The metabolism and availability of essential fatty acids in animal and human tissues

Bézard, J.; Blond, JP; Bernard, A.; Clouet, Pierre

doi:10.1051/rnd:19940603

Cited by 191 publications

(116 citation statements)

References 110 publications

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“…Changes in hepatic desaturase activity during aging vary according to species (Bourre 2004). They are reported to be decreased in mice (Bourre and Piciotti 1992), but slightly modified (Bourre et al 1990;Dinh et al 1995) or unchanged (Bezard et al 1994) in rats, which is consistent with our results showing age invariance of the conversion coefficients. Despite the unchanging plasma concentrations of esterified n-3 PUFAs with age, each of the respective unesterified concentrations declined (Table 2).…”

Section: Discussionsupporting

confidence: 93%

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RETRACTED ARTICLE: Aging decreases rate of docosahexaenoic acid synthesis-secretion from circulating unesterified α-linolenic acid by rat liver

Gao

Taha

et al. 2012

AGE

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Docosahexaenoic acid (DHA,, an n-3 polyunsaturated fatty acid (PUFA) found at high concentrations in brain and retina and critical to their function, can be obtained from fish products or be synthesized from circulating α-linolenic acid (α-LNA, 18:3n-3) mainly in the liver. With aging, liver synthetic enzymes are reported reduced or unchanged in the rat. To test whether liver synthesis-secretion of DHA from α-LNA changes with age, we measured whole-body DHA conversion coefficients and rates in unanesthetized adult male Fischer-344 rats aged 10, 20, or 30 months, fed an eicosapentaenoic acid (EPA, 20:5n-3)-and DHAcontaining diet. Unesterified [U-13 C]α-LNA bound to albumin was infused intravenously for 2 h, while [ 13 C]-esterified n-3 PUFAs were measured in arterial plasma, as were unlabeled unesterified and esterified PUFA concentrations. Plasma unesterified n-3 PUFA concentrations declined with age, but esterified n-3 PUFA concentrations did not change significantly. Calculated conversion coefficients were not changed significantly with age, whereas synthesis-secretion rates (product of conversion coefficient and unesterified plasma α-LNA concentration) of esterified DHA and n-3 DPA were reduced. Turnovers of esterified n-3 PUFAs in plasma decreased with age, whereas half-lives increased. The results suggest that hepatic capacity to synthesize DHA and other n-3 PUFAs from circulating α-LNA is maintained with age in the rat, but that reduced plasma α-LNA availability reduces net synthesis-secretion. As unesterified plasma DHA is the form that is incorporated preferentially into brain phospholipid, its reduced synthesis may be deleterious to brain function in aged rats.

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Section: Discussionsupporting

confidence: 93%

“…However, reported changes in hepatic desaturase activities during aging vary according to species (Bourre 2004). They are decreased in mice (Bourre and Piciotti 1992), but are slightly modified (Bourre et al 1990;Dinh et al 1995) or unchanged (Bezard et al 1994) in rats. Thus, there is a lack of agreement on liver synthesis of n-3 PUFAs with aging in rodents.…”

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confidence: 91%

RETRACTED ARTICLE: Aging decreases rate of docosahexaenoic acid synthesis-secretion from circulating unesterified α-linolenic acid by rat liver

Gao

Taha

et al. 2012

AGE

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“…Similar effects have been found in rats (Bé zard et al, 1994) and piglets (Theil and Lauridsen, 2007). In contrast, in a human hepatoma cell line a suppression of D6-desaturase mRNA content was seen after the addition of LA or ALA (Portolesi et al, 2008).…”

Section: Discussionsupporting

confidence: 81%

“…In contrast to our study, these authors compensated the higher intake of ALA with a decrease in the intake of other fatty acids. We believe that caution should be taken in choosing this exchange approach, as there is evidence that other lipids such as LA, oleic acid and myristic acid (c14:0) can alter hepatic desaturase activity as well (Bé zard et al, 1994;Jan et al, 2004;Portolesi et al, 2008;Rioux et al, 2008). These fatty acids may contribute to the observed opposite effects on plasma DHA in their studies.…”

Section: Discussionmentioning

confidence: 99%

Linoleic and α-linolenic acid as precursor and inhibitor for the synthesis of long-chain polyunsaturated fatty acids in liver and brain of growing pigs

