Ingvill Tolås, Tharmini Kalananthan, Ana S Gomes, Floriana Lai, Sissel Norland, Koji Murashita, Ivar Rønnestad
Neuropeptide Y (NPY) is known as a potent orexigenic signal in vertebrates, but its role in Atlantic salmon has not yet been fully established. In this study, we identified three paralogs, named , in the Atlantic salmon genome. analysis revealed that these genes are well conserved across the vertebrate's lineage and the mature peptide sequences shared at least 77% of identity with the human homolog. We analyzed mRNA expression of paralogs in eight brain regions of Atlantic salmon post-smolt, and the effect of 4 days of fasting on the expression level. Results show that was the most abundant paralog, and was predominantly expressed in the telencephalon, followed by the midbrain and olfactory bulb. mRNA was highly abundant in hypothalamus and midbrain, while was found to be highest expressed in the telencephalon, with low mRNA expression levels detected in all the other brain regions. 4 days of fasting resulted in a significant ( < 0.05) decrease of mRNA expression in the olfactory bulb, increased mRNA expression in the midbrain and decreased mRNA expression in the pituitary. In the hypothalamus, the vertebrate appetite center, expression of the paralogs was not significantly affected by feeding status. However, we observed a trend of increased mRNA expression ( = 0.099) following 4 days of fasting. Altogether, our findings provide a solid basis for further research on appetite and energy metabolism in Atlantic salmon.
