Short-chain Polyunsaturated Fatty Acids Research Articles

70 Ahiflower (Buglosoides Arvensis) oil supplementation alters whole blood and muscle fatty acid profile in mature horses

The omega-3 (n-3) profile of common plant-based ingredients are derived from α-linolenic acid (ALA). Previous research has indicated that horses lack the ability to convert ALA or other short-chain polyunsaturated fatty acids (SC-PUFA) into the biologically relevant docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Ahiflower (Buglossoides Arvensis) oil is a novel plant-based source of omega-3 fatty acids derived from n-3 stearidonic acid (SDA), and gamma-linolenic acid (GLA), an omega-6 fatty acid (see Table 1 for fatty acid profile). The objective of this trial was to evaluate how supplementation of Ahiflower oil to horses would alter whole blood and muscle fatty acid composition. Mature Quarter Horses (n = 20) were balanced by age, BW, and BCS and assigned to one of 4 treatment groups. LOW (n = 5; BW = 507.12 ± 2.3kg; BCS = 5.4 ± 0.3) was offered 30mL/day of Ahiflower oil. HIGH (n = 5; BW = 517.45 ± 4.5kg; BCS = 5.7 ± 0.1) was offered 60mL/day of Ahiflower oil. FLAX (n = 5; BW = 497.25 ± 3.5kg; BCS = 6.1 ± 0.7) was offered a flaxseed pellet (CP = 15.42%, Total omega-3 = 3.75%) formulated to provide the same amount of total omega-3′s as LOW was offered. PAST (n = 5; BW = 508.14 ± 3.6kg; BCS = 5.2 ± 0.6) was allowed free-choice access to mixed grass pasture (CP = 16.0%, Total omega-3 = 0.79%). All horses were offered 1.81kg/d of Purina® Strategy GX® (CP = 14.24%, Total omega-3 = 0.44%) daily. LOW, HIGH, and FLAX were housed in drylots by treatment group and were offered 2.0% BW as Timothy grass hay (CP = 10.10%, Total omega-3 = 0.35%). On d 0, 30, and 60 blood samples were collected along with a mid-gluteal muscle sample (∼1g). Samples were analyzed for fatty acid profile via LC-HPLC (UF ATCL).Data were analyzed via ANOVA (SAS 9.4). Horses in the LOW group had a 12.5% increase in total omega-3, while horses in HIGH had a 40.1% increase. Similar differences were observed for EPA (LOW = 19.2%; HIGH = 40.1%), and GLA (LOW = 60.1%; HIGH = 167%). Horses in HIGH had a greater increase from baseline in muscle EPA + DHA compared with all other groups (250%). All differences were significant at P < 0.05. Taken together these data indicate that horses had the ability to convert the PUFA's in Ahiflower oil into EPA. Increased EPA in whole blood and muscle tissue potentially allows for increased production of anti-inflammatory eicosanoids and prostaglandins. Further research is necessary to elucidate the mechanism by which this conversion occurs.

Associations between plasma fatty acid concentrations and schizophrenia: a two-sample Mendelian randomisation study

