Resumen
- The bagre rayado (Pseudoplatystoma fasciatum) is a siluridae of the Amazon and Orinoco basins whose natural population is diminishing gradually, due to disturbance of its habitat, transforming it into a species in extinction risk; however, few investigation works have been guided to their conservation, particularly of their gametes. This work sought to characterize the semen of the species, to evaluate the toxicity of the dimethyl sulfoxide (DMSO) on motility spermatic and to study two protocols for its cryopreservation. Six mature males were used, induced to the espermiation with extract of carp hypofisis. The seminal characteristics of 19 samples were registered and aliquots of 250 mL were diluted in two different solutions with 0, 5, 10 or 15% of DMSO, then stored low refrigeration and the motility monitored at 0, 1, 2, 4, 8, 16, 24, 32, 40 and 48 h Finally, diluted semen (1:4) was cryopreserved in pellets form or in 0,5 mL straws using different concentrations of DMSO like cryoprotector (3, 5, 7.5, 10 o 15 %). The seminal volume was 3.7 ± 0.3 mL, white color and milky appearance; the motility and spermatic concentration were 95% and 23433 x 106 sperms for mL, respectively. An inverse relationship was observed between DMSO concentration and spermatic motility. Only semen diluted in solutions with 5 and 7.5% of DMSO and packed in straws showed motility posthawing. In conclusion, DMSO concentrations above 10% are toxic for the sperm of bagre rayado and their cryopreservation protocol still requires standardization