Source Of Docosahexaenoic Acid Research Articles

Influence of cooking methods and storage time on colour, texture, and fatty acid profile of a novel fish burger for the prevention of cognitive decline

Western diets are poor in healthy n-3 polyunsaturated fatty acids (n-3 PUFA), namely eicosapentaenoic (EPA) and docosahexaenoic acid (DHA), iodine (I), and other nutrients that may protect against cognitive ageing. Given DHA richness in chub mackerel (Scomber colias), high vitamin B9 levels in quinoa (Chenopodium quinoa), and I abundance in the seaweed Saccorhiza polyschides, a functional hamburger rich in these nutrients by using these ingredients was developed. This research focused on the factors affecting its quality by examining the impact of cooking (steaming at 100 °C, roasting at 180 °C, grilling at 180 °C) and storage time (after 4 and 6 months at −20 °C) upon the product's properties.Cooking treatments were found to influence the burger's colour and texture, whereas storage duration impacted FA levels and the polyene index. Cooked burgers presented lighter (L*, 45.1–55.0 vs 36.9 ± 2.4) and more yellow colouration (b*, 15.8–17.8 vs 13.6 ± 1.0) than raw burgers. Cooked burgers also exhibited higher textural values across various parameters than their raw versions. Grilled burgers (excluding initial time) were firmer (50.0 ± 5.1 N) than those cooked otherwise (37.0–39.9 N). Regarding FA levels, a decrease in DHA was recorded after four months (21.8–23.0% vs 26.4–30.6%). The polyene index followed a similar trajectory, declining from 2.6 to 3.6 initially to 1.8–1.9 in the fourth month. Hence, the studied mackerel burger could be a promising source of EPA, DHA, and other n-3 PUFAs in human diets, optimally with a frozen storage duration of fewer than four months to preserve nutritional integrity.

Contribution of elovl5a to Docosahexaenoic Acid (DHA) Synthesis at the Transcriptional Regulation Level in Common Carp, Cyprinus carpio.

Docosahexaenoic acid (DHA) is an essential nutrient for humans and plays a critical role in human development and health. Freshwater fish, such as the common carp (Cyprinus carpio), have a certain degree of DHA biosynthesis ability and could be a supplemental source of human DHA needs. The elongase of very-long-chain fatty acid 5 (Elovl5) is an important enzyme affecting polyunsaturated fatty acid (PUFA) biosynthesis. However, the function and regulatory mechanism of the elovl5 gene related to DHA synthesis in freshwater fish is not clear yet. Previous studies have found that there are two copies of the elovl5 gene, elovl5a and elovl5b, which have different functions. Our research group found significant DHA content differences among individuals in Yellow River carp (Cyprinus carpio var.), and four candidate genes were found to be related to DHA synthesis through screening. In this study, the expression level of elovl5a is decreased in the high-DHA group compared to the low-DHA group, which indicated the down-regulation of elovl5a in the DHA synthesis pathways of Yellow River carp. In addition, using a dual-luciferase reporter gene assay, we found that by targeting the 3'UTR region of elovl5a, miR-26a-5p could regulate DHA synthesis in common carp. After CRISPR/Cas9 disruption of elovl5a, the DHA content in the disrupted group was significantly higher than in the wildtype group; meanwhile, the expression level of elovl5a in the disrupted group was significantly reduced compared with the wildtype group. These results suggest that elovl5a may be down-regulating DHA synthesis in Yellow River carp. This study could provide useful information for future research on the genes and pathways that affect DHA synthesis.

The characteristics of PUFAs-rich virgin fish oil as affected by size of tuna eye

