Seasonal and photoperiodic regulation of reproductive hormones and related genes in Yangzhou geese.

This study aimed at the reproductive endocrine profile under a natural photoperiod in Yangzhou female geese. Geese in the breeding industry were exposed to a natural photoperiod and the results showed the breeding season of Yangzhou geese initiated in autumn, reached peak in February and March, and terminated in June. Fifteen female geese were randomly selected for blood collection samples monthly. The results showed serum luteinizing hormone (LH) concentrations in female geese were higher in the breeding season than in the non-breeding season. The concentrations of Prolactin (PRL) were also high in the breeding season. Follicle-stimulating hormone (FSH) concentrations were high from March to May and decreased to low levels in other periods. Furthermore, 6 female birds were selected randomly monthly, sacrificed, and the hypothalamus and pituitary isolated. The expressions of FSH were also high in the breeding season, while the expressions of the gonadotropin-releasing hormone (GnRH) fluctuated. These results indicated that the reproductive hormones and their transcript expressions were closely related to the reproductive activities in Yangzhou geese.