Vitrification of Porcine In Vitro‐Produced Embryos at the Pronuclear and Blastocyst Stages Using Ampholytic Polymer Compounds as Cryoprotective Agents

Porcine in vitro‐produced embryos at the pronuclear or blastocyst stage were vitrified by the Cryotop method with different concentrations of carboxylated poly‐L‐lysine (CPLL) or 3,3‐dimethylglutaric anhydride poly‐L‐lysine (DMGA‐PLL) to determine the efficacy of these ampholytic polymer compounds as cryoprotective agents (CPAs). The concentration of CPLL or DMGA‐PLL in the vitrification solution had a significant effect on the viability of vitrified‐warmed blastocysts and expanded blastocysts, with the highest survival rates at 10% (v/v). When blastocysts and expanded blastocysts were vitrified with or without 10% CPLL or DMGA‐PLL, there were significant differences in the survival rates after warming among the different supplements, with the highest rates obtained when 10% DMGA‐PLL was added. The concentration of CPLL or DMGA‐PLL in the vitrification solution did not affect the viability of vitrified‐warmed pronuclear stage embryos, but the addition of 10% CPLL or DMGA‐PLL improved the cleavage and blastocyst formation rates following in vitro culture. Furthermore, embryos vitrified with 10% DMGA‐PLL had similar in vitro developmental potential as nonvitrified embryos. The results showed the usefulness of ampholytic polymer compounds, especially DMGA‐PLL, as CPAs in the vitrification of porcine embryos at the pronuclear and blastocyst stages.