Kinematic study on the effect of pH on bull sperm function

Area of Science:

• Reproductive Biology
• Sperm Physiology
• Environmental Factors in Gamete Function

Background:

• Spermatozoa are highly dependent on their surrounding environment for function.
• Previous research suggests pH influences sperm kinetics, but objective data is lacking.
• Understanding optimal pH is crucial for semen handling and fertility.

Purpose of the Study:

• To objectively assess the impact of various environmental pH levels on bull sperm kinetic parameters.
• To evaluate the effects of pH on sperm viability, mitochondrial activity, and morphology.
• To compare calcein AM viability staining with traditional methods.

Main Methods:

• Bull semen was evaluated across a pH range of 5.5 to 8.5.
• Kinetic parameters, viability, mitochondrial activity, and morphology were measured immediately and 1 hour post-dilution.
• Flow cytometry was used for viability assessment with calcein AM and propidium iodide/SYBR-14.

Main Results:

• Optimal sperm motility, viability, and mitochondrial activity were observed at pH 7 and 7.5.
• Sperm function significantly declined at pH levels below 6.5 and above 8.
• A notable decrease in motility with preserved viability was seen at pH 8 and 8.5, linked to reduced mitochondrial activity.
• Calcein AM viability staining showed high consistency with membrane integrity assessed by propidium iodide/SYBR-14.

Conclusions:

• Environmental pH critically affects bull sperm motility, viability, and mitochondrial function.
• pH 7 and 7.5 represent the optimal range for maintaining bull sperm quality.
• Calcein AM offers a reliable and potentially advantageous alternative for sperm viability assessment in flow cytometry.