The Effect of the Central Administration of the Neuropeptide VF on Feed Intake and Its Possible Interactions with Glutamate and Opioid Systems in Broiler Chicken

Arginine-phenylalanine-amide (RFamide)-related peptides known as neuropeptide VF (NPVF) have a crucial role in feeding regulation. The present study purposed to determine the effect of intracerebroventricular (ICV) injection of the NPVF on dietary intake and possible interactions of NPVF with glutamate and opioid systems in broiler chicken. In experiment 1, chickens received ICV administration of the control solution, NPVF (16 nmol), 15 nmol of MK-801 (NMDA glutamate receptors antagonist), and injection of the NPVF with MK-801 together. In experiments, 2–8 chickens were injected intracerebroventricularly with 390 nmol of CNQX (antagonist of AMPA glutamate receptors), 2 nmol of AIDA (an antagonist of mGLUR1 glutamate receptors), 150 nmol of LY341495 (an antagonist of mGLUR2 glutamate receptors), 2 nmol of UBP1112 (an antagonist for mGLUR3 glutamate receptors), 5 µg of β-FNA (an antagonist for mu (µ) receptors), 5 µg of NTI (an antagonist for delta (δ) receptors), nor-BNI (kappa (κ) receptors antagonist; 5 µg) instead of MK-801. Following the injection, at 30, 60, and 120 min, the chick's dietary intake was recorded. As a result, NPVF (16 nmol) reduced feed intake in broilers (P < 0.05). NPVF + MK-801 co-injection reduced the hypophagic action of the NPVF (P < 0.05). Injection of NPVF + CNQX together reduced the anorectic action of NPVF (P < 0.05). Co-injection of NPVF + β-FNA reduced the effects of NPVF injection (P < 0.05). Thus, in newborn broilers, NPVF-induced anorexia is probably mediated by NMDA/ AMPA glutamate and µ opioid receptors.