Aquaculture Reports (Jun 2022)

Adjustment of common carp sperm concentration prior to cryopreservation: Does it matter?

  • Bernadett Pataki,
  • Ákos Horváth,
  • Gergely Mészáros,
  • Nevena Kitanović,
  • András Ács,
  • Árpád Hegyi,
  • József Molnár,
  • Balázs Csorbai,
  • Béla Urbányi

Journal volume & issue
Vol. 24
p. 101109

Abstract

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Absorbance and computer-assisted sperm analysis (CASA) was used to assess the sperm concentration of common carp (Cyprinus carpio) as an alternative to hemocytometer counting. Also the effect of different sperm concentrations on post-thaw sperm parameters and fertilizing capacity were tested. The main goal of the research was to find out whether the tested methods are suitable for fast measurement of sperm concentration and if the pre-setting of sperm concentration before cryopreservation offers any advantages over dilution of sperm to a given ratio. A linear relationship of sperm concentration measured with CASA (N = 12) as well as sperm absorbance assessed with a microplate reader with spectrophotometry module (N = 18) with sperm concentration counted in a Bürker-Türk type hemocytometer was established. For cryopreservation, 4 sperm concentrations were used (0.5; 1; 2; 4 × 109 spermatozoa per ml) and compared to dilution to a ratio of 1:9. A significant positive relationship was found between the absorbance and sperm concentration (p < 0.0001, r2 = 0.8289) as well as between immotile cell concentration measured with CASA and that counted in a hemocytometer (p < 0.0001, r2 = 0.8559). No significant main effect of sperm concentration was found on any post-thaw motility parameters measured by CASA with the exception of linearity (p = 0.0056). Sperm concentration had a significant main effect (p = 0.0156) on the fertilizing capacity of sperm samples diluted to various concentrations prior to cryopreservation. Only the highest concentration of 4 × 109 spermatozoa per ml (66 ± 6% fertilization) showed a significant difference (p = 0.0121) in comparison to the pre-set dilution ratio (49 ± 5% fertilization). The results show that both spectrophotometry and CASA are suitable for the assessment of common carp sperm concentration and that maximizing sperm concentration prior to cryopreservation results in higher fertilization.

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