Docosahexaenoic Acid Requirements Research Articles

Escaping malnutrition by shifting habitats: A driver of three-spined stickleback invasion in Lake Constance.

Fatty acids, and especially long-chain polyunsaturated fatty acids, are biologically important components in the metabolism of vertebrates, including fish. Essential fatty acids (EFA) are those that in a given animal cannot be synthesized or modified from precursors and must therefore be acquired via the diet. Because EFAs are often unevenly distributed in nature, this requirement may drive species to make behavioral or ecological adaptations to avoid malnutrition. This is especially true for fish like the three-spined stickleback (Gasterosteus aculeatus L.) of Upper Lake Constance (ULC), whose recent marine ancestors evolved with access to EFA-rich prey, but which found themselves in an EFA-deficient habitat. An unexpected and unprecedented ecological shift in the ULC stickleback population from the littoral to pelagic zones in 2012 might be linked to EFA availability, triggering ecological release and enabling them to build a hyperabundant population while displacing the former keystone species, the pelagic whitefish Coregonus wartmanni. To test this hypothesis, sticklebacks from the littoral and pelagic zones of ULC were sampled seasonally in two consecutive years, and their stomach contents and fatty acid profiles were analysed. Pelagic sticklebacks were found to possess significantly higher values of an important EFA, docosahexaenoic acid (DHA), especially during autumn. Evaluation of the DHA supply suggests that sticklebacks feeding in the littoral zone during autumn could not meet their DHA requirement, whereas DHA availability in the pelagic zone was surplus to demand. During autumn, pelagic sticklebacks consumed large amounts of DHA-rich prey, that is, copepods, whereas littoral sticklebacks relied mainly mostly on cladocerans, which provide much lower quantities of DHA. Access to pelagic zooplankton in 2012 was possibly facilitated by low densities of previously dominant zooplanktivorous whitefish. The present study offers a convincing physiological explanation for the observed expansion of invasive sticklebacks from the littoral to the pelagic zones of Lake Constance, contributing to a phase shift with severe consequences for fisheries.

High-Dose Docosahexaenoic Acid in Newborns Born at Less Than 29 Weeks’ Gestation and Behavior at Age 5 Years

Children born at less than 29 weeks' gestation are at risk of behavioral difficulties. This may be due in part to the lack of transplacental supply of docosahexaenoic acid (DHA), a key fatty acid with structural and functional roles in the brain. To determine whether meeting the neonatal DHA requirement through supplementation is associated with improved behavioral functioning of children born at less than 29 weeks' gestation. This was a follow-up of children from 10 Australian participating centers in a multi-center, blinded, parallel group randomized clinical trial of infants born at less than 29 weeks' gestation conducted from June 2012 and September 2015, excluding those with additional fatty acid supplementation or major congenital or chromosomal abnormalities. Follow-up took place from August 2018 to May 2021. Parents of surviving children who had not withdrawn from the original trial were invited to complete questionnaires when the child turned 5 years' corrected age. Infants were randomized to receive daily enteral emulsions providing 60 mg/kg/d of DHA or a soy-oil emulsion (with no DHA) from within the first 3 days of enteral feeding until 36 weeks' postmenstrual age or discharge home, whichever occurred first. The primary outcome of this follow-up was parent-rated behavior and emotional functioning as indicated by the Total Difficulties score of the Strengths and Difficulties Questionnaire. Parents also completed questionnaires about their child's behavioral manifestations of executive functioning, as well as a range of health outcomes to assess potential longer-term side effects of DHA intervention. Primary outcome data were available for 731 children (76% of 958 surviving eligible children; 361 in the intervention group and 370 in the control group). Of these 731, 452 (47%) were female, and the mean (SD) corrected age at follow-up was 5.4 (0.5) years. Following imputation for missing data, the mean Total Difficulties score was the same in both groups (intervention group, n = 465; mean [SD], 11.8 [6.3]; control group, n = 493; mean [SD], 11.8 [6.0]; mean difference adjusted for sex, gestational age stratum, and hospital, 0.01; 95% CI, -0.87 to 0.89; P = .98). There was no evidence for differences between the groups in any secondary outcomes of behavior, executive functioning, or health. In this follow-up of a randomized clinical trial, enteral DHA supplementation at the equivalent of the estimated in utero dose for infants born at less than 29 weeks' gestation did not improve behavioral functioning at age 5 years. There were no indications of adverse effects with DHA supplementation. Australian New Zealand Clinical Trial Registry: ACTRN12612000503820.

