Reprod Dom Anim. 2019;00:1–6. wileyonlinelibrary.com/journal/rda | 1 © 2019 Blackwell Verlag GmbH Received: 8 July 2019 | Revised: 17 September 2019 | Accepted: 26 September 2019 DOI: 10.1111/rda.13573 ORIGINAL ARTICLE Induction of superovulation using inhibin antiserum and competence of embryo development in wild large Japanese field mice ( Apodemus speciosus ) Kanna Meguro 1 | Kazuki Komatsu 1 | Takuya Ohdaira 1 | Naomi Nakagata 2 | Akifumi Nakata 3 | Manabu Fukumoto 4 | Tomisato Miura 5,6 | Hideaki Yamashiro 1 1 Graduate School of Science and Technology, Niigata University, Niigata, Japan 2 Center for Animal Resources and Development (CARD), Kumamoto University, Kumamoto, Japan 3 Division of Life Science, Hokkaido University of Science, Hokkaido, Japan 4 Department of Molecular Pathology, Tokyo Medical University, Tokyo, Japan 5 Department of Bioscience and Laboratory Medicine, Graduate School of Health Sciences, Hirosaki University, Hirosaki, Japan 6 Department of Radiation Biology, Institute of Radiation Emergency Medicine, Hirosaki University, Hirosaki, Japan Correspondence Hideaki Yamashiro, Laboratory of Animal Reproduction, Graduate School of Science and Technology, Niigata University, Niigata 959‐2181, Japan. Email: hyamashiro@agr.niigata‐u.ac.jp Funding information Japan Atomic Energy Agency; Ministry of Education; Japan Society for the Promotion of Science Abstract Seasonally, bred wild mice provide a unique bioresource, with high genetic diversity that differs from wild‐derived mice and laboratory mice. This study aimed to establish an alternative superovulation method using wild large Japanese field mice ( Apodemus speciosus) as the model species. Specifically, we investigated how the application of inhibin antiserum and equine chorionic gonadotropin (IASe) during both the repro- ductive and non‐reproductive seasons impact the ovulation rate and competence of embryo development after in vitro fertilization (IVF) with fresh and cryopreserved sperm. When the wild mice were superovulated by injecting eCG followed by human chorionic gonadotropin (hCG), few oocytes were collected during the reproductive and non‐reproductive seasons. In comparison, the number of ovulated oocytes was dramatically enhanced by the administration of IASe, followed by isolation of ovu- lated oocytes 24 hr after 30 IU hCG administration. The IVF oocytes that were in vitro cultured (IVC) with medium containing serum further developed to the 2‐ and/ or 4‐cell stage using both fresh and frozen‐thawed sperm. In conclusion, we success- fully established an alternative protocol for collecting ovulated oocytes from wild large Japanese field mice by administering IASe and hCG during both the reproduc- tive and non‐reproductive seasons. This study is the first to develop IVF–IVC wild large Japanese field mice beyond the 2‐ and/or 4‐cell stage in vitro using fresh and cryopreserved sperm. This approach could be used in other species of wild or endan- gered mice to reduce the number of animals used for experiments, or in maintaining stocks of germ cells or embryos. KEYWORDS embryo development, inhibin antiserum, sperm, superovulation, wild mice 1 | INTRODUCTION The genetic diversity of laboratory strains of mice is limited in terms of individual variation, with the original behavioural phenotypes of wild mice no longer being expressed in laboratory mice (Koide et al., 2011). Thus, using wild‐derived mice strains, including outbred rodents, is advantageous for studying novel and diverse behavioural phenotypes (Choi & He, 2015). Recently, we reported that morphological and histological changes to the testes of wild large Japanese field mice ( Apodemus speciosus) are associated with seasonal changes (Akiyama et al., 2015). Seasonally, bred wild mice provide a unique bioresource,