Assessment of Fertilizing Ability of Frozen-thawed Stallion Semen in Glutamine Extender

The fertilizing ability of stallion spermatozoa frozen-thawed in glutamine extender was evaluated, using servel functional tests: post-thaw motility, chromatin structure, plasma membrane integrity, acrosomal status, and sperm-zona pellucida binding. Fifteen ejaculates were collected from 3 fertile stallions. Each ejaculate was divided into 2 parts, respectively frozen in INRA freezing extender (Control: INRA82 + 2% (v/v) egg yolk + 2.5% (v/v) glycerol + 20mM hepes) and Glutamine (control + 50mM glutamine) extenders. Semen functional characteristics were evaluated after thawing, by computer automated sperm analyser, acridine orange (AO) staining, fluorescein isothiocyanate-Pisum sativum agglutinin (FITC-PSA) technique, hypo-osmotic swelling (HOS) test, and hemi zona assay (HZA). Results showed that glutamine extender afforded more protection to stallion spermatozoa than control extender. It was concluded that glutamine at 50mM in INRA freezing extender could enhance fertility of stallion semen after freezing and thawing.