Evaluación de diferentes crioprotectores para la crioconservación de espermatozoides de yamú (Brycon amazonicus)

the effect of dimethyl sulphoxide (dmso), ethylene glycol (etg), propylene glycol (ppg) and methanol (met) in yamú (brycon amazonicus - spix & agassiz, 1829) semen cryopreservation was evaluated with the aim of determining the post-thawing quality and in vitro fertility. for this purpose, sexually mature yamú females and males were induced to promote ovulation and spermation with carp pituitary extract. the semen obtained was evaluated and diluted 1:4 in a solution with 12% egg yolk and 5.5% glucose. different concentrations (3.75, 5, 7.5, 10, 11.25 and 15%) for each one of the 4 cryoprotectants were used for a total of 24 treatments. the diluted semen was frozen into 0.5 ml straws by liquid nitrogen vapours (ln) during 30 minutes and then transferred to a container with ln until be assayed. the straws (n= 6) corresponding to each treatment were thawed at 35 °c for 60 seconds and evaluated to select the best concentration for each cryoprotector for the fertility test. 5% dmso, 3.75% et, 3.75% ppg and 3.75% met treatments presented the highest motility percentages (mp) and activation time (at) being 5% dmso the best (mp 76 ± 2.4; at 88.2 ± 6.1). on the other hand, 3.75% ppg and 3.75% met treatments showed the highest fertility percentages (50 ± 1.4 and 47.8 ± 1.4, respectively); however, these percentages were significantly lower (p<0.05) than these obtained with fresh semen (64.7 ± 1.7). in general, it was observed that the increase in the cryoprotector concentration decreased semen quality post-thawing, and there was not direct relationship between sperm motility and fertility