Effects of intracerebroventricular injection of apelin-13 on food intake in broiler chicks

Apelin is an endogenous peptide ligand for G protein coupled apelin receptors (APJ orphan receptors) which are very similar to angiotensin II receptors. Apelin is expressed in most tissues of the body including hypothalamus that is responsible for regulating water and food intake, the gastrointestinal tract, the circulatory system, adipose and muscle tissues, and the immune system. The physiological actions of apelin, including food intake, has not yet been reported in birds. In this study, the effect of intracerebroventricular injection of different doses of apelin-13 was investigated on food intake in neonatal broilers at the age of five and seven days. The chicks had access to food immediately after injection and cumulative food intake was measured at half, 1, 2, 3, 4, 8 and 21 hr after injection. The 2-way ANOVA analyzed data showed that apelin-13 at dose of 1.00 μg significantly reduced food intake at 21 hr after injection in five-day old chicks. In addition, in dose of 1.50 μg, it could significantly reduce food intake at 2, 3, 4, 8 and 21 hr after injection. In seven-day-old chicks, the doses of 1.00 and 4.00 μg of apelin-13 had no effect on food intake compared to the control group. Apelin-13 at dose of 2.00 μg significantly reduced food intake at 8 and 21 hr after injection. The results of this study showed that apelin-13 had a reducing effect on food consumption in neonatal broiler chicks.