Lower DHA Levels Research Articles

Transition from endogenous to exogenous feeding in longfin yellowtail Seriola rivoliana larvae under simultaneous effects of daily temperature fluctuation and rotifer Brachionus rotundiformis enrichment.

Temperature and nutrition are suggested as the primary factors affecting larval survival during the transition from endogenous to exogenous feeding in fish. However, little is known about its simultaneous impact during this period. In this study, Seriola rivoliana eggs were subjected to a constant 24°C (CTE) and a daily temperature fluctuation (DTF) between 22.8 and 25.2°C until oil droplet exhaustion (5.5days after hatching). On the other hand, marine fish larvae mostly rely on live feed, with certain nutritional deficiencies such as poor long-chain fatty acids. Thus, rotifer Brachionus rotundiformis enrichment was simultaneously evaluated with temperature using three enrichment diets: Ori-green, S.presso, and a Domestic emulsion. For this purpose, the five experimental groups were established in triplicate using six 100-L tanks with three 10-L containers inside (18 experimental units in total). One hundred eggs were incubated, using a green water system, and 10 rotifers mL-1 were offered at mouth opening. After oil droplet exhaustion, survival was only affected by temperature (P < 0.01), being higher at DTF compared to CTE. At the same stage, Domestic emulsion resulted in bigger larvae than Ori-green. In a further assay at 3.7 DAH, the relative expression of the trypsin gene was higher at Domestic emulsion compared to S.presso and Ori-green. This study indicates that daily temperature fluctuation can improve larval performance and low levels of EPA and DHA in Domestic emulsion enriched rotifers were not critical for Seriola rivoliana at first feeding.

Testing maternal effects of vitamin-D and omega-3 levels on offspring neurodevelopmental traits in the Norwegian Mother, Father and Child Cohort Study.

Maternal vitamin-D and omega-3 fatty acid (DHA) deficiencies during pregnancy have previously been associated with offspring neurodevelopmental traits. However, observational study designs cannot distinguish causal effects from confounding. First, we conducted Mendelian randomisation (MR) using genetic instruments for vitamin-D and DHA identified in independent genome-wide association studies (GWAS). Outcomes were (1) GWAS for traits related to autism and ADHD, generated in the Norwegian mother, father, and child cohort study (MoBa) from 3 to 8 years, (2) autism and ADHD diagnoses. Second, we used mother-father-child trio-MR in MoBa (1) to test causal effects through maternal nutrient levels, (2) to test effects of child nutrient levels, and (3) as a paternal negative control. Associations between higher maternal vitamin-D levels on lower ADHD related traits at age 5 did not remain after controlling for familial genetic predisposition using trio-MR. Furthermore, we did not find evidence for causal maternal effects of vitamin-D/DHA levels on other offspring traits or diagnoses. In the reverse direction, there was evidence for a causal effect of autism genetic predisposition on lower vitamin-D levels and of ADHD genetic predisposition on lower DHA levels. Triangulating across study designs, we did not find evidence for maternal effects. We add to a growing body of evidence that suggests that previous observational associations are likely biased by genetic confounding. Consequently, maternal supplementation is unlikely to influence these offspring neurodevelopmental traits. Notably, genetic predisposition to ADHD and autism was associated with lower DHA and vitamin-D levels respectively, suggesting previous associations might have been due to reverse causation.

Fatty acid content and profile of round sardinella (Sardinella aurita), an expanding thermophilic species in the NW Mediterranean

