Summary The aim of this study was to evaluate the effect of the addition of Ficoll 70 into the cryopreservation medium containing @entity969 and @entity3733 ( @entity3733 ) on @entity95 spermatozoa characteristics following freezing/thawing. This large molecular weight polymer elevates the viscosity of medium and, therefore, could better protect spermatozoa during the freezing process. Only ejaculates of good initial motility (>80%) were used in the experiments. Heterospermic pools were diluted in a freezing medium composed of commercial diluent, 16% @entity3733 ( @entity3733 ) and 2% @entity969 (control) or in the same medium enriched with 4% Ficoll 70 (Ficoll) and frozen in liquid @entity1568 vapours for 10 min before being plunged in liquid @entity1568 . The quality of fresh and frozen/thawed spermatozoa samples was evaluated in vitro using the Computer Assisted Semen Analysis (CASA) system, fluorescent probes (peanut agglutinin (PNA)-Alexa Fluor  ; annexin V-FLOUS) and by electron microscopy. Better cryoprotective effect was observed when Ficoll 70 was added, compared with the semen cryopreserved with @entity969 and @entity3733 only. The higher values (P < 0.05) of motile and progressively moving spermatozoa immediately after thawing and at 30 min following incubation at 37  C were obtained in the Ficoll group. Moreover, the higher number (P < 0.05) of acrosome intact sperm was found in the Ficoll compared with the control group. Furthermore, no significant differences in kindling rates and number of pups born between frozen/thawed and fresh semen group were found. In conclusion, our study showed that the addition of Ficoll 70 might improve several characteristics of @entity95 spermatozoa measured in vitro following freezing/thawing.

The cryoprotective effect of Ficoll on the XXXX spermatozoa quality.

@entity969 :: ('MESH:D013395', 'Chemical') :: ['sucrose'] @entity1568 :: ('MESH:D009584', 'Chemical') :: ['nitrogen'] @entity95 :: ('9986', 'Species') :: ['rabbit'] @entity3733 :: ('MESH:D004121', 'Chemical') :: ['dimethyl sulphoxide', 'dimethyl sulfoxide', 'DMSO']
@entity95 :: (9986,Species) :: ['rabbit']
