Background and aims: RFamide-related Peptide-3 (RFRP-3) belongs to the RFamide family which plays a key role in appetite regulation by stimulation of NPFF receptor in vertebrates. The present study aimed to investigate the effects of NPFF receptor on feeding behavior and its interaction with melanocortin systems in neonatal chickens.
Methods: Two hundred and Twenty neonatal male broiler-type (ROSS 308) chickens were divided randomly into 5 experimental groups. Each experiment had a control group and three treatment groups (n=11). Cumulative food intake was recorded and analyzed in five-day-old chicks, after intracerebroventricular injection at 30, 60 and 120 minutes after injection.
Results: Injection of MC3R receptor agonist (γ1-MSH; 5, 10 pmol) and MC4R receptor agonist (PG-931; 25, 50 pmol) decreased food intake (p ˂ 0.05). However, injection of 8 and 16 nmol of NPFF receptor antagonist (RF9) increased food intake in neonatal chicks in all time-points (p ˂ 0.05).  Co-injection of RF9 and γ1-MSH showed no significant alteration on hypophagic effect induced by γ1-MSH (p ≥ 0.05). Yet, co-injection of RF9 and PG-931attenuated the hypophagic effect of PG-931 in all time-points (p ˂ 0.05).
Conclusion: The results of the present study indicate that the hypophagic effect of MC4R in neonatal male broiler-type (ROSS 308) chickens may be mediated by NPFF receptor.