Inter- and intra-individual variability of total antioxidant capacity of bovine seminal plasma and relationships with sperm quality before and after cryopreservation.

The aim of the present study was to investigate inter- and intra-individual variability of total antioxidant capacity (TAC) in seminal plasma of bulls. In addition, relationships between TAC and glutathione peroxidase (GPx), superoxide dismutase activities (SOD), and parameters of sperm quality, respectively, were examined. Eight consecutive ejaculates were collected from nine Holstein-Friesian bulls. The percentage of plasma membrane and acrosome intact (PMAI) sperm was measured by using the FITC-PNA/PI assay, the amount of membrane lipid peroxidation (LPO) without and with stimulation(s) of LPO was quantified by using the BODIPY assay before cryopreservation and immediately (0 h) as well as 3h after thawing. The percentage of sperm with a greater DNA fragmentation index was measured by the sperm chromatin structure assay. The amount of TAC differed (P < 0.0001) between bulls but not (P > 0.05) between ejaculates within bulls. The amounts of TAC were not related (P > 0.05) to amounts of SOD and GPx, but were negatively associated with LPO 0 h (r = -0.85; P ≤ 0.01). The amounts of SOD showed positive relationships with LPO 0 h (r = 0.71; P ≤ 0.05) and LPO 3h (r = 0.80; P ≤ 0.05). In conclusion, total antioxidant activity varied among bulls, but not between ejaculates within bulls. While the amounts of antioxidative enzyme GPx was not related to sperm quality and SOD was positively related with lipid peroxidation after thawing of sperm, whereas total antioxidative capacity was negatively correlated with lipid peroxidation of cryopreserved sperm.