Vitrification of stallion sperm using 0.25 ml straws: Effect of volume, concentration and carbohydrates (sucrose/trehalose/raffinose)

Abstract Sperm vitrification is a rapid freezing method in which carbohydrates are used as cryoprotectants. The aim of this study was to determine the optimal volume, concentration and type of carbohydrates for stallion sperm vitrification using 0.25 ml straws in comparison to conventional freezing. Ejaculates ( n  = 54) were collected from six stallions. For vitrification, straws were filled with different volumes (30, 70, 100 μl), sperm concentrations (50, 100, 200 × 10 6 sperm/ml) and extenders containing sucrose (20, 100, 200 mM), trehalose (50, 100, 200 mM) and raffinose (50, 100, 200 mM) and plunged into LN 2 . Conventional freezing was performed in 0.5 ml straws frozen in LN 2 vapors. Sperm motility, plasma and acrosome membrane integrities and DNA fragmentation were compared among treatments. The use of straws filled with 100 μl at 100 × 10 6 sperm/ml with the extender containing 100 mM trehalose resulted in greater values for sperm quality than the other concentrations, volumes and carbohydrates. With vitrification, there were greater values (mean ± SEM; P 6 sperm/ml using an extender with 100 mM of trehalose, obtaining better sperm quality after warming than conventional freezing.