Ehsan Najafi - Department of Basic Sciences, Faculty of Veterinary Medicine, University of Tehran, ۱۴۱۵۵-۶۴۵۳ Tehran, Iran
Kimia Mahdavi - Department of Basic Sciences, Faculty of Veterinary Medicine, University of Tehran, ۱۴۱۵۵-۶۴۵۳ Tehran, Iran
Morteza Zendehdel - Department of Basic Sciences, Faculty of Veterinary Medicine, University of Tehran, ۱۴۱۵۵-۶۴۵۳ Tehran, Iran
Mina Khodadadi - Institute of Cognitive Neuroscience, Department of Biopsychology, Faculty of Psychology, Ruhr University Bochum, Universit¨atsstraße ۱۵۰, ۴۴۷۸۰ Bochum, Germany

According to previous studies, the serotonergic system plays a remarkable role in regulating meal intake, however, its role in the mediation of feeding caused by neuromodulin S (NMS) has not been investigated in birds. In the present research, ۵ trials were considered in order to determine the links between these systems. In treatment ۱, chickens received intracerebroventricular (ICV) infusion of NMS (۰.۲۵, ۰.۵, and ۱ nmol). NMS (۱ nmol), SB۲۴۲۰۸۴ (۱.۵ μg), a ۵-HT۲C receptor antagonist, and NMS + SB۲۴۲۰۸۴ were injected in the treatment ۲. In subsequent treatments, instead of SB۲۴۲۰۸۴, ۸-OH-DPAT (agonist of ۵-HT۱A receptor, ۱۵.۲۵ nmol), PCPA (serotonin synthesis inhibitor, ۱.۲۵ μg), and Fluoxetine (serotonin reuptake inhibitor, ۱۰ μg) were applied. Then, total food consumption was recorded for ۱۲۰ minutes. Based on observations, NMS dose-dependently attenuated meal intake (P<۰.۰۵). Hypophagia was diminished with NMS + SB۲۴۲۰۸۴ administration (P<۰.۰۵). ICV infusion of NMU + ۸-OH-DPAT had no significant effect on the hypophagia (P≥۰.۰۵). The NMS-induced decreasing feed intake was attenuated with co-infusion of NMS+ PCPA (P< ۰.۰۵). Also, hypophagia was strengthened by NMS+ Fluoxetine co-infusion (P< ۰.۰۵). According to the results, the NMS-induced hypophagia is possibly mediated via ۵-HT۲c receptors in layer-type chickens.

Neuromodulin S, Serotonergic receptors, Food intake, Layers, Hypophagia