Proportion Of Essential Fatty Acids Research Articles

A taste of youth: Seasonal changes in the diet of immature white sharks in eastern Australia

White sharks (Carcharodon carcharias) play a crucial ecological role, shaping ecosystems through direct predation and risk effects. On the east coast of Australia, immature white sharks are broadly distributed, inhabiting a wide range of habitats and ecosystems from temperate Tasmania to tropical North Queensland. Using stable isotopes and fatty acids of muscle and plasma, we examined the diet and habitat use of 136 immature white sharks (152–388 cm total length) captured on SMART drumlines on the East Australian coast. This facilitated the temporal assessment of white shark trophic ecology from a few weeks to approximately a year. Biochemistry of muscle samples showed that white sharks predominantly feed on low trophic level prey from coastal environments. A seasonal shift in diet was evident, with the increasing proportions of essential fatty acids in muscle tissues during spring and summer suggesting a greater consumption of high-nutrition preys during those months compared to autumn and winter. By combining stable isotope and fatty acid analysis, we gain a comprehensive understanding of immature white shark diet in eastern Australia. Our results confirm that white sharks are generalist predators that exhibit seasonal shifts in their diet. Their high use of coastal habitats reinforces the importance of these areas for foraging, which is crucial for growth and development during this critical life stage.

Fermented Products Enriched with Polyunsaturated Fatty Acids in Broiler Chicken Nutrition and Fat Quality of Produced Meat

Broiler chicken meat is the preferred meat among the human population. Broiler meat contains high-quality protein and a low-fat content, alongside a desirable fatty acid profile. A frequent problem in human nutrition is an insufficient PUFA intake in the diet. One possible strategy to increase the dietary intake of polyunsaturated fatty acids (PUFA) in humans is to produce, and thereby enrich, broiler chicken meat with sufficient amounts of essential PUFA. A method to increase the proportion of essential fatty acids in chicken meat is by changing the fatty acid composition of the feed. Feed production via solid-state fermentation using lower filamentous fungi can be used to prepare valuable feed from cereal by-products enriched with important PUFA and pigments and can thus be included as a suitable feed ingredient in the diet of chickens. From previously published studies, it can be concluded that the application of 3–10% of the prepared fermented products to the diet of broiler chickens increased the proportion of essential fatty acids in the fat of the chicken meat and had a beneficial effect on the growth parameters of chickens.

Analysis for lipid nutrient differences in the milk of 13 species from a quantitative non-targeted lipidomics perspective

Lipids are essential organic components in milk and have been associated with various health benefits for newborns. However, a comprehensive analysis of lipid profiles across multiple species and levels has been lacking. In this study, we employed liquid chromatography-tandem mass spectrometry (LC-MS/MS) to accurately determine the absolute content of lipid molecules. It revealed that ruminants exhibit a higher concentration of short-chain fatty acids compared to non-ruminants. Additionally, we identified ALC (camel), MGH (horse), and DZD (donkey) as species that display similarities to components found in human milk fat. Remarkably, it reveals that porcine milk fat is characterized by long chain lengths, low saturation, and a high proportion of essential fatty acids. PS (22:5_18:2) could potentially serve as a biomarker in porcine milk. These unique characteristics present potential opportunities for the utilization of porcine milk. Overall, our findings provide valuable insights into the lipidomics profiles of milk from different species.

Influence of biostimulants and humic extracts treatment on the fatty acid profile of the spring oilseed rape variety

