| Sumario: | The present work shows a practical and of cheap methodology for Engraulis ringens sperm cryopreservation, with the purpose to optimize its reproduction techniques in captivity. The investigation was divided in three stages. The first one consisted to evaluate toxicity of four cryoprotectants; dimethylsulfoxide (ME2SO), ethanol (ET), propylene glycol (PG), glycerol (GL) to three molars concentrations (0.5 M; 1.0 M and 1.5 M) on spermatic motility. Motility percentages of sperms incubated in ME2SO were significantly bigger than that observed in others three cryoprotectants. In the second stage, the optimal freezing rates were determinate, using ME 2 SO only. In this case, the biggest motility percentages were obtained with 1.5 M ME2SO with freezing rates of -20 to -40 degrees C min(-1) (61.3 +/- 7.6% and 53.8 +/- 4.9% respectively). Finally, the effect of addition of not permeable cryoprotectant in cryoprotective solution (egg hen yolk, VHG) was evaluated to optimize the post-thawing spermatic motility; nevertheless, the results did not change significantly respect to control without VHG.
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