Criopreservação de sémen como estratégia de conservação de raças autóctones ovinas e caprinas
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2017
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A criopreservação de sémen e a inseminação artificial (IA) em pequenos ruminantes tem vindo a ser uma prática crescente nos últimos anos como uma estratégia de conservação genética. A criopreservação induz alterações estruturais e funcionais na membrana dos espermatozóides (spz) reduzindo a fertilidade após a IA. Vários protocolos de congelação e diluidores foram desenvolvidos para reduzir estes danos e melhorar a sua capacidade fertilizante.
O objetivo do estudo 1 foi comparar três protocolos de congelação de sémen de carneiro e bode utilizando distintos diluidores, através da avaliação da viabilidade dos spz, após a descongelação, em termos de motilidade individual progressiva (MIP) e da sua utilização na IA. O diluidor EZN mostrou-se mais eficiente que os diluidores Bioxcell® e Ovixcell® na criopreservação de sémen de ambas as espécies, apesar de estatisticamente não existirem diferenças significativas na MIP antes da congelação e após a descongelação (caprinos: p> 0,05 MIP congelação: Bioxcell®-70,0%, EZN-62,5%, MIP descongelação: Bioxcell®-25,0%, EZN-27,5%; ovinos: p> 0,05 MIP congelação: Ovixcell®-69,2%, EZN- 80,0%, MIP descongelação: Ovixcell®-35%, EZN-63,8%).
O estudo 2 teve como objetivo a testagem de sémen de ovino criopreservado no Centro de Reprodução Animal da Herdade da Abóbada (CRAHA) recorrendo a dois protocolos de congelação através da fertilidade à IA por laparoscopia. A taxa de fertilidade foi de 32%. O protocolo de congelação com EZN mostrou-se mas eficiente que o diluidor Ovixcell® na criopreservação de spz ovinos para IA com sémen congelado.
O estudo 3 teve como objetivo a testagem da fertilidade de sémen de caprino criopreservado no CRAHA recorrendo a dois protocolos de congelação através da fertilidade à IA por via cervical. A taxa de fertilidade foi de 27,9%. O diluidor Bioxcell® mostrou-se mais eficiente que o diluidor EZN na criopreservação de spz ovinos para IA com sémen congelado, pois nasceram um maior número de crias provenientes da congelação de sémen com Bioxcell® (n=15) do que com EZN (n=5).
The cryopreservation of semen and the artificial insemination (AI) in small ruminants has become an increasing practice as a strategy for the implementation of genetic conservation programs in the last few years. The cryopreservation process results in structural and functional changes in membrane sperm cells (spz) reducing the fertility after AI. Several semen extenders have been developed to lessen the damage and improve the fertilizing capacity. The aim of study 1 was to compare three protocols in terms of their effects on the conservation of ram and buck sperm cells using different semen extenders after the freezing process, evaluated through their individual progressive motility (IPM) with the purpose of using it in AI programs. The EZN protocol has proved to be more effective than the Bioxcell® and Ovixcell® in the cryopreservation of the semen of both species, although statistically there were no major differences in the IPM before freezing and after thawing (caprine: p> 0,05 MIP freezing: Bioxcell®-70,0%, EZN-62,5%, MIP thawning: Bioxcell®-25,0%, EZN- 27,5%; ovine: p> 0,05 MIP freezing: Ovixcell®-69,2%, EZN-80,0%, MIP thawning: Ovixcell®- 35%, EZN-63,8%). The purpose of study 2 was testing cryopreserved ovine semen in the Herdade da Abóbada Breeding Center (CRAHA) using two freezing semen protocols through the fertility in the laparoscopic insemination. The fertility rate was 32%. The EZN semen protocol has proved to be more effective than the Ovixcell® semen protocol in the cryopreservation of ovine spz for AI with frozen semen. The aim of study 3 was to test the fertility of caprine semen cryopreserved in CRAHA, using two semen protocols through the fertility in cervical AI. The fertility rate was 27,9%. The Bioxcell® protocol proved to be more effective than EZN in the cryopreservation of ovine spz for AI with frozen semen, since there was a bigger number of offspring coming from the semen freezing with Bioxcell® (n=15) than from EZN (n=5).
The cryopreservation of semen and the artificial insemination (AI) in small ruminants has become an increasing practice as a strategy for the implementation of genetic conservation programs in the last few years. The cryopreservation process results in structural and functional changes in membrane sperm cells (spz) reducing the fertility after AI. Several semen extenders have been developed to lessen the damage and improve the fertilizing capacity. The aim of study 1 was to compare three protocols in terms of their effects on the conservation of ram and buck sperm cells using different semen extenders after the freezing process, evaluated through their individual progressive motility (IPM) with the purpose of using it in AI programs. The EZN protocol has proved to be more effective than the Bioxcell® and Ovixcell® in the cryopreservation of the semen of both species, although statistically there were no major differences in the IPM before freezing and after thawing (caprine: p> 0,05 MIP freezing: Bioxcell®-70,0%, EZN-62,5%, MIP thawning: Bioxcell®-25,0%, EZN- 27,5%; ovine: p> 0,05 MIP freezing: Ovixcell®-69,2%, EZN-80,0%, MIP thawning: Ovixcell®- 35%, EZN-63,8%). The purpose of study 2 was testing cryopreserved ovine semen in the Herdade da Abóbada Breeding Center (CRAHA) using two freezing semen protocols through the fertility in the laparoscopic insemination. The fertility rate was 32%. The EZN semen protocol has proved to be more effective than the Ovixcell® semen protocol in the cryopreservation of ovine spz for AI with frozen semen. The aim of study 3 was to test the fertility of caprine semen cryopreserved in CRAHA, using two semen protocols through the fertility in cervical AI. The fertility rate was 27,9%. The Bioxcell® protocol proved to be more effective than EZN in the cryopreservation of ovine spz for AI with frozen semen, since there was a bigger number of offspring coming from the semen freezing with Bioxcell® (n=15) than from EZN (n=5).
Descrição
Orientação : Carlos Bettencourt
Palavras-chave
MESTRADO INTEGRADO EM MEDICINA VETERINÁRIA, MEDICINA VETERINÁRIA, INSEMINAÇÃO ARTIFICIAL, OVINOS, CAPRINOS, CRIOPRESERVAÇÃO DE SÉMEN, VETERINARY MEDICINE, ARTIFICIAL INSEMINATION, SHEEP, GOATS, SEMEN CRYOPRESERVATION