High-throughput characterisation of bull semen motility using differential dynamic microscopy

Area of Science:

• Reproductive Biology
• Biophysics
• Microscopy Techniques

Background:

• Sperm motility is crucial for male fertility.
• Accurate and efficient characterization of sperm motility is essential for reproductive diagnostics.
• Existing methods can be time-consuming or lack throughput.

Purpose of the Study:

• To develop and validate a high-throughput technique for characterizing sperm motility.
• To enable rapid, on-farm assessment of sperm quality.
• To measure mean swimming speed, head oscillation parameters, and fraction of motile spermatozoa.

Main Methods:

• Utilizing differential dynamic microscopy (DDM).
• Employing a large field of view (∼10mm²) to record thousands of spermatozoa simultaneously.
• Analyzing averaged motion parameters including mean speed, standard deviation, head oscillation amplitude (A0), frequency (f0), and motility fraction (α).

Main Results:

• The DDM technique allows simultaneous measurement of multiple motility parameters for thousands of cells.
• Swimming spermatozoa were observed to enhance the motion of non-swimming cells, facilitating motility fraction (α) measurement.
• On-farm characterization of bull spermatozoa demonstrated the method's ease and rapidity.
• Laboratory validation confirmed the accuracy of the DDM technique compared to traditional tracking.

Conclusions:

• Differential dynamic microscopy offers a high-throughput, efficient, and accurate method for sperm motility analysis.
• The technique is suitable for both laboratory and field applications, aiding in reproductive assessments.
• The findings support theoretical predictions regarding sperm swimming dynamics.