Reprod. Nutr. Dev.
Volume 43, Number 1, January-February 2003
|Page(s)||17 - 28|
Influence of maternal environment on the number of transferable embryos obtained in response to superovulatory FSH treatments in ewesAntonio González-Bulnesa, Rosa María García-Garcíaa, Vanesa Castellanosb, Julián Santiago-Morenoa, Carmen Ariznavarretab, Verónica Domíngueza, Antonio López-Sebastiána, Jesús A.F. Tresguerresb and María Jesús Coceroa
a Dpto. de Reproducción Animal, INIA, avda. Puerta de Hierro s/n, 28040-Madrid, Spain
b Dpto. de Fisiología, Facultad de Medicina, Universidad Complutense de Madrid, 28040-Madrid, Spain
(Received 30 January 2002; accepted 10 June 2002)
In a first experiment, embryo viability was estimated after recovery in the uterus or the oviduct of 70 Manchega ewes following a treatment of superovulation with decreasing doses of OVAGEN TM. Fewer viable embryos (5.6 0.9 vs. 8.3 0.8, P < 0.05) and more degenerative embryos (31.3% vs. 6.8%, P < 0.005) were obtained from the uterus than from the oviduct respectively. In a second experiment performed on 14 ewes, embryo viability was analyzed in relation to the follicular population estimated by ultrasonography (follicles 2 mm) at the first FSH administration. Progesterone (P4) and oestradiol 17 (E2) concentrations were also determined from the beginning of the superovulation treatment to the recovery of the embryos. The number of viable embryos (4.3 1.4) was positively correlated ( r = 0.824) with of 2-4 mm diameter follicles ( P < 0.05), and with E2 concentrations at -12 h ( r = 0.891, P < 0.01) , 0 h ( r = 0.943, P < 0.0001) and +24 h ( r = 0.948, P < 0.05) from estrus detection. Prolonged high levels of E2 up to 72 h with low levels of P4 on days 3 and 4 after estrus had a negative ( P < 0.05) effect on embryo viability. These results indicate that ovarian response to superovulatory protocols is related to the individual variations in the number of follicles of 2-4 mm at the start of FSH treatment, and that embryo viability is conditioned by the steroid patterns during the time spent in the genital tract of the super-ovulated ewes.
Key words: embryo viability / ewe / follicular status / super-ovulation / steroid
Correspondence and reprints: Antonio González-Bulnes
© INRA, EDP Sciences 2003