Review on n-3 HUFA and Live Food Organism for Marine Fish Larvae Nutrition

Marine fish farm industries face ongoing challenges due to a lack of quality seed, a low survival rate and a slow growth rate of marine fish larvae. One of the most sensitive problems is a nutritionally balanced quality feed for rearing these larval fish at the first feeding stage. Many studies have reported high requirements of n-3 highly unsaturated fatty acids, mainly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) for proper development, which have also been reported to increase the survival and growth status of larval fish. Marine fish larvae have difficulties accepting artificial feed at their weaning stage, so live food plays a vital role in the rearing process. Artemia is one of the most commonly used live food organisms in marine fish larvae production systems. However, they are deficient in EPA and DHA, which are most critical for larval development. Recent advancements in live food production systems have developed several techniques of bio-encapsulation and enrichment of nutrients in live food. But the instability of DHA and the high cost of enrichment procedures remain-bottlenecks for supplying proper nutrients through live food. This short review emphasizes challenges in marine fish larvae culture in terms of HUFAs nutrition with a comparative study on DHA requirements of marine larval fish and its availability in live food organism Artemia. We also highlighted several factors affecting DHA enrichment process and its degradation following enrichment procedures.

Fatty acids, selenium, and vitamin B12 in chub mackerel (Scomber colias) as nourishment considering seasonality and bioaccessibility as factors

Chub mackerel (Scomber colias) is an underutilised fish abundant in the North Atlantic and a nutritious food with high docosahexaenoic acid (DHA), selenium (Se), and vitamin B12 contents, affected by seasonality. Hence, the bioaccessibility of fatty acid (FA), Se, and vitamin B12 in chub mackerel was studied. Daily consumptions of 51 g, 35 g, and 14 g of March, June, and October chub mackerel, respectively, would ensure EPA + DHA requirements. Vitamin B12 requirements would be met by daily consumptions of 15–18 g of chub mackerel. For Se, larger amounts would be needed, 126–133 g/day. For FA, bioaccessibility often exceeded 80 %. Additionally, Se and vitamin B12 bioaccessibilities were 91–95 % and 77–83 %, respectively. Thus, bioaccessibility-based consumption frequencies for meeting dietary requirements are similar to those above, being the highest consumption frequencies associated to Se requirements, 137–146 g/day. Chub mackerel proved to be an excellent source of bioaccessible essential nutrients.

Complexity of understanding the role of dietary and erythrocyte docosahexaenoic acid (DHA) on the cognitive performance of school-age children

ABSTRACTBackgroundEarly childhood is a period of rapid brain development, with increases in synapses rich in the omega-3 (ω-3) fatty acid, DHA (22:6ω-3) continuing well beyond infancy. Despite the importance of DHA to neural phospholipids, the requirement of dietary DHA for neurodevelopment remains unclear.ObjectivesThe aim was to assess the dietary DHA and DHA status of young children, and determine the association with cognitive performance.MethodsThis was a cross-sectional study of healthy children (5–6 y), some of whom were enrolled in a follow-up of a clinical trial (NCT00620672). Dietary intake data (n = 285) were assessed with a food-frequency questionnaire (FFQ) and three 24-h recalls. Family characteristics were collected by questionnaire, and anthropometric data measured. Venous blood was collected, cognitive performance assessed using several age-appropriate tools including the Kaufman Assessment Battery for Children. The relation between dietary DHA, RBC DHA, and child neurodevelopment test scores was determined using Pearson's correlation or Spearman's rho, and quintiles of test scores compared by Mann–Whitney U test.ResultsChild DHA intakes were highly variable, with a stronger association between RBC DHA and DHA intake assessed by FFQ (rho = 0.383, P < 0.001) compared with one or three 24-h recalls. Observed ethnic differences in DHA intake status as well as neurodevelopmental test scores led to analysis of the association between DHA intake and status with neurodevelopment test scores for White children only (n = 190). Child RBC DHA status was associated with neurodevelopment test scores, including language (rho = 0.211, P = 0.009) and short-term memory (rho = 0.187, P = 0.019), but only short-term memory was associated with dietary DHA (rho = 0.221, P = 0.003).ConclusionsChild RBC DHA but not dietary DHA was associated with multiple tests of cognitive performance. In addition, DHA intake was only moderately associated with RBC DHA, raising complex questions on the relation between diet, DHA transfer to membrane lipids, and neural function.

