Effect of Corticosterone on Hypothalamic Corticotropin-releasing Hormone Expression in Broiler Chicks (Gallus gallus domesticus) Fed a High Energy Diet

Abstract

This paper reports the peripheral and central effect of corticosterone on feed intake and hypothalamic corticotropin- releasing hormone (CRH) gene expression in chicks fed a high energy diet. Three experiments were conducted: corticosterone was supplemented to the feed (30 mg/kg diet), injected subcutaneously (s.c., 4 mg/kg body weight) or intracerebroventricularly (i.c.v., 4 ng). The results showed that dietary corticosterone significantly increased feed intake. The s.c. corticosterone administration increased feed intake within 1 to 3 h and at 1 to 5 h after the injection. The i.c.v. corticosterone administration increased feed intake within 1 h after the injection, but not at 1 to 3 h. Dietary supplementation and s.c. injection of corticosterone decreased the CRH gene expression in the hypothalamus. Therefore, peripheral corticosterone exerted a decreased effect on hypothalamic CRH mRNA levels, and corticosterone had a stimulating effect on feed intake in broiler chicks fed a high energy diet. (Key Words : Broiler Chicks, Corticosterone, Corticotropin-releasing Hormone, Feed Intake)