Melatonin Secretion in Regulating the Circadian Rhythms of Reproduction in Goose (<i>Anser cygnoides</i>)

Abstract

Circadian rhythms affect the physiology and behavior of most organisms. The ovulation–laying cycle of poultry exhibits evident rhythmic patterns. However, the underlying biological mechanism has remained unclear. Herein, Yangzhou goose (Anser cygnoides) were selected at 6:00, 12:00, 18:00, and 24:00 (n = 6/timepoint) to investigate the regulation of circadian egg-laying through the light-driven melatonin secretion. Our study revealed that the laying rates displayed diurnal fluctuations, with a peak of 40% of eggs being laid between 4:00 and 7:00. The cosine analysis revealed that the expression of clock genes exhibited rhythmicities (p p p < 0.01). Taken together, these data suggested cyclical secretion of melatonin in response to photoperiod, which acts as a neuroendocrine transducer of circadian rhythm and the time preference of reproduction in domestic geese.

Keywords

• circadian rhythms
• goose
• hypothalamic–pituitary–gonadal (HPG) axis
• melatonin
• reproduction