Fertilization rate of Siberian sturgeon (Acipenser baeri, Brandt) milt cryopreserved with methanol

Milt obtained from three Siberian Sturgeon males (Acipenser baeri, Brandt) were cryopreserved using three extenders: Tris -sucrose-KCl (30 mM Tris, 23.4 mM sucrose, 0.25 mM KCl, pH 8.0), Tris-NaCl (10 mM Tris, 25 mM NaCl, pH 8.5), and Tris-sucrose (20 mM Tris, 400 mM sucrose, pH 8.0) supplemented with 10% methanol. Semen was diluted 1:1 with appropriate extender and frozen in liquid nitrogen vapor. After fertilization with cryopreserved milt, hatching rates of 29.6+/-5.0%, 18.2+/-42.4%, and 6.0+/-3.0% were recorded for Tris-sucrose-KCl, Tris-NaCl, and Tris-sucrose extender, respectively. Rates for the first two extenders were similar to data of fresh semen obtained from two males(17.9% and 26.0% for male #1 and #2, respectively). Our results indicate that Tris-sucrose-KCl and Tris-NaCl are useful extenders and methanol is a useful cryoprotectant for cryopreservation of sturgeon semen. (C) 2002 Elsevier Science B.V. All rights reserved.