Changes in gonadotrophins during the egg laying cycle in Fayoumi hens [Egypt]
1989
El-Toukhy, N.E. (Cairo Univ. (Egypt). Faculty of Veterinary Medicine) | El-Nahla, A.M. | Nour, A.M. | Farouk, W.A. | Soliman, F.A.
The present study was done to clarify the cyclic variation in follicle stimulating hormone, (FSH) ovulation inducing hormone (OIH) and prolactin (PRL) in pituitary and serum of Fayoumi hens during egg laying cycle. The results obtained from this study revealed that, pituitary FSH was significantly increased at 8 and 32 hours, while minimal concentration was observed at 16 hours after egg laying. High FSH level in serum was observed at 8 hours after egg laying. Maximal level of serum OIH was observed at 32 hours after oviposition, while minimal level was observed at 8 hours while its activity was only detected at 8 hours after oviposition in the pituitaries. This lead to suggest that both FSH and LH surges are necessary to induce maturation of the next follicle. Maximal concentration in serum prolactin was obtained at a time of 16 hours after egg laying, and minimal at 24 hours. Pituitary prolactin tended to be steady during egg laying cycle except 24 hours after egg laying. Thus the prolactin level in the blood of Fayoumi hens showed cyclic variation during the ovulatory cycle, being low at the preovulatory stage.
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