Abstract. For two consecutive economic years, a field experiment was conducted with spring rapeseed hybrid Rasna. The aim is to trace the effect of phytostimulant treatment on the total fat content of rapeseed and the proportion of essential fatty acids. The application of biostimulants (organic acid and humic complexes) in the cultivation of rapeseed variety Rasna leads to changes in the fatty acid composition of the seeds. The use of biostimulants HL100, HLN 55 and TH1-20% in the first year leads to a decrease in the content of saturated by 3.5%, 1.74% and 4.7% and polyunsaturated fatty acids by 2.74%, 0.59% and 3.15% due to the higher content of monounsaturated fatty acids by 0.99%, 0.58 and 1.47%. Biostimulator TH1-10% leads to an increase in saturated by 0.06%, monounsaturated by 0.26% and a decrease in polyunsaturated fatty acids by 1.35% compared to the control group of seeds. In the second year of treatment of rapeseed variety Rasna saturated fatty acids decreased compared to the control group to a lesser extent: with the application of biostimulant TH1-10% and HLN 55 by 0.33% and 0.11%, while with biostimulants HL 100, TH1-20% and H40 their content increases by 0.97, 0.06% and 0.04% respectively. Monounsaturated fatty acids decreased in humic complexes by 0.34%, biostimulator TH1-10% by 0.72% and biostimulator TH1-20% by 0.23%. Polyunsaturated fatty acids have the highest degree of reduction when applying biostimulant HL 100-2.77%. Saturated and polyunsaturated fatty acids had a higher content in the first year of treatment in rapeseed hybrid Rasna, while the concentration of monounsaturated fatty acids increased with a high degree of confidence (P≤0.001) in the second marketing year. This, on the one hand, is due to environmental factors, and on the other – to the type of preparation for treatment. The improved fatty acid composition of the seeds makes them a suitable raw material for the production of fats and their use in feed for monogastric and ruminant animals

Lipidomics of common octopus' (Octopus vulgaris) arm muscle using untargeted high-resolution liquid chromatography-mass spectrometry

The common octopus, Octopus vulgaris, is one of the most important cephalopod fisheries in the world. In Mediterranean cuisine, the common octopus is perceived as an ingredient highly valued for its palatability and nutritional value (source of omega-3 fatty acids). However, the polar lipids of this species are still poorly understood. The present study performed the first fingerprinting of the polar lipidome of the arm muscle of O. vulgaris using a high-resolution mass spectrometry HILIC-LC-MS lipidomics approach. Samples of common octopus were sourced from specimens landed in Santa Luzia (Tavira, Algarve, Portugal), the most important octopus mono-specific fishing harbour in mainland Portugal. Nearly 400 lipid species have been identified from 13 classes of polar lipids. Phosphatidylcholine and phosphatidylethanolamine were the main phospholipids recorded, while the phosphonolipid CAEP and ceramides were the main sphingolipids identified. The structural characterization recognised a high proportion of essential fatty acids, such as EPA, DHA and several other very-long-chain fatty acids (24:5, 24:6) esterified in the polar lipids. The present study provides an unprecedented elucidation of the polar lipidome of O. vulgaris that can be used as a reference for future studies on nutritional value, ecology and traceability of geographic origin.

Urban living influences the nutritional quality of a juvenile shark species

The field of marine urban ecology is a nascent, but growing area of research. An understanding of how urbanization may alter the diets and nutrition of marine species living in urbanized coastal habitats is limited. In the present study, we investigated the influence of urbanization on dietary patterns and nutritional quality of the nurse shark Ginglymostoma cirratum, a coastal epibenthic mesopredator. We tested the hypothesis that sharks sampled in urbanized areas (hereafter, ‘urban sharks’) would exhibit lower nutritional quality than individuals sampled in adjacent, but more pristine areas (hereafter ‘non-urban sharks’). To accomplish this, we compared plasma fatty acid profiles of juvenile nurse sharks in proximity to Miami, a large coastal city, within Biscayne Bay, Florida. Results revealed that urban sharks contained higher levels of plasma saturated and bacterial fatty acids compared to non-urban sharks. Urban sharks also exhibited lower proportions of essential fatty acids (i.e., highly unsaturated fatty acids, HUFAs), mainly due to low contributions of omega-6 HUFAs. These results suggest that urban sharks consumed lower-quality food resources than conspecifics in less impacted areas. The apparent poor nutritional quality of prey consumed by shark living in urban areas may have several long-term consequences on their health and growth.

Seaweeds as a Functional Ingredient for a Healthy Diet.

