[Ultrastructure and sperm cryopreservation of the amazon catfish (Leiarius marmoratus) in captivity]

ABSTRACT The aims of this study were to describe the spermatozoon ultrastructure and to evaluate the sperm cryopreservation of the amazon catfish with three cryoprotectant agents (10% methanol, 10% DMSO, and 10% ethylene glycol) and two activator agents (0.29% NaCl and 1% NaHCO3). Glucose 5% extender was used as a diluent solution and sperm loaded in 0.25 straws was frozen in nitrogen vapor (dry shipper). Fresh spermatozoon was 25.46±2.54μm long, the head was spherical (1.51±0.18μm) with no acrosome, the midpiece was cone shaped (0.93±0.17μm) with presence of vesicles, slightly asymmetric, and the flagellum was single (21.48±2.45μm). Post-thawed semen presented higher values (P