Abstract. Trilaksani W, Riyanto B, Ramadhan W, Sinulingga F, Fauziah S. 2023. The characteristics of PUFAs-rich virgin fish oil as affected by size of tuna eye. Biodiversitas 24: 6545-6556. The food supplement market expects growth in demand for long-chain omega-3 fatty acids, particularly Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA), which play crucial for brain development and can lower the chances of health issues like depression, Myocardial Infarction (MI), thromboembolism, and cardiac arrhythmias, and have anti-viral effects, boosting the immune system during the pandemic. Therefore, to meet this demand, exploring new sources is crucial. Tuna eyes have emerged as a potential source of DHA; however, quality and standardized sizes pose a challenge as they are by-products. The purpose of this research was to determine how the eye size of tuna affected the quality and yield of fish oil, which is a novel source of omega-3 fatty acids. This study determined the virgin oil profile of tuna eyes, which met the quality standards. The investigation covered morphology, chemical composition, heavy metal content, oil yield and quality, fatty acid composition, and related health lipid indices (Atherogenicity Index (AI) and Thrombogenicity Index (TI)). For the size specifications, tuna eyes were classified into three groups based on their diameter, namely 'small' (<6 cm), 'medium' (6-9 cm), and 'large' (>9 cm). The results showed that eye size directly influenced the weight, fat content, and oil yield, with negligible disparity in chemical composition except for the fat content; the larger the eyes, the higher the oil yield. Tuna eye oil had a safe composition for consumption with low or undetected heavy metals, the oil's oxidative level met CODEX standards, and the fatty acid profile revealed DHA as the most abundant fatty acid, reaching 36.95%. The predominance of n-3 series values in the fatty acid composition of tuna's eye was 9-12 times greater than that of n-6 fatty acid values. The values of AI and TI were 0.33 and 0.12; 0.47 and 0.20; 0.55 and 0.20 for large, small, and medium eyes, respectively. The study highlights tuna eyes' unique characteristics and potential applications in the food supplement industry.

Athletes Can Benefit from Increased Intake of EPA and DHA—Evaluating the Evidence

Fatty fish, which include mackerel, herring, salmon and sardines, and certain species of algae (e.g., Schizochytrium sp., Crytthecodiniumcohnii and Phaeodactylumtricornutum) are the only naturally rich sources of the omega-3 polyunsaturated fatty acids (n-3 PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA and DHA are the most biologically active members of the n-3 PUFA family. Limited dietary sources and fluctuating content of EPA and DHA in fish raise concerns about the status of EPA and DHA among athletes, as confirmed in a number of studies. The beneficial effects of EPA and DHA include controlling inflammation, supporting nervous system function, maintaining muscle mass after injury and improving training adaptation. Due to their inadequate intake and beneficial health-promoting effects, athletes might wish to consider using supplements that provide EPA and DHA. Here, we provide an overview of the effects of EPA and DHA that are relevant to athletes and discuss the pros and cons of supplements as a source of EPA and DHA for athletes.

Use of Genetically Modified Canola Oil as a Replacement for Fish Oil in Practical Diets for Whiteleg Shrimp Litopeneaus vannamei Reared in Green Water Conditions

With current advancements in technology allowing for genetic modification of crops, canola has been modified to contain n3 long-chain polyunsaturated fatty acids such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). The purpose of this study was to determine the efficacy of using genetically modified canola oil as a DHA and EPA replacement for Menhaden fish oil (FO) in practical diets for Pacific white shrimp Litopeneaus vannamei. This trial was conducted using twenty-four 750 L tanks stocked at 40 shrimp per tank (0.1 ± 0.007 g initial weight) and grown for 63 days. Shrimp were fed one of five experimental diets (36% protein, 8% lipid) with supplemental FO replacement varying from 75% to 100% twice daily (7 a.m. and 7 p.m.). Two of the diets contained 15% fishmeal (FM) as the basal protein source, while the other three diets were FM free, allowing for complete removal of DHA sources in the basal formulation. While basal FO was removed, none of the experimental diets were completely devoid of FO. Shrimp were harvested and frozen after 9 weeks to be used for lipid extraction and taste and texture analysis by an untrained panel to mimic consumer responses. Results were subjected to a two-way analysis of variance, with significant differences observed in final mean weight (8.47–10.59 g) ( p = 0.0275 ), individual weight gain (8.37–10.48 g) ( p = 0.0279 ), and weekly gain (0.84–1.05 g) ( p = 0.0378 ). Human sensory analysis did not yield significant differences between measured taste parameters ( p > 0.05 ). Lipid extraction and analysis results showed that fatty acid concentrations from whole shrimp samples correlate with diet lipid profiles except for EPA. There is no significant difference ( p > 0.05 ) in EPA concentrations in whole shrimp samples regardless of diet. These results suggest that Latitude™ oil can be successfully used as a partial replacement for FO in commercial shrimp diets.

Trends in dietary intake and food sources of long-chain polyunsaturated fatty acids among Korean adults between 2007 and 2018.

