Fifty semen samples were collected from sixteen buffalo-bulls (4-10 years old) and evaluated before cryopreservation. The activity of superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) as well as the levels of glutathione (GSH) and malondialdehyde (MDA) were assayed in the seminal plasma before freezing. Aspartate aminotransferase (AST) activity and cholesterol content were assayed in seminal plasma before freezing and after thawing. Results revealed the presence of SOD and GPx activities (0.07 ± 0.01 U/ml and 14.59 ± 0.50 nmol/min/ml, respectively) in buffaloes' seminal plasma. SOD activity was positively correlated with both of GSH level and GST activity in seminal plasma, and showed an inverse relationship with both cholesterol efflux and post-thaw abnormal tails of buffalo spermatozoa. A positive correlation was found between GPx activity in seminal plasma and abnormal tails and an inverse relationship with both post-thaw viability indices and increased motility in response to PTx. GST activity showed a positive correlation with the increased motility after addition of PTx and negative correlations with both of cholesterol level and AST activity. MDA levels were negatively correlated with motility after addition of PTx and positive correlations with both post-thaw abnormal acrosomes and tails. Buffalo seminal plasma contains high activities of SOD, GPx and GST enzymes and GSH levels that have an influence on the functional competence of cryopreserved spermatozoa.
Keywords: Buffalo; Cryopreservation; Glutathione peroxidase.; Semen; Superoxide dismutase.
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