Liver Transcriptome Profiling Reveals That Dietary DHA and EPA Levels Influence Suites of Genes Involved in Metabolism, Redox Homeostasis, and Immune Function in Atlantic Salmon (Salmo salar).

The optimal dietary requirement of omega-3 long-chain polyunsaturated fatty acids (ω3 LC-PUFA), namely docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), for Atlantic salmon that promotes growth and health warrants careful investigation. We used 44K microarrays to study the influence of increasing levels of dietary DHA + EPA (0, 1.0, and 1.4% of the diet, as formulated) in the presence of high linoleic acid (LA) on Atlantic salmon growth and liver transcriptome. After a 14-week feeding trial, Atlantic salmon fed diet ω3LC0 (i.e. 0% of DHA + EPA) showed significantly lower final weight and weight gain, and higher feed conversion ratio compared with ω3LC1.0 and ω3LC1.4 diet groups. The microarray experiment identified 55 and 77 differentially expressed probes (Rank Products analyses; PFP < 10%) in salmon fed diets ω3LC1.4 and ω3LC1.0 compared with those fed diet ω3LC0, respectively. The comparison between ω3LC1.4 and ω3LC1.0 revealed 134 differentially expressed probes. The microarray results were confirmed by qPCR analyses of 22 microarray-identified transcripts. Several key genes involved in fatty acid metabolism including LC-PUFA synthesis were upregulated in fish fed ω3LC0 compared with both other groups. Hierarchical clustering and linear regression analyses of liver qPCR and fatty acid composition data demonstrated significant correlations. In the current study, 1.0% ω3 LC-PUFA seemed to be the minimum requirement for Atlantic salmon based on growth performance; however, multivariate statistical analyses (PERMANOVA and SIMPER) showed that fish fed ω3LC1.0 and ω3LC1.4 diets had similar hepatic fatty acid profiles but marked differences in the transcript expression of biomarker genes involved in redox homeostasis (mgst1), immune responses (mxb, igmb, irf3, lect2a, srk2, and lyz2), and LC-PUFA synthesis (srebp1, fadsd5, and elovl2). This research has provided new insights into dietary requirement of DHA and EPA and their impact on physiologically important pathways in addition to lipid metabolism in Atlantic salmon.

Re-evaluating the dietary requirement of EPA and DHA for Atlantic salmon in freshwater

The requirement for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is recommended at 0.50–1.0% of the dry diet for juvenile Atlantic salmon (Salmo salar). Current commercial aquafeed formulations for Atlantic salmon tend to contain a physiological excess of these fatty acids. The aim of this study was to re-evaluate the EPA and DHA requirement by Atlantic salmon parr in freshwater since it was determined 20 years ago, and feed formulations and salmon production have changed. This study evaluated the effect of different dietary levels of EPA and DHA (0.25 to 2.0%) on growth performance, overall health, and whole-body EPA and DHA content. Salmon (initial weight 22.6 g ± 1.2) were fed four levels (0.25, 0.5, 0.75 and 2%) of EPA + DHA diets for 6 weeks in freshwater at 12 °C. Diets were fed to triplicate tanks, with 20 fish per tank. There were no mortalities throughout the trial and fish nearly doubled their weight after 6 weeks. Categorically, there were no discrete significant differences in growth performance among treatments after 6 weeks. However, weight gain was exponentially related to diet EPA + DHA levels (p < .0001; r2 = 28.3%), and the feed conversion ratio was inversely related. In both cases, these relationships suggested that the asymptote is reached between 0.25% and 0.5% dietary EPA + DHA. Whole body DHA and EPA showed positive linear relationships with diet DHA (p < .001; r2 = 88.7%) and EPA (p < .001; r2 = 92.9%). Based on growth performance and whole-body fatty acid content, salmon fed a diet containing 0.50% EPA + DHA diet exhibited similar growth performance and haematocrit with control diet (2%). Therefore, 0.5% is considered the lowest required EPA + DHA level for Atlantic salmon parr in freshwater in this study.

The effect of APOE genotype on Alzheimer's disease risk is influenced by sex and docosahexaenoic acid status.

