Title
In vitro-production of embryos using immature oocytes collected transvaginally from superstimulated wood bison (Bison bison athabascae)
Date Issued
01 April 2017
Access level
metadata only access
Resource Type
journal article
Author(s)
University of Saskatchewan
Publisher(s)
Elsevier Inc.
Abstract
Two experiments were done to test the hypothesis that morphologic characteristics of wood bison cumulus-oocyte complexes (COC) are reflective of the ability of the oocyte to develop to an advanced embryonic stage after in vitro maturation, fertilization and culture, and to determine the effect of prolonging the interval from the end of superstimulation treatment to oocyte collection (FSH starvation period). Experiments were done during the anovulatory season. In Experiment 1, ovarian superstimulation was induced in 10 bison with two doses of FSH given at 48 h intervals beginning at the time of follicular wave emergence. COC were collected 3 days (72 h) after the last dose of FSH by follicular aspiration and classified as compact, expanded or denuded. The COC were matured in vitro for 24 h before fertilization in vitro (Day 0). Embryo development was assessed on Days 3, 7 and 8. The blastocyst rate was 7/34, 2/10 and 0/3 in COC classified as compact, expanded and denuded, respectively; however, only compact COC resulted in embryos that reached the expanded blastocyst stage. In Experiment 2, COC were collected at either 3 or 4 days (72 or 96 h) after the last dose of FSH (n = 16 bison/group) to determine the effect of the duration of FSH starvation on oocyte competence. The COC were classified as compact good (>3 layers of cumulus cells), compact regular (1–3 layers of cumulus cells), expanded or denuded, and then matured, fertilized and cultured in vitro. Although follicles were larger (P < 0.05) in the 4-day FSH starvation group, there was no effect of starvation period on the distribution of COC morphology; overall, 112/194 (57.7%) were compact, 29/194 (26.3%) were expanded, 39/194 (20.1%) were denuded, and 14/194 (7.2%) were degenerated (P < 0.05). Similarly, there was no effect of starvation period on embryo development. Compact good COC had the highest cleavage (88%) and blastocyst rates (54%; P < 0.05), followed by compact regular COC at 73% and 25%, respectively. Expanded and denuded COC had low cleavage (40% vs. 59%, respectively) and blastocyst rates (5% vs. 8%, respectively). We conclude that morphologic characteristics of wood bison COC are reflective of the ability of the oocyte to develop into an embryo in vitro. Importantly, oocytes collected from superstimulated bison during the anovulatory season were competent to develop to the blastocyst stage following in vitro maturation, fertilization and culture.
Start page
103
End page
110
Volume
92
Language
English
OCDE Knowledge area
Ciencia veterinaria
BiologÃa reproductiva
Scopus EID
2-s2.0-85010000361
PubMed ID
Source
Theriogenology
ISSN of the container
0093691X
Sponsor(s)
This study was supported by grants from the University of Saskatchewan and the Toronto Zoo. The authors gratefully acknowledge Elk Island National Park as the original source of the wood bison used in the study, and Dr. Murray Woodbury (Agriculture and Agri-Food Canada Specialized Livestock Chair, University of Saskatchewan) for fostering the bison research program. The authors gratefully acknowledge Dr. Rodrigo Carrasco, Dr. Serena Caunce, and Mrs. Mary Von der Porten for help with data collection, and the farm staff at the Native Hoofstock Centre, University of Saskatchewan for maintaining the animals used in the study. We also thank Vetoquinol Canada Inc. for providing Folltropin-V, MAP-5, and supplies for oocyte collection and handling.
Sources of information:
Directorio de Producción CientÃfica
Scopus