Over the past few decades, due to sea warming driven by global climate change, the habitat range of round sardinella (Sardinella aurita) has expanded into the north-western Mediterranean Sea. This study evaluates the fatty acid content and fatty acid profile of this small, warm-water pelagic fish caught in this area, specifically the northern Catalan coast. The findings provide important insights into the nutritional status of the species under changing environmental conditions. The study confirms that fatty acid content varies according to the individual specimen’s maturity stages (immature, pre-spawners, and spawners). Pre-spawners showed higher fat levels compared to spawners, whose lipids are allocated to their gonads to enhance the survival of their offspring. While a high content of omega-3 polyunsaturated fatty acids (n-3 PUFAs) was generally found at all stages of maturity, pre-spawners had higher levels of EPA but lower levels of DHA than immature individuals and spawners. Moreover, compared to small pelagic fish more typical of the temperate waters in the region (European anchovy, Engraulis encrasicolus, and European sardine, Sardina pilchardus), round sardinella generally have a higher level of PUFAs, especially DHA. Encouraging consumption of this warm water species could provide significant nutritional benefits while reducing fishing pressure on European sardine and European anchovy, whose populations are currently in a very poor state.

Dietary Level of the Omega-3 Fatty Acids EPA and DHA Influence the Flesh Pigmentation in Atlantic Salmon.

Atlantic salmon with a start weight of 53 g were fed diets with different levels of EPA and DHA or a diet with 1 : 1 EPA+DHA (0%, 1.0%, and 2.0% of the diet). At 400 g, all fish groups were mixed and equally distributed in new tanks and fed three diets with 0.2%, 1.0%, or 1.7% of EPA+DHA. At 1200 g, the fish were transferred to seawater pens where they were fed the same three diets until they reached a slaughter size of 3.5 kg. The fillet concentration of astaxanthin and its metabolite idoxanthin was analysed before transfer to seawater pens at 1200 g and at slaughter. The fatty acid composition in the fillet was also analysed at the same time points. Salmon fed low levels of EPA and DHA had lower fillet astaxanthin concentration and higher metabolic conversion of astaxanthin to idoxanthin compared to salmon fed higher dietary levels of EPA and/or DHA. DHA had a more positive effect on fillet astaxanthin concentrations than EPA. There were positive correlations between fillet DHA, EPA, sum N-3 fatty acids, and fillet astaxanthin concentration. A negative correlation was found between the concentration of N-6 fatty acids in the fillet and the astaxanthin concentration.

Roles of Lipids in Health and Disease.

This literature review is an update of the functions of lipids, with emphasis on their roles in health and disease conditions. Fats transport micronutrients and phytochemicals, thus raising their bioavailability. Fatty acids are needed to maintain brain integrity and function with omega-3 fatty acids being necessary for brain development during fetal and postnatal period upto about 2 years of age. Decosahexaenoic acid is required for optimal maturation of the retina and visual cortex, with visual acuity and mental development seemingly improved by extra DHA. Lipids regulate cell signalling, gene transcription and expression and govern all immune processes. Bioactive lipid mediators are generated from PUFAs, especially EPA, DHA and DPA. Eicosapentaenoic acid promotes antiplatelet aggregation and vasodilation, is anti-inflammatory and maintains plasma triglyceride levels low. Decosapentaenoic acid enables alterations in membrane structure and function, influences membrane protein function, cellular signalling and lipid mediator production. Low DHA levels have been linked to poor cognitive development and visual function, while DPA reduces platelet aggregation, improves lipid metabolism, endothelial cell migration, and resolution of chronic inflammation. Omega-3 PUFAs minimize bone mineral loss in old age and may prevent age-related macular degeneration and dry eye disease. However, the association of bone mineral density with n-3 fatty acid intake requires further research. Although immunomodulation through the essential fatty acids has shown promising results in the potential for lipids as therapeutic molecules, the mechanisms of action require further investigation. Lipid ratios are proving to be useful biomarkers for CVD, Alzheimer’s disease and diabetes.