An apolipoprotein E ε4 (APOE-ε4) genotype is the strongest common genetic determinant of Alzheimer's disease (AD). The pleiotropic nature of apolipoprotein E has made elucidation of the aetiological basis difficult to establish, which is further complicated by the fact that the penetrance of the APOE-ε4 allele is modulated by sex, age, and nutrition. A greater metabolic consequence of the APOE-ε4 allele is likely to contribute to the fact that two-thirds of AD patients are female. A higher tissue status of the marine n-3 fatty acid docosahexaenoic acid (DHA) is associated with a lower AD risk. However, APOE-ε4 carriers appear less sensitive to the neurocognitive benefits, which may be due to defective blood-brain barrier transport of DHA exacerbated by aging and possibly sex. This suggests higher DHA requirements in this large population subgroup. This narrative review will consider the influence of sex and DHA in modulating APOE-ε4-mediated AD risk.

Curcumin and linseed oil co-delivered in phospholipid nanoemulsions enhances the levels of docosahexaenoic acid in serum and tissue lipids of rats

Docosahexaenoic acid (DHA) is an important long chain omega-3 polyunsaturated fatty acid (PUFA) primarily found in marine fishes. The diets of vegetarian population do not contain preformed DHA, but they can derive it from shorter chain α-linolenic acid (ALA) found in plant oils. However, the conversion efficiency of ALA to DHA is minimal in human adults. This may cause insufficiency of DHA in the vegetarian population. Curcumin, diferuloyl methane found in the spice turmeric, has the potential to increase the formation of DHA from ALA by activating the enzymes FADS2 and elongase 2. The present study was designed to prepare curcumin nanoemulsion using phospholipid core material (Lipoid™) and exploring the possibility of enhancing its bioavailability and its impact on DHA levels in rats. Curcumin was dissolved in coconut oil (CNO, MCFA rich), Sunflower oil (SNO, n-6 PUFA rich) or Linseed oil (LSO, n-3 PUFA rich) and nanoemulsions were prepared after mixing with Lipoid™ using high pressure homogenizer. The nanoemulsions were fed to weaning rats for 60 days along with AIN-93 diets. Rats fed nanoemulsion containing curcumin in LSO showed high levels of curcumin in serum liver, heart and brain. Significant increase in DHA levels of serum and tissue lipids were observed in rats given LSO with curcumin in nanoemulsions. Therefore, supplementation of diets with ALA rich LSO and curcumin could increase DHA concentrations in serum, liver, heart and brain lipids which have implications for meeting the DHA requirements of vegetarian populations.

A Comparison of Growth, Survival, and Fatty Acid Composition of the Lined Seahorse, Hippocampus erectus , Juveniles Fed Enriched Artemia and a Calanoid Copepod, Schmackeria dubia

The purpose of this study was to evaluate the effect of varying dietary levels of highly unsaturated fatty acids (HUFAs) in live prey (Artemia nauplii and a calanoid copepod, Schmackeria dubia) on the growth performance, survival, and fatty acid composition of the lined seahorse, Hippocampus erectus, juveniles. Artemia nauplii were enriched with a commercial product (SS™ 50DE-microcapsule as HUFA source, 2/3 DHA, 1/3 EPA. Shengsuo Fishery Feed Research Center of Shandong Province, Qingdao, China) at four concentrations of 0.0, 14.0, 28.0, and 56.0. Newly hatched juveniles were cultured for 35 days. The content of docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and n-3 HUFAs in the Artemia nauplii was positively related to the enrichment concentration. At the end of the trials, growth performance of the juveniles was positively related to the enrichment concentration as well. However, the juveniles fed prey enriched with the highest concentration of enrichment (56.0 μL/L) had the significantly lower (P < 0.05) survival rate. The juveniles fed the copepod had the best growth performance and the highest survival rate, suggesting that the copepod, S. dubia, is suitable for feeding the seahorse juveniles. The comparisons between the growth, survival, and fatty acid profiles of the juveniles fed Artemia and copepods indicate that the seahorse juveniles require dietary levels of DHA beyond those achieved by enriching prey with the HUFA enrichment. Surplus EPA resulted from an imbalance between DHA and EPA in the enriched Artemia nauplii probably caused an adverse effect on the seahorse juveniles. This study suggests that DHA and EPA requirement of the lined seahorse juveniles is roughly 32% of total fatty acid, and the optimal DHA/EPA ratio for the species is circa 4:1. To avoid an adverse effect resulting from excessive EPA, maximum proportion of EPA in enriched Artemia nauplii should not exceed 13% of total fatty acid, and a recommended minimum DHA/EPA ratio in the enriched Artemia nauplii is 1.46. Arachidonic acid (20:4n-6) might not be an essential fatty acid for the seahorse juveniles.

