Abstract
Ghrelin is a prolactin (PRL)-releasing factor in animal species. The aim of this study was to investigate the effects of in ovo ghrelin administration on plasma PRL levels in hatched chicks. We divided 350 fertilized eggs into 7 groups: group T1 as the control (without injection), group T2 (in ovo injected with solvent: 1% acetic acid, without ghrelin on day 5), group T3 (in ovo injected with solvent without ghrelin on day 10), group T4 (in ovo injected with 50ng/egg ghrelin on day 5), group T5 (in ovo injected with 100ng/egg ghrelin on day 5), group T6 (in ovo injected with 50ng/egg ghrelin at day 10) and group T7 (in ovo injected with 100ng/egg ghrelin at day 10). After the eggs hatched, we determined serum PRL concentrations. Group T6 and T7 showed significantly higher serum PRL levels (1.18 and 1.19ng/ml, respectively) compared with groups T1, T2, T3, T4 or T5 (0.87, 0.86, 0.89, 0.90 and 0.90ng/ml, respectively). This result suggested that in ovo administration of ghrelin on day 10 affects PRL release in newly hatched chicks, while ghrelin administration during the early embryonic period (day 5) could not.
