Effects of vitamin B12 addition on hydrogen peroxide generation and motility characteristics of fresh and chilled ram spermatozoa

Abstract

The antioxidant ability of vitamin B12 (VitB12) and its effects on motility characteristics of fresh and chilled ram spermatozoa were investigated. Three concentrations of VitB12 including 1, 2 and 4 mg/ml were added to tris media and spermatozoa samples collected from five Awassi rams were incubated in these media at 37 and 5 °C for 2 and 24 hours respectively. Formation of hydrogen peroxide (H2O2) was estimated using a fluorometric assay and motility characteristics were analyzed using computer aided sperm analyzer (CASA). A significant decrease (P<0.05) of H2O2 formation was noted after VitB12 addition and the generation levels decreased when the concentration of VitB12 was increased. The values of motility characteristics including percentage of motility (MOT %), percentage of sperm showing progressive motility (PMOT %) and average path velocity (VAP) were increased (P<0.05) after 2 hours of incubation with 1 and 2 mg/ml of VitB12 for the fresh spermatozoa and after 24 hours of incubation for the chilled ones. In contrast, 4 mg/ml of VitB12 was able to decrease (P<0.05) the motility values for the fresh and chilled spermatozoa types. No differences were noted for percentage straightness (STR %) as well as percentage linearity (LIN %). It was concluded that VitB12 has an antioxidant capacity expressed by its ability to suppress H2O2 formation. The effects of this compound were related to the used concentration. VitB12 can be used as an antioxidant agent and motility stimulant in the semen media used for ram spermatozoa.