This study examined trends in the dietary intake and food sources of long-chain polyunsaturated fatty acids (LC-PUFAs) in Korean adults from 2007 to 2018. In total, 46,307 adults (aged 19-64 years) were selected from the 2007-2018 Korea National Health and Nutrition Examination Surveys. Dietary data were obtained using 24-hour dietary recall. Intake levels and food sources of LC-PUFAs, including alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and linoleic acid (LA), were evaluated across the survey years and assessed based on compliance with dietary recommendations over the 2007-2018 period. Linear trends in LC-PUFAs intake levels over time were examined through multiple linear regression analysis. From 2007 to 2018, ALA and LA consumption increased from 1.1 g (0.5% of energy) to 1.4 g (0.6% of energy) and from 8.6 g (3.9% of energy) to 10.0 g (4.5% of energy), respectively. EPA intake decreased from 0.14 g to 0.12 g, and EPA+DHA intake showed a decreasing trend. The proportion of individuals who did not meet the recommended intake of EPA+DHA (250 mg/day) increased (64.4 to 68.4%). Regarding changes in food sources of ALA and LA, the contributions from mayonnaise, eggs, and bread increased, while those from plant food sources decreased. Among food sources of EPA and DHA, anchovy, saury, and Atka mackerel showed lower contributions over time. Our findings suggest that strategies to encourage the consumption of EPA and DHA from healthy food sources are necessary to improve cardiovascular health in the Korean population.

OMEGA-3 FATTY ACIDS ARE ASSOCIATED WITH DECREASED PRESENCE AND SEVERITY OF DIABETIC RETINOPATHY: A Combined Analysis of MESA and GOLDR Cohorts.

Inflammation is associated with diabetic retinopathy development and progression, and previous studies have demonstrated that omega-3 polyunsaturated fatty acids have anti-inflammatory properties. Therefore, the goal of this study was to determine if omega-3 polyunsaturated fatty acids, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), are associated with decreased risk and severity of retinopathy in individuals with type 2 diabetes. In a combined population of 1,356 individuals with type 2 diabetes from the Multi-Ethnic Study of Atherosclerosis and Genetics of Latino Diabetic Retinopathy cohorts, odds ratios using logistic regression were determined to assess the association between polyunsaturated fatty acids and retinopathy. In 1,356 participants with type 2 diabetes, individuals in the fourth quartile of DHA were 17% less likely to have retinopathy compared with the first quartile ( P = 0.009, CI: 0.72-0.95). Secondary analysis revealed 38% lower severity of retinopathy in individuals in the fourth quartile compared with the first quartile of DHA ( P = 0.006; CI: 0.44-0.87) and EPA + DHA ( P = 0.004; CI: 0.44-0.85). No significant associations were observed between EPA and retinopathy. DHA is inversely associated with the presence and severity of diabetic retinopathy. Increased intake of dietary sources of DHA may provide some protection against retinopathy in individuals with type 2 diabetes and warrants more research as a preventative option.

Effect of a parenteral fish-oil-containing lipid emulsion on liver lipid perioxidation and antioxidative defenses in Lewis rats.

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), naturally abundant in fish oil (FO), are known for their anti-inflammatory and potential antioxidant properties. The aim in this article is to evaluate the effect of the infusion of a parenteral FO-containing lipid emulsion on markers of liver lipid peroxidation and oxidative stress in rats undergoing central venous catheterization (CVC). After 5-day acclimatization, adult Lewis rats (n = 42) receiving a 20-g/day AIN-93M oral diet were randomly subdivided into four groups: (1) basal control (BC) (n = 6), without CVC or LE infusion; (2) SHAM (n = 12), with CVC but without LE infusion; (3) soybean oil (SO)/medium-chain triglyceride (MCT) (n = 12), with CVC and receiving LE without FO (4.3 g/kg fat); and (4) SO/MCT/FO (n = 12), with CVC and receiving LE containing 10% FO (4.3 g/kg fat). Animals from the BC group were euthanized immediately after acclimatization. The remaining groups of animals were euthanized after 48 or 72 h of surgical follow-up to assess profiles of liver and plasma fatty acids by gas chromatography, liver gene transcription factor Nrf2, F2-isoprostane lipid peroxidation biomarker, and the antioxidant enzymes glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) by enzyme-linked immunosorbent assay. R program (version 3.2.2) was utilized for data analysis. Compared with the other groups, liver EPA and DHA levels were higher in the SO/MCT/FO group, which also showed the highest liver Nrf2, GPx, SOD, and CAT levels and lower liver F2-isoprostane (P < 0.05). Experimental delivery of FO via EPA and DHA sources in a parenteral LE was associated with a liver antioxidant effect.

