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|1. (WO2018038115) COMPOSITION FOR CRYOPRESERVATION OF BOVINE REPRODUCTIVE CELLS AND CRYOPRESERVATION METHOD THEREFOR|
|Title:||COMPOSITION FOR CRYOPRESERVATION OF BOVINE REPRODUCTIVE CELLS AND CRYOPRESERVATION METHOD THEREFOR|
Provided are a liquid for cryopreservation of bovine reproductive cells such as bovine sperms and a cryopreservation method therefor. Use is made of a cryopreservation liquid wherein 0.3-0.9 w/w% of an amphoteric polyelectrolyte (an antifreeze polyamino acid), said amphoteric polyelectrolyte being prepared by, relative to 50-99 mol% of amino groups in ε-poly-L-lysine having a number-average molecular weight of 1,000-20,000, reacting succinic anhydride and thus introducing an appropriate amount of carboxyl groups thereinto, and 2-4 w/w% of glycerol are dissolved in a physiological solution. A preferred embodiment of the cryopreservation method comprises: a first dilution step for diluting bovine semen 2.5-10 fold with a physiological solution and maintaining at 2-8oC; and a second dilution step for adding dropwise a physiological solution containing the amphoteric polyelectrolyte (antifreeze polyamino acid) and glycerol to the suspension obtained in the first dilution step while maintaining at 2-8oC so as to further dilute the bovine semen 5-20 fold.