EN
The objectives of this study were: sperm cryopreservation, computer assisted sperm motility analysis (CASA) and improvement of sperm motility through in vitro incubation of rainbow trout neomale spermatozoa. In vitro incubation of sperm in ASP (Artificial Seminal Plasma) solution resulted in an increase of the percentage of motile spermatozoa, while other sperm motility characteristics remained unchanged. The highest hatching rates were obtained for sperm cryopreserved in straws (16.3% and 25.0%): cryopreservation in pellets was less successful (7.7% and 3.8%), for non-incubated and incubated sperm, respectively. There were significant regressions between hatching rates and straight-line velocity (VSL; R² = 0.75) and average path velocity (VAP; R² = 0.74) for sperm preincubated in ASP and cryopreserved in straws. These data indicate that sperm of rainbow trout neomales may be successfully cryopreserved and CASA analysis is useful for the prediction of fertilizing ability of cryopreserved sperm.