EFFECT OF IMPERMEANT CRYOPROTECTANTS ON THE IN VITRO VIABILITY OF FROZEN SPERMATOZOA OF SWISS-ALBINA AND BALB/C MICE (Mus musculus) EFEITO DE CRIOPROTETORES IMPERMEÁVEIS SOBRE A VIABILIDADE IN VITRO DE ESPERMATOZOIDES CONGELADOS DE CAMUNDONGOS (Mus musculus) DAS LINHAGENS SWISS-ALBINA e BALB/c

The objective of this study was to evaluate the effect of three disaccharides (sucrose, threalose and lactose) used as nonpenetrating cryoprotectants in extender for mice semen. The parameters evaluated were sperm motility (MOT) and cleavage rate (CLV) after in vitro fertilization in the SWISS-ALBINA and BALB/c lines. The treatments were S1=sucrose; S2=threalose; S3=lactose, for SWISS-ALBINA; and B1=lactose; B2=threalose for BALB/c. MOT was evaluated after: thawing (THA), centrifugation and re-suspension in P-1 medium (CEN) and after 10 minutes of incubation (10M). The MOT for the SWISS-ALBINA line was higher for S2 (P