Although studies suggest that concentrations of omega-3 and omega-6 fatty acids are lower in individuals with schizophrenia, evidence for beneficial effects of fatty acid supplementation is scarce. Therefore, in this study, we aimed to determine whether omega-3 and omega-6 fatty acid concentrations are causally related to schizophrenia. We did a two-sample Mendelian randomisation study, using deidentified summary-level data that were publicly available. Exposure-outcome relationships were evaluated using the inverse variance weighted two-sample Mendelian randomisation method using results from genome-wide association studies (GWASs) of fatty acid concentrations and schizophrenia. GWAS results were available for European (fatty acids) and European and Asian (schizophrenia) ancestry samples. Overall age and gender information were not calculable from the summary-level GWAS results. Weighted median, weighted mode, and Mendelian randomisation Egger regression methods were used as sensitivity analyses. To address underlying mechanisms, further analyses were done using single instruments within the FADS gene cluster and ELOVL2 gene locus. FADS gene cluster and ELOVL2 gene causal effects on schizophrenia were calculated by dividing the single nucleotide polymorphism (SNP)-schizophrenia effect estimate by the SNP-fatty acid effect estimate with standard errors derived using the first term from a delta method expansion for the ratio estimate. Multivariable Mendelian randomisation was used to estimate direct effects of omega-3 fatty acids on schizophrenia, independent of omega-6 fatty acids, lipoproteins (ie, HDL and LDL), and triglycerides. Mendelian randomisation analyses indicated that long-chain omega-3 and long-chain omega-6 fatty acid concentrations were associated with a lower risk of schizophrenia (eg, inverse variance weighted odds ratio [OR] 0·83 [95% CI 0·75-0·92] for docosahexaenoic acid). By contrast, there was weak evidence that short-chain omega-3 and short-chain omega-6 fatty acids were associated with an increased risk of schizophrenia (eg, inverse variance weighted OR 1·07 [95% CI 0·98-1·18] for α-linolenic acid). Effects were consistent across the sensitivity analyses and the FADS single-SNP analyses, suggesting that long-chain omega-3 and long-chain omega-6 fatty acid concentrations were associated with lower risk of schizophrenia (eg, OR 0·74 [95% CI 0·58-0·96] for docosahexaenoic acid) whereas short-chain omega-3 and short-chain omega-6 fatty acid concentrations were associated with an increased risk of schizophrenia (eg, OR 1·08 [95% CI 1·02-1·15] for α-linolenic acid). By contrast, estimates from the ELOVL2 single-SNP analyses were more imprecise and compatible with both risk-increasing and protective effects for each of the fatty acid measures. Multivariable Mendelian randomisation indicated that the protective effect of docosahexaenoic acid on schizophrenia persisted after conditioning on other lipids, although evidence was slightly weaker (multivariable inverse variance weighted OR 0·84 [95% CI 0·71-1·01]). Our results are compatible with the protective effects of long-chain omega-3 and long-chain omega-6 fatty acids on schizophrenia, suggesting that people with schizophrenia might have difficulty converting short-chain polyunsaturated fatty acids to long-chain polyunsaturated fatty acids. Further studies are required to determine whether long-chain polyunsaturated fatty acid supplementation or diet enrichment might help prevent onset of schizophrenia. National Institute for Health Research Biomedical Research Centre at University Hospitals Bristol and Weston NHS Foundation Trust and the University of Bristol.

Red Blood Cell Polyunsaturated Fatty Acids and Vascular Diseases: A Mendelian Randomization Study

Abstract Objectives To evaluate the causal association of omega-3 and omega-6 polyunsaturated fatty acids (PUFAs), as measured in red blood cells (RBC), with cardiovascular disease (CVD), cerebrovascular disease (CBVD), and peripheral vascular disease (PVD). Methods Applying a two-sample Mendelian Randomization approach, we first developed genetic instruments for RBC-PUFAs by utilizing summary statistics from previous genome-wide association study in the Framingham Heart Study. We then evaluated the association of these instrumental variables with CVD, CBVD, PVD, and their subtypes in the UK Biobank cohort. Results Strong evidence of causal association with at least one RBC-PUFAs was observed for the overall risk of PVD and three of its subtypes (aortic aneurysm and dissection, arterial embolism and thrombosis, and other PVDs), but only for two CVD subtypes (hypertensive heart disease, and chronic ischemic heart disease) and for two CBVD subtypes (stroke, and cerebral infarction). Based on their effects on all examined diseases, RBC-PUFAs clustered into two groups: a protective group with alpha-Linolenic acid (ALA), linoleic acid (LA), eicosadienoic acid (EDA), and dihomo-gamma-linolenic acid (DGLA); and the other risk group with docosapentaenoic acid (DPA), gamma-linolenic acid (GLA), arachidonic acid (AA), and adrenic acid (AdrA). PUFAs in the protective group are protective, while those in the risk group are risk-increasing, for all diseases with significant associations except for hypertensive heart diseases. In the metabolic pathway converting short-chain PUFAs into long-chain ones, the protective group is mapped to precursors of desaturases, while the risk group corresponds to their products. Conclusions Genetically regulated RBC-PUFAs are associated with the risk of PVD, and subtypes of PVD, CVD, and CBVD. Funding Sources University of Georgia Research Foundation.

The Important In Terms of Health of Flax (Linum usitatissimum L.)

