Amounts Of Docosahexaenoic Acid Research Articles

Delta-5 elongase knockout reduces docosahexaenoic acid and lipid synthesis and increases heat sensitivity in a diatom.

Recent global marine lipidomic analysis reveals a strong relationship between ocean temperature and phytoplanktonic abundance of omega-3 long-chain polyunsaturated fatty acids (LC-PUFAs), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are essential for human nutrition and primarily sourced from phytoplankton in marine food webs. In phytoplanktonic organisms, EPA may play a major role in regulating the phase transition temperature of membranes, while the function of DHA remains unexplored. In the oleaginous diatom Phaeodactylum tricornutum, DHA is distributed mainly on extraplastidial phospholipids, which is very different from the EPA enriched in thylakoid lipids. Here, CRISPR/Cas9-mediated knockout of delta-5 elongase (ptELO5a), which encodes a delta-5 elongase (ELO5) catalyzing the elongation of EPA to synthesize DHA, led to a substantial interruption of DHA synthesis in P. tricornutum. The ptELO5a mutants showed some alterations in transcriptome and glycerolipidomes, including membrane lipids and triacylglycerols under normal temperature (22°C), and were more sensitive to elevated temperature (28°C) than wild type. We conclude that PtELO5a-mediated synthesis of small amounts of DHA has indispensable functions in regulating membrane lipids, indirectly contributing to storage lipid accumulation, and maintaining thermomorphogenesis in P. tricornutum. This study also highlights the significance of DHA synthesis and lipid composition for environmental adaptation of P. tricornutum.

Gestational Diabetes Mellitus Remodels the Fetal Brain Fatty Acid Profile Through Placenta-Brain Lipid Axis in C57BL/6J Mice

BackgroundPolyunsaturated fatty acids (PUFAs), especially docosahexaenoic acid (DHA), are critical for proper fetal brain growth and development. Gestational diabetes mellitus (GDM) could affect maternal–fetal fatty acid metabolism. ObjectiveThis study aimed to explore the effect of GDM and high-fat (HF) diet on the DHA transport signaling pathway in the placenta-brain axis and fatty acid concentrations in the fetal brain. MethodsInsulin receptor antagonist (S961) and HF diet were used to establish an animal model of GDM. Eighty female C57BL/6J mice were randomly divided into control (CON), GDM, HF, and HF+GDM groups. The fatty acid profiles of the maternal liver and fetal brain were analyzed by gas chromatography. In addition, we analyzed the protein amounts of maternal liver fatty acid desaturase (FADS1/3), elongase (ELOVL2/5) and the regulatory factor sterol-regulatory element-binding protein (SREBP)-1c, and the DHA transport signaling pathway (Wnt3/β-catenin/MFSD2a) of the placenta and fetal brain using western blotting. ResultsGDM promoted the decrease of maternal liver ELOVL2, ELOVL5, and SREBP-1c. Accordingly, we observed a significant decrease in the amount of maternal liver arachidonic acid (AA), DHA, and total n–3 PUFA and n–6 PUFA induced by GDM. GDM also significantly decreased the amount of DHA and n–3 PUFA in the fetal brain. GDM downregulated the Wnt3/β-catenin/MFSD2a signaling pathway, which transfers n–3 PUFA in the placenta and fetal brain. The HF diet increased n–6 PUFA amounts in the maternal liver, correspondingly increasing linoleic acid, gamma-linolenic acid, AA, and total n–6 PUFA in the fetal brain, but decreased DHA amount in the fetal brain. However, HF diet only tended to decrease placental β-catenin and MFSD2a amounts (P = 0.074 and P = 0.098, respectively). ConclusionsMaternal GDM could affect the fatty acid profile of the fetal brain both by downregulating the Wnt3/β-catenin/MFSD2a pathway of the placental–fetal barrier and by affecting maternal fatty acid metabolism.

