Nutrigenomic study of lipid metabolism in Atlantic salmon (Salmo salar L.) : the effects of dietary plant oil inclusion

• Published in: Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology
• Main Author: Jordal, Ann-Elise Olderbakk
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: The University of Bergen 2006
• Subjects: VDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480::Marinbiologi: 497; VDP::Matematikk og Naturvitenskap: 400::Basale biofag: 470; Atlantic salmon; Salmo salar
• Online Access: http://hdl.handle.net/1956/1883

The two dietary trials conducted in the present study (Papers I-III) used dietary rapeseed oil fed in a regression design and a full plant oil blend replacement for fish oil, respectively. The metabolic response of Atlantic salmon was examined in relation to gene expression (Paper I-III), lipid storage (Paper II and III) and fatty acid oxidation (Paper II). Furthermore, intracellular fatty acid uptake and transport (Paper II) and lipoprotein metabolism (Paper III) was studied. In order to examine gene expression of lipid metabolic genes thorough technical validation and quality control of microarray studies (Paper I) and evaluation of reference genes for Q-PCR were prioritised (Paper IV). Dietary rapeseed oil induced D5 fatty acid desaturase mRNA expression (Paper I), and lipogenic enzyme activities were partially increased for Atlantic salmon fed high dietary inclusion of plant oils (Paper III). Dietary long term partial rapeseed oil inclusion resulted in reduced expression of several mitochondrial transport proteins, transcription factors, co-activators and signal transducers (Paper I). The expression of these proteins is known to be indirectly influenced by dietary fatty acids mediated through changes in membranes phospholipids compositions. Partial dietary rapeseed oil inclusion had no impact on FABP3 or FABP10 gene expression in Atlantic salmon liver or muscle tissues (Paper II). Nonetheless, a tendency for decreased FABP3 protein expression with decreasing inclusion of dietary rapeseed oil was observed. Overall, liver and muscle tissues of Atlantic salmon seem to express several FABPs, possibly linked to different metabolic functions. Relative FABP3 mRNA levels dominated in both red and white muscle tissues. Red muscle appeared to express higher levels of FABP3 than white muscle and heart. Liver FABP10 mRNA appeared to be expressed at high levels compared to liver FABP3. Modest changes in liver and muscle FABPs mRNA levels between different life stages were observed. Liver TAG stores, plasma lipid and LDL ...