scholarly journals A complete enzymatic capacity for biosynthesis of docosahexaenoic acid (DHA, 22 : 6n–3) exists in the marine Harpacticoida copepod Tigriopus californicus

Open Biology ◽  
2021 ◽  
Vol 11 (4) ◽  
Author(s):  
Naoki Kabeya ◽  
Masanari Ogino ◽  
Hideki Ushio ◽  
Yutaka Haga ◽  
Shuichi Satoh ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Docosahexaenoic Acid ◽  
De Novo ◽  
Essential Fatty Acids ◽  
Harpacticoid Copepod ◽  
Fatty Acyl ◽  
Trophic Levels ◽  
Biosynthetic Pathways ◽  
Tigriopus Californicus ◽  
Front End

The long-standing paradigm establishing that global production of Omega-3 (n–3) long-chain polyunsaturated fatty acids (LC-PUFA) derived almost exclusively from marine single-cell organisms, was recently challenged by the discovery that multiple invertebrates possess methyl-end (or ω x) desaturases, critical enzymes enabling the biosynthesis of n–3 LC-PUFA. However, the question of whether animals with ω x desaturases have complete n–3 LC-PUFA biosynthetic pathways and hence can contribute to the production of these compounds in marine ecosystems remained unanswered. In the present study, we investigated the complete enzymatic complement involved in the n–3 LC-PUFA biosynthesis in Tigriopus californicus , an intertidal harpacticoid copepod. A total of two ω x desaturases, five front-end desaturases and six fatty acyl elongases were successfully isolated and functionally characterized. The T. californicus ω x desaturases enable the de novo biosynthesis of C 18 PUFA such as linoleic and α-linolenic acids, as well as several n–3 LC-PUFA from n–6 substrates. Functions demonstrated in front-end desaturases and fatty acyl elongases unveiled various routes through which T. californicus can biosynthesize the physiologically important arachidonic and eicosapentaenoic acids. Moreover, T. californicus possess a Δ4 desaturase, enabling the biosynthesis of docosahexaenoic acid via the ‘Δ4 pathway’. In conclusion, harpacticoid copepods such as T. californicus have complete n–3 LC-PUFA biosynthetic pathways and such capacity illustrates major roles of these invertebrates in the provision of essential fatty acids to upper trophic levels.

scholarly journals Elevated temperature and browning increase dietary methylmercury, but decrease essential fatty acids at the base of lake food webs

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pianpian Wu ◽  
Martin J. Kainz ◽  
Fernando Valdés ◽  
Siwen Zheng ◽  
Katharina Winter ◽  
...  
Keyword(s):  
Climate Change ◽  
Fatty Acids ◽  
Organic Matter ◽  
Food Webs ◽  
Essential Fatty Acids ◽  
Trophic Levels ◽  
Climate Change Scenarios ◽  
Essential Nutrients ◽  
Aquatic Food Webs ◽  
Aquatic Food

AbstractClimate change scenarios predict increases in temperature and organic matter supply from land to water, which affect trophic transfer of nutrients and contaminants in aquatic food webs. How essential nutrients, such as polyunsaturated fatty acids (PUFA), and potentially toxic contaminants, such as methylmercury (MeHg), at the base of aquatic food webs will be affected under climate change scenarios, remains unclear. The objective of this outdoor mesocosm study was to examine how increased water temperature and terrestrially-derived dissolved organic matter supply (tDOM; i.e., lake browning), and the interaction of both, will influence MeHg and PUFA in organisms at the base of food webs (i.e. seston; the most edible plankton size for zooplankton) in subalpine lake ecosystems. The interaction of higher temperature and tDOM increased the burden of MeHg in seston (< 40 μm) and larger sized plankton (microplankton; 40–200 μm), while the MeHg content per unit biomass remained stable. However, PUFA decreased in seston, but increased in microplankton, consisting mainly of filamentous algae, which are less readily bioavailable to zooplankton. We revealed elevated dietary exposure to MeHg, yet decreased supply of dietary PUFA to aquatic consumers with increasing temperature and tDOM supply. This experimental study provides evidence that the overall food quality at the base of aquatic food webs deteriorates during ongoing climate change scenarios by increasing the supply of toxic MeHg and lowering the dietary access to essential nutrients of consumers at higher trophic levels.

scholarly journals Effects of Essential Fatty Acids Containing Natural and Commercial Diets on Larvae Rearing of the Green Mud Crab Scylla Paramamosain (Estampador 1949)

2017 ◽  
Vol 9 (1) ◽  
pp. 109-126
Author(s):  
M. L. Islam ◽  
M. S. Islam ◽  
K. Yahya ◽  
R. Hashim
Keyword(s):  
Fatty Acids ◽  
Docosahexaenoic Acid ◽  
Eicosapentaenoic Acid ◽  
Essential Fatty Acids ◽  
Scylla Paramamosain ◽  
Mud Crab ◽  
Growth And Survival ◽  
Commercial Diet ◽  
Larval Stages ◽  
Commercial Diets

Effect of essential fatty acids (EFA) on growth and survival of the green mud crab (Scylla paramamosain) larvae was assessed by feeding with natural to commercial diets. The feeding schemes were: larvae reared with Artemia (T1); larvae initially fed with rotifers (up to Z2) and ended (Z3 to megalopa) with Artemia (T2); and larvae fed with rotifers up to Z2 and ended (Z3 to megalopa) with commercial diet (T3). The commercial diet had significantly (p<0.05) higher levels of docosahexaenoic acid (11.23%), ?n-3’s (15.90%) and ?n-6’s (4.21%); and lacked in eicosapentaenoic acid (2.25%) than rotifer and Artemia. The earliest commencement of megalopa stage within 15 days with significantly (p<0.05) higher larval stage index (LSI) of 5.90±0.17 was achieved from the feeding scheme of T2 than other two feeding schemes. This feeding scheme deposited 17.32±0.19% eicosapentaenoic acid (EPA) and 3.82±0.11% docosahexaenoic acid (DHA); the ?n-3 to ?n-6 ratio of 0.20 and EPA to DHA ratio of 0.22 in megalopa, that stimulated significantly higher (p<0.05) megalopa survival (20.00±6.96%) indicating the superiority over rest feeding schemes. Meanwhile, some deformities and mortalities in Z5 and megalopa stages suggested further studies for optimization of specific fatty acid requirements for late larval stages (Z5 and megalopa).

