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

Abstract

-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 17β (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.embryo viability / ewe / follicular status / super-ovulation / steroid Reprod. Nutr. Dev. 43 (2003) 17-28 17

Does supplemental LH changes rate and time to ovulation and embryo yield in Santa Ines ewes treated for superovulation with FSH plus eCG?

“…This occurs in approximately 20-30% of the ewes (GONZALEZ-BULNES et al, 2000). A possible cause may a deficient or inexistent preovulatory LH surge (GONZALEZ-BULNES et al, 2003) or the presence of non-responsive follicles due to a downregulation of the granulosa and theca LH receptors (LOPEZ-DIAZ & BOSU, 1992). COGNIÉ et al (1986) suggested that the administration of LH at the end of SOV treatment with exogenous FSH might increase the ovulation rate and the number of recovered embryos.…”

Glucogenic supply increases ovulation rate by modifying follicle recruitment and subsequent development of preovulatory follicles without effects on ghrelin secretion

“…The concentration of peripheral oestradiol was measured using the Spectria RIA kit (Orion Diagnostic Corp., Espoo, Finland), as described by Romeu et al (1995) and adapted for use in ovine plasma (Gonzalez-Bulnes et al 2003). Sensitivity for oestradiol was 5 pmol/l and the inter-and intra-assay variation coefficients were 17.6 and 18.1% respectively.…”

Live Weight Changes and Their Relationship with the Ovarian Status of Maiden Fat-Tailed Barbarine Ewes

“…Cross-reactivity with IGF-II, insulin and proinsulin was negligible. Estradiol concentrations were measured in one single assay using the Spectria radioimmunoassay kit (Orion Diagnostic Corp., Espoo, Finland), as described by Romeu et al (1995) and adapted for use in ovine plasma (Gonzalez-Bulnes et al, 2003). Sensitivity for estradiol was 0.5 pg/ml and the intra-assay variation coefficient was 6.6%.…”