Diluidores e crioprotetores no resfriamento e congelamento do sÃmen de piracanjuba ( Brycon orbignyanus) / Semen cool storage and cryopreservation of piracanjuba Brycon orbignyanus.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The aim of this study was to develop a protocol for semen storage of piracanjuba (Brycon orbignyanus) by cool storage at 4ÂC and cryopreservation. The experiments were carried out at the Fish Culture unit of Hydrelectric Company of Minas Gerais, Itutinga-MG. In experiment 1, some extenders, cryoprotectors (DMSO, methanol ot methyl glycol) and antibiotic (gentamicin sulfat) were tested on cool storage of semen. In experiment 2, the extenders that maintained the highest motility rate of semen on experiment 1, were combined with 10% cryoprotector (DMSO, methanol and methyl glycol) and 5% egg yolk, and used as cryodiluent for semen cryopreservation. Semen was frozen in liquid nitrogen vapour (vessel Taylor-Warton, model CP 300, âdry shipperâ) and thawed at 60ÂC water-bath for 8 seconds. In experiment 3, the hatching rate of frozen sperm were evaluated. In experiment 1, semen diluted in Saad solution (NaCl 200 mM; tris 30 mM) yielded the highest motility rate (80%) after 24 h of cooling. Control undiluted semen produced only 33% motility after the same period of cooling. There was no difference on motility of semen diluted in extender compared to samples diluted in extender plus cryoprotectors. The only exception was the combination of NaCl 0,9% plus DMSO that produced 77% motility, compared to 60% motility of samples diluted in NaCl 0.9% only. Semen diluted in Saad solution or NaCl 200 mM only produced motility rates similar to those samples diluted in NaCl 0,9% plus DMSO. This indicates that there is no need to add cryoprotectants to the cooling medium when Saad solution or NaCl 200 mM are used as extenders. When semen was stored for 7 days in NaCl 200 mM or Saad solution containing gentamicin, motility rates were similar to those samples stored in the same extender without gentamicin. In experiment 2, semen frozen in NaCl 0,9% + egg yolk + methyl glycol, M III (glucose; sodium citrate; EDTA; gentamicin sulfat; NaHCO3) + egg yolk + methyl glycol and; BTS (glucose; sodium citrate; EDTA; gentamicin sulfat; NaHCO3; KCl) + methyl glycol produced post-thawed motility rates above 60%. When those samples semen was used to fertilize fresh eggs, the hatching rates were between 40 and 66%, while control fresh semen produced 86% of hatching.

ASSUNTO(S)

cryopreservation fish aquicultura cool storage semen resfriamento piracanjuba piracanjuba peixe sÃmen criopreservaÃÃo

ACESSO AO ARTIGO

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