Efficiency of embryo transfer in sheep under different nutritional status of donors and recipient ewes

BRUNO GALARRAGA MACARENA; CUETO MARCELA; FERNANDEZ J; GIBBONS A,; DE LA SOTA, R.L.; LACAU, I.M.

Buenos Aires

Jornada; Reunion Conjunta de Sociedades de Biociencias; 2017

SAB- SOCIEDADES DE BIOCIENCIAS

The objective of this study was to evaluate the effect of the nutritional status of embryo donors and recipients on embryo survival after direct transfer of embryos in sheep. The experimental study was carried out at the Reproduction Laboratory Facilities of INTA Bariloche. A total of 36 donor and 75 recipient Merino ewes received either 1.5 (S, Supplemented) or 0.5 (R, Restricted) times daily maintenance requirements (S donors n = 19, R donors n = 17, S recipients n = 36, R recipients n = 39), from the beginning of the estrus synchronization treatment until day 30 post estrus. On day 7 post estrus, one transferable embryo of donor females S or R was transferred into a recipient female S or R, defining the following groups: SS (n = 11), SR (n = 11), RS (n = 25) and RR (n = 28). The concentration of progesterone and metabolic hormones in donor and recipient ewes was determined according to nutritional status. The pregnancy rate on day 17 of gestation was similar between groups (73, 45, 72 and 64% for SS, SR, RS and RR, respectively; P > 0.1). However, embryo losses between days 17 and 35 of gestation were higher in the SR group (18%) than in the other three groups (9, 8 and 7% for SS, RS and RR, respectively; P < 0.1). Moreover, pregnancy rate on day 35 of gestation was lower in the SR group (27%) compared to the other groups (64, 64 and 57% for SS, RS and RR, respectively; P < 0.1). Donors and recipients under nutritional restriction had lower concentrations of IGF-1 (P < 0.01). In conclusion, failure to establish and maintain pregnancy may be related to an asynchrony between an unfavorable uterine environment in restricted recipient ewes and embryos produced by donors in a high nutritional condition.