Nutrient and Fatty Acid Composition of Pike Perch (Sander lucioperca) and Evaluation of Important Indexes Related to Human Health

The nutrient and fatty acid composition of the muscle tissues in the dorsal (D), ventral (V), and caudal (C) regions of the pike perch were determined in this study. Pike perch had 19.63% protein, 0.92% lipid, 78.36% moisture, and 1.04% ash. The whole muscle (WM) (0.92%) of pike perch had the highest lipid content, followed by C (0.82%), V (0.73%), and D regions (0.69%). The results of the study revealed that total polyunsaturated fatty acid (PUFA) (32.37%–37.05%) values were higher than those of total saturated fatty acids (SFA) (29.96%–31.76%) and monounsaturated fatty acid (MUFA) (17.26%–20.81%) in all whole muscle (WM) and different regions (D, V, and C) of the pike perch. The highest SFA, MUFA, and PUFA amounts were in D, WM, and D regions, respectively. In all groups, the amount of Docosahexaenoic acid (DHA) (12.97-15.43%) was higher than Eicosapentaenoic acid (EPA) (5.66-6.97%). While there was no difference between regions in terms of EPA value, the difference between regions in terms of DHA values was found to be important (p <0.05). The highest EPA and DHA values were detected in the D region. Atherogenicity index (AI) (0.47–0.48), thrombogenicity index (TI) (0.33–0.35), hypocholesterolemic/hypercholesterolemic ratio (H/H) (1.53–1.57) and n-6/n-3 (0.47–0.51) ratios were at recommended levels in all regions (WM, D, V, and C) and there was no regional difference (p > 0.05). The results showed that the fatty acid composition of the pike perch varies according to different body regions, it is rich in nutrient content and has the recommended level of AI, TI, H/H, and n-6/n-3 ratios. It can be concluded that pike perch has beneficial health effects on human nutrition.

Dynamics of Docosahexaenoic Acid Utilization by Mouse Peritoneal Macrophages.

In this work, the incorporation of docosahexaenoic acid (DHA) in mouse resident peritoneal macrophages and its redistribution within the various phospholipid classes were investigated. Choline glycerophospholipids (PC) behaved as the major initial acceptors of DHA. Prolonged incubation with the fatty acid resulted in the transfer of DHA from PC to ethanolamine glycerophospholipids (PE), reflecting phospholipid remodeling. This process resulted in the cells containing similar amounts of DHA in PC and PE in the resting state. Mass spectrometry-based lipidomic analyses of phospholipid molecular species indicated a marked abundance of DHA in ether phospholipids. Stimulation of the macrophages with yeast-derived zymosan resulted in significant decreases in the levels of all DHA-containing PC and PI species; however, no PE or PS molecular species were found to decrease. In contrast, the levels of an unusual DHA-containing species, namely PI(20:4/22:6), which was barely present in resting cells, were found to markedly increase under zymosan stimulation. The levels of this phospholipid also significantly increased when the calcium-ionophore A23187 or platelet-activating factor were used instead of zymosan to stimulate the macrophages. The study of the route involved in the synthesis of PI(20:4/22:6) suggested that this species is produced through deacylation/reacylation reactions. These results define the increases in PI(20:4/22:6) as a novel lipid metabolic marker of mouse macrophage activation, and provide novel information to understand the regulation of phospholipid fatty acid turnover in activated macrophages.

Microalgae as functional feed for Atlantic salmon: effects on growth, health, immunity, muscle fatty acid and pigment deposition

Microalgae are increasingly being investigated as functional feed additives in a variety of fish species, but our knowledge on how microalgae supplementation affects Atlantic salmon remains limited. We hypothesized that microalgae inclusion of 8% in the feed would improve performance, fatty acid and pigment deposition as well as health and immunity of Atlantic salmon reared in recirculating aquaculture systems (RAS). We fed Atlantic salmon smolts with five different microalgae enriched diets containing Tetraselmis chuii (TC), Arthrospira platensis (AP), Schizochytrium limacinum (SL) or Chlorella vulgaris, either intact (CVI) or as broken cell wall derivative (CVB) or a control diet (CD). After eight weeks of feeding in brackish water (13 psu), all groups were transferred to seawater (32 psu) for additional two weeks. Our results indicate that CVB improved feed conversion and protein retention, but reduced condition factor (p < 0.05) compared to fish fed with a control diet. Voluntary feed intake decreased in seawater, but was similar among diet groups. The amount of docosahexaenoic acid was particularly high in SL-fed fish and alpha-linolenic acid was enriched in fish fed CVI, CVB and TC (p < 0.05). Following seawater transfer, fat content and monounsaturated fatty acids decreased in the muscle, while polyunsaturated fatty acids increased. Lutein was present in all muscle samples, but highest concentrations were found in CVB-, CVI- and TC-fed fish. In the anterior intestine, microalgae supplementation induced differentially regulated trout protein 1 (drtp1) expression in CVI- and CVB-fed fish, but reduced the expression of interleukin 1 and 10 receptor (il1r2 & il10rb) in CVI-fed fish. In the liver, feeding CVI and SL induced complement C1q like 2 (c1ql2) expression, while reducing serum amyloid A5 (saa5) expression. Superoxide-dismutase protein concentration was induced in the liver of fish fed SL, while myeloperoxidase was reduced in most microalgae-fed groups. In conclusion, we show that commercially relevant microalgae can be used as functional feed additives for Atlantic salmon promoting different health aspects without negatively affecting their growth performance when cultivated in RAS.

