Abstract: Recently, researchers found that β-endorphin regulates the activity of the central melanocortin system and its activation provides an inhibitory feedback mechanism in the brain of neonatal chicks. It is known that fragments of β-endorphin have biological activities. Thus, the present study was done to elucidate whether N- or C-terminal of β-endorphin fragment affects the insulin-induced anorexia in chicks. Researchers found that intracerebroventricular injection of insulin with N-terminal fragment, β-endorphin-(1-27), accelerated the insulin-induced hypophagia in neonatal chicks during the 60 min period postinjection. Conversely, the anorexic effect of insulin was attenuated by C-terminal fragment, β-endorphin-(30-31). These data suggest that both fragments involve in the regulation of feeding behavior and they may modulate the activity of the central melanocortin system in the brain of neonatal chicks.