The Effect of RFamide-Related Peptide-3 (RFRP-3 or NPVF) on Food Intake in Neonatal Chickens: The Role of MC3/MC4 and CRF1/CRF2 Receptors

RFamide-related Peptide-3(RFRP-3) plays a key role in appetite regulation. The current study aimed to determine the effect of RFRP-3(Neuropeptide VF) on feeding behavior and its interaction with the melanocortin and corticotropin systems on food intake in the neonatal broiler-type chickens. In experiments 1 and 2, chickens received intracerebroventricular (ICV) injection of control solution besides RFRP-3 (4, 8, and 16 nmol) and RF9 (NPFF receptors antagonist; 4, 8 and 16 nmol) respectively to investigate the effective doses of RFRP-3 and RF9. Experiments 3-8 have been designed to investigate the mediatory role of CRF1/CRF2 and MC3R/MC4R on food intake induced by RFRP-3 in chickens. Finally, in experiments 8-11, the synergistic effect between the MC3R and MC4R with RFRP-3 have been investigated via ICV co-injection of sub-effective doses of RFRP-3 + gamma 1-MSH and PG-931. Then, cumulative food intake was recorded at 30, 60, and 120 min after injection. According to the results, co-injection of astressin-B and RFRP-3, significantly attenuated hypophagic effect of RFRP-3; while astressin2-B reversed this effect of RFRP-3 (p < 0.01). Besides, co-administration of SHU9119 and MCL0020 significantly attenuated the hypophagia induced by RFRP-3 in chickens (p < 0.01). However, co-administration of RFRP-3 and PG-931 synergistically decreased food intake in neonatal chicken (p < 0.01). These results suggested hypophagic effect of RFRP-3 is possibly mediated via corticotropin CRF2 and melanocortin MC4R in neonatal broiler chickens.