Influence of biopsy sexing and<i>in vitro</i>culture on losses of female mouse and bovine embryos

Abstract

Abstract A study was performed to determine whether micromanipulation or in vitro culture had a disproportionately detrimental effect on female embryos. In this experiment 2‐cell mouse embryos, mouse morulae and bovine morulae were cultured to hatched blastocyst using CZB or M‐16 for mouse, and M‐199 for bovine embryos. Other groups of mouse morulae and bovine morulae were biopsied and cultured afterwards to the same stage. After culture, sex was determined using PCR. Our results showed that in mouse embryos 72 h of in vitro culture in M‐16 had a significant detrimental effect on the development of female embryos (36% females vs 64% males; p<0.05). Meanwhile, CZB did not produce sex ratio imbalance. We also found that a significant higher proportion of male embryos developed to hatched blastocyst after biopsy of both mouse (35% females vs 65% males; p<0.01) and bovine embryos (32% females vs 68% males; p<0.05).