ABSTRACT
A recuperação e a criopreservação de espermatozoides do epidídimo constituem alternativas viáveis para a preservação de material genético de animais valiosos. O objetivo deste estudo foi comparar o desempenho de dois diluentes comerciais Botu-Bov(r) (BB) e Bovimix(r) (BV), sobre a viabilidade pós-descongelação de espermatozoides do epidídimo de touros Tabapuã (Bos taurus indicus) pós-castração. Os espermatozoides foram colhidos da cauda de 20 epidídimos utilizando a técnica de fluxo retrógrado, centrifugados e diluídos com BB ou BV para posterior criopreservação a -196°C. Após a descongelação, as amostras foram avaliadas utilizando a análise computadorizada (CASA) e por análises microscópicas para a determinação da integridade de membranas plasmáticas, acrossomal e morfologia espermática. A avaliação estatística dos dados foi realizada pela análise de variância (ANOVA) com o pós-teste de comparações múltiplas de Tukey-Kramer, com nível de significância (P<0,05). Os resultados do movimento espermático avaliado pelo CASA, não diferiram para o diluente BB e BV. Também não foi observada diferença significativa entre os grupos no percentual de espermatozoides morfologicamente deformados, defeitos de acrossoma e espermatozoides com membrana plasmática íntegra após o descongelamento. Conclui-se que ambos os diluentes (BB e BV) são eficientes e podem ser utilizados na tecnologia do congelamento de espermatozoides colhidos da cauda do epidídimo de touros, não apresentando diferença na viabilidade espermática para os parâmetros estudados.
Recovery and cryopreservation of epididymal sperm is a viable alternative for preservation of genetically valuable animals. The aim of this study was to verify and to compare the effect of two commercial extenders for conventional semen on post-thawing viability of bovine epididymal sperm. For this purpose, the spermatozoa was recovered from the tail of 20 epididymis of Tabapuã bulls (Bos Taurus indicus) using retrograde flow method. After sperm recovery, the cells were centrifuged and divided for dilution with the diluents Botu-Bov(r) (BB) or Bovimix(r) (BV) for cryopreservation at -196°C. After thawing, all samples were evaluated using computer assisted sperm analysis (CASA), and by microscopic analysis for determination of integrity of plasma and acrossomal membrane and morphology. Statistical evaluation was performed by analysis of variance (ANOVA) with post-test for multiple comparisons, the Tukey-Kramer test, with significance level (P<0.05). The results of the sperm movement for diluent BB and BV evaluated with CASA, showed no difference for both (P>0.05). There was also no difference between the percentage of deformed sperm, acrosome defects and the sperm with intact plasma membrane after thawing with BB or BV. We conclude that both extenders (BB and BV) are efficient and can be used for freezing sperm collected from the epididymis of bulls, showing no difference for all the parameters studied.
ABSTRACT
The aim of this study was to evaluate the viability of bull spermatozoa collected from the cauda epididymis stored at 18-20°C, which were compared with semen collected by electro-ejaculation method and preserved at 5°C. Ten pairs of testes from Tabapuã bulls were removed by orchiectomy and stored for 6 (G6), 12 (G12), 18 (G18), 24 (G24) and 30 (G30) h at room temperature (18-20°C). Seven days before orchiectomy, semen was collected by electro-ejaculation method. The sperm parameters evaluated were: sperm motility, vigor, concentration, morphology and acrosome defects. Sperm motility declined (p<0.05) when spermatozoa were stored for 30 h in the epididymis. The spermatozoa from the epididymis showed lower sperm motility than that of spermatozoa collected via electro-ejaculation. There was a little expressive decrease in sperm vigor and increased in morphological defects with storage time, but the acrosome integrity was not affected. Cold storage (5°C) maintained sperm viable for 15 to 40.8 h. Thus, it was possible to recover viable sperm with 41.25% of motility from the cauda epididymis stored at room temperature of 18-20°C for 30 h. There were differences between the ejaculated and epididymal sperm for the bulls and the conservation at 5°C allowed short-term preservation of the gametes.