Influence of dietary n‐3 polyunsaturated fatty acids (PUFAs) on growth, PUFA composition and the expression of FAD6 and ELOV5 in pacific white shrimp ( Litopenaeus vannamei )

Long-chain polyunsaturated fatty acids (LC-PUFAs) play crucial roles in growth, development and reproduction of Litopenaeus vannamei, one of the most important shrimp species cultivated in China in recent years. To investigate the effect of dietary n-3 PUFA composition on growth and the expression of LvFAD6 and LvELOV5 genes and fatty acid composition of this species, ten diets, which contain different levels of α-linolenic acid (C18:3 n-3, ALA), eicosapentaenoic acid (C20:5 n-3, EPA) and docosahexaenoic acid (C22:6 n-3, DHA), respectively, were prepared for the culture of this species lasting 42 days. The results showed that the identified cDNA sequence of fatty acyl desaturases 6 from L. vannamei (LvFAD6) was 739 bp, encoding a protein of 210 amino acids. The LvFAD6 peptide sequence possessed two histidine-rich motifs (QHHA and QIEHH), shared 96.6% identity with Apostichopus japonicus FAD6 and strongly clustered with FAD6 from A. japonicus and Octopus bimaculoides. The expression of LvFAD6 and LvELOV5 in muscle decreased with increase in dietary EPA, but increased with increase in dietary DHA. Dietary ALA has the potential to further increase the production of these health-beneficial LC-PUFAs in L. vannamei fed a diet with low levels of EPA and DHA, implying L. vannamei had the capacity to convert dietary ALA into EPA and DHA. These results suggest that the supplementation of ALA, EPA and DHA in diets for better growth of L. vannamei in ranges of 2.5% to 3.89%, 1.7% to 3.19% and 2.7% to 5.84% of total fatty acids respectively.

Maternal Docosahexaenoic Acid Status during Pregnancy and Its Impact on Infant Neurodevelopment.

Dietary components are essential for the structural and functional development of the brain. Among these, docosahexaenoic acid, 22:6n-3 (DHA), is critically necessary for the structure and development of the growing fetal brain in utero. DHA is the major n-3 long-chain polyunsaturated fatty acid in brain gray matter representing about 15% of all fatty acids in the human frontal cortex. DHA affects neurogenesis, neurotransmitter, synaptic plasticity and transmission, and signal transduction in the brain. Data from human and animal studies suggest that adequate levels of DHA in neural membranes are required for maturation of cortical astrocyte, neurovascular coupling, and glucose uptake and metabolism. Besides, some metabolites of DHA protect from oxidative tissue injury and stress in the brain. A low DHA level in the brain results in behavioral changes and is associated with learning difficulties and dementia. In humans, the third trimester-placental supply of maternal DHA to the growing fetus is critically important as the growing brain obligatory requires DHA during this window period. Besides, DHA is also involved in the early placentation process, essential for placental development. This underscores the importance of maternal intake of DHA for the structural and functional development of the brain. This review describes DHA’s multiple roles during gestation, lactation, and the consequences of its lower intake during pregnancy and postnatally on the 2019 brain development and function.

Assessment of dietary lipid sources in tropical gar,Atractosteus tropicuslarvae: Growth parameters and intermediary lipogenic gene expression

Five experimental diets containing different lipid sources, fish oil (D1), soybean lecithin (D2), corn oil (D3), canola oil (D4) and olive oil (D5), were evaluated in Atractosteus tropicus larvae for the relative gene expression of the enzymes fatty acid synthase (fas), acetyl‐CoA carboxylase 1 (acc1) and carnitine palmitoyltransferase 1C (cpt1c), in addition to their effects on larval growth, survival and cannibalism during a 30‐day feeding trial. Higher growth and survival were obtained in treatments D1 and D2, and lower performance in diets D3, D4 and D5. The highest levels of expression of fas and acc1 occurred in larvae fed with D1, which contained high amounts of n‐3 long‐chain polyunsaturated fatty acids (LC‐PUFA), mainly DHA and EPA FA are regulators of lipogenesis. The higher cpt1c expression in plant‐based diets is attributed to the fact that these diets are rich in α‐linolenic acid (ALA) and low DHA, EPA and ARA levels that favour s‐oxidation. In conclusion, the diets with fish oil (D1) and soybean lecithin (D2) were the best treatments for larval growth, survival and cannibalism and thus appear to meet both lipid and energy requirements of A. tropicus larvae, meanwhile the use of vegetable oils influences the expression of intermediary lipogenic genes.