Utilizing lipidomics and fatty acid synthase inhibitors to explore lipid accumulation in two thraustochytrid species

Thraustochytrids are marine protists with an excellent ability to produce health-beneficial docosahexaenoic acid (DHA)-rich lipids. Since the demand for DHA sources for food and feed is increasing, a deeper understanding of the potential to enhance the DHA-production in thraustochytrids is important for a sustainable DHA supply. In most thraustochytrids, including the strains used in this work, DHA is synthesized by a polyketide synthase-like pathway (PKS), and not through the common fatty acid synthetase (FAS) pathway. Both pathways use the same precursors. The aim of this study was to determine if inhibiting the production of fatty acids (FA) through the FAS pathway under nitrogen starvation would result in higher net DHA production rates measured as DHA content, and if the channeling of the synthesized fatty acids to different lipids species is similar in two different thraustochytrid strains. We found that the DHA production rates in Aurantiochytrium limacinum SR21 and Aurantiochytrium sp. T66 were not affected when treated with the FAS-inhibitor cerulenin, despite a reduction of FAS-derived FAs. This indicates that precursor availability is less likely to be the limiting factor for DHA synthesis. Still, cerulenin-treatment in the lipid accumulation phase resulted in higher concentrations of the triacylglycerol (TAG) TG(22:6/22:6/22:6) than in the untreated cells after three hours, demonstrating that FAS inhibition is a possible strategy to enhance the content of DHA-rich lipids. Moreover, the relatively high abundance of the diacylglycerol DG(22:6/22:6) suggests the presence of an obstacle for using DG(22:6/22:6) as substrate to synthesize DHA-rich TAGs, a step that potentially can be improved by metabolic engineering.

Lipid translocation in the omega-3 fatty-acid transporter MFSD2A.

The omega-3 fatty-acid docosahexaenoic acid (DHA) is a key component of cellular membranes in the central nervous system (CNS) and essential for neurological functions. In human cerebral cortex, DHA contributes to around 25% of total fatty acids. Deficiency of DHA results in several CNS-related disorders, such as memory deficits, dyspraxia, and dyslexia. The major source of DHA in the brain is obtained from the diet and transported in the form of lysophosphatidylcholine (LPC) across the blood-brain-barrier (BBB) by MFSD2A in a Na+-dependent manner. The detailed transport mechanism of LPC across the lipid bilayer is still elusive. Here, by using single particle cryo-EM, we revealed the structure of Danio rerio MFSD2A (59 kDa) in a complex with FAB in the inward-open conformation with ligands bound to amphipathic pockets between N- and C-terminal domains at 2.9 Å. Multiple MFSD2A structures with individual ligands located at unique positions along the translocation pathway were further identified by extensive classification of particles. These structures depicted the DHA-LPC translocating trajectory along the cavity, where a ∼70 degree rotation of LPC headgroup followed by translation of the ligand towards the cytoplasmic exit occurred after the initial lipid flipping step. Together these results provide a detailed model for omega-3 fatty-acid transport and potential for the design of the delivery strategies for amphipathic drugs across the BBB.

Omega-3 and Omega-6 Polyunsaturated Fatty Acid Intakes, Determinants and Dietary Sources in the Spanish Population: Findings from the ANIBES Study.

