New knowledge about salmon’s adipose tissue
The adipose tissue in salmon performs a greater variety of functions than previously thought, a new Doctoral dissertation shows.
The development and functions of the adipose tissue in fish has been relatively unknown, until recently. Large amounts of visceral fat in salmon leads to production losses during processing and can significantly influence the health of the fish.
This has created an increased demand for knowledge about the development and functions of the adipose tissue in salmon.
Through her doctoral project, Marijana Todorčević has shown that the recruitment of new fat cells from unspecialised stem cells and fat cell maturation are controlled by a complex network that is very similar to the development of adipose tissue in humans.
Her studies have shown that the adipose tissue in salmon perform a greater variety of functions than previously thought. Fat cells in salmon, for example, secrete hormone-like substances that are important for regulating both energy utilisation and inflammatory reactions.
An increasing degree of lipid accumulation in fat cells leads to increased expression of genes involved in endoplasmic reticulum stress, oxidative stress and inflammation. Todorčević’s results indicate that the composition and functions of the adipose tissue are very important for the health of the fish.
The fat in fish feeds is to an increasing degree based on plant oils, which has resulted in a reduced level of the healthy omega-3 fatty acids in the adipose tissue of the fish.
Another important objective in Todorčević’s doctoral project was to study whether fatty acids from plant oils influence the amount of visceral fat and stress markers in salmon.
The studies showed that fatty acids, which are found in abundance in plant oils, lead to a higher degree of fat accumulation in adipose cells and that higher fat accumulation leads to expression of stress-related genes.
The dissertation also shows that the salmon’s adipose tissue possesses a series of mechanisms that protect the fat cells against effects from exaggerated fat storage that pose health hazards.
Adipose tissue has a relatively low capacity to utilize fatty acids for energy production, but as this tissue represent a reasonably high percentage of the total body weight; the metabolic capacity of the adipose tissue can influence the total amount of deposited fat.
Todorčević’s studies show that lipid peroxidation of mitochondrial membranes leads to reduced metabolism of adipose tissue and as such influences the fat storage in fish.
Continuing at Nofima
Marijana Todorčević is 30-years-old and originates from Serbia. She has a Master’s degree in Feed Manufacturing Technology from the Norwegian University of Life Sciences (UMB) in Ås.
She commenced her doctoral project at UMB and Nofima in 2005. Her academic supervisors have been Professor Bente Ruyter and former Senior Scientist Anne Vegusdal at Nofima Marin.
Todorčević presented her doctoral dissertation on Friday, March 5. The dissertation was entitled “Development and functions of adipose tissue in Atlantic salmon”.
The assessment committee consisted of Professor Isabel Navarro (University of Barcelona) Professor Arild Rustan (University of Oslo) and Professor Magny S. Thomassen (UMB).
Todorčević will continue working as a scientist at Nofima Marin.