Influence of varying dietary ratios of ω6 to ω3 fatty acids on the hepatic global gene expression, and association with phenotypic traits (growth, somatic indices and tissue lipid composition) in Atlantic salmon (Salmo salar)

The present 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, and the relationships with tissue (i.e. liver, muscle) lipid composition, and growth performance. The current microarray study identified several genes involved in immune and inflammatory response (lect2, itgb5, p43), lipid metabolism (helz2), cell growth (htra1), muscle development (mef2d), and translation (eif2a, eif4b1, p43), that were differentially expressed between the two extreme ω6:ω3 dietary treatments (i.e. high ω6 vs. high ω3). Atlantic salmon were fed the two experimental diets (high ω6 and high ω3 ; four tanks per diet) for 12 weeks. Liver samples were taken from 5 fish from each tank at week 12. A universal reference design was used for the microarray experiment. For the test samples, RNA was used from individual livers of fish from the 2 treatment groups. For each treatment group we used 8 biological replicates (2 fish from each of 4 tanks). All test samples were labeled with Cy5. The common reference was a pool of 16 RNA samples from livers of fish from all individuals invovled in microarray experiment. The common reference was labeled with Cy3. Each individual test sample was hybridized together with the common reference sample on an array, so the experiment consisted of 16 arrays. Please note that sample titles represent 'diet_tank number_individual fish number' for each sample. variable: Highω6_T3_F1, Highω6_T3_F5, Highω6_T7_F2, Highω6_T7_F4, Highω6_T21_F2, Highω6_T21-F3, Highω6_T24_F3, Highω6_T24_F4 variable: Highω3_T2_F1, Highω3_T2_F4, Highω3_T8_F2, Highω3_T8_F5, Highω3_T20_F3, Highω3_T20_F5, Highω3_T26_F1, Highω3_T26_F2 biological replicate: Highω6_T3_F1, Highω6_T3_F5, Highω6_T7_F2, Highω6_T7_F4, Highω6_T21_F2, Highω6_T21-F3, Highω6_T24_F3, Highω6_T24_F4 biological replicate: Highω3_T2_F1, Highω3_T2_F4, Highω3_T8_F2, Highω3_T8_F5, Highω3_T20_F3, Highω3_T20_F5, Highω3_T26_F1, Highω3_T26_F2