Seaweeds have been used since ancient times as food, mainly by Asian countries, while in Western countries, their main application has been as gelling agents and colloids for the food, pharmaceuticals, and the cosmetic industry. Seaweeds are a good source of nutrients such as proteins, vitamins, minerals, and dietary fiber. Polyphenols, polysaccharides, and sterols, as well as other bioactive molecules, are mainly responsible for the healthy properties associated with seaweed. Antioxidant, anti-inflammatory, anti-cancer, and anti-diabetic properties are attributed to these compounds. If seaweeds are compared to terrestrial plants, they have a higher proportion of essential fatty acids as eicosapentaenoic (EPA) and docosahexaenoic (DHA) fatty acids. In addition, there are several secondary metabolites that are synthesized by algae such as terpenoids, oxylipins, phlorotannins, volatile hydrocarbons, and products of mixed biogenetic origin. Therefore, algae can be considered as a natural source of great interest, since they contain compounds with numerous biological activities and can be used as a functional ingredient in many technological applications to obtain functional foods.

The Ratio of Dietary n-3 Polyunsaturated Fatty Acids Influences the Fat Composition and Lipogenic Enzyme Activity in Adipose Tissue of Growing Pigs.

Currently, there is a growing interest among consumers in selecting healthier meat with a greater proportion of essential fatty acids (FA). This experiment was conducted to evaluate the role of different ratios of dietary n-6:n-3 on growth performance, FA profile of longissimus dorsi (LD), relative gene expression of cytokines, meat quality, and blood parameters in finishing pigs. A total of 108 finishing pigs was randomly allotted to three treatments including a control (basal diet) and low ratios (4:1 and 2:1) of n-6:n-3. The 4:1 and 2:1 diets decreased the overall stearic acid in LD. There were reductions in the content of stearic acid, palmitoleic acid, total saturated acid, and n-6:n-3 ratio of LD in pigs fed 4:1 and 2:1 diet compared with the control diet. The 4:1 and 2:1 diets increased the concentration of α-Linolenic acid and polyunsaturated FA in the LD of pigs. Acetyl-CoA carboxylase enzyme gene was down-regulated in pigs fed 2:1 diet compared with finishing pigs fed the control or 4:1 diets. The relative expression of hormone-sensitive lipase was increased in pigs fed 2:1 and 4:1 ratio diets. Lower total cholesterol of plasma was observed in finishing pigs fed 2:1 and 4:1 diets. The cooking loss ratio of meat was lower in pigs fed the 2:1 and 4:1 diets compared with the control diet. Pigs fed the 4:1 and 2:1 diets had greater final body weight. In conclusion, the 2:1 and 4:1 diets have the potential to increase the meat quality and growth performance of pigs.

High Altitude Adaptability and Meat Quality in Tibetan Pigs: A Reference for Local Pork Processing and Genetic Improvement.

Simple SummaryThe increase in altitude will bring about a complex change in a series of elements of nature, which will have a profound impact on human production and life. Studying domestic animals in the native environment is an effective way to explore the impact of high altitude on human life, and at the same time is conducive to the development of local animal husbandry. Here, we found that the hypoxic adaptation of Tibetan pigs may be related to higher levels of VEGFA, HIF1 and myoglobin expression. The higher aerobic oxidative capacity of Tibetan pigs is beneficial to improve energy utilization, and the higher UFA content of Tibetan pigs is beneficial to cold resistance. In addition, Tibetan pigs have higher levels of BCAA and Myh2 expression, which serve to relieve muscle fatigue and improve endurance. In addition, it was observed that there are obvious differences in carcass and meat quality traits of different altitudes pigs. Taken together, our findings illustrate the adaptability of Tibetan pigs to high altitude from various perspectives and compare carcass and meat quality traits of three pig breeds.The carcass and meat quality traits of pig breeds living at three different altitudes (Yorkshire pigs, YP: 500m; Qingyu Pigs, QYP: 1500m; Tibetan pigs, TP: 2500m) were compared. It was observed that there are obvious differences in pig breeds with respect to performance parameters. Specifically, YP had the best carcass traits, showing high slaughter rates and leanest meat. Conversely, QYP had the highest back fat thickness and intramuscular fat (IMF) content. For the high-altitude breed TP, the animals exhibited low L* and high a* values. The genotypes contributing to the observed phenotypes were supported by a PCR analysis. The glycolytic genes expression (HK, PFK, PK) were highest in YP, whereas expression of genes related to adipogenesis (C/EBPα, FABP4, SCD1) were highest in QYP. As expected, genes associated with angiogenesis and hypoxia (HIF1a, VEGFA) were expressed at the highest levels in TP. The composition and proportion of amino and fatty acids in pig muscles at the three altitudes examined also varied substantially. Among the breeds, TP had the highest proportion of umami amino acids, whereas QYP had the highest proportion of sweet amino acids. However, TP also exhibited the highest proportion of essential fatty acids and the lowest proportion of n6:n3. This study explains the high-altitude adaptive evolution and the formation of meat quality differences in different altitude pigs from various angles and provides a reference for local pork food processing and genetic improvement of local pigs.

