HORMONAL INFLUENCE ON OOCYTE DEVELOPMENT: AN EVALUATION OF LH AND FSH EFFECTS IN AWASSI AND HAMDANI SHEEP BREEDS

This investigation aimed to assess the effects of circulating follicle stimulating hormone (FSH) and luteinizing hormone (LH) levels on oocyte maturity in sheep of the indigenous Awassi and Hamdani breeds. Oocytes were obtained from 48 mature females and evenly distributed between the two breeds for experimental use. The same reproductive synchronization protocol was used for both breeds which included the insertion of a P4 (progesterone)-loaded intravaginal device followed by injecting pregnant mare serum gonadotropin (PMSG) after removal of the device. Blood samples for analysis of circulating gonadotropin levels (measured by ELISA) were collected from the jugular vein 48 hours after removal of the P4. Oocyte maturity was assessed morphologically using conventional light microscopic techniques. Statistical analysis of the data demonstrated significant differences between breeds in regard to oocyte maturity. The Awassi breed exhibited significantly higher levels of LH (0.41 ± 0.36) as well as a greater number of developmentally competent oocytes (76.48 ± 1.33) and fewer degenerative oocytes (10.29 ± 1.41) and immature gametes (13.38 ± 0.38) than the Hamdani breed. Additionally, the FSH (0.53 ± 0.19) levels of the Awassi were significantly higher than the Hamdani. Therefore, it can be concluded that gonadotropic hormones are important markers of oocyte developmental potential and that the Awassi breed has greater hormonal regulation and reproductive potential than the Hamdani breed. This data supports the concept that specific_ breed hormonal protocols stimulation could greatly enhance the success rate of assisted reproductive technologies and genetically selective breeding programs utilizing indigenous ovine genetic resources.