Evaluation of Ethylene Glycol as a Cryoprotectant in the Sperm Cryopreservation of Trans-andean Shovelnose Catfish (Sorubim Cuspicaudus, Pimelodidae)

Abstract

The catfish Sorubim cuspicaudus cryopreservation semen was evaluated using three levels (5, 10, 15%) of ethylene glycol (ETG). Males (n = 13) undergoing spermiation and in final maturation females (n = 6) were induced with 0.4 ml Ovaprim®/Kg, after 12 and 14 post-induction the semen was collected in 2 ml Eppendorf vials. The different cryoprotectants solutions were prepared with glucose 6% (w/v) skimmed milk powder 5% (w/v) and distilled water. The semen was diluted in ratio 1:3 (semen:extender), packed in macrotubes of 2.5 ml and frozen in liquid nitrogen (NL) vapor for 30 minutes, then the macrotubes were stored in cryogenic tanks submerged directly in NL. The sperm were thawed in serological bath to 35 °C for 90 seconds. The total motility, total progressivity and velocities in fresh and thawed semen were analyzed with the Sperm Class Analyzer software (SCA Microptic SL, Spain). Fertility and hatching rates were assessed with 1.0-1.5 g of oocytes in experimental up flow incubators 2 L, a completely randomized design was used. The hatching rate of fresh semen was 51.8 ± 21.0%, with no significant differences with semen cryopreserved with ETG 5% (38.6±13.9%) (p>0.05), while ETG 15% (9.6±2.9%), recorded the lower hatching rate (p0.05); mientras que ETG 15% (9.6±2.9%) reportó la menor eclosión (p<0.05). Los resultados sugieren que la solución crioprotectora compuesta por ETG 5%, glucosa 6% y leche en polvo 5% es una alternativa viable para la crioconservación de semen de Sorubim cuspicaudus con fecundaciones similares al usar semen fresco.

Keywords

• cryoprotective agents
• fertility
• reproduction
• semen analysis
• análisis seminal
• crioprotectores