Chromosomal abnormalities in Day-6, in vitro-produced pig embryos

Area of Science:

• Cytogenetics
• Embryology
• Reproductive Biology

Background:

• In vitro production (IVP) of porcine embryos is crucial for swine reproduction and research.
• Assessing the chromosomal health of IVP embryos is essential for improving efficiency and success rates.
• Previous studies have limited data on chromosomal abnormalities in Day-6 IVP porcine embryos.

Purpose of the Study:

• To quantify the incidence and types of chromosomal abnormalities in Day-6 IVP porcine embryos.
• To compare the chromosomal status of IVP porcine embryos with in vivo-produced embryos.
• To identify factors influencing chromosomal abnormalities in IVP porcine embryos.

Main Methods:

• Chromosomal karyotyping of morphologically normal Day-6 porcine blastocysts produced in vitro (n=318).
• Classification of embryos into groups based on cell number (< or =20 to 61-70).
• Analysis of 248 suitable embryos for chromosomal abnormalities: haploidy, polyploidy, and mixoploidy.

Main Results:

• 39.1% (97/248) of IVP porcine embryos exhibited chromosomal abnormalities.
• Polyploidy (71.1%) was the most common abnormality, followed by mixoploidy (19.6%) and haploidy (9.3%).
• Chromosomally abnormal embryos had significantly fewer cells than normal embryos (31.8 vs. 35.9).

Conclusions:

• Polyploidy significantly affects IVP porcine embryos developing to the blastocyst stage.
• The incidence of chromosomal abnormalities in IVP porcine embryos is higher than previously reported for in vivo embryos.
• Careful consideration of factors like polyspermic fertilization is needed for evaluating IVP porcine embryo production schemes.