Effects of centrifugation through three different discontinuous Percoll gradients on boar sperm function

Area of Science:

• Reproductive Biology
• Animal Science
• Spermatozoa Function

Background:

• Optimizing sperm selection is crucial for improving artificial insemination and in vitro fertilization (IVF) success rates in livestock.
• Discontinuous density gradient centrifugation is a common method for sperm separation, but gradient composition can influence outcomes.

Purpose of the Study:

• To evaluate the effects of three different discontinuous Percoll gradients (45/60%, 60/75%, and 45/90%) on boar sperm function and in vitro penetrating capacity.
• To identify the optimal Percoll gradient for selecting high-quality boar spermatozoa.

Main Methods:

• Spermatozoa from fertile boars were centrifuged using three different 2-step discontinuous Percoll gradients.
• Sperm function parameters including motility, viability, morphology, acrosome status, chromatin condensation, DNA fragmentation, ROS generation, tyrosine phosphorylation, and intracellular calcium were assessed.
• In vitro oocyte penetrating capacity was evaluated using an IVF system.

Main Results:

• All Percoll treatments significantly improved sperm morphology, DNA integrity, chromatin condensation, motility (CASA), and capacitation markers (tyrosine phosphorylation) compared to controls.
• All Percoll gradients enhanced in vitro oocyte penetration rates and the mean number of sperm per penetrated oocyte.
• The 45/90% Percoll gradient (P45/90) showed the highest efficiency in selecting spermatozoa with improved capacitation, indicated by tyrosine phosphorylation and intracellular calcium levels.

Conclusions:

• Discontinuous Percoll gradient centrifugation effectively selects boar spermatozoa with enhanced functional parameters and in vitro penetrating capacity.
• The 45/90% Percoll gradient is the optimal choice for preselecting boar spermatozoa, leading to superior capacitation and fertilization potential.