Tag Archive for: Omega 3

Post-mortem storage conditions and cooking methods affect long-chain omega-3 fatty acid content in Atlantic mackerel (Scomber scombrus)

Omega-3 fatty acids are essential for human health and are found especially in marine fish. They degrade easily over time and at high temperatures, but to what extent? This is what we tested on mackerel. The loss of omega-3 was not particularly high in the first few hours after the fishes were caught, but it was still best to store them as cold as possible. For cooking, it is better to grill the mackerel fillet with its skin than to steam it. Bon appétit !

 

Abstract

Long-chain omega-3 fatty acids such as eicosapentaenoic (EPA) and docosahexaenoic acids (DHA) are health beneficial lipids found in high concentration in pelagic fishes, including Atlantic mackerel. While EPA and DHA are sensitive to oxidation during fish storage and processing, post-mortem degradation in the first hours following fish death is poorly documented. Here, we stored fish at two temperatures (2–4 °C and 18–20 °C) and monitored EPA + DHA content in dorsal fillet 6, 12 and 24 h after fish death and after cooking (grill or steam). Storage duration was the only influencing factor, and EPA + DHA loss was faster at 18–20 °C. Six hours after fish death, EPA + DHA content decreased by 1.3 ± 1.3 mg.g−1 dw (9.6 ± 9.5% of the initial content) but it was highly variable among individuals. Handling between fishing and storage should be as short and as cool as possible to preserve EPA + DHA and food safety. Regarding cooking, EPA + DHA and mono-unsaturated fatty acids increased in grilled fillets.

 

Graphical abstract

Fig.1: Outline of the sampling design testing for the influence of storage temperature (2–4 ◦C and 18–20 ◦C), storage duration (from T6 to T24 hours), and cooking method (grill and steam) on the fatty acid content of the Atlantic mackerel Scomber scombrus. Dark squares indicate the muscle sampling position at each step, and the grey ones the previously sampled positions. For cooking, we sampled the left side of the fish.

 

Highlights

  • Storage duration (< 24h) had a higher impact than storage temperature on EPA + DHA content in mackerel dorsal fillet.
  • EPA + DHA and mono-unsaturated fatty acids content increased in grilled fillets.
  • EPA + DHA losses in mackerel dorsal fillet were highly variable among individuals.

 

Reference

Fany Sardenne, Eleonora Puccinelli, Marie Vagner, Laure Pecquerie, Antoine Bideau, et al.. Post-mortem storage conditions and cooking methods affect long-chain omega-3 fatty acid content in Atlantic mackerel (Scomber scombrus). Food Chemistry, Elsevier, 2021, 359, pp.129828. ⟨10.1016/j.foodchem.2021.129828⟩.

The article is also available in open access on HAL : https://hal.archives-ouvertes.fr/hal-03215360

Relationship between membrane n-3 HUFA content and mitochondrial efficiency

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The relationship between membrane fatty acid content and mitochondrial efficiency differs within- and between- omega-3 dietary treatments

 

Abstract

An important, but underappreciated, consequence of climate change is the reduction in crucial nutrient production at the base of the marine food chain: the long-chain omega-3 highly unsaturated fatty acids (n-3 HUFA). This can have dramatic consequences on consumers, such as fish as they have limited capacity to synthesise n-3 HUFA de novo. The n-3 HUFA, such as docosahexaenoic acid (DHA, 22:6n-3) and eicosapentaenoic acid (EPA, 20:5n-3), are critical for the structure and function of all biological membranes. There is increasing evidence that fish will be badly affected by reductions in n-3 HUFA dietary availability, however the underlying mechanisms remain obscure. Hypotheses for how mitochondrial function should change with dietary n-3 HUFA availability have generally ignored ATP production, despite its importance to a cell’s total energetics capacity, and in turn, whole-animal performance. Here we (i) quantified individual variation in mitochondrial efficiency (ATP/O ratio) of muscle and (ii) examined its relationship with content in EPA and DHA in muscle membrane of a primary consumer fish, the golden grey mullet Chelon auratus, receiving either a high or low n-3 HUFA diet. Mitochondria of fish fed on the low n-3 HUFA diet had higher ATP/O ratio than those of fish maintained on the high n-3 HUFA diet. Yet, mitochondrial efficiency varied up about 2-fold among individuals on the same dietary treatment, resulting in some fish consuming half the oxygen and energy substrate to produce the similar amount of ATP than conspecific on similar diet. This variation in mitochondrial efficiency among individuals from the same diet treatment was related to individual differences in fatty acid composition of the membranes: a high ATP/O ratio was associated with a high content in EPA and DHA in biological membranes. Our results highlight the existence of interindividual differences in mitochondrial efficiency and its potential importance in explaining intraspecific variation in response to food chain changes.

 

Figure 2: A golden grey mullet’s mitochondrial efficiency of ATP production under Low and High n-3 HUFA diet is related to the n-3 content (docosahexaenoic acid (DHA, 22:6n-3) and eicosapentaenoic acid (EPA, 20:5n-3)) of its membrane phospholipids, with individuals that have mitochondria with higher ability to make ATP had higher membrane n-3 content.

 

Reference

Salin K, Mathieu-Resuge M, Graziano N, Dubillot E, Le Grand F, Soudant P, Vagner M. 2020. The relationship between membrane fatty acid content and mitochondrial efficiency differs within- and between- omega-3 dietary treatments. Marine Environmental Research:105205.

https://doi.org/10.1016/j.marenvres.2020.105205

Effects of Omega 3 depletion on marine fish: ecophysiological approach

There is increasing evidence that climate change might critically deplete nutrients in food web of marine fish. In particular, a reduction in the production of Omega 3 (Ω3) in phytoplankton as a result of ocean warming can have negative impact on fish. Ω3 are fatty acids that are essential components of cell membranes. Such depletion in Ω3 in membranes can impair fish performance, however, the underlying mechanisms remain obscure. Mitochondria are likely to be involved in the fish response to Ω3 depletion. Changes in the composition of membrane fatty acid of mitochondria affect their efficiency. Organisms that have less efficient mitochondria are less able to maintain ATP [Adenosine TriPhosphate) production, a feature that is likely to affect the overall animal performance. This PhD work will therefore evaluate how the reduction in dietary Ω3 affect mitochondrial function and in turn the performance of a fish, the mullet (Liza aurata)

Thesis supervisor: José-Luis Zambonino-Infante

Thesis co-supervisor: Karine Salin

Read the terms and conditions and download the application form here:

https://wwz.ifremer.fr/Actualites-et-Agenda/Toutes-les-actualites/Theses-2019

Applications must be submitted before 30 June 2019, but we strongly encourage you to announce your intention to apply as soon as possible, by contacting the persons in charge of the subject.

Tag Archive for: Omega 3

Mathilde BERTRAND thèse

PERON Mickaël thèse

Quemeneur Jean-Baptiste thèse

Tag Archive for: Omega 3

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