Project DyAdd: Fatty acids and cognition in adults with dyslexia, ADHD, or both

Both attention deficit hyperactivity disorder (ADHD) and dyslexia are suggested to co-occur with altered fatty acid (FA) metabolism, but it is unknown how FAs are associated with the cognitive domains that characterize these disorders. In the project DyAdd, we investigated the associations between FAs in serum phospholipids and phonological processing, reading, spelling, arithmetic, executive functions, and attention. Healthy controls (n=36), adults with ADHD (n=26), dyslexia (n=36), or both (n=9) were included in the study. FAs included saturated, monounsaturated, total polyunsaturated, n-3, and n-6 FAs, together with n-6/n-3, AA/EPA, and LA/ALA ratios. When all the study subjects were included in the analyses, especially polyunsaturated FAs (PUFAs) were positively associated with cognition, but reading was least associated with FAs. These associations were modulated by gender, intelligence, n-3 PUFA intake, and group. Accordingly, within the ADHD group, only few associations emerged with PUFAs, n-6 PUFAs, and cognitive domains, whereas in the dyslexia group the more prevalent associations appeared with PUFAs and n-3 PUFAs.     

Effect of slaughter age and feeding system on the neutral and polar lipid composition of horse meat

This study was undertaken to provide a thorough analysis of the neutral lipid (NL) and polar lipid (PL) fractions of horse meat that included the content and distribution of acyl and alkenyl moieties in foals under different rearing conditions. Two groups of crossbred horses were studied; the first group was selected from suckling foals produced under grazing conditions and slaughtered at 4 months of age (n=8), and the second group was selected from concentrate-finished foals and slaughtered at 12 months of age (n=7). There were significant differences related to the age and feeding practices of foals which affected the intramuscular (IM) fat content and the fatty acid (FA) composition of NL and PL fractions. Samples from suckling foals were leaner and provided the highest content of methylation products from the plasmalogenic lipids, and total and n-3 polyunsaturated fatty acid (PUFA). By contrast, the meat from concentrate-finished foals had a higher IM fat level resulting in a greater accumulation of 16:0 and total monounsaturated FAs in the NL fraction, whereas the muscle PL fraction retained a similar FA composition between both groups. Linolenic acid was preferentially deposited in the NL fraction, but linoleic acid and the long-chain n-3 and n-6 PUFAs were incorporated into the PL fraction where they served as cell membrane constituents and in eicosanoid formation.     

Feeding habitat and silvering stage affect lipid content and fatty acid composition of European eel Anguilla anguilla tissues

Lipids, particularly fatty acids (FAs), are major sources of energy and nutrients in aquatic ecosystems and play key roles during vertebrate development. The European eel Anguilla anguilla goes through major biochemical and physiological changes throughout its lifecycle as it inhabits sea- (SW), and/or brackish- (BW) and/or freshwater (FW) habitats. With the ultimate goal being to understand the reasons for eels adopting a certain life history strategy (FW or SW residency vs. ‘habitat shifting’), we explored differences in lipid content and FA composition of muscle, liver and eyes from eels collected across Norwegian SW, BW and FW habitats, and at different lifecycle stages (yellow to silver). FW and SW eels had a higher lipid content overall compared to BW eels, reflecting differences in food availability and life history strategies. SW eels had higher proportions of certain monounsaturated FAs (MUFAs; 18:1n-9, 20:1n-9), and of the essential polyunsaturated FAs 20:5n-3 (eicosapentaenoic acid, EPA) and 22:6n-3 (docosahexaenoic acid) than FW eels, reflecting a marine-based diet. In contrast, the muscle of FW eels had higher proportions of 18:3n-3, 18:2n-6 and 20:4n-6 (arachidonic acid), as is typical of FW organisms. MUFA proportions increased in later stage eels, consistent with the hypothesis that the eels accumulate energy stores prior to migration. In addition, the decrease of EPA with advancing stage may be associated with the critical role that this FA plays in eel sexual development. Lipid and FA information provided further understanding of the habitat use and overall ecology of this critically endangered species.     