The flax is one of the oldest known cultivated plants of the World that benefited from seeds and fibers. It is an important nutrient because of the rich α-linolenic acid (ALA, omega-3 fatty acid), lignans, short chain polyunsaturated fatty acids, soluble and insoluble fibers, phytoestrogenic lignans (secoisolariciresinol diglycoside-SDG), waxy and mucilage compounds, protein and antioxidant compounds. In addition, the seed contains components effective in reducing cardiovascular disorders, diabetes, digestive system, urinary tract disorders, osteoporosis, cancer, arthritis, autoimmune and neurological diseases. Seed protein content varies between 20-30%, of which approximately 80% consists of globulins and 20% glutelines. The amino acid level is so rich and gluten-free. The unconscious consumption of seed may cause toxicity due to trypsin, myo-inositol phosphate inhibitors, cadmium and cyanogenic glycosides in the seed. The seed should be consumed as milled flour after absolute heat treatment. Side effects may be seen in pregnant and young men due to hormonal effects of lignan. It may be oxidized shortly after grinding due to the fatty acids present in the seed. Flax fibers (Linen) have been used in house and fabric textiles, sailing and tent making since 7040 BC. The fibers are gold-yellow in color, the qualitative and moisture absorption capacity is very low, easily creasing. For this reason, the linen keeps the skin cool and does not sweat. Fiber is also an important source for healthy insulation materials, biocomposites, structural application materials for automotive, contributing both to the environment and to human health. In this paper, the effects of flax on human health and methods of traditional uses in Turkey were discussed with references.

Assessment of the fecundity, population growth and fatty acid composition of Apocyclops royi (Cyclopoida, Copepoda) fed on different microalgal diets

The brackish cyclopoid copepod Apocyclops royi is used in Taiwanese aquaculture industry as a prey for fish larvae. This study investigated the effects of seven microalgal diets, namely single-species diets of Isochrysis galbana (ISO), Nannochloropsis oculata (NAN), and Tetraselmis chui (TET), two-species diets (ISO+NAN, ISO+TET and TET+NAN), and a three-species diet (ISO+NAN+TET), on the population growth, female fecundity and fatty acid composition of A. royi. For reproductive traits, the combination ISO+NAN was found to be the most supportive diet for both population growth and female fecundity. For nutritional value, copepods fed ISO and ISO+NAN were detected to have the highest content of docosahexaenoic acid (DHA) (18.99% and 10.73% total fatty acid, respectively) and, more importantly, a high DHA/EPA ratio (6.09 and 4.09, respectively). Additionally, a comparison of fatty acid composition between copepods and microalgae gives a tentative indication that A. royi may have the ability to synthesize long-chain polyunsaturated fatty acids (PUFA) from short-chain PUFA. Our findings illustrate that ISO+NAN is the most suitable microalgal diet for mass culturing A. royi because it increases productivity and enhances the nutritional value of the copepods for use as fish larvae prey.

Selection in Europeans on Fatty Acid Desaturases Associated with Dietary Changes.

FADS genes encode fatty acid desaturases that are important for the conversion of short chain polyunsaturated fatty acids (PUFAs) to long chain fatty acids. Prior studies indicate that the FADS genes have been subjected to strong positive selection in Africa, South Asia, Greenland, and Europe. By comparing FADS sequencing data from present-day and Bronze Age (5–3k years ago) Europeans, we identify possible targets of selection in the European population, which suggest that selection has targeted different alleles in the FADS genes in Europe than it has in South Asia or Greenland. The alleles showing the strongest changes in allele frequency since the Bronze Age show associations with expression changes and multiple lipid-related phenotypes. Furthermore, the selected alleles are associated with a decrease in linoleic acid and an increase in arachidonic and eicosapentaenoic acids among Europeans; this is an opposite effect of that observed for selected alleles in Inuit from Greenland. We show that multiple SNPs in the region affect expression levels and PUFA synthesis. Additionally, we find evidence for a gene–environment interaction influencing low-density lipoprotein (LDL) levels between alleles affecting PUFA synthesis and PUFA dietary intake: carriers of the derived allele display lower LDL cholesterol levels with a higher intake of PUFAs. We hypothesize that the selective patterns observed in Europeans were driven by a change in dietary composition of fatty acids following the transition to agriculture, resulting in a lower intake of arachidonic acid and eicosapentaenoic acid, but a higher intake of linoleic acid and α-linolenic acid.

