Investigation of respiration of individual bovine embryos produced in vivo and in vitro and correlation with viability following transfer

Author： Lopes A.S. Madsen S.E. Ramsing N.B. Løvendahl P. Greve T. Callesen H.

Publisher： Oxford University Press

ISSN： 1460-2350

Source： Human Reproduction, Vol.22, Iss.2, 2007-02, pp. : 558-566

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Abstract

BACKGROUND: Quantification of oxygen consumption by individual preimplantation embryos has the potential to improve embryo selection. This study investigated whether respiration rates of individual embryos are useful indicators of embryo viability. The effect of the Nanorespirometer on embryo viability was also evaluated. METHODS: The respiration rates of individual day 7 bovine in vivo- (n = 44) and in vitro-produced (n = 156) embryos were measured using the Nanorespirometer. in vivo-produced embryos were individually transferred to recipients. RESULTS: The respiration rates of in vivo-produced embryos increased with increasing morphological quality and stage of development (P < 0.05).="" pregnancy="" rates="" on="" days="" 35="" and="" 60="" were="" 65="" and="" 60%,="" respectively.="" the="" mean="" respiration="" rate="" did="" not="" differ="" significantly="" between="" embryos="" producing="" and="" not="" producing="" a="" pregnancy,="" but="" the="" transfer="" of="" embryos="" with="" respiration="" rates=""><0.78 nl/h,="" between="" 0.78="" and="" 1.10="" nl/h,="" and="">1.10 nl/h resulted in 48, 100 and 25% pregnancy rate, respectively. The mean respiration rate of in vitro-produced embryos was higher than that of in vivo-produced embryos because of differences in the morphological quality and stage of development. CONCLUSION: The Nanorespirometer does not adversely influence embryo viability, but the sample size was too small to confirm the significance of the correlation observed between respiration rates and viability.