A comparison of the trophic transfer of fatty acids in freshwater plankton by cladocerans and calanoid copepods

1. Analyses of zooplankton fatty acid (FA) composition in laboratory experiments and samples collected from lakes in New Zealand spanning a wide gradient of productivity were used to assess the extent to which FAs might infer their diet. We used the cladocerans, Daphnia and Ceriodaphnia, and the calanoid copepod, Boeckella, as test organisms, and monocultures of cryptophytes, chlorophytes and cyanobacteria as food. Based on reproductive success, cryptophytes were the highest food quality, chlorophytes were intermediate and cyanobacteria the poorest. 2. Several FA groups were highly correlated between zooplankton and their diets. They were monounsaturated fatty acids (MUFAs), and ω3 and ω6 polyunsaturated fatty acids (PUFAs) for cladocerans, and saturated fatty acids (SAFAs) and ω3 PUFAs for copepods. Several FAs varied significantly less in the zooplankton than in their monoculture diets, e.g. MUFAs in Daphnia, and ω3 and ω6 PUFAs in Ceriodaphnia, despite clear dietary dependency for these FAs. 3. Zooplankton collected from lakes in New Zealand had more eicosapentaenoic acid (EPA) (Daphnia), more highly unsaturated ω3 and ω6 FAs (C₂₀, C₂₂; Daphnia, Ceriodaphnia, Boeckella) and less ω3 C₁₈ PUFAs (Daphnia, Ceriodaphnia, Boeckella) and ω6 C₁₈ PUFAs (Daphnia, Ceriodaphnia) than measured in the same species reared on phytoplankton in the laboratory. 4. Analyses of FA composition of seston and freshwater zooplankton globally showed that, in general, zooplankton had a significantly higher proportion of arachidonic acid and EPA than seston, and copepods also had a higher percentage of docosahexaenoic acid than seston. 5. These results suggest that zooplankton selectively incorporate the most physiologically important FAs. This could be a consequence of preferential assimilation, selective feeding on more nutritious cells or locating and feeding within higher food quality food patches.     

Biosynthesis of polyunsaturated fatty acids in zooxanthellae and polyps of corals

The fatty acid (FA) composition of zooxanthellae, polyp tissue, and intact colonies was determined in soft coral Sinularia sp. and hard coral Acropora sp. Analysis of the distribution of polyunsaturated fatty acids (PUFAs) among the zooxanthellae and the host organism showed that 18: 3n-6 and C_18–22 PUFAs of the n-3 series (18: 4n-3, 20: 5n-3, 22: 5n-3, and 22: 6n-3) were mainly synthesized by the zooxanthellae and that C_20–22 PUFAs of the n-6 series (20: 3n-6, 20: 4n-6, and 22: 4n-6) were synthesized in the polyp tissue. Soft coral polyps were able to synthesize tetracosapolyenoic FAs (24: 5n-6 and 24: 6n-3) and 18: 2n-7, their zooxanthellae synthesized C₁₆ PUFAs (16: 2n-7, 16: 3n-4, and 16: 4n-1). It is supposed that the biosynthesis of 16: 2n-7 in Sinularia sp. and 18: 3n-6 in Acropora sp. is catalyzed by Δ6 desaturase. The relatively even distribution of three FAs (18: 2n-6, 18: 3n-6, and 16: 2n-7) among lipids of zooxanthellae and coral polyps indicates the possible transport of these FAs between symbionts and the host organism.     

Relationship between Erythrocyte Fatty Acid Composition and Psychopathology in the Vienna Omega-3 Study

This study investigated the relationship between erythrocyte membrane fatty acid (FA) levels and the severity of symptoms of individuals at ultra-high risk (UHR) for psychosis. Subjects of the present study consisted of 80 neuroleptic-naïve UHR patients. Partial correlation coefficients were calculated between baseline erythrocyte membrane FA levels, measured by gas chromatography, and scores on the Positive and Negative Syndrome Scale (PANSS), Global Assessment of Functioning Scale, and Montgomery–Asberg Depression Rating Scale (MADRS) after controlling for age, sex, smoking and cannabis use. Subjects were divided into three groups according to the predominance of positive or negative symptoms based on PANSS subscale scores; membrane FA levels in the three groups were then compared. More severe negative symptoms measured by PANSS were negatively correlated with two saturated FAs (myristic and margaric acids), one ω-9 monounsaturated FA (MUFA; nervonic acid), and one ω-3 polyunsaturated FA (PUFA; docosapentaenoic acid), and were positively correlated with two ω-9 MUFAs (eicosenoic and erucic acids) and two ω-6 PUFAs (γ-linolenic and docosadienoic acids). More severe positive symptoms measured by PANSS were correlated only with nervonic acid. No associations were observed between FAs and MADRS scores. In subjects with predominant negative symptoms, the sum of the ω-9 MUFAs and the ω-6:ω-3 FA ratio were both significantly higher than in those with predominant positive symptoms, whereas the sum of ω-3 PUFAs was significantly lower. In conclusion, abnormalities in FA metabolism may contribute to the neurobiology of psychopathology in UHR individuals. In particular, membrane FA alterations may play a role in negative symptoms, which are primary psychopathological manifestations of schizophrenia-related disability.     

