Estudo preliminar para a caracterização de sémen equino da raça Puro Sangue Lusitano: análise do processamento de criopreservação
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2017
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Resumo
A raça Puro Sangue Lusitano (PSL) é uma raça equina autóctone portuguesa sobre a qual não existe muita informação relativamente ao modo como o sémen se comporta e suporta as técnicas de criopreservação. Assim, constituíram objetivos deste trabalho (utilizando semén proveniente de animais desta raça) se existiam diferenças entre diferentes métodos: • de quantificação da concentração espermática (Spermacue, Minitube ® vs. Câmara de Neubauer); • de aferição da mobilidade espermática (avaliação subjetiva da mobilidade vs. avaliação com recurso ao sistema CASA); • de criopreservação (manual e com recurso a uma máquina de criopreservação automática) e protocolos de centrifugação do sémen. Avaliou-se ainda o número total de espermatozóides (spz) e mobilidade espermática durante a estação reprodutiva e fora dela. Foram avaliados 327 ejaculados de 29 garanhões PSL, tendo-se concluído que a variação do nº total de spz durante a época reprodutiva e fora dela apresenta diferenças significativas (p=0,006) e a mobilidade total não se encontraram diferenças significativas (p <0,001) e na mobilidade progressiva foram encontradas diferenças significativas no sémen fresco e centrifugado (p=0,007). Foram comparados 2 protocolos de centrifugação: I-600 x g durante 10 a 15 min; II- 2000 e 2400 x g durante cinco minutos as percentagens de perda para o número total de espermatozóides foram 41% e 42% respetivamente. Relativamente à mobilidade total existiam diferenças significativas entre a categoria I e II no sémen criopreservado enquanto que para a mobilidade progressiva existiam diferenças significativas entre as categorias I e II para o sémen fresco e centrifugado. Ao comparar criopreservação manual e com recurso a uma máquina de criopreservação automática verificou-se que existiam diferenças significativa para a mobilidade total e progressiva enquanto que em relação ao número total de spz não existiam diferenças significativas p=0,278. Ao comparar o Spermacue, Minitube ® vs. Câmara de Neubauer verificou-se que existiam diferenças significativas. Ao comparar avaliação subjetiva da mobilidade vs. avaliação com recurso ao sistema CASA verificou-se que existiam diferenças significativas na mobilidade total e progressiva. Verificou-se também que existiam correlações negativas e significativas entre a concentração espermática e a mobilidade total do sémen criopreservado (Rho = - 0,239; p = 0,02) e também com a mobilidade progressiva no sémen criopreservado (Rho = - 0;216; p = 0,03).
The Lusitano breed is a Portuguese native breed and there aren’t a lot of studies performed about how the semen behaves and supports cryopreservation techniques. It is known that we need to collect more knowledge about equine spermatozoa (spz) in relation how semen behavior during cryopreservation. For this reason all the information collect is important in order to characterize semen behavior face to cryopreservation so that we can better predict fertility. The aim of this study was to evaluate only on Lusitano breed animals if there were differences on: sperm concentration measured with Spermacue, Minitube ® vs. Neubauer chamber); sperm motility measured subjectively vs. CASA system; cryopreservation method (programmable freezing machine vs. liquid nitrogen vapour); centrifugation protocols and semen parameters during or out of breeding season. During the study 327 samples of 29 stallions were evaluated and it was concluded that: the total number of spz during and out the breeding season showed significant differences (p = 0.006), total motility showed no significant differences (p <0.001) and progressive motility showed significant differences when fresh and centrifuged were compared (p = 0.007). Three centrifugation protocols were compared: I-600 x g for 10 to 15 min; II-1800-1960 x g for 5 minutes. The loss percentage on the total number of spz were 41% and 42% respectively. For the total motility significant differences were found between the categories I and II in cryopreserved semen while for progressive motility significant differences were found between the category I and II in centrifuged and fresh semen. When programmable freezing machine and liquid nitrogen vapour cryopreservation were compared significant differences were found for total and progressive motility in spite of when the total number of spz was considered no significant differences were found (p = 0.278). When Spermacue, Minitube ® and Neubauer Chamber were compared significant differences were found. When comparing subjective assessment of motility with the assessment using the CASA system significant differences were found in total and progressive motility. It was also found there were significant negative correlations between and sperm concentration and total motility on cryopreserved semen (Rho = - 0; 239; p = 0.02) and also with the progressive motility on cryopreserved semen (Rho = - 0; 216; p = 0.03).
The Lusitano breed is a Portuguese native breed and there aren’t a lot of studies performed about how the semen behaves and supports cryopreservation techniques. It is known that we need to collect more knowledge about equine spermatozoa (spz) in relation how semen behavior during cryopreservation. For this reason all the information collect is important in order to characterize semen behavior face to cryopreservation so that we can better predict fertility. The aim of this study was to evaluate only on Lusitano breed animals if there were differences on: sperm concentration measured with Spermacue, Minitube ® vs. Neubauer chamber); sperm motility measured subjectively vs. CASA system; cryopreservation method (programmable freezing machine vs. liquid nitrogen vapour); centrifugation protocols and semen parameters during or out of breeding season. During the study 327 samples of 29 stallions were evaluated and it was concluded that: the total number of spz during and out the breeding season showed significant differences (p = 0.006), total motility showed no significant differences (p <0.001) and progressive motility showed significant differences when fresh and centrifuged were compared (p = 0.007). Three centrifugation protocols were compared: I-600 x g for 10 to 15 min; II-1800-1960 x g for 5 minutes. The loss percentage on the total number of spz were 41% and 42% respectively. For the total motility significant differences were found between the categories I and II in cryopreserved semen while for progressive motility significant differences were found between the category I and II in centrifuged and fresh semen. When programmable freezing machine and liquid nitrogen vapour cryopreservation were compared significant differences were found for total and progressive motility in spite of when the total number of spz was considered no significant differences were found (p = 0.278). When Spermacue, Minitube ® and Neubauer Chamber were compared significant differences were found. When comparing subjective assessment of motility with the assessment using the CASA system significant differences were found in total and progressive motility. It was also found there were significant negative correlations between and sperm concentration and total motility on cryopreserved semen (Rho = - 0; 239; p = 0.02) and also with the progressive motility on cryopreserved semen (Rho = - 0; 216; p = 0.03).
Descrição
Dissertação de Mestrado Integrado em Medicina Veterinária
Palavras-chave
Sémen , Criopreservação , Cavalo , Reprodução , Fertilidade , Tereogenologia equina , Medicina veterinária