Hypothalamic agrp and pomc mRNA Responses to Gastrointestinal Fullness and Fasting in Atlantic Salmon ( Salmo salar , L.)

The orexigenic agouti-related protein (AgRP) and the anorexigenic pro-opiomelanocortin (POMC) are crucial players in the control of feed intake in vertebrates, yet their role in teleosts has not been fully established. Triplicate groups of Atlantic salmon ( ) post smolts were subjected to (1) fasting for 3 days (fast) and (2) normal feeding (fed), resulting in a significant ( < 0.05) upregulation of hypothalamic transcripts levels in the fast group. Moreover, the mRNA abundance of was significantly ( < 0.05) correlated with the stomach dry weight content. Corresponding inverse patterns were observed for , albeit not statistically significant. No significant differences were found for the other paralogues, and and between fed and fast groups. The significant correlation between stomach fullness and mRNA expression suggests a possible link between the stomach filling/distension and satiety signals. Our study indicates that hypothalamic acts as an orexigenic signal in Atlantic salmon.