The fatty acid composition of edible grasshopper Ruspolia differens (Serville) (Orthoptera: Tettigoniidae) feeding on diversifying diets of host plants

AbstractRuspolia differens (Serville) (Orthoptera: Tettigoniidae) is a highly valued edible grasshopper species in Africa. However, the effects of plant diets on lipid content and fatty acid composition of R. differens are not well understood. We tested the effects of four diets on the total lipid content and fatty acid composition of R. differens. Sixth instar nymphs of R. differens were reared on one, and mixtures of two, three, and six natural plant inflorescences. Individuals collected from the field constituted a control treatment. We extracted lipids and analyzed the fatty acid methyl esters using gas chromatography–mass spectrometry. We analyzed if the total lipid content, body weight, and fatty acid composition differed among diets and between the sexes using two‐way ANOVAs and a PERMANOVA model, respectively. The total lipid content and weight of R. differens did not differ among the diets. The nine common fatty acids were palmitic (mean across treatments, 26%), oleic (22%), palmitoleic (18%), linoleic (13%), stearic (7%), myristic (6%), myristoleic (4%), α‐linolenic (2%) and arachidic acid (1%). The composition of fatty acids and the proportion of essential fatty acids significantly differed among the diets. The proportion of essential fatty acids was highest in the control treatment (21%) but low in less diversified (one to three feed) diets (12–13%). This study demonstrates that the fatty acid composition in R. differens can be influenced through diet. Thus, with dietary manipulations, using local plants in Africa, it is possible to produce R. differens with preferred high quality essential fatty acids for human consumption.

Asymmetric assimilation of an anthropogenic resource subsidy in a freshwater food web

Anthropogenic subsidies occur readily, especially with growing human development neighboring natural systems. Determining how these subsidies permeate into native food webs is important, but currently not well understood. Here, we used a combination of stable isotopes and fatty acids as bio-tracers to explore the pathway(s) of assimilation of an anthropogenic resource (aquaculture feed) provided by freshwater cage aquaculture. Our results point to an asymmetric assimilation of aquaculture feed by native organisms into and through the food web. Specifically, two pelagic fish species (an intermediate consumer and a top predator) show elevated trophic positions (based on δ15N signatures driven by aquaculture feed) and higher proportions of essential fatty acids (18:2n-6 and 18:3n-3) in waters surrounding the aquaculture facility compared to control sites lacking aquaculture cages, suggesting feed consumption. Fish that appeared to assimilate feed also had higher n-3 long chain poly unsaturated fatty acids (LC PUFA) proportions, indicating a possible role of the feed subsidy for fish health. Alternatively, there was no evidence of feed assimilation through the littoral energy channel. Our findings provide new insight into an emerging research area that asks how anthropogenic resource subsidies affect species health and properties of food webs. Since many habitats experience both natural and anthropogenic subsidy inputs, the multiple tracer approach employed here shows promise for studying how subsidies may affect species health and behavior, as well as food web structure and ultimately stability.

Lipid and fatty acid dynamics in mature female albacore tuna (Thunnus alalunga) in the western Indian Ocean.