Changes in Tissue Lipid and Fatty Acid Composition of Farmed Rainbow Trout in Response to Dietary Camelina Oil as a Replacement of Fish Oil

Camelina oil (CO) replaced 50 and 100% of fish oil (FO) in diets for farmed rainbow trout (initial weight 44±3gfish(-1)). The oilseed is particularly unique due to its high lipid content (40%) and high amount of 18:3n-3 (α-linolenic acid, ALA) (30%). Replacing 100% of fish oil with camelina oil did not negatively affect growth of rainbow trout after a 12-week feeding trial (FO=168±32gfish(-1); CO=184±35gfish(-1)). Lipid and fatty acid profiles of muscle, viscera and skin were significantly affected by the addition of CO after 12weeks of feeding. However, final 22:6n-3 [docosahexaenoic acid (DHA)] and 20:5n-3 [eicosapentaenoic acid (EPA)] amounts (563mg) in a 75g fillet (1 serving) were enough to satisfy daily DHA and EPA requirements (250mg) set by the World Health Organization. Other health benefits include lower SFA and higher MUFA in filets fed CO versus FO. Compound-specific stable isotope analysis (CSIA) confirmed that the δ(13)C isotopic signature of DHA in CO fed trout shifted significantly compared to DHA in FO fed trout. The shift in DHA δ(13)C indicates mixing of a terrestrial isotopic signature compared to the isotopic signature of DHA in fish oil-fed tissue. These results suggest that~27% of DHA was synthesized from the terrestrial and isotopically lighter ALA in the CO diet rather than incorporation of DHA from fish meal in the CO diet. This was the first study to use CSIA in a feeding experiment to demonstrate synthesis of DHA in fish.

Effect of lipid composition of diets and environmental temperature on the performance and fatty acid composition of juvenile European abalone (Haliotis tuberculata L. 1758)

Juvenile abalone Haliotis tuberculata groups hatched in the lab from wild broodstock were fed with diets free of long chain polyunsaturated fatty acids (LC-PUFAs) (restriction diet) but with high amount of molecular precursors like 18:3n-3 and 18:2n-6 from linseed and corn oils compared to a control diet formulated with fish oil. Three different temperatures (12, 16 and 20°C) were chosen to measure the effect of fatty acid accumulation or synthesis compared to the control diet. After 200days of experimentation, abalone exhibited different growth between each temperature, whereas no differences were observed between diets. However, a higher fatty acid accumulation was observed in muscle tissue at 12°C. The relative amount of long chain polyunsaturated fatty acids (LC-PUFAs) in the muscle tissue was similar between those individuals fed with the restriction (LC-PUFA free) and full diets. This was clearly observed within the LC-PUFAs eicosapentaenoic acid (EPA) and docosapentaenoic acid (DPA), but not with docosahexaenoic acid (DHA), suggesting that H. tuberculata is able to synthesize the former FAs from their precursors. This pattern was also observed with arachidonic acid (ARA). In general abalone is able to synthesize and accumulate the necessary fatty acids to sustain growth at a wide range of temperatures and dietary sources, especially at lower temperatures, that could mean that this species is able to cope with a broad range of environmental conditions. However, DHA requirement in the H. tuberculata seems to be much inferior than previously reported, and its biosynthesis is undetectable under the present experimental conditions.

Effects of docosahexaenoic acid on growth, survival and swim bladder inflation of larval amberjack (Seriola dumerili, Risso)