The multiple roles of polyunsaturated fatty acids (PUFA) in growth and general health are well documented. However, available intake data for the Spanish population are limited and lack gender and age considerations. Therefore, our goal was to assess dietary intake adequacy of omega-3 and omega-6 PUFA, their determinants and their major food sources among the Spanish population. Due to their influence on various beneficial functions attributed to omega-3 PUFA, combined intake adequacy with folic acid (FA), vitamin B₁₂ and choline was also assessed. Intake data were obtained from the ANIBES cross-sectional study on a representative sample of the Spanish population (9-75 years; n = 2009), where dietary intake was analysed with a three-day dietary record. Median intake of total omega-3 PUFA stood at 0.81 g/day (0.56-1.19 g/day), with α-linolenic acid (ALA) at 0.61 g/day (0.45-0.85 g/day), eicosapentaenoic acid (EPA) at 0.03 g/day (0.01-0.12 g/day) and docosahexaenoic acid (DHA) at 0.06 g/day (0.0-0.20 g/day). Accordingly, 65% of the Spanish population showed insufficient intakes for total omega-3 PUFA; 87% for ALA, and 83% for combined EPA and DHA. Inadequate intakes were significantly higher in children, adolescents, and younger women of childbearing age (18-30 years). In contrast, inadequacy due to excessive intakes was almost negligible. Regarding omega-6 PUFA, total intake was 10.1 g/day (7.0-14.0 g/day), 10.0 g/day (6.9-13.9 g/day) for linoleic acid (LA) and 0.08 g/day (0.05-0.13 g/day) for arachidonic acid (AA). Non-compliance due to either insufficient or excessive intakes of LA stood at around 5% of the sample, with the elderly showing significantly higher degrees of inadequacy due to insufficient intakes (10%; p ≤ 0.05). Median omega-6 to omega-3 ratio was 12:1, and significantly higher in men compared to women (p ≤ 0.05); in children, adolescents and adults compared to the elderly (p ≤ 0.05); and in younger women of childbearing age compared to the older group (31-45 years) (p ≤ 0.001). Oils and fats and meat and meat products were the main dietary sources for the essential fatty acids LA and ALA, respectively. Meat and meat products were as well the main providers of AA, while fish and shellfish were almost exclusively the only sources of EPA and DHA. However, main food sources identified showed important differences across age groups. Finally, the total combined degree of inadequacy observed for omega-3 PUFA, FA, vitamin B₁₂ and choline reached 21.3% of the ANIBES population. The observed degree of inadequacy of omega-3 PUFA intakes among the Spanish population makes it urgent to increase its consumption and to consider the need for supplementation. This should also be the main strategy for the optimization of the omega-6/omega-3 ratio, as the adequacy observed for omega-6 intakes is relatively acceptable. Additional improvement of the dietary intake of FA, vitamin B12 and choline could contribute to the beneficial effects of omega-3 PUFA.

Dietary Betaine Interacts with Very Long Chain n-3 Polyunsaturated Fatty Acids to Influence Fat Metabolism and Circulating Single Carbon Status in the Cat.

Simple SummaryThe domestic cat can metabolize and thrive on a range of intakes of different dietary polyunsaturated fatty acids (PUFA). However, changes in the intake of PUFA have relatively unknown effects on concentrations of other fatty acids and metabolites. Similarly, the effect of increasing dietary betaine (which is a single carbon donor) on circulating concentrations of metabolites and fatty acids is relatively unreported. As might be expected, increasing intake of specific dietary fatty acids resulted in an increased concentration of that fatty acid and moieties containing that fatty acid. Dietary betaine increased concentration of many compounds associated with single carbon metabolism (e.g., dimethyl glycine, sarcosine, methionine) and many PUFA such as the n-6 PUFA linoleic acid (LA) and arachidonic acid (ARA) and the n-3 fatty acids α-linolenic acid (αLA), and docosahexaenoic acid (DHA). Dietary betaine interacted with the addition of dietary fish oil to dampen diet-induced increase of ARA while potentiating the increase of circulating DHA occurring with increased DHA dietary intake. Dietary betaine and fish oil also combined to reduce the circulating concentration of the renal toxin 3-indoxyl sulfate, suggesting a positive effect on the gut microbiota. These data suggest a positive effect of a daily betaine intake which exceeds 60 mg per kg body weight. The data also support an added benefit of a combined EPA+DHA daily intake of greater than 26 mg/kg body weight as well as a daily intake of 75 mg/kg body weight of alpha linolenic acid.Six foods were used to evaluate the interaction of dietary betaine and n-3 PUFA in the cat. There was no ingredient added to the control food to specifically increase betaine or n-3 fatty acids. The experimental design was a 3 × 2 factorial (fatty acids were varied from the control food which had no added source of n-3 fatty acids, flax was included as a source of 18 carbon n-3, or menhaden fish oil as a source of EPA and DHA). Foods were then formulated using these three foods as a base with added betaine or without added betaine. Forty eight cats were used in this study. Equal numbers of cats were allotted by age and gender to each of the six dietary treatments. The cats were offered food amounts to maintain weight and consumed the food to which they were assigned for the length of the study (60 days). Metabolomics, selected circulating analytes and fatty acids were analyzed at the beginning and end of the feeding period. There was an increase in single carbon metabolites (betaine, dimethyl glycine, and methionine) with the consumption of dietary betaine. Betaine also increased the concentration of specific PUFA (ARA, αLA, DHA, and the sum of all circulating PUFA). The combination of dietary betaine and fish oil resulted in a reduction of circulating 3-indoxyl sulfate which suggests a renal benefit from their combined dietary presence.

