Arquivo Brasileiro de Medicina Veterinária e Zootecnia (Apr 2013)

Efeito da adição de glutationa peroxidase e cisteína ao diluidor de congelação do sêmen equino Effect of glutathione peroxidase and cysteine addition in an equine frozen semen medium

  • L.O. Barros,
  • S.V. Silva,
  • F.C. Almeida,
  • E.C.B. Silva,
  • G.F. Carneiro,
  • M.M.P. Guerra

Journal volume & issue
Vol. 65, no. 2
pp. 430 – 438

Abstract

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Foram utilizados ejaculados (n=25) de garanhões para avaliar o efeito de glutationa peroxidase (GPx) e cisteína na viabilidade de espermatozoides congelados. O sêmen foi diluído em Botu Crio, com antioxidantes, e foram formados os grupos: G1, Controle; G2, 1U GPx ; G3, 5U GPx; G4, 0,5mM cisteína; G5, 1mM cisteína. Depois foi envasado em palhetas (0,5mL) e congelado. Após descongelação, 37°C por 30 segundos, alíquotas foram analisadas quanto à integridade de membrana plasmática (IMP) e acrossoma (IAc), potencial de membrana mitocondrial (PMM) e cinética, nos tempos zero (T0) e 60 minutos (T60). GPx 5U e cisteína 0,5mM determinaram maior (PEjaculates (n=25) of horses were used to assess the effect of glutathione peroxidase (GPx) and cysteine on the viability of frozen sperm cells. Semen was extended at Botu Crio with antioxidants, and divided in groups: G1, control; G2, 1 U GPx; G3, 5U GPx; G4, 0.5mM cysteine and G5, 1mM cysteine, packed in 0.5mL straws, and frozen. After thawing (37° C for 30 seconds) samples were analyzed for plasma membrane (IMP) and acrosome integrity (IAc), mitochondrial membrane potential (MMP) and kinematic, at zero (T0) and 60 minutes after (T60). GPx 5U and cysteine 0.5mM increased (P<0.05) IAc at T0, when compared to T60. Cysteine 1mM resulted in a higher (P<0.05) IAc on T60, than GPx 1 and 5U, and cysteine 0.5mM. The PMM from a stallion on T60 was higher (P<0.05) than those of two stallions. In sperm kinematic, VCL and VAP were higher (P<0.05) at T0 compared to T60 for the control group, and one stallion showed larger (P<0.05) kinematic values than other animals. It is concluded that the addition of glutathione peroxidase at concentrations 1U and 5U, and cysteine, at concentrations of 0.5mM and 1mM, does not interfere with the integrity of cryopreserved equine sperm, but preserves the kinetic parameters VCL and VAP after 60 minutes of incubation. It should be noted also that the stallion has a strong influence on sperm characteristics post-freezing.

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