Tissue-specific fatty acid composition,cellularity, and gene expression in diverse cattle breeds

The nutritional quality of beef relates to the fatty acid (FA) composition of bovine adipose tissue. Those molecular mechanisms that induce the differing amounts and composition of fat in cattle breeds according to age at maturity and purpose of production remain unclear. Therefore, this study investigated the composition of total FAs, adipocyte size, and expression of some key genes involved in several adipogenesis and lipogenesis pathways measured in distinct adipose tissue depots from bulls of the genetically diverse cattle breeds Aberdeen Angus (n = 9), Gascon (n = 10), Holstein (n = 9), and Fleckvieh (n = 10). The animals were finished under identical housing and feeding conditions until slaughter at a similar age of 17 months. After slaughter, cod adipose tissue (CAT), subcutaneous adipose tissue (SAT), and M. longissimus lumborum (MLL) samples were collected. The saturated FA proportions were higher (P < .01) in CAT than in SAT across all breeds, whereas monounsaturated FA proportions were consistently higher (P < .001) in SAT compared to CAT and MLL. Aberdeen Angus bulls were distinguished from the other breeds in the proportions of mostly de novo synthesized C14:0, C16:0, C14:1n-5, C16:1n-7, and conjugated linoleic acid (P < .05). Adipocyte size decreased in the order CAT > SAT > MLL, and the largest adipocytes were observed in CAT of Holstein bulls (P < .05). Gene expression differences were more pronounced between adipose tissue depots than between breeds. The expression levels of ACACA, FASN, and SCD1 genes were related to tissue-specific, and to a lesser extent also breed-specific, differences in FA composition.     

Changes in the content and composition of lipid fatty acids in tobacco leaves and roots at low-temperature hardening

Changes in the fatty acid (FA) composition of leaf and root lipids of heat-loving tobacco (Nicotiana tabacum L., cv. Samsun) plants during low-temperature hardening (8°C for 6 days) were studied. Hardening could improve leaf but not root cold tolerance. As this took place, the relative content of polyunsaturated (18:2n-6 and 18:3n-3) FAs increased and the proportion of saturated and monounsaturated FAs decreased. In contrast, in the roots hardening slightly increased the concentration of saturated FAs (16:0 and 18:0) and reduced the level of unsaturated FAs (18:1n-9, 18:2n-6, and 18:3n-3). At the same time, root lipids contained much C_20–24 FAs, and their content increased during hardening. It was suggested that an increased FA saturation and elevated proportion of C_20–24 FAs in the root lipids resulting in the lower membrane fluidity could be a reason for incapability of heat-loving tobacco plant roots of hardening and plant death at the lowtemperature stress.     

Fatty acid composition of the blubber in white whales (Delphinapterus leucas)

Fatty acid (FA) composition of the blubber in free-ranging white whales (Delphinapterus leucas) from Svalbard's waters was determined and compared with the fatty acid composition of potential prey species in an attempt to assess diet. This methodology is based on the common assumption that unique arrays of FAs found within groups of organisms are transferred, largely unaltered, up marine food chains and thus may be useful for assessment of diet composition. Complete-column blubber biopsies were sampled from white whales (n=7) during the summers of 1996 and 1997. All captured animals were adult males. FAs were extracted from 2–4 replicates taken from an area about 10 cm in front of the mid-dorsal ridge. FA data from a total of 12 potential prey species from the Svalbard area were compared to the white-whale blubber samples. Twenty-two FAs were consistently found in relative amounts >0.5% of the total FA composition in white whales. These FAs accounted for 94–96% of the total FAs present. The blubber was composed almost entirely of triacylglycerols. The major saturated FAs were 14:0 and 16:0; 16:1(n-7), 18:1(n-9) and 20:1(n-9) were the major monounsaturated FAs and 20:5(n-3) and 22:6(n-3) were the major polyunsaturated FAs. Sixteen of the 22 FAs consistently found in the white-whale blubber were also found in considerable amounts (>0.5% of total FAs) in most of the potential species. Principal Component Analysis run on these 16 FAs suggests that polar cod (Boreogadus saida) had the most similar FA composition to the white-whale blubber, followed by capelin (Mallotus villosus), the copepod Calanus hyperboreus and the shrimp Pandalus borealis. Accepted: 27 November 1999     