Lipid composition in the reproductive and somatic tissues were investigated for female albacore tuna, Thunnus alalunga, in the western Indian Ocean, between latitude 18–21°S and longitude 56–60°E, from January 2014 to March 2015. Highest total lipids (TL) were found in the gonads of spawning-capable females (SCP) (mainly phospholipids, PL, triacylglycerols, TAG and wax esters, WE) and in the liver of females in the late regressing and regenerating ovary phases (mainly TAG, PL and sterols, ST). Muscle TL was low but exhibited high inter-individual variability. Correlations between gonadosomatic and hepatosomatic indices with TL and the lipid classes in albacore gonads and liver describes a pattern of reallocation of energy from the liver to the gonads during SCP. Female albacore were also observed to pursue foraging activities even during this period. Therefore, female albacore can be considered as a capital-income breeder relying mostly on stored lipids before the onset of reproduction and to a lesser extent on energy derived from concurrent feeding during the spawning season. Overall, the three examined tissues had similar general fatty acid profiles with the dominance of 22:6ω3 (docosahexaenoic acid, DHA), 16:0, 18:0 and 18:1ω9. The proportions of fatty acids varied with maturity stage and ovary lobe, with the smaller lobe having significantly higher proportions of essential fatty acids, as well as 16:0 and 18:1n9, compared to the larger one. Our results provide new information on the life-history and energy allocation strategy of albacore which will assist fisheries managers.

Spatial and temporal variability in the nutritional quality of basal resources along a temperate river/estuary continuum

The nature and quality of basal resources within aquatic food webs are complex and have the potential to shift over space and time. We used fatty acid analysis to assess variations in the nutritional structure of the suspended and basal pools along an entire river system, and to assess the contributions of vascular plant (i.e., mainly of terrestrial origin, but could include aquatic macrophytes) vs algal (i.e., aquatic origin) sources to the suspended particulate matter (SPM) pools. Samples were collected in a temperate South African river on four occasions between September 2012 and June 2013. We found orderly patterns in the fatty acid composition of the basal resources at the sites during most seasons. Regardless of site or season, the benthic algal pools (epiphyton, epipelon and epilithon) were the most nutritionally rich resources based on essential fatty acid contents and diatom indices. During early and late spring, proportions of essential fatty acids in the epiphyton decreased downstream where increased light was available, consistent with predictions from the light:nutrient hypothesis (but inconsistent with epilithon and epipelon results). There were substantial changes in vascular plant contributions to the SPM pools along the river, but the same patterns were not produced in all seasons. Of all the river models considered, the data were more consistent with the riverine productivity model, which particularly emphasises the importance of autotrophic production in rivers. Our study provides new detail on the complexity of basal resource nutritional quality and how it can shift along a lotic system over time.

Fatty acid profile ofPleurotus ostreatusandGanoderma australegrown naturally and in a batch bioreactor

Non-polar lipid content and fatty acid (FA) composition of the commercial edible strain of Pleurotus ostreatus and the medicinal wild strain of Ganoderma australe were determined. A comparison of the FA profile was conducted between mycelium grown under optimum bioreactor conditions and naturally occurring fruit bodies in both species. Both strains contained unsaturated FA (UFA), amounting to 55–77% of total FA content, whereas the proportion of essential FA was contributive, permitting their consideration as potential food ingredients. Bioreactor process resulted in a significant total FA content increase accompanied with a considerable effect on ratios of nutritional interest (MUFA/SFA, PUFA/SFA, oleic/linoleic).

Bagaço de uva como ingrediente alternativo no arraçoamento de coelhos em crescimento

O presente trabalho teve como objetivo avaliar efeitos da inclusão do bagaço de uva em substituição ao feno de alfafa sobre desempenho, rendimento de carcaça e parâmetros morfohistológicos do trato gastrointestinal de coelhos em fase de crescimento. Foram utilizados 30 coelhos da raça Nova Zelândia Branca divididos igualmente em três tratamentos, compostos pela dieta experimental padrão (sem inclusão de bagaço de uva); e pelas dietas com 25% e 50% de substituição de alfafa por bagaço de uva nas respectivas rações experimentais. A inclusão de bagaço de uva causou aumento linear no consumo total de ração e no ganho de peso. A presença em maior proporção dos ácidos graxos essenciais ômega3 e ômega6 nos tratamentos T25BU e T50BU promoveu melhores respostas zootécnicas, uma vez que esses nutrientes agem positivamente no equilíbrio homeostático. Os resultados morfohistológicos demonstraram que a altura das vilosidades intestinais do ceco aumentou com a inclusão de bagaço de uva na dieta, possuindo correlação positiva. A inclusão de bagaço de uva em dietas para coelhos na fase de crescimento altera o desempenho dos animais, aumentando o consumo total de ração e o ganho de peso. Evidenciou-se também que o aumento desse co-produto melhora as características morfológicas das vilosidades intestinais referentes ao ceco.