Associations Between Systemic Omega-3 Fatty Acid Levels With Moderate-to-Severe Dry Eye Disease Signs and Symptoms at Baseline in the Dry Eye Assessment and Management Study.

Omega-3 (n-3) fatty acid supplementation is used to treat systemic inflammatory diseases, but the role of n-3 in the pathophysiology and therapy of dry eye disease (DED) is not definitive. We evaluated the relationship of systemic n-3 levels with signs and symptoms at baseline in the Dry Eye Assessment and Management (DREAM) Study. Blood samples from participants at baseline were analyzed for n-3 and n-6, measured as relative percentage by weight among all fatty acids in erythrocytes. Symptoms were evaluated using the Ocular Surface Disease Index. Signs including conjunctival staining, corneal staining, tear breakup time (TBUT), and Schirmer's test with anesthesia were also evaluated. There was no correlation between the systemic n-3 levels and DED symptoms. When the associations with signs of DED were assessed, lower DHA levels were associated with higher conjunctival staining, with mean scores of 3.31, 2.96, and 2.82 for low, medium, and high levels of DHA, respectively (linear trend P=0.007). None of the other signs were associated with DHA or the other measures of n-3. Previous studies have found varying results on the role of n-3 supplementation with the signs and symptoms of DED. Among patients with DED enrolled in the DREAM Study, lower systemic n-3 levels were not associated with worse symptoms and most signs of DED.

Status of nutrients important in brain function in phenylketonuria: a systematic review and meta-analysis

BackgroundDespite early and ongoing dietary management with a phe-restricted diet, suboptimal neuropsychological function has been observed in PKU. The restrictive nature of the PKU diet may expose patients to sub-optimal nutritional intake and deficiencies which may impact normal brain function. A systematic review of the published literature was carried out, where possible with meta-analysis, to compare the status of nutrients (Nutrients: DHA, EPA phospholipids, selenium, vitamins B6, B12, E, C, A, D, folic acid, choline, uridine, calcium, magnesium, zinc, iron, iodine and cholesterol) known to be important for brain development and functioning between individuals with PKU and healthy controls.ResultsOf 1534 publications identified, 65 studies met the entry criteria. Significantly lower levels of DHA, EPA and cholesterol were found for PKU patients compared to healthy controls. No significant differences in zinc, vitamins B12, E and D, calcium, iron and magnesium were found between PKU patients and controls. Because of considerable heterogeneity, the meta-analyses findings for folate and selenium were not reported. Due to an insufficient number of publications (< 4) no meta-analysis was undertaken for vitamins A, C and B6, choline, uridine, iodine and phospholipids.ConclusionsThe current data show that PKU patients have lower availability of DHA, EPA and cholesterol. Compliance with the phe-restricted diet including the micronutrient fortified protein substitute (PS) is essential to ensure adequate micronutrient status. Given the complexity of the diet, patients’ micronutrient and fatty acid status should be continuously monitored, with a particular focus on patients who are non-compliant or poorly compliant with their PS. Given their key role in brain function, assessment of the status of nutrients where limited data was found (e.g. choline, iodine) should be undertaken. Standardised reporting of studies in PKU would strengthen the output of meta-analysis and so better inform best practice for this rare condition.

Omega-3 Polyunsaturated Fatty Acids in Youths with Attention Deficit Hyperactivity Disorder: a Systematic Review and Meta-Analysis of Clinical Trials and Biological Studies.