Polyunsaturated fatty acids and prostate cancer risk: a Mendelian randomisation analysis from the PRACTICAL consortium.

Background:Prostate cancer is a common cancer worldwide with no established modifiable lifestyle factors to guide prevention. The associations between polyunsaturated fatty acids (PUFAs) and prostate cancer risk have been inconsistent. Using Mendelian randomisation, we evaluated associations between PUFAs and prostate cancer risk.Methods:We used individual-level data from a consortium of 22 721 cases and 23 034 controls of European ancestry. Externally-weighted PUFA-specific polygenic risk scores (wPRSs), with explanatory variation ranging from 0.65 to 33.07%, were constructed and used to evaluate associations with prostate cancer risk per one standard deviation (s.d.) increase in genetically-predicted plasma PUFA levels using multivariable-adjusted unconditional logistic regression.Results:No overall association was observed between the genetically-predicted PUFAs evaluated in this study and prostate cancer risk. However, risk reductions were observed for short-chain PUFAs, linoleic (ORLA=0.95, 95%CI=0.92, 0.98) and α-linolenic acids (ORALA=0.96, 95%CI=0.93, 0.98), among men <62 years; whereas increased risk was found among men ⩾62 years for LA (ORLA=1.04, 95%CI=1.01, 1.07). For long-chain PUFAs (i.e., arachidonic, eicosapentaenoic, and docosapentaenoic acids), increased risks were observed among men <62 years (ORAA=1.05, 95%CI=1.02, 1.08; OREPA=1.04, 95%CI=1.01, 1.06; ORDPA=1.05, 95%CI=1.02, 1.08).Conclusion:Results from this study suggest that circulating ω-3 and ω-6 PUFAs may have a different role in the aetiology of early- and late-onset prostate cancer.

Long-chain PUFA enrichment in microalgae and metabolic dynamics inTapes philippinarumlarvae

The possibility of increasing n-3 and n-6 long-chain polyunsaturated fatty acids (PUFA) content in microalgal mixtures used to feed Tapes philippinarum larvae was explored by lowering culture temperature from 26 to 14 °C. Although fatty acid composition of different microalgal species has a genetic basis, the algal cultures grown at 14 °C significantly increased the content of long-chain n-3 PUFA in Isocrysis galbana and in Thalassiosira pseudonana, while in Tetraselmis tetrathelo, the PUFA increase only involved shorter chain PUFA, namely 16:4n-3 and 18:4n-3. However, larvae fed on the PUFA enriched microalgal mixture did not show improvements in growth and survival performances with respect to the control group fed the microalgal mixture grown at 26 °C. From a biochemical perspective, two key aspects emerged from the results: (i) clam larvae have adequate biotransformation and selection skills to adjust fatty acid profile to their requirements as they can even modulate the incorporation of essential long-chain PUFA as 20:5n-3 and 22:6n-3 when the dietary supply exceeds the physiological requirements; (ii) bivalve can biosynthesize non-methylene-interrupted dienoic (NMID) fatty acids as confirmed by the constancy of relative proportion with larvae growth in spite of the NMID fatty acid absence in the diet.

Dietary flaxseed intake exacerbates acute colonic mucosal injury and inflammation induced by dextran sodium sulfate.

