Detection of osteopontin transcript in seminal plasma and its association with post-freeze-thaw quality of cryopreserved spermatozoa in mithun (Bos frontalis)

The study aimed to detect osteopontin (OPN) transcript in seminal plasma and to assess the relationship between the presence of the transcript and post-freeze-thaw quality of cryopreserved spermatozoa in mithun (Bos frontalis). Semen samples were collected from five adult bulls through rectal massage method and cryopreserved in tris-egg yolk-glycerol extender. OPN transcript was detected by RT-PCR in the RNA purified from seminal plasma. OPN transcript was found to be present consistently in three animals (OPN+) and absent in two animals (OPN-). Although, sperm viability and acrosomal integrity were found similar at different stages of cryopreservation in both the groups, tail abnormality after final dilution and, head and tail abnormalities after equilibration were found significantly (P<0.05) lesser in the OPN+ compared to OPN-animals. The results indicated that OPN is probably important in stabilizing sperm membrane that resulted in better resistance of sperm to cryopreservation process in OPN+ animals.