Post-biopsy bovine embryo viability and whole genome amplification in preimplantation genetic diagnosis

Objective

To evaluate the effect of the biopsy of 8-cell to 16-cell bovine embryos on their subsequent development and the effect of whole genome amplification (WGA) on removed blastomeres.

Design

Randomized study.

Setting

Molecular genetics and animal reproduction laboratories.

Patient(s)

Cow ovaries obtained from slaughterhouses.

Intervention(s)

The ovaries were punctured, and the oocytes were matured and fertilized in vitro. On the fourth day after fertilization, 8-cell to 16-cell bovine embryos were biopsied, one quarter of each embryo being removed. The blastomeres were submitted to WGA followed by polymerase chain reaction (PCR). The embryos were returned to culture for evaluation of their development.

Main Outcome Measure(s)

Subsequent rate of blastocyst development, embryo cell number, WGA efficiency, and sex determination.

Result(s)

A total of 92 embryos were submitted to biopsy. The blastocyst production was 53.3%, with 44.9% of hatching rate. These results were similar to those of the control group (66.0% and 42.6%) of 103 embryos. Overall, no impact was detected on embryo quality in blastocyst cell number between the two groups. Removed blastomeres were submitted to WGA, resulting in 98.2% of efficiency. However, only 59% of the samples were sexed by PCR.

Conclusion(s)

Biopsy of 8-cell to 16-cell bovine embryos did not affect their subsequent development. WGA was successful in removed blastomeres.

Key Words: PGD, sexing, embryo quality, hatching rate