**5.2 Effect of cryopreservation on phosphorylation state of proteins involved in sperm motility initiation in sea bream** *Sparus aurata*

The quality of gilthead sea bream semen was decreased by cryopreservation procedure. Even though the viability (82 ± 5%) of spermatozoa following the freezing–thawing procedure was only slightly (but significant) decreased with respect to that measured in fresh samples (93 ± 4), only the 50% of the thawed spermatozoa could be activated, and showed a motility duration which was one third of that measured in fresh samples. The reduction of sperm motility (percent and duration) is attributable (at least partially) to the effect that the freezing-thawing procedure has on the phosphorylation state of proteins involved in motility initiation (Zilli et al., 2008b).