Flaxseed (FS), a dietary oilseed, contains a variety of anti-inflammatory bioactives, including fermentable fiber, phenolic compounds (lignans), and the n-3 polyunsaturated fatty acid (PUFA) α-linolenic acid. The objective of this study was to determine the effects of FS and its n-3 PUFA-rich kernel or lignan- and soluble fiber-rich hull on colitis severity in a mouse model of acute colonic inflammation. C57BL/6 male mice were fed a basal diet (negative control) or a basal diet supplemented with 10% FS, 6% kernel, or 4% hull for 3 wk prior to and during colitis induction via 5 days of 2% (wt/vol) dextran sodium sulfate (DSS) in their drinking water (n = 12/group). An increase in anti-inflammatory metabolites (hepatic n-3 PUFAs, serum mammalian lignans, and cecal short-chain fatty acids) was associated with consumption of all FS-based diets, but not with anti-inflammatory effects in DSS-exposed mice. Dietary FS exacerbated DSS-induced acute colitis, as indicated by a heightened disease activity index and an increase in colonic injury and inflammatory biomarkers [histological damage, apoptosis, myeloperoxidase, inflammatory cytokines (IL-6 and IL-1β), and NF-κB signaling-related genes (Nfkb1, Ccl5, Bcl2a1a, Egfr, Relb, Birc3, and Atf1)]. Additionally, the adverse effect of the FS diet was extended systemically, as serum cytokines (IL-6, IFNγ, and IL-1β) and hepatic cholesterol levels were increased. The adverse effects of FS were not associated with alterations in fecal microbial load or systemic bacterial translocation (endotoxemia). Collectively, this study demonstrates that although consumption of a 10% FS diet enhanced the levels of n-3 PUFAs, short-chain polyunsaturated fatty acids, and lignans in mice, it exacerbated DSS-induced colonic injury and inflammation.

Fish oil–based finishing diets strongly increase long‐chain polyunsaturated fatty acid concentrations in farm‐raised common carp ( C yprinus carpio L.)

This study investigated effects of linseed or fish oil–enriched finishing diets on the polyunsaturated fatty acids (PUFA) composition in dorsal muscle tissues of pond-cultured common carp (Cyprinus carpio). After 180 days of dietary exposure to cereal diet containing vegetable oil (1%), carp were exposed to 7% linseed (LO) or 7% fish oil–enriched (FO) finishing diets for 30 days. FO supplied 17 and 20 mg fish−1 day−1, respectively, of the long-chain n-3 fatty acids eicosapentaenoic and docosahexaenoic acid for 30 days and doubled long-chain PUFA concentrations in carp of the FO pond. The increased supply of short-chain PUFA in LO resulted in higher short chain, but not long-chain PUFA, showing that there was very little PUFA conversion. Thus, dietary short-chain PUFA could not compensate for the low levels of dietary long-chain PUFA in LO. However, moderate supply of dietary long-chain PUFA in finishing diets for 30 days is very efficient in increasing nutritionally important long-chain PUFA concentrations in carp.

Omega-3 fatty acids

Fish oil contains a complex mixture of omega-3 fatty acids, which are predominantly eicosapentaenoic acid (EPA), docosapentaenoic acid, and docosahexaenoic acid (DHA). Each of these omega-3 fatty acids has distinct biological effects that may have variable clinical effects. In addition, plasma levels of omega-3 fatty acids are affected not only by dietary intake, but also by the polymorphisms of coding genes fatty acid desaturase 1-3 for the desaturase enzymes that convert short-chain polyunsaturated fatty acids to long-chain polyunsaturated fatty acids. The clinical significance of this new understanding regarding the complexity of omega-3 fatty acid biology is the purpose of this review. FADS polymorphisms that result in either lower levels of long-chain omega-3 fatty acids or higher levels of long-chain omega-6 polyunsaturated fatty acids, such as arachidonic acid, are associated with dyslipidemia and other cardiovascular risk factors. EPA and DHA have differences in their effects on lipoprotein metabolism, in which EPA, with a more potent peroxisome proliferator-activated receptor-alpha effect, decreases hepatic lipogenesis, whereas DHA not only enhances VLDL lipolysis, resulting in greater conversion to LDL, but also increases HDL cholesterol and larger, more buoyant LDL particles. Overall, these results emphasize that blood concentrations of individual long-chain polyunsaturated fatty acids, which reflect both dietary intake and metabolic influences, may have independent, but also complementary- biological effects and reinforce the need to potentially provide a complex mixture of omega-3 fatty acids to maximize cardiovascular risk reduction.

