Cryopreservation of Atlantic sturgeon Acipenser sturio L., 1758 sperm: first results and associated problems

Abstract

We present our attempts to adapt the established cryopreservation techniques for sturgeon sperm to Acipenser sturio L., 1758, using the sperm of a wild male which matured in vivo. The sperm, from a ripe male caught in the Gironde estuary in 1996 and obtained 4 h after its catch and transport, was diluted 1 : 1 with media containing 56.0-76.0 % tris-HC1-buffer, 14.4-24.0 % dimethylsulfoxide and 9.6-20.0 % egg yolk. The suspension was poured into 1.5 ml tubes, sealed and frozen in -196°c liquid nitrogen vapour in a three-stage programme. Thawing took place in a 40°c water bath. The motility of thawed sperm was 10-15 %, whereas the motility in native sperm before cryopreservation was 50%. After one month storage time in liquid nitrogen, sperm was thawed and used for fertilization of sterlet Acipenser ruthenus L., 1758 eggs with the help of two activator media. After fertilization, 38.3 % of the embryos were developing on the second day, compared with 23.2 % when activator without sucrose was used. In the control group, fertilization of eggs with fresh sterlet sperm resulted in 43 % developing embryos.