Free Access
Reprod. Nutr. Dev.
Volume 43, Number 1, January-February 2003
Page(s) 17 - 28
Reprod. Nutr. Dev. 43 (2003) 17-28
DOI: 10.1051/rnd:2003003

Influence of maternal environment on the number of transferable embryos obtained in response to superovulatory FSH treatments in ewes

Antonio 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 $\pm$ 0.9 vs. 8.3 $\pm$ 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 $\geq$ 2 mm) at the first FSH administration. Progesterone (P4) and oestradiol 17 $\beta$ (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 $\pm$ 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