Growth and adiposity in newborns study (GAINS): The influence of prenatal DHA supplementation protocol

BackgroundObesity and central fat mass (FM) accrual drive disease development and are related to greater morbidity and mortality. Excessive gestational weight gain (GWG) increases fetal fat accretion resulting in greater offspring FM across the lifespan. Studies associate greater maternal docosahexaenoic acid (DHA) levels with lower offspring FM and lower visceral adipose tissue during childhood, however, most U.S. pregnant women do not consume an adequate amount of DHA. We will determine if prenatal DHA supplementation is protective for body composition changes during infancy and toddlerhood in offspring exposed to excessive GWG. Methods and designInfants born to women who participated in the Assessment of DHA on Reducing Early Preterm Birth randomized controlled trial (ADORE; NCT 02626299) will be invited to participate. Women were randomized to either a high 1000 mg or low 200 mg daily prenatal DHA supplement starting in the first trimester of pregnancy. Offspring body composition and adipose tissue distribution will be measured at 2 weeks, 6 months, 12 months, and 24 months using dual energy x-ray absorptiometry. Maternal GWG will be categorized as excessive or not excessive based on clinical guidelines. DiscussionEffective strategies to prevent obesity development are lacking. Exposures during the prenatal period are important in the establishment of the offspring phenotype. However, it is largely unknown which exposures can be successfully targeted to have a meaningful impact. This study will determine if prenatal DHA supplementation modifies the relationship between maternal weight gain and offspring FM and FM distribution at 24 months of age. Ethics and disseminationThe University of Kansas Medical Center Institutional Review Board (IRB) approved the study protocol (STUDY00140895). The results of the trial will be disseminated at conferences and in peer reviewed publications.Trial registration: ClinicalTrials.gov ID: NCT03310983

Improvement of retinal function in Alzheimer disease-associated retinopathy by dietary lysophosphatidylcholine-EPA/DHA

Alzheimer disease (AD) is the most prevalent cause of dementia in the elderly. Although impaired cognition and memory are the most prominent features of AD, abnormalities in visual functions often precede them, and are increasingly being used as diagnostic and prognostic markers for the disease. Retina contains the highest concentration of the essential fatty acid docosahexaenoic acid (DHA) in the body, and its deficiency is associated with several retinal diseases including diabetic retinopathy and age related macular degeneration. In this study, we tested the hypothesis that enriching retinal DHA through a novel dietary approach could ameliorate symptoms of retinopathy in 5XFAD mice, a widely employed model of AD. The results show that 5XFAD mice have significantly lower retinal DHA compared to their wild type littermates, and feeding the lysophosphatidylcholine (LPC) form of DHA and eicosapentaenoic acid (EPA) rapidly normalizes the DHA levels, and increases retinal EPA by several-fold. On the other hand, feeding similar amounts of DHA and EPA in the form of triacylglycerol had only modest effects on retinal DHA and EPA. Electroretinography measurements after 2 months of feeding the experimental diets showed a significant improvement in a-wave and b-wave functions by the LPC-diet, whereas the TAG-diet had only a modest benefit. Retinal amyloid β levels were decreased by about 50% by the LPC-DHA/EPA diet, and by about 17% with the TAG-DHA/EPA diet. These results show that enriching retinal DHA and EPA through dietary LPC could potentially improve visual abnormalities associated with AD.

Light induces peridinin and docosahexaenoic acid accumulation in the dinoflagellate Durusdinium glynnii.