The role of omega-3 polyunsaturated fatty acids (omega-3 or n-3 PUFAs) in the pathogenesis and treatment of children and adolescents with attention deficit hyperactivity disorder (ADHD) is unclear. A systematic review followed by meta-analysis was conducted on: (1) randomized controlled trials (RCTs) assessing the effects of n-3 PUFAs on clinical symptoms and cognition in children and adolescent with ADHD; and (2) case-control studies assessing the levels of n-3 PUFAs in blood and buccal tissues of children and adolescents with ADHD. In seven RCTs, totalling n=534 randomized youth with ADHD, n-3 PUFAs supplementation improves ADHD clinical symptom scores (g=0.38, p<0.0001); and in three RCTs, totalling n=214 randomized youth with ADHD, n-3 PUFAs supplementation improves cognitive measures associated with attention (g=1.09, p=0.001). Moreover, children and adolescents with ADHD have lower levels of DHA (seven studies, n=412, g=-0.76, p=0.0002), EPA (seven studies, n=468, g=-0.38, p=0.0008), and total n-3 PUFAs (six studies, n=396, g=-0.58, p=0.0001). In summary, there is evidence that n-3 PUFAs supplementation monotherapy improves clinical symptoms and cognitive performances in children and adolescents with ADHD, and that these youth have a deficiency in n-3 PUFAs levels. Our findings provide further support to the rationale for using n-3 PUFAs as a treatment option for ADHD.

EPA, DHA, and Lipoic Acid Differentially Modulate the n-3 Fatty Acid Biosynthetic Pathway in Atlantic Salmon Hepatocytes.

The aim of the present study was to investigate how EPA, DHA, and lipoic acid (LA) influence the different metabolic steps in the n-3 fatty acid (FA) biosynthetic pathway in hepatocytes from Atlantic salmon fed four dietary levels (0, 0.5, 1.0 and 2.0%) of EPA, DHA or a 1:1 mixture of these FA. The hepatocytes were incubated with [1-14C] 18:3n-3 in the presence or absence of LA (0.2mM). Increased endogenous levels of EPA and/or DHA and LA exposure both led to similar responses in cells with reduced desaturation andelongation of [1-14C] 18:3n-3 to 18:4n-3, 20:4n-3, and EPA, in agreement with reduced expression of the Δ6 desaturase gene involved in the first step of conversion. DHA production, on the other hand, was maintained even in groups with high endogenous levels of DHA, possibly due to a more complex regulation of this last step in the n-3 metabolic pathway. Inhibition of the Δ6 desaturase pathway led to increased direct elongation to 20:3n-3 by both DHA and LA. Possibly the route by 20:3n-3 and then Δ8 desaturation to 20:4n-3, bypassing the first Δ6 desaturase step, can partly explain the maintained or even increased levels of DHA production. LA increased DHA production in the phospholipid fraction of hepatocytes isolated from fish fed 0 and 0.5% EPA and/or DHA, indicating that LA has the potential to further increase the production of this health-beneficial FA in fish fed diets with low levels of EPA and/or DHA.

Fatty acid composition in the fillets of rainbow trout grown in different conditions

The aim of this study was to determine the influence of different feed composition and cultivation on the composition of fatty acids, their relationships, and the cholesterol content in the tissue of rainbow trout (Oncorhynchus mykiss). Trout were reared in ponds at two different altitudes and raised on different feeds. The total amount of monounsaturated fatty acids in fillets of both groups showed no statistically significant difference. However, higher levels of n‐6 fatty acids were found in Pond I trout fillets than in Pond II fillets, while Pond II fillets contained almost even amounts of n‐3 and n‐6 fatty acids. Total cholesterol content in Pond I trout fillets was significantly lower (p &lt; 0.05) than in Pond II fillets. The results indicate that the final composition of the trout fillets was mostly dependent on the feed the live fish had consumed; the altitude of the ponds had less effect. Also, both groups of trout could be used in the human diet as biologically valuable foods.Practical application: Our results show influence of altitude, feed, and fatty acid composition of feed on trout fillets. The average fatty acid level in the trout fillets increased in the order SFA &lt;MUFA &lt;PUFA. Trout fillets contain low levels of cholesterol but high levels of EPA, DPA, and DHA. These facts are important for fish industries and aquaculture producers to design a healthy food.The trout, although grown at two different altitudes, showed differences in their basic chemical composition and in their fatty acid composition which more tended to be related to the composition of their feed. Low cholesterol levels and high levels of EPA, DPA, and DHA, as well as reasonably favorable ratios of n‐3 and n‐6 fatty acids indicate that the trout from both groups could be suitable for use in the human diet as biologically valuable foods.

