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Year 2018 - Volume 38, Number 9
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Cryopreservation of boar semen in 0.5mL straws at low spermatozoa concentration is better than high concentration to maintain sperm viability, 38(9):1726-1730
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ABSTRACT.- Ravagnani G.M., Torres M.A., Leal D.F., Martins S.M.M.K., Papa F.O., Dell’Aqua Junior J.A., Alvarenga M.A. & Andrade A.F.C. 2018. Cryopreservation of boar semen in 0.5mL straws at low spermatozoa concentration is better than high concentration to maintain sperm viability. [A manutenção da viabilidade do sêmen suíno criopreservado em palhetas de 0,5mL em baixas concentrações espermáticas é melhor do que em altas concentrações.] Pesquisa Veterinária Brasileira 38(9):1726-1730. Núcleo de Pesquisa em Suínos, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Pirassununga, SP 13635-900, Brazil. E-mail: andrefc@usp.br
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. |
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