Following the methodological development of the first year, the second year has been largely devoted to carrying out and collecting samples from a number of studies. In particular, large scale feeding-trials have been conducted aiming to better understand the control of growth and adiposity, and samples have been taken to analyse hormones that are important for growth and energy balance; GH, IGF-I and ghrelin. Hormonal and data analysis is still being carried out, so any major conclusions cannot be drawn yet. However, as data on ghrelin in fish is largely lacking, it is foreseen that these studies will improve our understanding of the role of this hormone in fat metabolism and product quality. In addition, methods to study the role of the ghrelin receptor (also called the growth hormone secretagogue receptor) in GH secretion and its distribution in brain centra important for regulating energy balance are being evaluated.
Investigation was made on the genetic variation in the lysyl oxidase (LOX) gene which codes for the enzyme responsible for collagen cross-linking in three populations of Atlantic salmon. Soft flesh is associated with a reduction of collagen cross-linking. A total of 11 variants of LOX were discovered which clustered into two groups based on the similarity of their sequences. There was a significance difference in collagen cross-linking between the two clusters and this is one of the first examples of a detailed genetic explanation for an important flesh quality trait.
