Influence of Varying Dietary ω6 to ω3 Fatty Acid Ratios on the Hepatic Transcriptome, and Association with Phenotypic Traits (Growth, Somatic Indices, and Tissue Lipid Composition), in Atlantic Salmon (Salmo salar)

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 influence plant-based diets (12-week exposure) with varying ω6:ω3 (0.4–2.7) hepatic transcriptome Atlantic salmon. Using 44 K microarray analysis, genes involved in immune inflammatory response (lect2a, itgb5, helz2a, p43), lipid metabolism (helz2a), cell proliferation (htra1b), control muscle neuronal development (mef2d) translation (eif2a, eif4b1, p43) were identified; these differentially expressed between two extreme treatments (high ω6 vs. high ω3) at week 12. Eight out 10 microarray-identified transcripts showed an agreement direction expression fold-change qPCR studies. PPARα activation-related transcript helz2a was confirmed by be down-regulated diet compared ω3 diet. helz2 paralogues positively correlated ω3, negatively FA both liver muscle, thus indicating their potential as biomarkers tissue variation. Mef2d suppressed balanced (ω6:ω3 2.7 0.9, respectively) fed fish, negative correlations tissues. lect2 viscerosomatic index, while htra1b salmon weight gain condition factor. Finally, p43 eif2a Σω3, eif4b2 18:2ω6 liver. suggested that some aspects protein synthesis influenced ω6:ω3. In summary, this nutrigenomic identified responsive variation ω6:ω3, relationships (liver, muscle) composition other phenotypic traits.