Atlantic Salmon Liver Transcriptome Response to Diets Containing Camelina Products

Due to increasing demand for fish oil (FO) and fish meal (FM) in aquafeeds, more sustainable alternatives such as plant-derived oils and proteins are needed. Camelina sativa products are viable feed ingredients given the high oil and crude protein content in its seed and meal, respectively. Atlantic salmon (initial weight ~240 g) were fed diets with complete or partial replacement of FO and/or FM with camelina oil (CO) and/or camelina meal (CM) in a 16 week feeding trial [Control diet: FO+FM; Test diets: 100%CO replacement of FO (100CO), or 100CO with a) solvent-extracted FM (SEFM), b) 10%CM, or c) SEFM+10%CM]. The growth performance (as measured by weight-specific growth rate) of salmon was significantly reduced in all camelina-containing diets except fish fed 100CO. A microarray experiment was conducted to identify transcripts in Atlantic salmon liver that respond to 100COSEFM10CM compared to control diet, and yielded 67 differentially expressed features (FDR < 5%). Ten out of eleven microarray-identified transcripts, including cpt1, pcb, lect-2 and clra, were validated by QPCR. In addition, QPCR assays including candidate genes involved in fatty acids biosynthesis (e.g. elovl2, fadsd5) were applied to all dietary treatments to study the impact of various camelina by-product containing diets on gene expression of these potential biomarkers. This nutrigenomic approach revealed several salmon genes involved in lipid metabolism, carbohydrate metabolism and immune function that responded to camelina-containing diets. Genes identified in this work could potentially be used as biomarkers to assist with the development of novel aquafeeds using camelina products.