Can Senegalese sole post-larvae effectively grow on low dietary DHA and lipid levels during weaning?

Senegalese sole (Solea senegalensis) is a highly-valuable flatfish species with interest for diversification of aquaculture in Mediterranean countries. Unlike other fish species known to have a high dietary DHA requirement during the larval stage, several studies have suggested dietary DHA could play a minor role for Senegalese sole during the early developmental stages. This suggestion was recently supported by studies that indicated an ability of Senegalese sole to biosynthesise DHA from its precursors during the larval period. However, it is still uncertain if Senegalese sole post-larvae can effectively grow on low dietary DHA levels during weaning. Moreover, recent studies focusing on the juvenile phase of Senegalese sole have suggested a possible impairment of this species to efficiently digest or absorb high dietary lipid levels. Yet, if a reduction of dietary lipid levels would affect a normal development of Senegalese sole during the early stages remains to be established. Therefore, this study aimed at determining if a reduction of dietary DHA and lipid levels would affect Senegalese sole performance and lipid metabolism during weaning and post-larval period. In this study, Senegalese sole post-larvae were reared according to four dietary treatments: low lipid levels (treatments LFAT and LFAT_DHA) and moderate lipid levels (MODFAT and MODFAT_DHA). DHA levels in LFAT_DHA and MODFAT_DHA diets were higher than in LFAT and MODFAT diets, respectively. Subsequently, effects of experimental diets on Senegalese sole post-larval growth, survival, fatty acid composition and histopathological condition of intestinal and liver tissues were evaluated. Results showed that feeding on diets with low DHA and lipid levels significantly reduced the growth performance of Senegalese sole post-larvae. However, at the end of the experimental period, no significant differences were observed for post-larval survival in response to dietary treatments. In overall, this study disadvises that weaning diets for Senegalese sole post-larvae should contain low DHA and lipid levels, as a reduction of these levels may compromise post-larval growth performance. Statement of relevanceDetermining essential fatty acid requirements in marine fish larvae is of utmost importance for the aquaculture industry, contributing to fulfil the growth potential of farmed species. In the case of Senegalese sole, a highly valued species farmed in Mediterranean countries, it may have the capacity to biosynthesise DHA from its precursors during the larval stage. However, the inclusion of DHA-rich oils in weaning diets is costly, considerable savings could be achieved by replacing DHA-rich oils by common fish oils in weaning diets for this species. Furthermore, Senegalese sole has also been shown a poor ability to deal with high dietary lipid levels during the juvenile stage. However, no studies have addressed this capacity in Senegalese sole larvae. This study comprises an evaluation on the effects of reducing dietary DHA and lipid levels during Senegalese sole weaning by integrating an assessment of these effects on post-larval growth, survival, fatty acid composition and histopathological condition.

Minor lipid metabolic perturbations in the liver of Atlantic salmon (Salmo salar L.) caused by suboptimal dietary content of nutrients from fish oil.

The present study was conducted to evaluate the effects on Atlantic salmon hepatic lipid metabolism when fed diets with increasing substitution of fish oil (FO) with a vegetable oil (VO) blend. Four diets with VOs replacing 100, 90, 79 and 65% of the FO were fed for 5months. The levels of eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) in the experimental diets ranged from 1.3 to 7.4% of fatty acids (FAs), while cholesterol levels ranged from 0.6 to 1.2gkg(-1). In hepatocytes added [1-(14)C] α-linolenic acid (ALA, 18:3n-3), more ALA was desaturated and elongated to EPA and DHA in cells from fish fed 100% VO, while in fish fed 65% VO, ALA was elongated to eicosatrienoic acid (ETE; 20:3n-3), indicating reduced Δ6 desaturation activity. Despite increased desaturation activity and activation of the transcription factor Sp1 in fish fed 100% VO, liver phospholipids contained less EPA and DHA compared with the 65% VO group. The cholesterol levels in the liver of the 100% VO group exceeded the levels in fish fed the 65% VO diet, showing an inverse relationship between cholesterol intake and liver cholesterol content. For the phytosterols, levels in liver were generally low. The area as a proxy of volume of lipid droplets was significantly higher in salmon fed 100% VO compared with salmon fed 65% VO. In conclusion, the current study suggests that suboptimal dietary levels of cholesterol in combination with low levels of EPA and DHA (1.3% of FAs) can result in minor metabolic perturbations in the liver of Atlantic salmon.

