brain, and mainly concerned phosphatidylcholine (PC). The fatty acid composition in total lipids of brain was hardly affected by nickel. In brain individual phospholipids nickel deficiency slightly, but significantly elevated the proportions of polyunsaturated fatty acids (PUFA), and in the case of PC additionally increased the levels of monounsaturated fatty acids (MUFA) at the extent of saturated fatty acids (SFA). Total lipids of erythrocytes from nickel-deprived rats had a significantly higher proportion of total MUFA than nickel-adequate rats, and a somewhat lower proportion of total (n-6) PUFA. Individual phospholipids in erythrocytes from nickel-deficient pups tended to have lower PUFA levels than nickel-adequate rats, and had additionally inconsistently altered levels of SFA and MUFA in PC and PE plasmalogen, respectively. Moreover, individual erythrocyte phospholipids from nickel-deficient rats tended to have lower 20:418:2 ratios than nickel-adequate rats.Copyright © 1996 Elsevier Science Inc.

The lipid composition of selected tissues from a Mediterranean monk seal, Monachus monachus.

The lipid composition of blubber, brain, muscle and heart from a Mediterranean monk seal Monachus monachus (an endangered species) were examined to allow comparisons with more common species of seals. Only neutral lipids (mainly triacylglycerols) were detectable in the blubber lipids, whereas polar lipids predominated in the heart and in the brain. Neutral and polar lipids comprised almost equal proportions in both liver and muscle. Choline glycerophospholipids (CGP) were the major polar lipids, followed by ethanolamine glycerophospholipids (EGP) in the liver, heart and muscle. Cerebrosides accounted for 28.8% of the brain lipids. All lipid classes of the liver contained high levels (31-47%) of polyunsaturated fatty acids (PUFA), with the exception of phosphatidylserine. The total proportion of n-6 PUFA exceeded that of n-3 PUFA in all lipid classes of the liver, due mainly to the high levels of 20:4n-6. The highest level of 20:4n-6 occurred in phosphatidylinositol, where it comprised 32.4% of the total fatty acids. The CGP and EGP of the brain contained lower levels of PUFA than those of the liver, muscle and heart. Alkenyl ethers accounted for 35.8% of the total long-chain moieties in brain EGP. The fatty acid composition of blubber triacylglycerols differed from those of the lipid classes from other tissues in that it had a very low ratio of n-6 to n-3 PUFA (0.3) as a result of a lower content of 20:4n-6.