Peridinin is a light-harvesting carotenoid present in phototrophic dinoflagellates and has great potential for new drug applications and cosmetics development. Herein, the effects of irradiance mediated by light-emitting diodes on growth performance, carotenoid and fatty acid profiles, and antioxidant activity of the endosymbiotic dinoflagellate Durusdinium glynnii were investigated. The results demonstrate that D. glynnii is particularly well adapted to low-light conditions; however, it can be high-light-tolerant. In contrast to other light-harvesting carotenoids, the peridinin accumulation in D. glynnii occurred during high-light exposure. The peridinin to chlorophyll-a ratio varied as a function of irradiance, while the peridinin to total carotenoids ratio remained stable. Under optimal irradiance for growth, there was a peak in docosahexaenoic acid (DHA) bioaccumulation. This study contributes to the understanding of the photoprotective role of peridinin in endosymbiont dinoflagellates and highlights the antioxidant activity of peridinin-rich extracts. KEY POINTS: • Peridinin has a protective role against chlorophyll photo-oxidation • High light conditions induce cellular peridinin accumulation • D. glynnii accumulates high amounts of DHA under optimal light supply.

A study of nutritional properties in European pilchard, Golden grey mullet, and Common sole caught in Mersin Bay, North-east Mediterranean Sea

European pilchard (Sardina pilchardus, Walbaum, 1792), Golden grey mullet (Liza aurata, Risso 1810), and Common sole (Solea solea, Quensel, 1806) are the commercially important fish species caught by trawl and purse seine in Mersin Bay, in the Mediterranean. This study was aimed to investigate proximate compositions, carbohydrate levels, energy contents, fatty acid profiles, and the lipid quality indexes of European pilchard, Golden grey mullet, and Common sole caught by trawl. The crude protein, lipid, moisture, and ash content were determined as proximate compositions. The protein levels were determined as the highest levels in sardine (24.08%) followed by the common sole (18.91%) and golden grey mullet (18.01%). An inverse correlation between the moisture contents and the lipid levels among the fish was observed in this study. The ash levels, carbohydrate values, and energy contents were in the following order: European pilchard > Golden grey mullet > Common sole. Palmitic acid (C16:0) and oleic acid (C18:1n9) were the highest level of fatty acids in SFA (saturated fatty acids) and MUFA (monounsaturated fatty acids) for the Golden grey mullet and Common sole, respectively. The levels of eicosapentaenoic acid (EPA) in all fish used in this study were found to be different from each other (P<0.05). The amount of docosahexaenoic acid (DHA) were lower than that of EPA in European pilchard and Golden grey mullet. Although the levels of EPA and DHA in fish are found to be in the range of 4.91 - 11.01% and 6.85 - 8.87%, respectively and different from each other, these two fatty acids are good for health.

Optimizing the production of docosahexaenoic fatty acid by Crypthecodinium cohnii and reduction in process cost by using a dark fermentation effluent

Recovery of omega-3 fatty acids (FAs) from microalgae constitutes a valuable alternative to fish oil, and offers the ability to isolate a single ω-3 FA, instead of a mixture. In the framework of the concept of circular economy and sustainability, in the current work, an alternative carbon source was used as feed for oleaginous microalga Crypthecodinium cohnii cultivation and, consequently, production of the omega-3 FA, docosahexaenoic acid (DHA). The conditions that improve DHA production in a fed-batch culture of C. cohnii, using an organic acid-rich liquid fraction of dark fermented biowaste as feed, were studied and optimized. The process was mathematically approached focusing on a proper Design of Experiments (DoE) method coupled with Response Surface Methodology (RSM). The temperature of 23 °C and the use of yeast extract (YE) as initial nitrogen source favored the amount of DHA recovered. In addition, the increase of the volatile FA (VFA) concentration of the feed enhanced the recovered cell biomass. In order to propose a final fermentation protocol with industrial potential and evaluate the annual total cost for the production of DHA, fermentation process was scaled-up and economically evaluated through cost analysis. The increase of bioreactor size from 1 to 20 m3 leads to a significant decrease in the cost of produced DHA while leveling at higher capacities.

Long-Chain Polyunsaturated Fatty Acids n-3 (n-3 LC-PUFA) as Phospholipids or Triglycerides Influence on Epinephelus marginatus Juvenile Fatty Acid Profile and Liver Morphophysiology.

