Background and Aim: The central dopaminergic system plays a crucial role in appetite regulation; however, its interaction with neuropeptide W (NPW) in birds remains poorly understood. This study was designed and conducted to investigate the role of dopaminergic receptors in hyperphagia induced by central NPW23 injection in broiler chicks.

Methods: A total of 220 broiler chicks (Ross-308) were involved in five experiments. In each experiment, the control solution, NPW23, dopaminergic receptor antagonists (D1: SCH23390, D2: AMI-193, D3: NGB2904, D4: L-741,742), or the dopaminergic neurotoxin (6-OHDA) were administered intracerebroventricularly (ICV) in sequence, either independently or in combination with NPW23. Subsequently, cumulative food intake was measured at 30, 60, and 120 minutes after injection.

Results: Injection of NPW23 at a dose of 3 nanomoles significantly increased food intake in the chicks (p ≤ 0.05). The concurrent injection of the D1 receptor antagonist with NPW23 enhanced this effect (p ≤ 0.05), whereas combined injections of D2, D3, and D4 receptor antagonists with NPW23 had no significant effect on NPW23-induced hyperphagia (p>0.05). Furthermore, although administration of 6-OHDA alone did not affect the chicks' appetite, its simultaneous injection with NPW23 significantly increased hyperphagia induced by NPW23 (p ≤ 0.05).

Conclusion: These findings indicate that the increase in appetite induced by NPW23 is mediated through interactions with the central dopaminergic system, particularly via D1 receptors in broiler chicks.