Realised genetic gains on growth, survival, feed conversion ratio and quality traits after ten generations of multi-trait selection in rainbow trout Oncorhynchus mykiss, fed a standard diet or a “future” fish-free and soy-free diet

There is limited scientific evidence on the real impact of selective breeding in aquaculture on the medium term, while the composition of aquafeeds is rapidly evolving towards plant-based raw materials. We compared a rainbow trout line selected in freshwater for fillet production (improved growth, carcass yield and fillet fat) for ten generations (G10) with an unselected control line from the same base population (G0). We crossed G10 and G0 neomales to the same G10 females, thus creating a Selected and a Control group expected to diverge by half the true difference between G0 and G10. Those were grown to 1.6 kg, and two feeds were compared across the two lines from 264 to 374 days post-hatching. One was a commercial standard, the second was a “future” feed devoid of fishmeal, fish oil and soy-based products, with microalgae as a source of docosahexaenoic acid (DHA). After doubling the difference between the Selected and the Control to estimate the true performance of G0, we saw that G10 was improved relative to G0 for body weight (+61%), feed conversion ratio (−17 to −20%), fillet fat (+28–53%) and carcass yield (+4.2%), but not for fillet yield. Survival was not affected by selection. Both feeds had a similar performance in terms of growth, but the future feed showed a higher FCR, probably due to a feed intake measurement issue. Fish had a good EPA+DHA content (>1.2 g/100 g wet weight) with both feeds, partly linked to endogenous synthesis of these fatty acids. There was little if any genotype by feed interaction. This study shows that selective breeding can produce fast growing, feed efficient and thus provide opportunity for more sustainable fish culture. We showed that highly nutritious fish can be produced with good growth performance without using any fish meal, fish oil or soy-based product.

The Biorefinery of the Marine Microalga Crypthecodinium cohnii as a Strategy to Valorize Microalgal Oil Fractions

Chrypthecodinium cohnii lipids have been almost exclusively used as a source of Docosahexaenoic acid (DHA). Such an approach wastes the remaining microalgal lipid fraction. The present work presents a novel process to produce C. cohnii biomass, using low-cost industrial by-products (raw glycerol and corn steep liquor), in a 7L-bioreactor, under fed-batch regime. At the end of the fermentation, the biomass concentration reached 9.2 g/L and the lipid content and lipid average productivity attained 28.0% (w/w dry cell weight) and 13.6 mg/L h, respectively. Afterwards the microalgal biomass underwent a saponification reaction to produce fatty acid (FA) soaps, which were further converted into FA ethyl ester (FA EE). C. cohnii FA EE mixture was then fractionated, using the urea complexation method at different temperatures, in order to obtain a polyunsaturated fatty acid ethyl ester (PUFA EE) rich fraction, that could be used for food/pharmaceutical/cosmetic purposes, and a saturated fatty acid ethyl ester (SAT EE) rich fraction, which could be used as biodiesel. The temperature that promoted the best separation between PUFA and SAT EE, was −18 °C, resulting in a liquid fraction with 91.6% (w/w) DHA, and a solid phase with 88.2% of SAT and monounsaturated fatty acid ethyl ester (MONOUNSAT), which could be used for biodiesel purposes after a hydrogenation step.

