Anorexigenic effect of serotonin in an alternative vertebrate model (728.18)

Abstract

Serotonin (5HT) is a central anorexia factor that inhibits food intake in mammals. Here, we used an avian model to study the effect of 5HT on appetite regulation, which may provide insight on the evolutionary aspects of food intake. Chicks treated with 24 nmol 5HT had reduced food intake up to 30 min following injection. Those that received 48 nmol 5HT had reduced food intake following injection throughout the 60 min observation time. The dose of 12 nmol was not effective. No chick treated with 5HT reduced water intake. We designed experiment 2 to determine if the anorexigenic effect of 5HT was primary by conducting a comprehensive behavior analysis. Those chicks treated with 5HT had increased deep rest, decreased feeding pecks, locomotion, steps, defecations, and chirps, but time spent sitting, standing, and preening were not affected. Exploratory pecks, jump, and drinks were also not affected. In sum, 5HT is associated with sedation, however, the effects on food intake are likely not due to malice because 5HT chicks did not reduce water intake and the number of drinks. These data support that 5HT function as a direct satiety factor in chicks.