Funding for this research was provided by:
Japan Society for the Promotion of Science (16K21717, 25292128)
Received: 12 May 2017
Accepted: 28 September 2017
First Online: 17 October 2017
Ethics approval and consent to participate
: Animal handling and sample collections were conducted by veterinary staffs in accordance with the Husbandry Guidelines (in Japanese) approved by the Ethics and Welfare Committee of Japanese Association of Zoos and Aquariums.
: Not applicable.
: The authors declare that they have no competing interests.
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