A dose-response study with omega-3 rich canola oil as a novel source of docosahexaenoic acid (DHA) in feed for Atlantic salmon (Salmo salar) in seawater; effects on performance, tissue fatty acid composition, and fillet quality

Long-chain omega-3 rich oils from crops genetically modified with algal genes are a promising new source of the omega-3 fatty acid DHA (docosahexaenoic acid; 22:6n-3) in Atlantic salmon diets. In this study, the fish oil and fish meal content were held constant across diets, and conventional canola oil was replaced with DHA canola (DHA-CA) oil in a step-wise manner at 0%, 25%, 50%, and 100% replacement, respectively. Growth of salmon, reared in seawater, from approximately 465 g to 1.5 kg was equal across all dietary treatments. Survival was >98% in all cases, with no difference between the dietary groups. Digestibility of lipids was high, approximately 93% in all dietary groups. Fatty acid retention in whole body was also high, with greater retention of α-linolenic acid (ALA, 18:3n-3) and eicosapentaenoic acid (EPA; 20:5n-3) in groups containing higher proportions of DHA-CA oil. Fillet, liver, and intestinal fatty acid compositions were influenced by the different fatty acid contents of the diets, with progressively higher inclusion of ALA, EPA, and DHA and a higher n-3:n-6 ratio in fish fed the 25%, 50%, and 100% DHA-CA diets. Increased dietary inclusion levels of DHA reduced the conversion to 1-14C labelled ALA to 1-14C EPA in liver cells, but some conversion of ALA to 1-14C EPA was maintained even at high dietary DHA levels. There was also a significant increase in anti-inflammatory pro-resolving lipid mediators, resolvins, with increased dietary DHA-CA. The visual colour impression of both muscle and skin was improved at higher DHA-CA inclusion levels in diets.Overall, our findings demonstrates that DHA-CA oil is an effective ingredient in Atlantic salmon diets in seawater, and that fatty acids (FA) from this oil are incorporated into the fish tissues in a manner equivalent to FA from conventional sources, with positive effects on fillet quality.

α-linolenic acid interconversion is sufficient as a source of longer chain ω-3 polyunsaturated fatty acids in humans: An opinion.

α-linolenic acid (αLNA) conversion into the functionally important ω-3 polyunsaturated fatty acids (PUFA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), has been regarded as inadequate for meeting nutritional requirements for these PUFA. This view is based on findings of small αLNA supplementation trials and stable isotope tracer studies that have been interpreted as indicating human capacity for EPA and, in particular, DHA synthesis is limited. The purpose of this review is to re-evaluate this interpretation. Markedly differing study designs, inconsistent findings and lack of trial replication preclude robust consensus regarding the nutritional adequacy of αLNA as a source of EPC and DHA. The conclusion that αLNA conversion in humans is constrained is inaccurate because it presupposes the existence of an unspecified, higher level of metabolic activity. Since capacity for EPA and DHA synthesis is the product of evolution it may be argued that the levels of EPA and DHA it maintains are nutritionally appropriate. Dietary and supra-dietary EPA plus DHA intakes confer health benefits. Paradoxically, such health benefits are also found amongst vegetarians who do not consume EPA and DHA, and for whom αLNA conversion is the primary source of ω-3 PUFA. Since there are no reported adverse effects on health or cognitive development of diets that exclude EPA and DHA, their synthesis from αLNA appears to be nutritionally adequate. This is consistent with the dietary essentiality of αLNA and has implications for developing sustainable nutritional recommendations for ω-3 PUFA.

Improved fillet quality in harvest-size Atlantic salmon fed high n-3 canola oil as a DHA-source

New sources of the very long-chain n-3 polyunsaturated fatty acids (n-3 VLC-PUFA) are needed for sustainable growth of salmon farming. In recent research high n-3 VLC-PUFA canola oil has shown promise as a safe and effective source of docosahexaenoic acid (DHA) and other n-3 PUFA in small Atlantic salmon. To study its long-term effects on performance and fillet quality under realistic farming conditions, a 12-month feeding experiment was carried out with Atlantic salmon growing to harvest weight (4.7 kg) in triplicate sea water cages. The fish were fed three diets containing graded inclusion levels of high n-3 canola oil resulting in levels of dietary DHA (22:6 n-3) of 4.0% (Standard; STD), 6.6% (Medium; MED) and 8.3% of total fatty acids (HIGH) and total EPA + DHA of 6.4, 9.1 and 11.0% of total fatty acids, respectively. The STD diet was considered to represent current commercial practice. There were no significant differences between the dietary groups in overall fish growth and weight at harvest, and no differences were seen in feed conversion ratio. Tissue FA-profiles mirrored the diets, giving increased DHA, EPA (20:5 n-3) and ALA (18:3 n-3) with increasing inclusion level of high n-3 LC-PUFA canola oil. Dietary inclusion of n-3 canola oil had no effect on muscle astaxanthin concentration, but instrumentally measured redness, yellowness and chroma increased with n-3 canola oil inclusion, suggesting a positive effect on colour via effects on muscle structure or composition. The prevalence and severity of dark melanin spots in the fillet was significantly reduced by increased inclusion level of n-3 canola oil. The prevalence of severe spots (score ≥ 2), average score and number of affected muscle segments were all lower in MED and HIGH, compared to STD.In conclusion, high n-3 canola oil is an efficient source of DHA and other n-3 fatty acids for harvest-size Atlantic salmon. Increased dietary supply of DHA and other n-3 PUFA, above minimum requirement levels for DHA, improved fillet pigmentation and reduced fillet melanin spots, without compromising fish growth.