N‐6 From Different Sources Protect From Metabolic Alterations to Obese Patients: A Factor Analysis

First, to analyze the interactions among fatty acids (FAs) from diet, plasma and subcutaneous and visceral adipose tissue (AT), and second, the relationship among FAs from these different sources and obesity‐related alterations in extreme obesity. We studied 20 extreme obese subjects. A food‐frequency questionnaire was used to determine the FA intakes. Serum and AT (subcutaneous and visceral) FA concentrations were determined by gas chromatography. Cardiometabolic risk parameters were assessed. Principal factor analysis was performed to define specific FA factors in the metabolic alterations. We found important associations among diet, plasma, and AT FA and cardiometabolic parameters. In this regard, it is interesting to highlight the negative associations between plasma cholesterol and dietary n‐3 FA. In the subcutaneous depot, as occurred in plasma, n‐6 and polyunsaturated FAs (PUFA) were negatively associated with triacylglycerols (TGs). Factor analysis revealed TGs as the unique cardiovascular risk parameter appearing in the first factor (F1), together with n‐6 (load factor = 0.94) and PUFA (0.91). Besides, n‐3 from diet and plasma appeared in the third factor inversely related to cholesterol, low‐density lipoprotein cholesterol (LDL‐c), and insulin. In an opposite way, dietary and AT trans FAs and saturated FA (SFA) were associated to an increase of the metabolic risk. We have shown, for the first time, the importance of n‐6 and PUFAs composition as protective factors against metabolic alterations in extreme obese subjects. These findings support current dietary recommendations to increase PUFA intakes and restrict saturated and trans FA intakes even in extreme obesity.     

Migrant blackbirds,Turdus merula,have higher plasma levels of polyunsaturated fatty acids compared to residents,but not enhanced fatty acid unsaturation index

Birds have been observed to have dietary preferences for unsaturated fatty acids during migration. Polyunsaturated fatty acids (PUFAs) may increase the exercise performance of migrant birds; however, PUFAs are also peroxidation prone and might therefore incur increased costs in terms of enhanced oxidative damage in migratory individuals. To shed light on this potential constraint, we analyzed plasma fatty acid (FA) composition and estimated the unsaturation index as a proxy for susceptibility to lipid peroxidation of migrants and residents of the partially migratory common blackbird (Turdus merula) at a stopover site during autumn migration. As predicted, migrant birds had higher relative and absolute levels of PUFAs compared to resident birds. This included the strictly dietary ω‐3 PUFA α‐linolenic acid, suggesting a dietary and/or storage preference for these FAs in migrants. Interestingly, the FA unsaturation index did not differ between migrants and residents. These findings suggest a mechanism where birds alter their levels of metabolic substrate without simultaneously increasing the susceptibility of the substrate to lipid peroxidation. In summary, our results are in line with the hypothesis that increased exercise performance during migration might be constrained by oxidative stress, which is manifested in changes in the composition of key FAs to retain the unsaturation index constant despite the increased levels of peroxidizable PUFAs.     

Polar Bear (Ursus maritimus) Adipose Tissue Fatty Acid Composition Compared to Fatty Acid Constituents of a Common Milk Replacer

This study compared the fatty acid composition of polar bear (Ursus maritimus) adipose tissue (n=2) to the fatty acid (FA) composition in published literature for maternal milk (n=3 samples) and a primary milk formula (liquid Esbilac, Pet Ag Inc., Hampshire, IL) commonly used in hand rearing, to look at possible dietary influences on ultimate body fat constituency. All tissue and commercial milk fatty acids were analyzed on a percent relative (% of fat) basis for consistency in reporting results and to make easier comparisons between samples with varying fat contents. Thirty‐eight individual fatty acid profiles were measured and the results tabulated into saturated, monounsaturated and polyunsaturated fats. The tissue adipose results for the two cubs had similar patterns throughout the assay. Saturated FA totals were 30% of the total fat, monounsaturated FA represented 50% of the total fat, and polyunsaturated FA was 15%. Similar fatty acid proportions were reported when comparing adipose to published data for maternal milk of polar bears. The most striking differences were between the commercial milk replacer (liquid Esbilac) and the tissue samples and maternal milk values. Esbilac FA summaries for saturated FAs were 24%, monounsaturated were 26%, and polyunsaturated comprised 50% of the total fat. Polyunsaturated fat in Esbilac is substantially higher than the tissue and milk scores. Although lipid sources from whole cream or half‐and‐half are used to increase the fat concentration of milk replacers for the hand‐reared polar bear cub, alternative ingredients such as fish oil may prove more suitable for this species, as their FA profiles better duplicate natural diets and resulting lipid stores in milk and adipose tissues of free‐ranging polar bears. Zoo Biol 0:1–11, 2006. © 2006 Wiley‐Liss, Inc.     

