Changes in oxidative stress and ultrastructure of the sperm of silver barb, Barbonymus gonionotus, related to cryopreservation using a dry shipper

An investigation was conducted to clarify the role of oxidative stress and ultrastructural changes on the sperm of the silver barb, Barbonymus gonionotus caused by the cryopreservation. The sperm was cryopreserved using a dry shipper and 500-mu l straws loaded with 160 mu l extended semen and 10% DMSO, frozen for 2 min within the upper chamber of the dry shipper, and immediately transferred into the lower chamber for cryostorage. Lipid peroxidation (LPO) levels of silver barb sperm were affected by the freezing and cryostorage period, progressively increasing (p < 0.01) throughout the 14-day cryostorage. The ultrastructural defects, apoptotic, and necrotic cells were higher (p < 0.01) in the post-thawed sperm. There were inverse correlations between ultrastructural damage and the sperm qualities (motility; r = -0.84, p < 0.0001 and viability; r = -0.72, p < 0.001). In conclusion, this cryopreservation procedure had the effect on the oxidative and ultrastructural damage in the sperm cells. There is a need for antioxidants supplement to avoid the oxidative damage and ultrastructural alteration during freezing-thawing process.