Simple SummaryFish feeding is responsible for almost 60% of the total cost of marine fish production, so nutritional studies are always in demand. Dusky grouper is a promising species for aquaculture, but studies of the species’ nutrition are still lacking. The present study investigated the effects of fatty acids, provided as different lipid classes in four different diets, for Epinephelus marginatus fingerlings and evaluated their physiological and morphological responses in order to provide new insights about grouper nutrition. The fatty acids, provided as different lipid classes, modified the physiological and morphological responses of E. marginatus, showing that the inclusion of these lipids as different classes should be considered in order to obtain better results in terms of fish fillet quality. These results provided valuable insights into the nutrition and physiology of dusky groupers, helping to pave the way for the establishment of this fish species as a produced species worldwide.Phospholipids (PL) are membrane components composed of fatty acids (FA), while triglycerides (TG) are a main source of energy and essential FA. Polyunsaturated FA (PUFA), such as docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA), are essential for marine carnivorous fish; thus, an 8-week experiment was performed to evaluate the influence of DHA and EPA, provided as PL and TG, on the morphophysiology of Epinephelus marginatus juveniles. A basal diet was manufactured, and DHA and EPA in PL form (PL1—low amount PL2—high amount) and TG form (TG1—low amount; TG2—high amount) were added. Dusky grouper juveniles were equally distributed in 12 tanks of 20 animals each, and liver and muscle were sampled for metabolic analysis. The total hepatic lipids in PL1 and PL2 were higher when compared to the initial, TG1 and TG2 groups. Total lipids in muscle were higher in PL2 and TG1 than PL1 and TG2, respectively. Diets rich in DHA and EPA in PL and TG resulted in higher deposition of these FA in the muscle polar fraction. However, fish fed diets containing lower amounts of DHA and EPA in PL and TG stored those in the muscle neutral fraction and liver, centralizing the storage of DHA and EPA.

Poor nutritional quality of primary producers and zooplankton driven by eutrophication is mitigated at upper trophic levels.

Eutrophication and rising water temperature in freshwaters may increase the total production of a lake while simultaneously reducing the nutritional quality of food web components. We evaluated how cyanobacteria blooms, driven by agricultural eutrophication (in eutrophic Lake Köyliöjärvi) or global warming (in mesotrophic Lake Pyhäjärvi), influence the biomass and structure of phytoplankton, zooplankton, and fish communities. In terms of the nutritional value of food web components, we evaluated changes in the ω‐3 and ω‐6 polyunsaturated fatty acids (PUFA) of phytoplankton and consumers at different trophic levels. Meanwhile, the lakes did not differ in their biomasses of phytoplankton, zooplankton, and fish communities, lake trophic status greatly influenced the community structures. The eutrophic lake, with agricultural eutrophication, had cyanobacteria bloom throughout the summer months whereas cyanobacteria were abundant only occasionally in the mesotrophic lake, mainly in early summer. Phytoplankton community differences at genus level resulted in higher arachidonic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) content of seston in the mesotrophic than in the eutrophic lake. This was also reflected in the EPA and DHA content of herbivorous zooplankton (Daphnia and Bosmina) despite more efficient trophic retention of these biomolecules in a eutrophic lake than in the mesotrophic lake zooplankton. Planktivorous juvenile fish (perch and roach) in a eutrophic lake overcame the lower availability of DHA in their prey by more efficient trophic retention and biosynthesis from the precursors. However, the most efficient trophic retention of DHA was found with benthivorous perch which prey contained only a low amount of DHA. Long‐term cyanobacterial blooming decreased the nutritional quality of piscivorous perch; however, the difference was much less than previously anticipated. Our result shows that long‐term cyanobacteria blooming impacts the structure of plankton and fish communities and lowers the nutritional quality of seston and zooplankton, which, however, is mitigated at upper trophic levels.