N-3 HUFAs affect fat deposition,susceptibility to oxidative stress,and apoptosis in Atlantic salmon visceral adipose tissue

We have investigated how n-3 highly unsaturated fatty acids (HUFAs) in the diet affect fatty acid (FA) utilization, fat storage and oxidative stress (OS) in Atlantic salmon (Salmo salar) white adipose tissue (WAT). Four groups of Atlantic salmon were fed for 21 weeks on one of the four diets supplemented with 23% (of dry matter) lipid. Docosahexaenoic acid (DHA; 22:6n-3) and eicosapentaenoic acid (EPA; 20:5n-3) levels increased from 10% of total FAs in the rapeseed oil (RO) diet, to 20% in the fish oil (FO) diet, and to 50% and 55% in the DHA-enriched and EPA-enriched diets, respectively. Increased dietary levels of n-3 HUFAs resulted in lower fat percentage in WAT. Furthermore, mitochondrial FA β-oxidation activity was higher in the FO group than it was in the RO group. The relative levels of DHA and EPA in phospholipids (PLs) from WAT and mitochondrial membranes increased with the increasing dietary levels of these HUFAs. In general, the mitochondrial membrane PLs were characterised by lower relative levels of n-3 HUFAs and higher relative levels of linoleic acid (LA; 18:2 n-6) than WAT membrane PLs. The predominance of LA relative to n-3 HUFAs in mitochondrial membrane PLs may help to protect these PLs from peroxidation. Cytochrome c oxidase measurements revealed higher incidence of disrupted mitochondrial membranes in the DHA and EPA dietary groups than in the FO and RO dietary groups. This disruption further affected the mitochondrial function, resulting in a marked reduction in FA β-oxidation capacities. The reduction in mitochondrial function and the increase in the activity of superoxide dismutase (SOD) in the DHA and EPA groups showed that high dietary dose of DHA and EPA resulted in oxidative stress (OS). The increased activity of caspase 3 in the high n-3 HUFA groups suggested the induction of apoptosis and increased incidence of cell death in WAT, which may be one of the factors explaining the lower fat percentage found in these groups.     

Different fatty acid composition in central and peripheral adipose tissues of the American mink (Mustela vison)

Fatty acid (FA) composition in the intraabdominal (IAB), subcutaneous (SC) and peripheral adipose tissues of the semiaquatic American mink (Mustela vison) was examined in comparison to the diet by gas-liquid chromatography. There was a clear compositional gradient from the IAB via SC to peripheral adipose tissues and the anatomically different adipose tissues accumulated or metabolized FA selectively. The total lipids of the body appendages had smaller proportions of saturated (SFA) and larger proportions of monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA) than the lipids of the trunk adipose tissues. Especially n-3 PUFA were enriched in the periphery. The appendages were also characterized with a high ratio of unsaturated FA to SFA, an increased Delta9-desaturation index and increased mean numbers of double bonds and carbon atoms in a FA molecule. The proportions of SFA and MUFA of the diet resembled the trunk adipose tissues while the dietary percentage of n-3 PUFA surpassed those of the trunk fat depots but was lower than those of the peripheral fats. These data confirm that the FA signatures of mammals reflect not only their dietary history but also metabolic modifications of ingested FA.     

