Gender preselection in cattle with intracytoplasmically injected, flow cytometrically sorted sperm heads

Area of Science:

• Reproductive Biology
• Animal Biotechnology
• Genetics

Background:

• Efficient methods for sex preselection in cattle are crucial for optimizing herd management and genetic improvement.
• Previous techniques for sperm sorting have limitations in accuracy and efficiency for practical application in bovine oocyte injection.

Purpose of the Study:

• To evaluate the developmental potential of in vitro-matured bovine oocytes after intracytoplasmic injection with flow cytometrically sorted bull sperm heads.
• To determine the live offspring production and sex preselection accuracy rates using this sperm sorting and oocyte injection technique.

Main Methods:

• Bull sperm heads were prepared using ultrasound sonication and sorted based on DNA content using a modified flow cytometer/cell sorter.
• Fluorescence in situ hybridization confirmed the Y-chromosome content in the sorted sperm fraction (82% Y sperm).
• In vitro-matured bovine oocytes were injected with single sorted sperm heads, followed by embryo culture, transfer to recipients, and assessment of pregnancy and offspring development.

Main Results:

• Intracytoplasmic injection resulted in 46.6% cleavage and 6.9% blastocyst development rates.
• Embryo transfer yielded 20.8% pregnancy and 20.8% normal live offspring production rates.
• The birth of 10 calves (8 male, 2 female) demonstrated an 80% sex preselection accuracy.

Conclusions:

• Flow cytometric sorting of bull sperm heads and subsequent intracytoplasmic injection into bovine oocytes can lead to viable live offspring.
• This technique offers a high rate of sex preselection accuracy, providing a valuable tool for genetic management in cattle breeding programs.