In vitro embryo production in wood bison (Bison bison athabascae) using in vivo matured cumulus-oocyte complexes

摘要

Experiments were conducted in wood bison to determine the effect of additional maturation time on embryo development of in vivo matured oocytes. In experiment 1, cumulus-ocyte complexes (COC) were collected 30 hours after hCG treatment in superstimulated wood bison, and expanded COC were fertilized immediately or after 4 hours of additional in vitro maturation. Embryo development was assessed on Days 3, 7, and 8 (Day 0 = day of fertilization). No difference in cleavage rate was detected (553% vs. 60.5%, P = 0.82), but the Day 8 blastocyst rate was higher after an additional 4 hours of in vitro maturation time (44.7 vs. 18.4%, P = 0.03). In experiment 2, COC were collected at either 30 hours or 34 hours after hCG treatment. Expanded COC from the 30 hours group were fertilized after 4 hours of in vitro maturation, whereas those from the 34 hours group were fertilized immediately. A higher cleavage rate (743 vs. 57.0%) and blastocyst rate (54.1 vs. 37.2%) were found in the 34 hours group versus the 30 hours group (P 0.05). In conclusion, an additional short period of in vitro maturation, or an extended period of in vivo maturation are beneficial for in vitro embryo production in wood bison. Crown Copyright (C) 2016 Published by Elsevier Inc. All rights reserved.