The effect of docosahexaenoic acid (DHA) on the growth performance, survival and swim bladder inflation of larval Seriola dumerili during the rotifer feeding period was investigated in two feeding experiments. Amberjack larvae at 3 day post hatching were fed rotifers enriched with (1) freshwater C hlorella (Chlo), (2) a mixture (2:1, v/v) of Chlo and DHA-enriched C hlorella (DHA-Chlo), (3) DHA-Chlo and (4) DHA-Chlo and commercial DHA emulsion, in triplicate for 7 days. The average DHA contents of the rotifers were 0.0, 0.4, 1.0 and 1.9 mg g−1 DM respectively. The survival rate was improved by the enrichment of rotifers with DHA-Chlo alone, and DHA-Chlo and emulsion. Growth and swim bladder inflation of fish fed rotifers enriched with DHA-Chlo were significantly (P < 0.05) improved, however, with increased levels of DHA further improvement was not found. DHA content in the larval whole body proportionally increased with the DHA level in the rotifers. These results suggest that DHA enrichment of rotifers is effective to improve the growth, survival rate and swim bladder inflation of amberjack larvae. The DHA requirement of amberjack larvae is estimated to be 1.5 mg g−1 on a dry matter basis of rotifers.

ドコサヘキサエン酸（DHA）要求に着目したマガレイの健苗性向上に関する研究

ドコサヘキサエン酸（DHA）要求に着目したマガレイの健苗性向上に関する研究

Risk of Ill-Informed Decision-Making When Choosing Your Favorite Fish

ABSTRACT Risk to children of women who choose a favorite fish without regard to its methylmercury or omega-3 content was estimated under three consumption scenarios: (1) current fish consumption rate by U.S. women if limited to orange roughy (Hoplostethus atlanticus), (2) 12 oz of roughy per week, and (3) roughy consumption to meet docosahexaenoic acid (DHA) requirements. Risks were similarly assessed if king mackerel (Scomberomorus cavalla) were eaten. Based on mercury concentrations in fillets purchased from 2004–2007 (0.73 ± 0.29 mg Hg/kg; n = 45), women would have an 85% probability of exceeding USEPA's reference dose (RfD) if they ate only roughy. Based on literature-derived concentrations, they would have a 91% probability of exceeding the RfD if they ate only mackerel. Increasing consumption of either fish to 12 oz per week would increase their probability of exceeding the RfD to 100%. Attempting to meet DHA requirements through eating these fish also results in a 100% probability of exceeding the RfD; however, owing to its very low DHA content, roughy consumption would result in exceedance by 100-fold. These results highlight recommendations of others that benefits and risks of fish consumption should be presented together to enable consumers to make informed decisions.

Importancia del ácido docosahexaenoico (DHA): funciones y recomendaciones para su ingesta en la infancia

Docosahexaenoic acid (DHA) is a n-3 polyunsaturated fatty acid with multiple functions, although these are still under study. The development of visual and neurological functions have been demonstrated in premature infants and neonates, however, its effects are still being studied in certain chronic neurological diseases, and inflammatory and metabolic disorders. The DHA requirements are not fixed but recommendations must be based on an intake similar to the composition of breastfeeding, and in older children and during pregnancy and lactation, to ensure consumption of oily fish at least twice a week. It is essential to recognise the need for supplementation of this fatty acid in some diseases that require restricted diet, and in metabolic alterations resulting in a deficiency, but also know the scientific evidence on the effects produced in different situations. This review updates this information to propose an adequate intake of DHA at different ages and in different diseases.

Docosahexaenoic acid requirement for the prevention of abnormal morphology in brown sole Pseudopleuronectes herzensteini during D–E larval stages

We examined the docosahexaenoic acid (DHA) requirement during the sensitive period (D–E stages) to prevent abnormal morphology in juvenile brown sole Pseudopleuronectes herzensteini. Rotifers and Artemia nauplii containing three graded levels (low, mid, and high level) of DHA were made by respective enrichment with oil emulsion. Larvae at 15 days post hatching (dph) (D stage) were fed for 10 days with rotifers and Artemia nauplii containing respective amounts of DHA. During F–I stages, larvae were fed Artemia nauplii enriched with a commercial supplementary diet. The DHA requirement to prevent morphological abnormalities in brown sole juveniles was estimated to be 1.7–3.2% in rotifer and 1.4–2.8% in Artemia nauplii on a dry weight basis. Moreover it was clearly demonstrated that DHA enrichment of rotifers is superior to that of Artemia nauplii for this purpose in larval brown sole during D–E stages.