Comparison of nutrient contents of wild and farmed rainbow trout ( Oncorhynchus mykiss , Walbaum 1792) from Keban Dam Lake in Eastern Anatolia region of Turkey

In this study, fatty acids, fat-soluble vitamins (A, D, E, K vitamins) and cholesterol contents of wild-caught and farm-raised rainbow trout (Oncorhynchus mykiss) were compared. The amounts of docosahexaenoic acid (22:6 n-3, DHA) in wild and farmed forms were 21.56%–18.14%, 18.79%–16.21% and 14.34%–11.49% in April, May and June, respectively. Vitamin E, which is one of the fat-soluble and antioxidant vitamins, showed highest level among the vitamins. Vitamin E levels in both wild and farmed fish were 5.11–4.26, 4.83–2.89 and 0.99–1.95 mg/100 g in April, May and June, respectively. The substantial difference between wild and farmed rainbow trout was found in May (p < 0.05). In conclusion, both wild and farmed rainbow trout from Keban Dam Lake (Pertek Region) can be considered as good sources of n-3 polyunsaturated fatty acids (PUFA). However, it was observed that the n-3 PUFA level in wild form was higher than the culture fish within the investigated monthly periods. On the other hand, farmed fish demonstrated higher levels of n-6 PUFA over the wild individuals.

Lipid Indexes and Quality Evaluation of Omega-3 Rich Oil from the Waste of Japanese Spanish Mackerel Extracted by Supercritical CO2.

Japanese Spanish mackerel (JSM) (Scomberomorus niphonius) is a marine fish species containing health-beneficial polyunsaturated fatty acids (PUFAs). In the present study, the quality of JSM by-products oils extracted by supercritical CO2 (SC-CO2) and organic solvent extraction was compared in terms of physico-chemical properties of the oils. Eicosapentaenoic acid (EPA) is one of the important polyunsaturated fatty acids present in SC-CO2-extracted skin and muscle oil 5.81 ± 0.69% and 4.93 ± 0.06%, respectively. The amount of docosahexaenoic acid (DHA) in SC-CO2-extracted skin and muscle oil was 12.56 ± 0.38% and 15.01 ± 0.28%, respectively. EPA and DHA are considered as important PUFAs for the development of brain function and the prevention of coronary heart diseases. Extracted oils showed considerable antioxidant activity. In the obtained oils, atherogenic index (AI) values varied from 0.72 to 0.93 and thrombogenic index (TI) ranged from 0.75 to 0.92, which is considered an acceptable level. Fatty acid composition, bio potentiality, thermogravimetric, and vitamin D analysis showed that oils extracted from JSM by-products can be a good source of oil for application in food, pharmaceutical and cosmetic industries. Therefore, the present research revealed the potentiality of green valorisation of S. niphonius by-products as a possible sustainable approach for targeting the era of zero waste.

High DHA algae meal as cost-effective alternative to high DHA fish oil in finisher feed for sobaity sea bream (Sparidentex hasta)

This study evaluated the effects of high DHA algae meal (AlgaPrime™ DHA) as cost-effective substitute for high DHA fish oil in finisher feeds on growth performance and nutritional quality of sobaity (Sparidentex hasta) muscle. The amount of docosahexaenoic acid (DHA) in finisher feeds were fixed at 9.34% DHA (i.e 0.1.82 g DHA 100−1 g feed), a level equivalent to a commercial finisher feed (Focus Omega 3 P, Skretting, Italy). Two experimental finisher diets (Diets 2 and 3) were prepared by adding high DHA fish oil and high DHA algae meal, respectively into a basal diet (Optibream 3 P, Skretting, Italy) which was used as grow out diet (Diet 1). A commercial finisher feed (Focus Omega 3 P, Skretting, Italy) was used as Diet 4. Each treatment had three replicates in a randomized block design. Fish in all treatments were fed with the same grow-out feed from the beginning for 3 month and then, three treatment received finisher feeds for another 2 months. All finisher feed treatments resulted in significantly (P < 0.05) better growth performance, feed utilization and higher tissue eicosapentaenoic acid (EPA) and DHA content compared to those receiving the grow-out feed (Diet 1). No significant (P > 0.05) differences were observed between growth and muscle DHA and EPA levels of fish receiving fish oil (Diet 2) and high DHA algae meal (Diet 3)-based finisher feeds. The muscle DHA levels of fish in finisher diets 2 and 3 were also higher (P < 0.05) than those receiving commercial finisher diet (Diet 4). Muscle DHA and EPA in fish receiving finisher feeds were also higher than those of wild sobaity muscle. No significant (P > 0.05) differences were observed between muscle sensory attributes of wild and cultured sobaity. The inclusion of high DHA algae meal at 7% level in the finisher diet also enhanced the non-immunity factors like lysozyme and phagocytic activity of fish. Compared to the grow-out diet, both high DHA algae meal and fish oil diets showed significant elevated levels of immune gene expression for interleukin and superoxide dismutase. The results of the present study demonstrated that high DHA algae meal can be a cost-effective alternative to high DHA fish oil in finisher feeds for sobaity bream.

