Stimulation of feeding behavior and food consumption in the goldfish, Carassius auratus, by orexin-A and orexin-B.

The neuropeptides, orexin-A and orexin-B, have been demonstrated to have a physiological role in the regulation of food intake in mammals. The effects of human orexin-A and orexin-B intracerebroventricular (i.c.v.) injection on the feeding behavior of goldfish (Carassius auratus) were investigated. I.c.v. injection of orexin-A and orexin-B both caused a significant increase in appetite, as indicated by an increased number of feeding acts. Orexin-A and orexin-B both significantly stimulated food consumption, as indicated by increased total food intake during a 60-min observation period; the actions of orexin-A were dose dependent. Orexin-A was more potent than orexin-B in stimulation of both feeding behavior and food intake. These results indicate that orexin peptides are involved in the hypothalamic regulatory pathways of feeding behavior in goldfish.