Double enrichment of chicken eggs with conjugated linoleic acid and n-3 fatty acids through dietary fat supplementation

Yolk fat fatty acid (FA) concentrations, sensory quality and firmness of eggs and laying hen performance were evaluated with respect to the combined inclusion in the diet of conjugated linoleic acid (CLA), high n-3 oil sources and high-oleic sunflower oil (HOSO). Nine diets were arranged factorially, with three levels of n-3 FA supplementation (2.9, 3.7 and 4.5 g/kg) from three different sources (two fish oils highly concentrated in eicosapentanoic (EPA) or docosahexanoic acid (DHA) and one algae oil with a very high-DHA content) in diets added with fixed amounts of CLA (2.5 g/kg) and HOSO (30 g/kg). A commercial feed with no CLA, n-3 or HOSO added, and another one containing 4.5 g/kg of high-DHA fish oil but not CLA or HOSO were also formulated. An increase in n-3 FA supplementation had little effect on proportions of CLA, monounsaturated FA, saturated FA or total polyunsaturated FA in yolk fat, but increased (P<0.005) long-chain n-3 FA and decreased (P<0.001) long-chain n-6 FA. An increment of dietary n-3 FA also impaired linearly (P<0.001) egg acceptability by consumers. An increment in the proportion of DHA with respect to total n-3 FA from 0.28 to 0.96 increased yolk concentrations of DHA (P<0.001) and total n-3 FA (P<0.01), but decreased (P<0.001) concentrations of EPA and docosapentanoic acid FA. Current data indicate that addition of HOSO to diets supplemented with moderate amounts of CLA and n-3 FA allows the production of double enriched eggs while maintaining sensory quality for consumers at acceptable levels.     

A genome-wide association study of n-3 and n-6 plasma fatty acids in a Singaporean Chinese population

Polyunsaturated fatty acids (PUFAs) have a major impact on human health. Recent genome-wide association studies (GWAS) have identified several genetic loci that are associated with plasma levels of n-3 and n-6 PUFAs in primarily subjects of European ancestry. However, the relevance of these findings has not been evaluated extensively in other ethnic groups. The primary aim of this study was to evaluate for genetic loci associated with n-3 and n-6 PUFAs and to validate the role of recently identified index loci using data from a Singaporean Chinese population. Using a GWAS approach, we evaluated associations with plasma concentrations of three n-3 PUFAs [alphalinolenic acid (ALA), eicosapentaenoic acid and docosahexaenoic acid], four n-6 PUFAs [linoleic acid (LA), gammalinolenic acid, dihomogammalinolenic acid (DGLA) and arachidonic acid], and estimates of delta-5 desaturase and delta-6 desaturase activities among the participants (N = 1361) of the Singaporean Chinese Health Study. Our results reveal robust genome-wide associations (p value <5 × 10⁻⁸) with ALA, all four n-6 PUFAs, and delta-6 desaturase activity at the FADS1/FADS2 locus. We further replicated the associations between common index variants at the NTAN1/PDXDC1 locus and n-6 PUFAs LA and DGLA, and between the JMJD1C locus and n-6 PUFA LA (p value between 0.0490 and 9.88 × 10⁻⁴). These associations were independent of dietary intake of PUFAs. In aggregate, we show that genetic loci that influence plasma concentrations of n-3 and n-6 PUFAs are shared across different ethnic groups.

Electronic supplementary material

The online version of this article (doi:10.1007/s12263-015-0502-2) contains supplementary material, which is available to authorized users.     

Lipid metabolism in the adipose tissues of a carnivore, the raccoon dog, during prolonged fasting

Previous studies on laboratory rodents, rabbits, and humans have demonstrated that adipose tissue fatty acid (FA) mobilization is selective, and its efficiency is related to the molecular structure of FAs. This study was undertaken to find out whether such preferences of FA mobilization are a general feature of mammalian white adipose tissue (WAT) and are also manifested in carnivores. Fractional mobilization of a wide spectrum of FAs was studied by gas-liquid chromatography from six subcutaneous (scapular, rump, ventral) and intra-abdominal (omental, mesenteric, retroperitoneal) WAT depots of raccoon dogs (Nyctereutes procyonoides) fed or fasted for 2 months. Fasting stimulated the mobilization of shorter-chain saturated, mono-unsaturated (MUFAs), and polyunsaturated FAs (PUFAs). The effects of unsaturation and the position of the first double bond from the methyl end were more inconsistent. The effect of double-bond position may be due to chain shortening of longer-chain MUFAs and preferential utilization of n-3 PUFAs over n-6 PUFAs. Moreover, there were site-specific differences in fractional mobilization, the omental adipose tissue being the most divergent. The in vivo FA mobilization from the regional WAT depots of a carnivore was selective, and the molecular structure of the FA affected its efficiency.     

