Improved fertility of frozen‐thawed porcine spermatozoa with 3,3‐dimethylglutaric anhydride poly‐L‐lysine as a novel cryoprotectant

Abstract In this study, we determined the efficacy of 3,3‐dimethylglutaric anhydride poly‐L‐lysine (DMGA‐PLL) as a cryoprotectant for porcine spermatozoa. Porcine spermatozoa were cryopreserved in a freezing extender containing 3% (v/v) glycerol and various concentrations of DMGA‐PLL. At 12 h after thawing, the motility index of spermatozoa cryopreserved with 0.25% (v/v) DMGA‐PLL (25.9) was significantly ( P < 0.01) higher than that of spermatozoa cryopreserved with 0%, 0.125%, or 0.5% DMGA‐PLL (10.0–16.3). In addition, the blastocyst formation rate of embryos derived from spermatozoa cryopreserved with 0.25% DMGA‐PLL (22.8%) was significantly ( P < 0.01) higher than that of embryos derived from spermatozoa cryopreserved with 0%, 0.125%, or 0.5% DMGA‐PLL (7.9%–10.9%). The mean number of total piglets born to sows inseminated with spermatozoa cryopreserved without DMGA‐PLL (9.0) was significantly ( P < 0.05) lower than that of total piglets born to sows inseminated with spermatozoa stored at 17°C (13.8). However, when spermatozoa cryopreserved with 0.25% DMGA‐PLL were used for artificial insemination, the mean number of total piglets (11.7) was not significantly different from that obtained following artificial insemination using spermatozoa stored at 17°C. The results showed the usefulness of DMGA‐PLL as a cryoprotectant in the cryopreservation of porcine spermatozoa.