Relationship between fish oil intake by dairy cows and the yield of eicosapentaenoic acid and docosahexaenoic acid in their milk

2001 ◽  
Vol 2001 ◽  
pp. 199-199 ◽  
Author(s):  
C. Rymer ◽  
C. Dyer ◽  
D.I. Givens ◽  
R. Allison
Keyword(s):  
Fatty Acids ◽  
Docosahexaenoic Acid ◽  
Eicosapentaenoic Acid ◽  
Fish Oil ◽  
Dairy Cows ◽  
Fish Consumption ◽  
Essential Fatty Acids ◽  
Epa And Dha ◽  
The Uk

The dietary essential fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are predominantly found in fish oil, but fish consumption in the UK is low. Increasing the yield of EPA and DHA in cows’ milk would increase human intakes of EPA and DHA, and this can be achieved by including fish oil in cows’ diets. However, because EPA and DHA are susceptible to rumen biohydrogenation, their transfer efficiency into milk is low.In vitroobservations by Gulatiet al. (1999) suggested that if the concentration of fish oil in the rumen exceeded 1 mg/ml, EPA and DHA were not hydrogenated. The objectives of this study were therefore to determine the relationships between fish oil intake by dairy cows, and the probable concentrations of fish oil in the cows’ rumen, with the yield of EPA and DHA in their milk.

scholarly journals Lipids in Marine Ecosystems

2013 ◽  
Vol 2013 ◽  
pp. 1-16 ◽  
Author(s):  
Christopher C. Parrish
Keyword(s):  
Fatty Acids ◽  
Organic Contaminants ◽  
Essential Fatty Acids ◽  
Marine Ecosystems ◽  
Sterol Composition ◽  
Trophic Levels ◽  
Data Sets ◽  
Objective Interpretation ◽  
Marine Lipids ◽  
Pollutant Bioaccumulation

Lipids provide the densest form of energy in marine ecosystems. They are also a solvent and absorption carrier for organic contaminants and thus can be drivers of pollutant bioaccumulation. Among the lipids, certain essential fatty acids and sterols are considered to be important determinants of ecosystem health and stability. Fatty acids and sterols are also susceptible to oxidative damage leading to cytotoxicity and a decrease in membrane fluidity. The physical characteristics of biological membranes can be defended from the influence of changing temperature, pressure, or lipid peroxidation by altering the fatty acid and sterol composition of the lipid bilayer. Marine lipids are also a valuable tool to measure inputs, cycling, and loss of materials. Their heterogeneous nature makes them versatile biomarkers that are widely used in marine trophic studies, often with the help of multivariate statistics, to delineate carbon cycling and transfer of materials. Principal components analysis has a strong following as it permits data reduction and an objective interpretation of results, but several more sophisticated multivariate analyses which are more quantitative are emerging too. Integrating stable isotope and lipid data can facilitate the interpretation of both data sets and can provide a quantitative estimate of transfer across trophic levels.

scholarly journals Role and significance of polyunsaturated fatty acids in nutrition in prevention and treatment of atherosclerosis

2003 ◽  
Vol 56 (1-2) ◽  
pp. 50-53 ◽  
Author(s):  
Vanja Ristic ◽  
Gordana Ristic
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Linoleic Acid ◽  
Docosahexaenoic Acid ◽  
Polyunsaturated Fatty Acids ◽  
Eicosapentaenoic Acid ◽  
Linolenic Acid ◽  
Essential Fatty Acids ◽  
Cell Functions ◽  
Starting Point

Introduction Hyperlipoproteinemia is a key factor in development of atherosclerosis, whereas regression of atherosclerosis mostly depends on decreasing the plasma level of total and LDL-cholesterol. Many studies have reported the hypocholesterolemic effect of linolenic acid. Types of polyunsaturated fatty acids (PUFA) Linoleic and ?-linolenic acids are essential fatty acids. The main sources of linoleic acid are vegetable seeds and of ?-linolenic acid - green parts of plants. ?-linolenic acid is converted to eicosapentaenoic and docosahexaenoic acid. Linoleic acid is converted into arachidonic acid competing with eicosapentaenoic acid in the starting point for synthesis of eicosanoids, which are strong regulators of cell functions and as such, very important in physiology and pathophysiology of cardiovascular system. Eicosanoids derived from eicosapentaenoic acid have different biological properties in regard to those derived from arachidonic acid, i.e. their global effects result in decreased vasoconstriction platelet aggregation and leukocyte toxicity. Role and significant of PUFA The n-6 to n-3 ratio of polyunsaturated fatty acids in the food is very important, and an optimal ratio 4 to 1 in diet is a major issue. Traditional western diets present absolute or relative deficiency of n-3 polyunsaturated fatty acids, and a ratio 15-20 to 1. In our diet fish and fish oil are sources of eicosapentaenoic and docosahexaenoic acid. Refined and processed vegetable oils change the nature of polyunsaturated fatty acids and obtained derivates have atherogenic properties.

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