The seasonal expression and the migratory phenotype is signalled by rapid and marked changes in food intake, fuelling, and amount of nocturnality. We used common quails (Coturnix coturnix) to assess if the hormone corticosterone and the gut-derived hormone ghrelin play a role in these astonishing physiological transitions. We exposed quails to controlled changes in day length to simulate autumn migration, followed by a wintering period. We compared corticosterone and ghrelin concentrations and assessed whether these two metabolic hormones varied between distinct migratory states. We found that the expression of the migratory phenotype was associated with a sharp elevation in circulating concentrations of ghrelin. Interestingly, we also found that concentrations of ghrelin correlated with changes in body mass (fat stores) of birds as they transitioned into their autumnal migratory state and as they entered the wintering state. Contrary to our predictions we did not detect functional links between plasma corticosterone and the physiological state of the birds and we also did not observe a link between circulating levels of ghrelin and corticosterone.
The article “Ghrelin, not corticosterone, is associated with transitioning of phenotypic states in a migratory Galliform” by Valeria Marasco, Hiroyuki Kaiya, Gianni Pola & Leonida Fusani can be accessed here. You can also access here the Vetmeduni Press Release.