Cryopreservation of boar semen in 0.5mL straws at low spermatozoa concentration is better than high concentration to maintain sperm viability

• Autor(a) principal: Ravagnani,Gisele M.
• Data de Publicação: 2018
• Outros Autores: Torres,Mariana A., Leal,Diego F., Martins,Simone M.M.K., Papa,Frederico O., Dell’Aqua Junior,José A., Alvarenga,Marco A., Andrade,André F.C.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Pesquisa Veterinária Brasileira (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-736X2018000901726
• topic: Cryopreservation; boar semen; spermatozoa concentration; sperm viability; cryoinjury; cryocapacitation; swine

ABSTRACT: To date, no studies have been performed evaluating the effect of boar spermatozoa concentration in 0.5mL freezing straws, leading us to examine this question. Each sperm-rich fraction of the ejaculate (n=25) was diluted at five different sperm concentrations (100, 200, 300, 600 and 800 x 106 spermatozoa/mL), packaged in 0.5mL straws, and subsequently frozen. After thawing, the sperm from all of treatment groups were analyzed to determine motility characteristics using a sperm class analyzer (SCA-CASA), and their plasma and acrosomal membrane integrity, mitochondrial membrane potential, sperm membrane lipid peroxidation and fluidity were analyzed by flow cytometry. An increase in spermatozoa concentration above 300x106 spermatozoa/mL in a 0.5mL straw impaired (p<0.05) the total and progressive motility, curvilinear velocity, straight-line velocity, linearity and beat cross frequency. However, the plasma and acrosomal membrane integrity, mitochondrial membrane potential, membrane lipid peroxidation and fluidity were not influenced (p>0.05) by high spermatozoa concentrations at freezing. Therefore, to increase spermatozoa survival and total and progressive motility after thawing, boar spermatozoa should be frozen at concentrations up to 300x106 spermatozoa/mL.