Dataset Information

Influence of Dietary Long-Chain Polyunsaturated Fatty Acids and ?6 to ?3 Ratios on Head Kidney Lipid Composition and Expression of Fatty Acid and Eicosanoid Metabolism Genes in Atlantic Salmon (Salmo salar).

ABSTRACT: The interaction of dietary eicosapentaenoic acid and docosahexaenoic acid (EPA+DHA) levels with omega-6 to omega-3 ratios (?6:?3), and their impact on head kidney lipid metabolism in farmed fish, are not fully elucidated. We investigated the influence of five plant-based diets (12-week exposure) with varying EPA+DHA levels (0.3, 1.0, or 1.4%) and ?6:?3 (high ?6, high ?3, or balanced) on tissue lipid composition, and transcript expression of genes involved in fatty acid and eicosanoid metabolism in Atlantic salmon head kidney. Tissue fatty acid composition was reflective of the diet with respect to C₁₈ PUFA and MUFA levels (% of total FA), and ?6:?3 (0.5-1.5). Fish fed 0.3% EPA+DHA with high ?6 (0.3% EPA+DHA??6) had the highest increase in proportions (1.7-2.3-fold) and in concentrations (1.4-1.8-fold) of arachidonic acid (ARA). EPA showed the greatest decrease in proportion and in concentration (by ~½) in the 0.3% EPA+DHA??6 fed fish compared to the other treatments. However, no differences were observed in EPA proportions among salmon fed the high ?3 (0.3 and 1.0% EPA+DHA) and balanced (1.4% EPA+DHA) diets, and DHA proportions were similar among all treatments. Further, the transcript expression of elovl5a was lowest in the 0.3% EPA+DHA??6 fed fish, and correlated positively with 20:3?3, 20:4?3 and EPA:ARA in the head kidney. This indicates that high dietary 18:3?3 promoted the synthesis of ?3 LC-PUFA. Dietary EPA+DHA levels had a positive impact on elovl5a, fadsd5 and srebp1 expression, and these transcripts positively correlated with tissue ?MUFA. This supported the hypothesis that LC-PUFA synthesis is positively influenced by tissue MUFA levels in Atlantic salmon. The expression of pparaa was higher in the 0.3% EPA+DHA??6 compared to the 0.3% EPA+DHA??3 fed fish. Finally, significant correlations between head kidney fatty acid composition and the expression of eicosanoid synthesis-related transcripts (i.e., 5loxa, 5loxb, cox1, cox2, ptges2, ptges3, and pgds) illustrated the constitutive relationships among fatty acids and eicosanoid metabolism in salmon.

SUBMITTER: Katan T

PROVIDER: S-EPMC7767880 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Influence of Dietary Long-Chain Polyunsaturated Fatty Acids and ω6 to ω3 Ratios on Head Kidney Lipid Composition and Expression of Fatty Acid and Eicosanoid Metabolism Genes in Atlantic Salmon (<i>Salmo salar</i>).

Katan Tomer T Xue Xi X Caballero-Solares Albert A Taylor Richard G RG Rise Matthew L ML Parrish Christopher C CC

Frontiers in molecular biosciences 20201214

The interaction of dietary eicosapentaenoic acid and docosahexaenoic acid (EPA+DHA) levels with omega-6 to omega-3 ratios (ω6:ω3), and their impact on head kidney lipid metabolism in farmed fish, are not fully elucidated. We investigated the influence of five plant-based diets (12-week exposure) with varying EPA+DHA levels (0.3, 1.0, or 1.4%) and ω6:ω3 (high ω6, high ω3, or balanced) on tissue lipid composition, and transcript expression of genes involved in fatty acid and eicosanoid metabolism ...[more]

PMID: 33381522

Similar Datasets

Project description:The importance of dietary omega-6 to omega-3 (ω6:ω3) fatty acid (FA) ratios for human health has been extensively examined. However, its impact on fish physiology, and the underlying molecular mechanisms, are less well understood. This study investigated the influence of plant-based diets (12-week exposure) with varying ω6:ω3 (0.4-2.7) on the hepatic transcriptome of Atlantic salmon. Using 44 K microarray analysis, genes involved in immune and inflammatory response (lect2a, itgb5, helz2a, p43), lipid metabolism (helz2a), cell proliferation (htra1b), control of muscle and neuronal development (mef2d) and translation (eif2a, eif4b1, p43) were identified; these were differentially expressed between the two extreme ω6:ω3 dietary treatments (high ω6 vs. high ω3) at week 12. Eight out of 10 microarray-identified transcripts showed an agreement in the direction of expression fold-change between the microarray and qPCR studies. The PPARα activation-related transcript helz2a was confirmed by qPCR to be down-regulated by high ω6 diet compared with high ω3 diet. The transcript expression of two helz2 paralogues was positively correlated with ω3, and negatively with ω6 FA in both liver and muscle, thus indicating their potential as biomarkers of tissue ω6:ω3 variation. Mef2d expression in liver was suppressed in the high ω6 compared to the balanced diet (ω6:ω3 of 2.7 and 0.9, respectively) fed fish, and showed negative correlations with ω6:ω3 in both tissues. The hepatic expression of two lect2 paralogues was negatively correlated with viscerosomatic index, while htra1b correlated negatively with salmon weight gain and condition factor. Finally, p43 and eif2a were positively correlated with liver Σω3, while these transcripts and eif4b2 showed negative correlations with 18:2ω6 in the liver. This suggested that some aspects of protein synthesis were influenced by dietary ω6:ω3. In summary, this nutrigenomic study identified hepatic transcripts responsive to dietary variation in ω6:ω3, and relationships of transcript expression with tissue (liver, muscle) lipid composition and other phenotypic traits.