Polyunsaturated Fatty Acids Are Associated With Behavior But Not With Cognition in Children With and Without ADHD: An Italian study

Objective: This study aimed to investigate the relationship between polyunsaturated fatty acids (PUFAs) status, cognitive, and behavioral traits of ADHD in school-aged children. Method: Seventy-three children with and without ADHD were assessed with cognitive tasks and behavioral rating scales including quality of life and global functioning at baseline of an intervention trial (clinicaltrials.gov NCT01796262). Correlation analyses were performed between the cognitive tasks/behavioral ratings and blood PUFA levels. Results: Children with ADHD had lower levels of DHA, omega-3 index, and total PUFA. PUFAs were positively associated with behavior but not consistently related to cognitive domains. Conclusion: The present study confirms that children with ADHD display abnormal fatty acid profiles within an Italian setting. Furthermore, PUFAs were associated with behavior but not with cognition. Accordingly, for the first time, lower blood levels of PUFA were associated not only with symptoms of ADHD but also with a poorer quality of life.

Circulating n-3 fatty acids and trans-fatty acids, PLA2G2A gene variation and sudden cardiac arrest.

Whether genetic factors influence the associations of fatty acids with the risk of sudden cardiac arrest (SCA) is largely unknown. To investigate possible gene-fatty acid interactions on SCA risk, we used a case-only approach and measured fatty acids in erythrocyte samples from 1869 SCA cases in a population-based repository with genetic data. We selected 191 SNP in ENCODE-identified regulatory regions of fifty-five candidate genes in fatty acid metabolic pathways. Using linear regression and additive genetic models, we investigated the association of the selected SNP with erythrocyte levels of fatty acids, including DHA, EPA and trans-fatty acids among the SCA cases. The assumption of no association in non-cases was supported by analysis of publicly available datasets containing over 8000 samples. None of the SNP-fatty acid associations tested among the cases reached statistical significance after correction for multiple comparisons. One SNP, rs4654990 near PLA2G2A, with an allele frequency of 0·33, was nominally associated with lower levels of DHA and EPA and higher levels of trans-fatty acids. The strongest association was with DHA levels (exponentiated coefficient for one unit (1% of total fatty acids), 0·90, 95% CI 0·85, 0·97; P=0·003), indicating that for subjects with a coded allele, the OR of SCA associated with one unit higher DHA is about 90% what it is for subjects with one fewer coded allele. These findings suggest that the associations of circulating n-3 and trans-fatty acids with SCA risk may be more pronounced in carriers of the rs4654990 G allele.

Dietary fatty acids affect semen quality: a review.

Mammalian spermatozoa are characterized by a high proportion of polyunsaturated fatty acids (PUFA) which play a crucial role in fertilization. This review focuses on analysis of sperm fatty acid profiles and the effects of omega-3, saturated and trans dietary and sperm fatty acids on sperm parameters. Two major points have been pivotal points of investigation in the field of sperm fatty acid profiles: first, the comparison between fatty acid profiles of fertile and infertile men and second, the effect of dietary fatty acids on sperm fatty acid profiles as well as sperm quality and quantity. Docosahexaenoic acid (DHA, C22:6n-3), and palmitic acid (C16:0) are the predominant PUFA and saturated fatty acids, respectively, in human sperm cells. Higher levels of DHA are concentrated on the sperm's head or tail varying among different species. However, the human sperm head contains a higher concentration of DHA. Dietary fatty acids influence on sperm fatty acid profiles and it seems that sperm fatty acid profiles are most sensitive to dietary omega-3 PUFA. Although improvements in sperm parameters are a response to omega-3 sources after more than 4 weeks of supplementation in the male diet, time-dependent and dose-dependent responses may explain the failure in some experiments. In human spermatozoa, elevated saturated or trans fatty acid concentration and a low DHA level is a concern. The regulations of the sperm fatty acid mean melting point as well as expression regulation of peroxisome proliferator-activated receptor gamma (PPARG) alongside with spermatozoon assembly, anti-apoptosis effects, eicosanoid formation, and hormone activity are the putative key factors that induce a response by inclusion of omega-3 PUFA.

Oral consumption of α-linolenic acid increases serum BDNF levels in healthy adult humans

Background aimsDietary omega-6 and omega-3 fatty acids have remarkable impacts on the levels of DHA in the brain and retina. Low levels of DHA in plasma and blood hamper visual and neural development in children and cause dementia and cognitive decline in adults. The level of brain-derived neurotrophic factors (BDNF) changes with dietary omega-3 fatty acid intake. BDNF is known for its effects on promoting neurogenesis and neuronal survival.MethodsIn this study, we examined the effect of the oral consumption of α-Linolenic acid (ALA) on blood levels of BDNF and Malondialdehyde (MDA) in healthy adult humans. 30 healthy volunteers, 15 men and 15 women, were selected randomly. Each individual served as his or her own control. Before consuming the Flaxseed oil capsules, 5cc blood from each individual was sampled in order to measure the plasma levels of BDNF and MDA as baseline controls. During the experiment, each individual was given 3 oral capsules of flaxseed oil, containing 500mg of alpha linolenic acid, daily for one week. Then, plasma levels of BDNF and MDA were tested.ResultsThe plasma levels of BDNF and MDA significantly (P < 0.05) increased in individuals who received the oral capsules of ALA. Plasma levels of BDNF increased more in the women in comparison with the men.ConclusionALA treatment could be a feasible approach to reduce size of infarcts in stroke patients. Thus, ALA could be used in adjunction with routine stroke therapies to minimize brain lesions caused by stroke.

Dietary LC-PUFA deficiency early in ontogeny induces behavioural changes in pike perch (Sander lucioperca) larvae and fry

Abstract This study examined whether dietary supply of DHA and phospholipids during early ontogeny affected the outcome of behavioural challenges in pike perch larvae and fry, and whether the history of lipid nutrition carried over in long-term effects on learning ability. Pike perch larvae were fed Artemia enriched with either refined olive oil high in oleic acid (A); refined olive oil supplemented with a low (B) or a high (C) level of DHA; or refined olive oil acid supplemented with fish oil with a high content of phospholipids (PL) and DHA (D). The enriched live diets were provided until 28 days post hatch (dph), at which time larval behavioural responses to visual and mechano-sensory stimuli were assessed. All dietary groups were subsequently fed an identical enriched live feed (diet D) and gradually weaned to an extruded dry feed, on which they were maintained for 112 days. At the end of this period, assessment of fry avoidance behaviour was repeated and individuals were tested for spatial learning ability in a maze. At the larval stage, individuals maintained on Artemia rich in DHA showed a 5–8 fold increase in swimming speed when subjected to a visually simulated predator test, a response that was not observed for larvae on diets low in DHA content. Independent of the predator simulation, larvae deficient or low in DHA exhibited significantly more time swimming along the edge of a test arena and had overall higher locomotor activities compared to larvae fed a diet with a high DHA content. Larvae on DHA rich diets showed an ability to achieve significantly higher peak acceleration rates during the escape response, which was maintained at 112 dph. Time spent locating the exit of a maze decreased with repetitious training sessions, although fish fed diets low in DHA spent longer time in the maze, caused by extended periods of inactivity or “freezing” behaviour (time lag) prior to the onset of active searching behaviour. The consistency of behavioural responses to mechano-sensory stimuli in larvae and fry suggests long-term effects on the neuromuscular path-way involved in escape responses. A longer period of freezing in the learning test may reflect a more anxious and fragile behaviour profile in fish fed low levels of DHA. Further studies should aim at verifying whether this affects performance related traits, such as immune competence and robustness.