Omega‐3 LC‐PUFA Supply and Neurological Outcomes in Children With Phenylketonuria (PKU)

Children with phenylketonuria (PKU) follow a diet with very low intakes of natural protein, which is devoid of food sources of the omega-3 docosahexaenoic acid (DHA). A resulting DHA depletion has been demonstrated in PKU children and may account for detectable subtle neurological deficits that are not explained by variation in plasma phenylalanine concentrations. We supplemented 36 children with PKU ages 1 to 11 years for 3 months with encapsulated fish oil providing a daily dose of 15 mg DHA/kg body weight. DHA supplementation resulted in significantly faster visual evoked potential latencies, indicating more rapid central nervous system information processing. In addition, DHA significantly improved outcomes in a test of motor function and coordination. No changes over time were seen in age-matched healthy controls. Because the PKU children had a good supply of the omega-3 precursor alpha-linolenic acid, these observations lead us to conclude that endogenous conversion of alpha-linolenic acid is not sufficient to provide adequate amounts of DHA that support optimal function, and hence DHA appears to be a conditional essential substrate for children with PKU. Because early treated PKU children are healthy, with normal fatty acid turnover, these data may indicate a need to supply some DHA to children in general. Further studies are ongoing aiming at establishing quantitative DHA requirements in children.

Higher dose of docosahexaenoic acid in the neonatal period improves visual acuity of preterm infants: results of a randomized controlled trial

Background: Preterm infants have improved visual outcomes when fed a formula containing 0.2–0.4% docosahexaenoic acid (DHA) compared with infants fed no DHA, but the optimal DHA dose is unknown.Objective: We assessed visual responses of preterm infants fed human milk (HM) and formula with a DHA concentration estimated to match the intrauterine accretion rate (high-DHA group) compared with infants fed HM and formula containing DHA at current concentrations.Design: A double-blind randomized controlled trial studied preterm infants born at <33 wk gestation and fed HM or formula containing 1% DHA (high-DHA group) or ≈0.3% DHA (current practice; control group) until reaching their estimated due date (EDD). Both groups received the same concentration of arachidonic acid. Sweep visual evoked potential (VEP) acuity and latency were assessed at 2 and 4 mo corrected age (CA). Weight, length, and head circumference were assessed at EDD and at 2 and 4 mo CA.Results: At 2 mo CA, acuity of the high-DHA group did not differ from the control group [high-DHA group (x̄ ± SD): 5.6 ± 2.4 cycles per degree (cpd), n = 54; control group: 5.6 ± 2.4 cpd, n = 61; P = 0.96]. By 4 mo CA, the high-DHA group exhibited an acuity that was 1.4 cpd higher than the control group (high-DHA: 9.6 ± 3.7 cpd, n = 44; control: 8.2 ± 1.8 cpd; n = 51; P = 0.025). VEP latencies and anthropometric measurements were not different between the high-DHA and control groups.Conclusion: The DHA requirement of preterm infants may be higher than currently provided by preterm formula or HM of Australian women.

Docosahexaenoic acid (DHA), essentiality and requirements: why and how to provide supplementation

Lipids comprize from 50-60% of the structural matter of the brain and docosahexaenoic acid (C22:6, DHA) is the most important omega-3 long-chain polyunsaturated fatty acid in the brain phospholipids comprizing 25% of the total fatty acids of the grey matter. The majority of the DHA present in the human brain is incorporated during the brain growth spurt which starts at week 26 of gestation and imposes a high demand for the fatty acid until about 2 years of age. DHA is required during brain development when neuronal and glial differentiation and migration, and active myelination and synaptogenesis take place. The fatty acid must be incorporated into the brain lipids as preformed DHA because less than 5% of its precursor (alpha linolenic acid, LNA) is converted to DHA. The human foetus has a limited ability to synthesize DHA from LNA, and therefore it must be largely supplied from maternal sources. Maternal DHA available for foetal nutrition can be provided from three main sources: adipose tissue, which is the main reservoir for the fatty acid; through biosynthesis from the precursor LNA, which occurs mainly in the liver; and as preformed DHA from dietary sources. In the postnatal period DHA is provided by the mother to the newborn through milk secretion. Western nutrition provides low LNA and DHA and Expert Nutrition Committees suggest that mothers should receive DHA supplementation during pregnancy and lactation. At present DHA supplementation can be provided from different sources: as purified free DHA, as an ethyl ester derivative, extracted from single-cell algae oils, from egg yolk phospholipids, or in the form of sn-2 DHA monoacylglycerol. In this review we revise and discuss the evidence of DHA requirements for the newborn, the need for maternal supplementation during pregnancy and nursing, and the alternatives at present for providing DHA supplementation.