Temperature effects on the molting, growth, and lipid composition of newly-settled red king crab

Red king crab (RKC) ( Paralithodes camtschaticus Tilesius, 1815) is one of the most important fishery resource species in Alaska. It is threatened by heavy fishing pressure and changing climate conditions, yet little is known about the species' first year of post-settlement life. This study was undertaken to explore how temperature mediates growth and energy allocation in newly metamorphosed juveniles. RKC were reared using four temperature treatments ranging from 1.5° to 12 °C for a period of 60 days, both individually and in low-density populations. Temperature had no significant effect on survival of RKC, and there was no consistent difference in survival between individually cultured crabs and those in populations. Growth was very slow at 1.5 °C, and increased rapidly with temperature with both a contracted intermolt period and small increase in growth increment. Twenty percent of the crabs held at 1.5 °C never molted, while more than 90% of the crabs in 12 °C reached juvenile stage 4 or higher. Overall growth increased as an exponential function of temperature, with slightly higher growth rates observed in populations than for isolated individuals. Growth records for individuals revealed an inverse exponential relationship between water temperature and intermolt period. There was also a small increase in growth increment from juvenile stage 1 to stage 2 with increasing temperature that appeared to be linear. Lipid class analysis revealed a trend towards higher proportions of storage lipids in larger crabs cultured at 12 °C than in crabs cultured at low temperatures. High proportions of essential fatty acids in all crab groups coupled with elevated levels of triacylglycerols in 12 °C animals, indicate that rapid growth does not negatively affect condition in juvenile RKC. Data provided by this study will help to model temperature-dependent growth and survival in the field, and assist in designing the best possible temperatures and diets for hatchery production of seed stock intended for enhancement of depleted RKC stocks.

Effect of dietary supplementation of phospholipids and highly unsaturated fatty acids on reproductive performance and offspring quality of Chinese mitten crab, Eriocheir sinensis (H. Milne-Edwards), female broodstock

This study was conducted to determine the optimum phospholipids: highly unsaturated fatty acids (PL/HUFA) ratio in maturation diets for female Chinese mitten crab, Eriocheir sinensis broodstock. Five isolipidtic and isonitrogenous diets were formulated to contain different amounts of pork lard, fish oil and soy lecithin with resulting PL/HUFA levels (%dry weight) of 1.4/0.3 (Diet 1), 1.6/2.5 (Diet 2), 2.3/2.0 (Diet 3), 3.8/1.5 (Diet 4) and 5.1/0.8 (Diet 5). Diet 1 lacked supplemental fish oil and soy lecithin and served as the control. Each of the five formulated diets was fed to a total of 150 female crabs for a period of 7 months. All diet treatments were triplicated with 50 crabs stocked in a pond as a replicate. After 6 months, male crabs were introduced into the ponds where females were kept, mating, spawning and egg hatching (in seawater) occurred in the following month. The nutritional value of various formulated diets was assessed based on survival, gonadosomatic index (GSI), egg production per female, fecundity (eggs/g female weight) of the females fed those diets and egg and larval (newly hatched zoea I larvae) quality.Females fed Diet 1 had the lowest GSI, egg production per female and fecundity while no significant difference were found for survival, hepatosomatic index (HSI) and the percentage of female spawned among the diet treatments (P>0.05). Although there were no significant differences in egg diameter, egg wet or dry weights among all treatments (P>0.05), the highest and the second highest proportions of essential fatty acids (EFA), i.e. 20:5n-3 (EPA), 22:6n-3 (DHA) and HUFA were found in the eggs produced by the females fed Diet 3 and Diet 2, respectively. Statistical analysis showed that EPA, DHA and HUFA in eggs produced by females fed Diet 3 were significantly higher than those from the other treatments (P<0.05). Meanwhile, zoea I larvae from crabs fed Diet 3 had significantly larger carapace length than those from the other four treatments (P<0.05). The zoea I larvae from crabs fed Diet 2 and Diet 3 also showed generally better tolerance to starvation and osmotic shock.In conclusion, our results indicated that diet included levels of PL/HUFA around 1.6/2.5 or 2.3/2.0 (% dry weight) fed female E. sinensis broodstock supported increased fecundity and elevated level of HUFA in egg, which in turn resulted in improved overall quality of newly hatched larvae.

