Competence of vitrified porcine spermatozoa to produce zygotes and early embryo development

Abstract

Porcine sperm cryopreservation allows genetic conservation but due to the difficulties forconventional freezing presented by this species, vitrification has been evaluated as an alternativeconservation method, obtaining sperm with intact, condensed chromatin. The objective of this studywas to evaluate if vitrified-warmed porcine sperm could maintain the capacity to generate zygotesand early embryo development in vitro. To this end, raw semen was vitrified using the spheresmethod, at a concentration of 5 × 106 sperm/mL in TALP medium supplemented with 1% bovineserum albumin (BSA), without cryoprotectants (treatment group) and using conventional frozenthawed semen as a control. Using ICSI, both vitrified-warmed and frozen-thawed semen wereinjected into in vitro matured porcine oocytes, and subsequent in vitro embryo development wasmonitored. No significant differences were observed between the treatment and control groups, bothfor the percentage of pronuclei (PN) obtained (p = 0.0682) and for embryo development attained(p=0.1669). Spheres vitrification in the absence of cryoprotectants is a simple, low-cost techniquethat allows porcine sperm preservation, conserving the capacity to produce zygotes and transferableembryos using ICSI.