Study summary · research use only
Influence of maternal environment on the number of transferable embryos obtained in response to superovulatory FSH treatments in ewes
Plain-language summary
Paraphrased from the published abstract below — not a verdict on whether anything works.
In a first experiment on 70 Manchega ewes given superovulation treatment with decreasing doses of OVAGEN, the authors compared embryo viability recovered from the uterus versus the oviduct, reporting fewer viable embryos (5.6 vs. 8.3) and more degenerative embryos (31.3% vs. 6.8%) from the uterus. In a second experiment on 14 ewes, the number of viable embryos (4.3) correlated positively with the number of 2-4 mm follicles and with oestradiol concentrations at several timepoints around estrus; prolonged high oestradiol with low progesterone on days 3 and 4 after estrus was associated with reduced embryo viability. The authors concluded ovarian response and embryo viability were related to follicle numbers and steroid patterns during superovulation.
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. 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 > or = 2 mm) at the first FSH administration. Progesterone (P4) and oestradiol 17beta (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.
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