Effects of maternal intake of docosahexaenoic acid on febrile status epilepticus and increased susceptibility to seizures after growth

Febrile seizures are caused by an abrupt increase in body temperature. They are sometimes recurrent, and the more seizures are triggered, the higher the risk of epilepsy and psychiatric disorders increase after growing up. Prevention of febrile seizure is considered to be one of the effective countermeasures in protecting the future health of children. Docosahexaenoic acid (DHA) is an important nutrient especially during pregnancy and childhood and is reported to suppress several types of epilepsy. Therefore, we challenged maternal DHA intake to prevent febrile seizures and secondary epilepsy after growth in mice. We used a heat chamber for febrile seizure induction. Intake of DHA during pregnancy and infancy increased the amount of DHA in the brain of offspring. DHA prolonged the seizure latency and increased body temperature at which the first seizure occurred, indicating that maternal DHA intake decreases febrile seizure sensitivity. The mice with febrile status epilepticus showed increased susceptibility to seizures induced by pentylenetetrazol. DHA intake during infancy suppressed the appearance of excitatory electroencephalography and prolonged the seizure latency. Collectively, DHA intake during pregnancy and infancy is of significance in protecting infant from seizures as well as conserving health after growth.

Comparative Study of Astaxanthin, Cholesterol, Fatty Acid Profiles, and Quality Indices Between Shrimp Oil Extracted From Hepatopancreas and Cephalothorax.

Shrimp oil from two different portions of Pacific white shrimp including cephalothorax and hepatopancreas was extracted using the mixture of hexane/isopropanol (1:1). The extracted oils from the cephalothorax (CPO) and hepatopancreas (HPO) were characterized for astaxanthin content, cholesterol levels, and fatty acid profiles. Nutrition indices of CPO and HPO were also compared. CPO had lower extraction yield (3.2 ± 0.1%, wet weight basis) than HPO (11.1 ± 0.5%, wet weight basis). High-performance liquid chromatography results indicated that the astaxanthin content in HPO was higher, compared to that of CPO. Nevertheless, the cholesterol level in HPO was 70% lower than that of CPO. Fatty acid profiles of HPO and CPO demonstrated that the polyunsaturated fatty acid (PUFA) content in HPO was higher than that of CPO. The amount of docosahexaenoic acid in the former was ~2 times higher than that of the latter. HPO contained 42.76 ± 0.36% PUFA, whereas PUFA content of CPO was 35.27 ± 0.19%. On the other hand, saturated fatty acids (SFA) were more pronounced in CPO (38.44 ± 0.26%) than HPO (30.82 ± 0.55%). Based on nutrition indices, namely, atherogenicity index, thrombogenicity index, hypocholesterolemic/hypercholesterolemic (h/H) ratio, and PUFA/SFA ratio, HPO possessed higher health benefit than CPO. The oxidation status of CPO and HPO measured in terms of peroxide value, thiobarbituric acid reactive substances, anisidine value, and conjugated dienes indicated that higher primary oxidation products were present in CPO, whereas HPO exhibited more secondary oxidation compounds. Fourier transform infrared spectra further substantiated the presence of oxidation products in CPO and HPO. Liquid chromatography-mass spectrometry identification showed the enhanced levels of phospholipids and glycolipids in the ethanolic fraction of CPO. Overall, HPO with a higher yield was more beneficial in terms of health benefits than CPO.

Chemical and Physical Culture Conditions Significantly Influence the Cell Mass and Docosahexaenoic Acid Content of Aurantiochytrium limacinum Strain PKU#SW8.

