Banca de DEFESA: MÁRCIO CALIXTO MATIAS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : MÁRCIO CALIXTO MATIAS
DATE: 11/03/2021
TIME: 15:00
LOCAL: Plataforma online (Google Meet)
TITLE:

Vitrification of ejaculated ram sperm

KEY WORDS:

Ultra-rapid freezing; Sperm cryopreservation; Glycerol; Galactose.

PAGES: 69
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUMMARY:

Semen cryopreservation is a biotechnique with substantial economic impact, since it is the basic technique to implement further biotechnologies on conservation and multiplication of genetic resources, such as artificial insemination and in vitro embryo production. Although classical freezing is the most common technique to cryopreserve sheep semen, it has some limitations in this species. Therefore, new methods of cryopreservation have been developed, with sperm vitrification being one of the most promising. Semen vitrification has several advantages, as a fast and low-cost method, but mainly due to avoid ice crystals formation. However, there are few
studies evaluating its efficiency with sheep ejaculated semen and the use of galactose as an extracellular cryoprotectant, as well as the effects that these cryoprotectants and cryopreservation techniques have on sperm. The present study was developed to evaluate the effect of galactose (0.01 M), associated or not with glycerol (3 and 7%) in commercial medium on vitrification of sheep sperm using the straw method. Ejaculates from six Dorper rams were collected with artificial vagina, individually diluted in tested media and the samples were packed in 0.25 ml straws. To assess the effect of different techniques on sperm quality after cryopreservation, the samples were cryopreserved using both classical and vitrification methods, and the kinematics, morphology, morphometry, viability, physical and functional integrity of the sperm membrane were analyzed. Sperm vitrification had lower results (p <0.05) than classic freezing, as no motility was detected in any tested extender, as well as lower values of viability, physical and functional integrity of the membrane were observed. The vitrification resulted in a higher percentage of coiled tail and a lower percentage of cells reactive to hyposmotic test in all extenders when compared to classical freezing (p <0.05). In addition, the use of extenders added with galactose without or with both 3% and 7% glycerol significantly increased the percentage of major defects. It was concluded that galactose and glycerol at the concentrations used were ineffective for vitrification of sheep sperm using the straw method.

BANKING MEMBERS:
Presidente - 1640234 - DIOGO RIBEIRO CAMARA
Externo à Instituição - GUSTAVO FERRER CARNEIRO - UFRPE
Externa à Instituição - VALESCA BARRETO LUZ