Smink

Gerrits

Gloaguen

et al. 2012

Animal

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Studies suggested that in human adults, linoleic acid (LA) inhibits the biosynthesis of n-3 long-chain polyunsaturated fatty acids (LC-PUFA), but their effects in growing subjects are largely unknown. We used growing pigs as a model to investigate whether high LA intake affects the conversion of n-3 LC-PUFA by determining fatty acid composition and mRNA levels of D5-and D6 desaturase and elongase 2 and -5 in liver and brain. In a 2 3 2 factorial arrangement, 32 gilts from eight litters were assigned to one of the four dietary treatments, varying in LA and a-linolenic acid (ALA) intakes. Low ALA and LA intakes were 0.15 and 1.31, and high ALA and LA intakes were 1.48 and 2.65 g/kg BW 0.75 per day, respectively. LA intake increased arachidonic acid (ARA) in liver. ALA intake increased eicosapentaenoic acid (EPA) concentrations, but decreased docosahexaenoic acid (DHA) (all P , 0.01) in liver. Competition between the n-3 and n-6 LC-PUFA biosynthetic pathways was evidenced by reductions of ARA (.40%) at high ALA intakes. Concentration of EPA (.35%) and DHA (.20%) was decreased by high LA intake (all P , 0.001). Liver mRNA levels of D5-and D6 desaturase were increased by LA, and that of elongase 2 by both ALA and LA intakes. In contrast, brain DHA was virtually unaffected by dietary LA and ALA. Generally, dietary LA inhibited the biosynthesis of n-3 LC-PUFA in liver. ALA strongly affects the conversion of both hepatic n-3 and n-6 LC-PUFA. DHA levels in brain were irresponsive to these diets. Apart from D6 desaturase, elongase 2 may be a rate-limiting enzyme in the formation of DHA.

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“…Ló pezFerrer et al (1999) reported that precursors of the n-3 and n-6 families linolenic acid (LNA and LA, respectively) were increased by diets containing FO, whereas AA decreased significantly. Bé zard et al (1994) reported that the fundamental explanation related to the decreased level of AA in serum or tissues is the presence of EPA and DHA in the diet, which are capable of inhibiting n-3 elongation, n-6 FA desaturation and LA metabolism, which is also demonstrated in rats (Grønn et al, 1992). n-3 PUFAs, especially EPA and DHA, are substantial factors in this regard (James et al, 2000;Das, 2006).…”

Section: Growth Performancementioning

confidence: 99%

Blood and tissue fatty acid compositions, lipoprotein levels, performance and meat flavor of broilers fed fish oil: changes in the pre- and post-withdrawal design

Aghaei

Safamehr

Mehmannavaz

et al. 2012

Animal

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Administration of fish oil (FO) in broiler diets can elevate a-linolenic acid (ALA), eicosapentanoic acid (EPA) and docosahexanoic acid (DHA) levels, which are protective against cardiovascular disease. However, optimization based solely on n-3 polyunsaturated fatty acid (n-3 PUFA) enrichment in chicken meat could lead to lower meat quality, unless the withdrawal period (plan) is applied for 1 week. The present study investigated whether the incorporation of FO in the diet for 32 days followed by its withdrawal for 1 week affected blood lipid profiles, lipoprotein particles, performance and meat flavor in male broiler chickens. Two hundred and forty birds (1-day-old, Ross 308) were assigned to 1 of 4 dietary groups: 0%, 1%, 2% or 3% FO with four replicates. Broilers were fed for 49 days according to a 4-phase feeding program. The experimental phase comprised day 11 to 42, and FO was removed on day 42. Blood samples were collected during the pre-and post-withdrawal period after the recordings before slaughter. The FO groups demonstrated decreased low-density lipoprotein (LDL) and increased high-density lipoprotein levels on day 42 (P , 0.01); however, these values were not significant after design withdrawal. Diet supplementation with FO elevated the blood levels of palmitic acid (C16:0) and n-3 PUFAs, especially long-chain (LC) PUFAs (EPA, C20:5n-3 and DHA, C22:6n-3), and caused a decline in the level of arachidonic acid (AA, C20:4n-6; P , 0.05). Application of a one-week withdrawal period resulted in a decrease in (P , 0.05) linoleic acid (C18:2n-6) and an increase in the level of AA, unlike their amounts on day 42. Although blood and tissue LC n-3 PUFA levels on day 49 were significantly higher in the FO groups compared with the control, they demonstrated a substantial decrease on day 49 compared with day 42. The best results, mainly the lowest n-6/n-3 fatty acids (FAs) and feed conversion ratio (FCRs), were observed for 3% FO (group T4), even after institution of the withdrawal design. Degradation of total n-3 FAs deposited in tissues occurred after instituting the withdrawal plan diet, but deposited levels of EPA and DHA in tissues could ensure omega-3 enrichment of broiler meat in groups 3 and 4. On the basis of the dissatisfaction of the panelists toward group 4 meats (scored as near to acceptable) and their satisfaction with cooked samples of T3 (scored as good), group 3 meats were selected as good-quality n-3-enriched broiler meat.

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The metabolism and availability of essential fatty acids in animal and human tissues

Cited by 191 publications

References 110 publications

RETRACTED ARTICLE: Aging decreases rate of docosahexaenoic acid synthesis-secretion from circulating unesterified α-linolenic acid by rat liver

RETRACTED ARTICLE: Aging decreases rate of docosahexaenoic acid synthesis-secretion from circulating unesterified α-linolenic acid by rat liver

Linoleic and α-linolenic acid as precursor and inhibitor for the synthesis of long-chain polyunsaturated fatty acids in liver and brain of growing pigs

Blood and tissue fatty acid compositions, lipoprotein levels, performance and meat flavor of broilers fed fish oil: changes in the pre- and post-withdrawal design

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