Project description:The high-affinity/low-capacity system Slc15a2 (PepT2) is responsible for the reuptake of di/tripeptides from the renal proximal tubule, but it also operates in many other tissues and organs. Information regarding PepT2 in teleost fish is limited and, to date, functional data are available from the zebrafish (Danio rerio) only. Here, we report the identification of two slc15a2 genes in the Atlantic salmon (Salmo salar) genome, namely slc15a2a and slc15a2b. The two encoded PepT2 proteins share 87% identity and resemble both structurally and functionally the canonical vertebrate PepT2 system. The mRNA tissue distribution analyses reveal a widespread distribution of slc15a2a transcripts, being more abundant in the brain and gills, while slc15a2b transcripts are mainly expressed in the kidney and the distal part of the gastrointestinal tract. The function of the two transporters was investigated by heterologous expression in Xenopus laevis oocytes and two-electrode voltage-clamp recordings of transport and presteady-state currents. Both PepT2a and PepT2b in the presence of Gly-Gln elicit pH-dependent and Na+ independent inward currents. The biophysical and kinetic analysis of the recorded currents defined the transport properties, confirming that the two Atlantic salmon PepT2 proteins behave as high-affinity/low-capacity transporters. The recent structures and the previous kinetic schemes of rat and human PepT2 qualitatively account for the characteristics of the two Atlantic salmon proteins. This study is the first to report on the functional expression of two PepT2-type transporters that operate in the same vertebrate organism as a result of (a) gene duplication process(es). KEY POINTS: Two slc15a2-type genes, slc15a2a and slc15a2b coding for PepT2-type peptide transporters were found in the Atlantic salmon. slc15a2a transcripts, widely distributed in the fish tissues, are abundant in the brain and gills, while slc15a2b transcripts are mainly expressed in the kidney and distal gastrointestinal tract. Amino acids involved in vertebrate Slc15 transport function are conserved in PepT2a and PepT2b proteins. Detailed kinetic analysis indicates that both PepT2a and PepT2b operate as high-affinity transporters. The kinetic schemes and structures proposed for the mammalian models of PepT2 are suitable to explain the function of the two Atlantic salmon transporters.

Project description:ObjectivePolyunsaturated fatty acids (PUFAs), including essential fatty acids linoleic and α-linolenic acid and derived long chain and very long chain ω3-and ω6-polyunsaturated fatty acids, are vital structures in mammalian membrane systems and signaling molecules, pivotal in brain development, lipid, and energy metabolism and in female and male fertility during human evolution. Numerous nutritional studies suggest imbalance of PUFA metabolism as a critical factor in the pathogenesis of several human lifestyle diseases: dyslipoproteinemia, obesity, cardiovascular and neurodegenerative diseases, and infertility. The lack of unbiased animal models impedes molecular interpretation of the role of synthesized and dietary supplied PUFAs in these conditions. In this study, we used a Δ6 fatty acid desaturase (FADS2) deficient mouse mutant lacking key enzyme activity in the biosynthesis of ω3-and ω6-PUFAs from EFAs to address the molecular role of PUFAs in female and male fertility. Infertility is a hallmark of the pleiotropic but auxotrophic fads2-/- phenotype and is therefore helpful for stringent dietary studies on the role of individual PUFAs.MethodsFeeding regimens: Age- and gender-matched infertile fads2-/- mice were maintained on defined diets, normal diet containing essential fatty acids, and supplemented with ω6-arachidonic acid, ω3-docosahexaenoic acid, and arachidonic/docosahexaenoic acid, starting (a) after weaning and (b) initiated in 4-month-old female and male fads2-/- mice. Phospho- and sphingolipidomes of ovarian and testicular membrane lipid bilayers in each cohort were established and the impact on the expression and topology of membrane marker proteins, membrane morphology, germ cell development, and female and male fertility in the respective cohorts was elaborated.ResultsPUFA synthesis deficiency caused a halt to folliculogenesis, atresia of oocytes, and infertility of fads2-/- female mice. A PUFA-deficient membrane lipid bilayer core structure led to the disassembly of the gap junction network of the follicular granulosa cells. In fads2-/- testis, the blood-testis barrier was disrupted and spermatogenesis arrested, leading to infertility. Sustained supply of combined AA and DHA remodeled the PUFA-deficient ovarian and testicular membrane lipidomes, facilitating the reassembly of the functional gap junction network for regular ovarian cycles and the reconstitution of the blood-testis barrier in Sertoli cells, reconstituting fertility not only in developing newborns, but surprisingly also in adult infertile fads2-/- mice.ConclusionsThese findings demonstrate the previously unrecognized membrane structure-based molecular link between nutrient ω3-and ω6-PUFAs, gonadal membrane structures, and female and male fertility and might foster studies of the pivotal role of dietary PUFAs in human fertility.

Dataset Information

Influence of Dietary Long-Chain Polyunsaturated Fatty Acids and ?6 to ?3 Ratios on Head Kidney Lipid Composition and Expression of Fatty Acid and Eicosanoid Metabolism Genes in Atlantic Salmon (Salmo salar).

Publications

Influence of Dietary Long-Chain Polyunsaturated Fatty Acids and ω6 to ω3 Ratios on Head Kidney Lipid Composition and Expression of Fatty Acid and Eicosanoid Metabolism Genes in Atlantic Salmon (<i>Salmo salar</i>).

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets