Arginine is an amino acid that body builders often use as a dietary supplement, as it has been proven to increase muscle mass while also reducing visceral fat mass in rodent models. The goal of this work was to study whether the addition of surplus arginine to salmon feed had a visible effect on muscle and fat tissue distribution. In addition to being a building block for proteins in the body, arginine is important in many metabolic processes in the body, including the generation of polyamines. Polyamines are important for the development and growth of cells, and a lot of energy is required to generate them. In her PhD thesis, Andersen wanted to find out whether arginine affected energy conversion in salmon via the polyamine metabolism.
Two feeding trials were conducted, one in small salmon weighing five grams and one in bigger salmon weighing one kilo. Surplus arginine had a minor positive effect on the growth of the small salmon, which could be related to polyamines. We also saw the increased expression of a genes that are important for fat metabolism in the liver. However, surplus arginine had no effect on growth or the distribution of muscle and fat mass in the adult salmon. This suggests that arginine does not have the same effect on salmon as has been proven in rodents and pigs. However, although arginine did not affect growth, it did affect the metabolic processes in the fish, which may be of significance to fish health and welfare. It was found through studying the liver cells of the salmon that arginine affected the glucose metabolism, among other things. No negative effects of the surplus arginine supplement were observed.
The thesis comprises five approved articles.