Comparison of fatty acid contents and composition in major lipid classes of larvae and adults of mosquitoes (Diptera: Culicidae) from a steppe region

Emerging aquatic insects, including mosquitoes, are known to transfer to terrestrial ecosystems specific essential biochemicals, such as polyunsaturated fatty acids (PUFA). We studied fatty acid (FA) composition and contents of dominant mosquito populations (Diptera: Culicidae), that is, Anopheles messeae, Ochlerotatus caspius, Oc. flavescens, Oc. euedes, Oc. subdiversus, Oc. cataphylla, and Aedes cinereus, inhabited a steppe wetland of a temperate climate zone to fill up the gap in their lipid knowledge. The polar lipid and triacylglycerol fractions of larvae and adults were compared. In most studied mosquito species, we first found and identified a number of short-chain PUFA, for example, prominent 14:2n-6 and 14:3n-3, which were not earlier documented in living organisms. These PUFA, although occurred in low levels in adult mosquitoes, can be potentially used as markers of mosquito biomass in terrestrial food webs. We hypothesize that these acids might be synthesized (or retroconverted) by the mosquitoes. Using FA trophic markers accumulated in triacylglycerols, trophic relations of the mosquitoes were accessed. The larval diet comprised green algae, cryptophytes, and dinoflagellates and provided the mosquitoes with essential n-3 PUFA, linolenic, and eicosapentaenoic acids. As a result, both larvae and adults of the studied mosquitoes had comparatively high content of the essential PUFA. Comparison of FA proportions in polar lipids versus storage lipids shown that during mosquito metamorphosis transfer of essential eicosapentaenoic and arachidonic acids from the reserve in storage lipids of larvae to functional polar lipids in adults occurred.

Influence of different sources and levels of dietary protein and lipid on the growth, feed efficiency, muscle composition and fatty acid profile of Snakehead Channa striatus (Bloch, 1793) fingerling

Nine isoenergetic (18.5 kJ g−1) diets were formulated, in a 3 × 3 factorial design, by varying three levels of dietary protein (350, 400 and 450 g kg−1) at each of three levels of dietary lipid (65, 90 and 115 g kg−1) accordingly. Each diet was hand fed two times daily for 8 weeks to triplicate homogenous groups of eight fish (average weight 3.34 ± 0.02 g) per tank connected to a recirculation system. Results showed that the feed efficiency and growth performance significantly (P<0.05) increased with increasing protein level at the two lower lipid levels (65 and 90 g kg−1), respectively, as indicated by indices such as %weight gain, specific growth rate, protein efficiency ratio, feed conversion ratio and feed intake, but did not at the highest lipid level (115 g kg−1). The muscle polyunsaturated fatty acids (PUFA) content declined with increasing dietary protein level at the lipid levels producing the highest growth, suggesting that the utilization of PUFA influences growth. Whereas the muscle monounsaturated fatty acids level was generally lower than the dietary levels in all the treatments tested, indicating preferential catabolism for energy, the muscle saturated fatty acids level was comparatively higher than in the diets, indicating selective deposition. Docosa hexaenoic acid (22:6n3, DHA), which was very low in the diet and in the initial fish, was higher in the muscle of some of the treatments, indicating the ability of Channa striatus to desaturate and elongate short-chain PUFA to long-chain HUFA, due to the availability of dietary 18:3n3 and 20:5n3 (the precursors for DHA biosynthesis). It could be concluded, based on the results of this trial, that a diet formulated to contain 65 g kg−1 lipid and 450 g kg−1 protein, with a gross energy of 18.5 kJ g−1 and a dietary n3/n6 PUFA ratio of about 0.1, is sufficient to promote good feed efficiency and growth performance in C. striatus fingerling.

Fatty acid composition of larvae of the sand dollar Dendraster excentricus (Echinodermata) might reflect FA composition of the diets

