Effects of intracerebroventricular injection of spexin and its interaction with NPY, GalR2 and GalR3 receptors on the central food intake regulation and nutritional behavior in broiler chickens

Abstract

Food intake and appetite in birds can be adjusted by the complex homeostatic control mechanisms. There seem to be many similarities between mammalian and avian species in terms of the regulatory feeding systems. Therefore, the aim of this study was to investigate the effects of ICV injection of spexin and its interaction with GalR and NPY receptors on central food intake regulation and nutritional behavior in broiler chickens. In experiment 1, chicken received ICV injection of saline, spexin (2.5 nmol), spexin (5 nmol) and spexin (10 nmol). In experiment 2, birds received ICV injection of saline, B5063 (NPY1 receptor antagonist 1.25 µg), spexin (10 nmol) and B5063 + spexin. In experiments 3–6, SF22 (NPY2 receptor antagonist,1.25 µg), ML0891 (NPY5 receptor antagonist,1.25 µg), M871 (GalR2 receptor antagonist,10 nmol) and SNAP37889 (GalR3 receptor antagonist,10 nmol) were injected in chickens instead of B5063. Then food intake was measured until 120 min after the injection and nutritional behavior was monitored at 30 min after the injection. Based on the data, a dose-dependent hypophagia was observed by the injection of spexin (P < 0.05). Concomitant injection of B5063 + spexin enhanced spexin-induced hypophagia (P < 0.05). Co-injection of SNAP37889 + spexin (10 nmol) attenuated -induced hypophagia (P < 0.05). Spexin (5 and 10 nmol) decreased number of steps, jumps, the exploratory food and pecks at 15 min after the injection (P < 0.05). Spexin (5 and 10 nmol) decreased standing time while siting time and rest time increased at 10 min after injection (P < 0.05). Based on observations, spexin-induced hypophagia could be mediated by NPY1 and GalR3 receptors in neonatal broiler chickens.