Genetic variability of milk fatty acids

The milk fatty acid (FA) profile is far from the optimal fat composition in regards to human health. The natural sources of variation, such as feeding or genetics, could be used to increase the concentrations of unsaturated fatty acids. The impact of feeding is well described. However, genetic effects on the milk FA composition begin to be extensively studied. This paper summarizes the available information about the genetic variability of FAs. The greatest breed differences in FA composition are observed between Holstein and Jersey milk. Milk fat of the latter breed contains higher concentrations of saturated FAs, especially short-chain FAs. The variation of the delta-9 desaturase activity estimated from specific FA ratios could explain partly these breed differences. The choice of a specific breed seems to be a possibility to improve the nutritional quality of milk fat. Generally, the proportions of FAs in milk are more heritable than the proportions of these same FAs in fat. Heritability estimates range from 0.00 to 0.54. The presence of some single nucleotide polymorphisms could explain partly the observed individual genetic variability. The polymorphisms detected onSCD1 andDGAT1 genes influence the milk FA composition. TheSCD1 V allele increases the unsaturation of C16 and C18. TheDGAT1 A allele is related to the unsaturation of C18. So, a combination of the molecular and quantitative approaches should be used to develop tools helping farmers in the selection of their animals to improve the nutritional quality of the produced milk fat.     

Contrasting effects of membrane enrichment with polyunsaturated fatty acids on phospholipid composition and cholesterol efflux from cholesterol-loaded J774 mouse or primary human macrophages

A high consumption of polyunsaturated fatty acids (PUFAs), particularly n-3 PUFAs, is atheroprotective. PUFAs incorporation into membrane phospholipids alters the functionality of membrane proteins. We studied the consequences of the in vitro supplementation of several PUFAs on the FA profiles and on ABCA1-dependent cholesterol efflux capacities from cholesterol-loaded macrophages. Arachidonic acid (AA, C20:4 n-6) and, to a lesser extent, eicosapentaenoic acid (EPA, C20:5 n-3), dose-dependently impaired cholesterol efflux from cholesterol-loaded J774 mouse macrophages without alterations in ABCA1 expression, whereas docosahexaenoic acid (DHA, C22:6 n-3) had no impact. AA cells exhibited higher proportions of arachidonic acid and adrenic acid (C22:4 n-6), its elongation product. EPA cells exhibited slightly higher proportions of EPA associated with much higher proportions of docosapentaenoic acid (C22:5 n-3), its elongation product and with lower proportions of AA. Conversely, both EPA and DHA and, to a lesser extent, AA decreased cholesterol efflux from cholesterol-loaded primary human macrophages (HMDM). The differences observed in FA profiles after PUFA supplementations were different from those observed for the J774 cells. In conclusion, we are the first to report that AA and EPA, but not DHA, have deleterious effects on the cardioprotective ABCA1 cholesterol efflux pathway from J774 foam cells. Moreover, the membrane incorporation of PUFAs does not have the same impact on cholesterol efflux from murine (J774) or human (HMDM) cholesterol-loaded macrophages. This finding emphasizes the key role of the cellular model in cholesterol efflux studies and may partly explain the heterogeneous literature data on the impact of PUFAs on cholesterol efflux.     

Does a large-scale continuous algal production system provide a stable supply of fatty acids to bivalve hatcheries?

The variation of fatty acid (FA) content and composition of the microalgal production (Isochrysis sp., Pavlova lutheri and Chaetoceros muelleri) in a continuous large-scale production system (500-L bags) used in hatcheries were analysed. The variation of the FAs was analysed in replicate bags over time for the different species. Total FA content (pg cell⁻¹) increased significantly (p < 0.05) in the P. lutheri and C. muelleri bags over time. The content of the essential FAs (arachidonic acid (ARA), eicosapentaenoic acid (EPA), n-6 docosapentaenoic acid (n-6 DPA) and docosahexaenoic acid (DHA)) increased over time in all of the species, except for DHA in Isochrysis sp. The content of EPA and ARA were highest in C. muelleri, whilst n-6 DPA and DHA were highest in Isochrysis sp. The FA composition in the C. muelleri bags showed large variability between bags at the beginning of the experiment, but decreased over time. In contrast, the FA composition of Isochrysis sp. and P. lutheri did not vary much over time, but larger variability was observed between the replicate bags. The results indicate that, even though the essential polyunsaturated FAs (PUFAs) varied between the different species, the total microalgal production secured a stable and increased supply of all the essential PUFAs to the scallop larvae and spat.