Short-chain fatty acids differentially regulate feed intake and hypothalamic appetite-related genes in layer-type chicks.

Introduction: Activation of hypothalamic neurons by short-chain fatty acids (SCFAs) has been recognized as one of the mechanisms of appetite regulation in mammals. However, their central effects on hypothalamic neuropeptides have not yet been fully investigated in chicks. In the present study, feed intake and mRNA expression of neuropeptides in chicks were evaluated under the influence of SCFAs. Methods: The experiments included intracerebroventricular (ICV) injection of SCFAs into five-day-old chicks. Feed intake was recorded up to 2 h post-injection, and PCR was used to determine the gene expression levels of neuropeptides. Results: Feed intake significantly increased following ICV administration of sodium acetate (0.25 mg) and sodium butyrate (0.5 mg) (P < 0.05), whereas it was reduced by ICV administration of sodium propionate (5 mg) (P < 0.05). NPY5R mRNA expression significantly increased by sodium acetate (0.25 mg) (P < 0.05); however, NPY, NPY4R, AgRP, and anorexigenic neuropeptides were not altered (P > 0.05). NPY mRNA expression was significantly increased by sodium butyrate (0.5 mg), whereas reductions in POMC and MC4R were observed following this treatment (P < 0.05); however, AgRP, NPY4R, and MC1R were not affected (P > 0.05). An increase in MC4R mRNA expression was induced by sodium propionate (5 mg) (P < 0.05), while no significant changes were detected in orexigenic neuropeptides or POMC and MC1R (P > 0.05). Conclusion: Our findings suggest that SCFAs regulate feed intake in chicks by acting in the hypothalamus.