Thraustochytrids are well-known unicellular heterotrophic marine protists because of their promising ability to accumulate docosahexaenoic acid (DHA). However, the implications of their unique genomic and metabolic features on DHA production remain poorly understood. Here, the effects of chemical and physical culture conditions on the cell mass and DHA production were investigated for a unique thraustochytrid strain, PKU#SW8, isolated from the seawater of Pearl River Estuary. All the tested fermentation parameters showed a significant influence on the cell mass and concentration and yield of DHA. The addition of monosaccharides (fructose, mannose, glucose, or galactose) or glycerol to the culture medium yielded much higher cell mass and DHA concentrations than that of disaccharides and starch. Similarly, organic nitrogen sources (peptone, yeast extract, tryptone, and sodium glutamate) proved to be beneficial in achieving a higher cell mass and DHA concentration. PKU#SW8 was found to grow and accumulate a considerable amount of DHA over wide ranges of KH2PO4 (0.125–1.0 g/L), salinity (0–140% seawater), pH (3–9), temperature (16–36 °C), and agitation (140–230 rpm). With the optimal culture conditions (glycerol, 20 g/L; peptone, 2.5 g/L; 80% seawater; pH 4.0; 28 °C; and 200 rpm) determined based on the shake-flask experiments, the cell mass and concentration and yield of DHA were improved up to 7.5 ± 0.05 g/L, 2.14 ± 0.03 g/L, and 282.9 ± 3.0 mg/g, respectively, on a 5-L scale fermentation. This study provides valuable information about the fermentation conditions of the PKU#SW8 strain and its unique physiological features, which could be beneficial for strain development and large-scale DHA production.

Method Development Progress in Genetic Engineering of Thraustochytrids.

Thraustochytrids are unicellular, heterotrophic marine eukaryotes. Some species are known to store surplus carbon as intracellular lipids, and these also contain the long-chain polyunsaturated fatty acid docosahexaenoic acid (DHA). Most vertebrates are unable to synthesize sufficient amounts of DHA, and this fatty acid is essential for, e.g., marine fish, domesticated animals, and humans. Thraustochytrids may also produce other commercially valuable fatty acids and isoprenoids. Due to the great potential of thraustochytrids as producers of DHA and other lipid-related molecules, a need for more knowledge on this group of organisms is needed. This necessitates the ability to do genetic manipulation of the different strains. Thus far, this has been obtained for a few strains, while it has failed for other strains. Here, we systematically review the genetic transformation methods used for different thraustochytrid strains, with the aim of aiding studies on strains not yet successfully transformed. The designs of transformation cassettes are also described and compared. Moreover, the potential problems when trying to establish transformation protocols in new thraustochytrid species/strains are discussed, along with suggestions utilized in other organisms to overcome similar challenges. The approaches discussed in this review could be a starting point when designing protocols for other non-model organisms.

Plant and algal lysophosphatidic acid acyltransferases increase docosahexaenoic acid accumulation at the sn-2 position of triacylglycerol in transgenic Arabidopsis seed oil.

Although docosahexaenoic acid (DHA), an important dietary omega-3 polyunsaturated fatty acid (PUFA), is at present primarily sourced from marine fish, bioengineered crops producing DHA may offer a more sustainable and cost-effective source. DHA has been produced in transgenic oilseed crops, however, DHA in seed oil primarily occupies the sn-1/3 positions of triacylglycerol (TAG) with relatively low amounts of DHA in the sn-2 position. To increase the amount of DHA in the sn-2 position of TAG and in seed oil, putative lysophosphatidic acid acyltransferases (LPAATs) were identified and characterized from the DHA-producing alga Schizochytrium sp. and from soybean (Glycine max). The affinity-purified proteins were confirmed to have LPAAT activity. Expression of the Schizochytrium or soybean LPAATs in DHA-producing Arabidopsis expressing the Schizochytrium PUFA synthase system significantly increased the total amount of DHA in seed oil. A novel sensitive band-selective heteronuclear single quantum coherence (HSQC) NMR method was developed to quantify DHA at the sn-2 position of glycerolipids. More than two-fold increases in sn-2 DHA were observed for Arabidopsis lines expressing Schizochytrium or soybean LPAATs, with one Schizochytrium LPAAT driving DHA accumulation in the sn-2 position to 61% of the total DHA. Furthermore, expression of a soybean LPAAT led to a redistribution of DHA-containing TAG species, with two new TAG species identified. Our results demonstrate that transgenic expression of Schizochytrium or soybean LPAATs can increase the proportion of DHA at the sn-2 position of TAG and the total amount of DHA in the seed oil of a DHA-accumulating oilseed plant. Additionally, the band-selective HSQC NMR method that we developed provides a sensitive and robust method for determining the regiochemistry of DHA in glycerolipids. These findings will benefit the advancement of sustainable sources of DHA via transgenic crops such as canola and soybean.