Fatty Acid Profiles of Venus Clam (Marcia opima) and Blood Cockles (Anadara granosa) Harvested at Different Geographical Locations in the Northwest Coast of Sri Lanka

ABSTRACT The present study elucidated the effects of species and geographical location on the fatty acid profile and lipid indices of bivalves. Lipid profiles of venus clam (Marcia opima) and blood cockles (Anadara granosa) harvested from Naruvilikulam and Achchankulam situated on the northwest coast of Sri Lanka were determined, and lipid indices were calculated. The dominant fatty acid group found in bivalves was saturated fatty acids. Total n-3 and n-6 fatty acid contents were similar between the two species. Both bivalve species were identified as potential sources of docosahexaenoic acid. Bivalves from Naruvilikulam site had significantly abundant levels of linolenic and eicosapentaenoic acids (0.83% and 5.69%, respectively). Thrombogenicity index was not influenced by species and geographical location of bivalves. M. opima and bivalves from Naruvilikulam site were detected with lower atherogenicity indices and higher hypocholesterolemic/hypercholesterole-mic ratios than their counterparts and, therefore, can be recommended for consumers interested in healthy food selection.

Effect of micro-algae Schizochytrium sp. supplementation in plant diet on reproduction of female rainbow trout (Oncorhynchus mykiss): maternal programming impact of progeny

BackgroundThe broodstock diet, and in particular the lipid and fatty acid composition of the diet, is known to play a key role in reproductive efficiency and survival of the progeny in fish. A major problem when replacing both fish meal and fish oil by plant sources is the lack of n-3 long chain polyunsaturated fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). To address this problem, we studied the effect of the plant-based diet supplemented with Schizochytrium sp. microalgae, source of DHA, compared to a conventional commercial diet rich in fish meal and fish oil on reproductive performance and egg quality and the consequences on progeny, in female rainbow trout broodstock.ResultsThe results demonstrated that DHA-rich microalgae supplementation in a plant-based diet allowed for the maintenance of reproductive performance and egg quality comparable to a conventional commercial feed rich in fish meal and fish oil and led to an increased significant fry survival after resorption. Moreover, when females were fed a plant-based diet supplemented with micro-algae, the 4-month-old progenies showed a significant higher growth when they were challenged with a similar diet as broodstock during 1 month. We provide evidence for metabolic programming in which the maternal dietary induced significant protracted effects on lipid metabolism of progeny.ConclusionsThe present study demonstrates that supplementation of a plant-based diet with DHA-rich microalgae can be an effective alternative to fish meal and fish oil in rainbow trout broodstock aquafeed.

Dietary Alpha-Linolenic Acid Supports High Retinal DHA Levels.

The retina requires docosahexaenoic acid (DHA) for optimal function. Alpha-linolenic acid (ALA) and DHA are dietary sources of retinal DHA. This research investigated optimizing retinal DHA using dietary ALA. Previous research identified 19% DHA in retinal phospholipids was associated with optimal retinal function in guinea pigs. Pregnant guinea pigs were fed dietary ALA from 2.8% to 17.3% of diet fatty acids, at a constant level of linoleic acid (LA) of 18% for the last one third of gestation and retinal DHA levels were assessed in 3-week-old offspring maintained on the same diets as their mothers. Retinal DHA increased in a linear fashion with the maximum on the diet with LA:ALA of 1:1. Feeding diets with LA:ALA of 1:1 during pregnancy and assessing retinal DHA in 3-week-old offspring was associated with optimized retinal DHA levels. We speculate that the current intakes of ALA in human diets, especially in relation to LA intakes, are inadequate to support high DHA levels in the retina.