Fatty Acid Profiles of Processed Chicken Egg Yolks

The fatty acid compositions of egg yolks subjected to industrial processing treatments, namely, homogenization, pasteurization, drying, and "omega-3-enrichment", were studied. In general, the total contents of C16:0, C18:0, C18:1 n-9, and C18:2 n-6 fatty acids accounted for close to 90% of the total fatty acids. Statistical analysis of the data revealed correlations among the fatty acids; significant differences existed depending on the egg source and type of processing. Yolk samples enriched with omega-3 fatty acids clustered together owing to their higher C16:0, C16:1 n-7, C18:3 n-6, and C24:0 contents. Nonpasteurized/non-heat-treated samples formed another cluster because of their higher C18:1 n-11 and C18:1 n-9 contents, and the remaining samples formed another group due to their higher proportions of C18:0, C18:2 n-6, and C20:4 n-6. The relative proportions of essential fatty acids were similar in the four types of samples examined.

Lipids in breast carcinogenesis

Excess dietary fat has been identified as a risk factor in the development of human breast carcinoma. However, the quality of fat may be more important than the overall quantity. We have studied the growth of human MCF7 breast carcinoma xenografts in athymic mice treated with dietary supplements of N-6 and N-3 series essential fatty acids given as natural preparations of evening primrose oil and fish oil. Olive oil and normal laboratory diet lacking the essential fatty acids served as controls. Animals treated with essential fatty acids developed tumours which were significantly smaller than both control groups (Mann-Whitney U test, P less than 0.001). Median tumour weights according to diet were: evening primrose oil, 133 mg; fish oil, 70 mg; olive oil, 212 mg; and control, 270 mg. Nutritional intervention to increase the proportion of essential fatty acids in the diet may have a role in the management of breast carcinoma.

Regulated expression of endothelial lipase by porcine brain capillary endothelial cells constituting the blood–brain barrier

Normal neurological function depends on a constant supply of polyunsaturated fatty acids to the brain. A considerable proportion of essential fatty acids originates from lipoprotein-associated lipids that undergo uptake and/or catabolism at the blood-brain barrier (BBB). This study aimed at identifying expression and regulation of endothelial lipase (EL) in brain capillary endothelial cells (BCEC), major constituents of the BBB. Our results revealed that BCEC are capable of EL synthesis and secretion. Overexpression of EL resulted in enhanced hydrolysis of extracellular high-density lipoprotein (HDL)-associated sn-2-labeled [(14)C]20 : 4 phosphatidylcholine. [(14)C]20 : 4 was recovered in cellular lipids, indicating re-uptake and intracellular re-esterification. To investigate local regulation of EL in the cerebrovasculature, BCEC were cultured in the presence of peroxisome-proliferator activated receptor (PPAR)- and liver X receptor (LXR)-agonists, known to regulate HDL levels. These experiments revealed that 24(S)OH-cholesterol (a LXR agonist), bezafibrate (a PPARalpha agonist), or pioglitazone (a PPARgamma agonist) resulted in down-regulation of EL mRNA and protein levels. Our findings implicate that EL could generate fatty acids at the BBB for transport to deeper regions of the brain as building blocks for membrane phospholipids. In addition PPAR and LXR agonists appear to contribute to HDL homeostasis at the BBB by regulating EL expression.