Fatty acid (FA) requirements of echinoderm larvae were examined by a study of the FA composition, growth, and development of Dendraster excentricus larvae fed a microencapsulated diet, and two algal diets. Larvae were assigned to three treatments with three replicates per treatment, a microencapsulated diet, a single algal diet of Dunaliella tertiolecta and a mixed algal diet of Isochrysis galbana and Dunaliella tertiolecta. The percentage of saturated fatty acids (SAFA), short and long chain polyunsaturated fatty acids (PUFA) differed significantly among the algal diets and the microencapsulated diet. Differences in dietary FA composition influenced larval tissue FA composition. Eight day-old sand dollar larvae fed the single and mixed algal diets had a significantly higher percentage of the SAFA myristic acid (14:0), while eight day-old larvae fed the microencapsulated diet had a significantly higher percentage of the SAFA palmitic acid (16:0). Sixteen day-old competent larvae fed all three diets did not differ significantly in the percentage of myristic or palmitic acid. The algal diets had a higher percentage of the short chain PUFAs linolenic (LNA, 18:3n-3) and stearidonic acid (SDA, 18:4n-3) while the microencapsulated diet had the highest percentage of the long chain PUFAs eicosapentanoic acid (EPA, 20:5n-3) docosahexanoic acid (DHA, 22:6n-3) and arachidonic acid (AA, 20:4n-6). The percentage of short chain PUFAs, though high in the algal diets, was low in the larval tissues, while the percentage of long chain PUFAs, though low in the algal diets, was high in the larval tissues. Competent larvae fed the two algal diets had up to ten times the percentage of EPA and AA than those fed the microencapsulated diet. Unexpectedly, despite a high percentage of DHA and EPA in the microencapsulated diet, the percentage of these long chain PUFAs in the tissues of larvae fed this diet was extremely low. Eight day-old larvae fed the three diets did not differ significantly in total larval length. Competent larvae fed algal diets had significantly longer larval arms, bigger stomachs and larger rudiments than those fed the microencapsulated diet. This study indicates that early larval growth and development of Dendraster excentricus were not discernibly affected by differences in dietary FA composition of microencapsulated and algal diets but the competent larval stages were. Similar growth and development of competent echinoderm larvae fed microencapsulated or algal diets might be obtained by enriching the microencapsulated diets with the short chain PUFAs LNA and SDA, and the long chain PUFAs EPA and AA. This is an important research tool as microencapsulated feeds can be used to establish nutritional requirements of fatty acids for echinoderm larval development.

Tu-P10:481 Relationship of dietary intake of fatty acids to plasma C-reactive protein in Japanese

Fatty acid (FA) requirements of echinoderm larvae were examined by a study of the FA composition, growth, and development of Dendraster excentricus larvae fed a microencapsulated diet, and two algal diets. Larvae were assigned to three treatments with three replicates per treatment, a microencapsulated diet, a single algal diet of Dunaliella tertiolecta and a mixed algal diet of Isochrysis galbana and Dunaliella tertiolecta. The percentage of saturated fatty acids (SAFA), short and long chain polyunsaturated fatty acids (PUFA) differed significantly among the algal diets and the microencapsulated diet. Differences in dietary FA composition influenced larval tissue FA composition. Eight day-old sand dollar larvae fed the single and mixed algal diets had a significantly higher percentage of the SAFA myristic acid (14:0), while eight day-old larvae fed the microencapsulated diet had a significantly higher percentage of the SAFA palmitic acid (16:0). Sixteen day-old competent larvae fed all three diets did not differ significantly in the percentage of myristic or palmitic acid. The algal diets had a higher percentage of the short chain PUFAs linolenic (LNA, 18:3n-3) and stearidonic acid (SDA, 18:4n-3) while the microencapsulated diet had the highest percentage of the long chain PUFAs eicosapentanoic acid (EPA, 20:5n-3) docosahexanoic acid (DHA, 22:6n-3) and arachidonic acid (AA, 20:4n-6). The percentage of short chain PUFAs, though high in the algal diets, was low in the larval tissues, while the percentage of long chain PUFAs, though low in the algal diets, was high in the larval tissues. Competent larvae fed the two algal diets had up to ten times the percentage of EPA and AA than those fed the microencapsulated diet. Unexpectedly, despite a high percentage of DHA and EPA in the microencapsulated diet, the percentage of these long chain PUFAs in the tissues of larvae fed this diet was extremely low. Eight day-old larvae fed the three diets did not differ significantly in total larval length. Competent larvae fed algal diets had significantly longer larval arms, bigger stomachs and larger rudiments than those fed the microencapsulated diet. This study indicates that early larval growth and development of Dendraster excentricus were not discernibly affected by differences in dietary FA composition of microencapsulated and algal diets but the competent larval stages were. Similar growth and development of competent echinoderm larvae fed microencapsulated or algal diets might be obtained by enriching the microencapsulated diets with the short chain PUFAs LNA and SDA, and the long chain PUFAs EPA and AA. This is an important research tool as microencapsulated feeds can be used to establish nutritional requirements of fatty acids for echinoderm larval development.

