Tesis de Pregrado

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Browsing Tesis de Pregrado by Author "Ayala Guanga, Luis Eduardo"

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    Relación entre los niveles de la hormona Anti-mülleriana y la respuesta ovárica a los tratamientos superovulatorios en vacas mestizas Holstein
    (Universidad Zulia, 0022-01-04) Dután Sanango, Jorge Bolívar; Hernández Fonseca, Hugo; Ayala Guanga, Luis Eduardo
    This research was conducted in the south-central region of Ecuador. Anti- Müllerian hormone (AMH) concentration was determined and a reference value was established to predict the ability of donor cows (Holstein crossbreds) to produce follicles in response to superovulation protocols that provide numerous oocytes and embryos in vivo. In the first experiment 140 cows received a synchronization protocol to reinitiate the follicular wave. On day 11 of the protocol, AMH concentration was measured and antral follicle counts (AFC) ≤ 4mm were performed. It was observed that AMH concentrations correlated positively with AFC (r=0.783). The second experiment related AFC, AMH levels and response of 36 in vivo embryo donors to a superovulation protocol. The number of follicles observed on day 9 in the high AMH group (23.1 ± 1.28 follicles) was greater than cows in the low AMH group (13.1 ± 0.76 follicles). The ovulation percentage was greater in the high AMH concentration group (26.3%) versus the low concentration group (13.3 ± 0.97 vs. 9.8 ± 0.57 CL). In addition, more embryos were recovered in the high (8.2 ± 0.77) vs. low AMH group (3.2 ± 0.50). Finally, the third experiment related AMH concentration to the number and quality of cumulus-oocyte complexes (COC’s) recovered from heifers by ultrasound-guided aspiration (OPU). Sixty-one crossbred Holstein heifers with high, medium and low AMH concentration were evaluated. It was determined that plasma AMH levels were positively and significantly related to the total number of antral follicles <4mm at the time of restarting the follicular wave (r=0.93). In addition, animals with high AMH concentration presented twice the number of follicles on the day of OPU compared to animals with low AMH concentration (24,8 ± 0,52) versus (11,6 ± 0,36) respectively. Likewise, although a similar recovery percentage (57%) was obtained in both groups, the greater number of follicles in the high AMH group allowed obtaining twice the number of suitable COC's for in vitro embryo production.