Regulation of PUFA metabolism: pharmacological and toxicological aspects

Levels of the long-chain polyunsaturated fatty acids (LCP) of the n-6 and n-3 series in animal plasma and cells are directly or indirectly dependent upon the intakes of either their precursors, the short-chain polyunsaturated fatty acids (SCP), linoleic (LA, 18:2 n-6) and alpha linolenic acid (ALA, 18:3 n-3), respectively, and/or of the preformed products (arachidonic, 20:4 n-6) and eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic acid (DHA, 22:6 n-3). We report here that pharmacological agents and cytotoxic compounds significantly affect the production of LCP from SCP in cultured cells. Using labelled substrates and radio HPLC separations, we observed that the potent hypocholesterolemic agent, simvastatin, activates the formation of AA from LA, mainly acting at the Δ5 desaturation step, and increases also the mRNA levels, in cultured monocytic cells (THP-1). Elevation of AA occurs also in plasma lipids of hyperlipemic patients treated with statins (but not with fibrates). Conversely, oxysterols (mainly 7-β-oxysterol), which are detected in circulating lipoproteins of rabbits on a hypercholesterolemic diet, potently inhibit the synthesis of AA from LA in hepatocytic cell lines (Hep-G2). At the same time plasma levels o AA are reduced vs controls, in spite of an identical intake of LA. Finally, on the basis of previous work showing reduced levels of LCP, mainly DHA, in the milk of cigarette-smoking mothers, we have observed that the incubation of human mammary gland cells with sera exposed to cigarette smoke results in marked inhibition of the production of DHA from ALA. The products in smoke responsible for this effect, are being identified through mass spectrometric techniques. In conclusion, pharmacological agents and toxic compounds, such as oxysterols and smoke products affect key steps in the synthesis of the LCP, major bioregulators in mammalian cells.

Lipids of arctic charr,Salvelinus alpinus (L.) II. Influence of dietary fatty acids on the elongation and desaturation of linoleic and linolenic acid

Arctic charr,Salvelinus alpinus L. were fed five test diets containing 0% or 1% of different polyunsaturated fatty acids (PUFA) for 93 days. The fish were injected intraperitoneally with (1-(14)C)-18:2(n-6) or (1-(14)C)-18:3(n-3), and the bioconversion to longer chain PUFA studied. The conversion rate in neutral lipids was slow, with most label found as the fatty acid injected, while extensive modification took place prior to or during incorporation into polar lipids. Linolenic acid was preferred over linoleic acid as substrate for elongation and desaturation regardless of diet. In polar lipids, the predominant products of (1-(14)C)-18:2(n-6) metabolism were generally 20:3(n-6) and 20:4(n-6), while 18:4(n-3), 20:5(n-3) and 22:6(n-3) were the major products of (1-(14)C)-18:3(n-3) metabolism. The lack of radioactivity in 22:5(n-6) suggests that Δ 4 desaturation is specific for (n-3) PUFA. Feeding the PUFA deficient diet reduced the Δ 5 desaturation compared to fish maintained on PUFA supplemented diets. The Δ 6 desaturation was only reduced in fish fed C18 PUFA and injected with (1-(14)C)-18:3(n-3). Longer chain C20 and C22 PUFA, particularly those of the (n-3) family, exerted some inhibition on the elongation and desaturation of injected fatty acids compared to those fed C18 PUFA. The incorporation of radiolabelled fatty acids into polar lipids of fish fed a commercial diet was very low, and the desaturation neglectible in both polar and neutral lipids, showing that Arctic charr under culture conditions do not convert short chain PUFA to longer chain metabolites.

The effects of a vegetarian and vegan diet on plasma and erythrocyte lipids

Vegetarians usually consume milk, cheese and eggs, whilst vegans consume a diet consisting entirely of plant foods. The protein in a vegan diet is therefore entirely of plant origin. The vegan diet also differs from that of vegetarians and omnivores in having a lower fat content, no cholesterol and a high proportion of short-chain polyunsaturated fatty acids, particularly linoleic acid. The diet of large numbers of people in the Third World is predominantly of plant origin and vegans are an excellent natural ‘experimental model’ for the study of the effects of such a diet on plasma and membrane lipids.