Effect of diet on faecal testosterone metabolite levels in a northern fur seal (Callorhinus ursinus) expressed as ash-free dry weight
The northern fur seal (Callorhinus ursinus) inhabits the North Pacific Ocean and Bering Sea, where it feeds on a variety of prey. In this study, we studied a captive male to determine how different prey affect the composition of and testosterone metabolites in the faeces. Faecal steroid metabolite l...
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International Coastal Research Center, Atmosphere and Ocean Research Institute, the University of Tokyo
2021
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ftunivtokyo:oai:repository.dl.itc.u-tokyo.ac.jp:02000461 2023-05-15T15:43:48+02:00 Effect of diet on faecal testosterone metabolite levels in a northern fur seal (Callorhinus ursinus) expressed as ash-free dry weight Otsuki, Mayuko Kohyama, Kaoru Goshima, Wataru Kobayashi, Motoki Hasegawa, Yuya Morita, Yuka Ijiri, Shigeho Mitani, Yoko 2021 application/pdf https://repository.dl.itc.u-tokyo.ac.jp/record/2000461/files/CMS440101.pdf eng eng International Coastal Research Center, Atmosphere and Ocean Research Institute, the University of Tokyo Coastal marine science 1 44 6 AA11957899 13493000 https://repository.dl.itc.u-tokyo.ac.jp/record/2000461/files/CMS440101.pdf Faecal composition ash-free dry weight steroid hormones 2021 ftunivtokyo 2022-12-23T01:13:54Z The northern fur seal (Callorhinus ursinus) inhabits the North Pacific Ocean and Bering Sea, where it feeds on a variety of prey. In this study, we studied a captive male to determine how different prey affect the composition of and testosterone metabolites in the faeces. Faecal steroid metabolite levels are often expressed per unit dry weight (DW) of faeces, but dry faeces contain both organic and inorganic matter, so we also measured the ash-free dry weight (AFDW), which can more accurately express the levels in samples with organic matter. The mean organic component of faeces was lower when the seal fed on fish than when it fed on squid. Testosterone metabolite levels in the AFDW and serum testosterone levels showed a significant relationship in faeces collected one day after the blood withdrawal. When the seal fed on squid, differences in testosterone metabolite levels between DW and AFDW were small. These results suggest that faecal testosterone metabolite levels expressed in quantities per unit of AFDW are more useful than DW to understand the reproductive physiology of seals. departmental bulletin paper Other/Unknown Material Bering Sea Callorhinus ursinus Northern fur seal The University of Tokyo: UT Repository Bering Sea Pacific |
institution |
Open Polar |
collection |
The University of Tokyo: UT Repository |
op_collection_id |
ftunivtokyo |
language |
English |
topic |
Faecal composition ash-free dry weight steroid hormones |
spellingShingle |
Faecal composition ash-free dry weight steroid hormones Otsuki, Mayuko Kohyama, Kaoru Goshima, Wataru Kobayashi, Motoki Hasegawa, Yuya Morita, Yuka Ijiri, Shigeho Mitani, Yoko Effect of diet on faecal testosterone metabolite levels in a northern fur seal (Callorhinus ursinus) expressed as ash-free dry weight |
topic_facet |
Faecal composition ash-free dry weight steroid hormones |
description |
The northern fur seal (Callorhinus ursinus) inhabits the North Pacific Ocean and Bering Sea, where it feeds on a variety of prey. In this study, we studied a captive male to determine how different prey affect the composition of and testosterone metabolites in the faeces. Faecal steroid metabolite levels are often expressed per unit dry weight (DW) of faeces, but dry faeces contain both organic and inorganic matter, so we also measured the ash-free dry weight (AFDW), which can more accurately express the levels in samples with organic matter. The mean organic component of faeces was lower when the seal fed on fish than when it fed on squid. Testosterone metabolite levels in the AFDW and serum testosterone levels showed a significant relationship in faeces collected one day after the blood withdrawal. When the seal fed on squid, differences in testosterone metabolite levels between DW and AFDW were small. These results suggest that faecal testosterone metabolite levels expressed in quantities per unit of AFDW are more useful than DW to understand the reproductive physiology of seals. departmental bulletin paper |
author |
Otsuki, Mayuko Kohyama, Kaoru Goshima, Wataru Kobayashi, Motoki Hasegawa, Yuya Morita, Yuka Ijiri, Shigeho Mitani, Yoko |
author_facet |
Otsuki, Mayuko Kohyama, Kaoru Goshima, Wataru Kobayashi, Motoki Hasegawa, Yuya Morita, Yuka Ijiri, Shigeho Mitani, Yoko |
author_sort |
Otsuki, Mayuko |
title |
Effect of diet on faecal testosterone metabolite levels in a northern fur seal (Callorhinus ursinus) expressed as ash-free dry weight |
title_short |
Effect of diet on faecal testosterone metabolite levels in a northern fur seal (Callorhinus ursinus) expressed as ash-free dry weight |
title_full |
Effect of diet on faecal testosterone metabolite levels in a northern fur seal (Callorhinus ursinus) expressed as ash-free dry weight |
title_fullStr |
Effect of diet on faecal testosterone metabolite levels in a northern fur seal (Callorhinus ursinus) expressed as ash-free dry weight |
title_full_unstemmed |
Effect of diet on faecal testosterone metabolite levels in a northern fur seal (Callorhinus ursinus) expressed as ash-free dry weight |
title_sort |
effect of diet on faecal testosterone metabolite levels in a northern fur seal (callorhinus ursinus) expressed as ash-free dry weight |
publisher |
International Coastal Research Center, Atmosphere and Ocean Research Institute, the University of Tokyo |
publishDate |
2021 |
url |
https://repository.dl.itc.u-tokyo.ac.jp/record/2000461/files/CMS440101.pdf |
geographic |
Bering Sea Pacific |
geographic_facet |
Bering Sea Pacific |
genre |
Bering Sea Callorhinus ursinus Northern fur seal |
genre_facet |
Bering Sea Callorhinus ursinus Northern fur seal |
op_relation |
Coastal marine science 1 44 6 AA11957899 13493000 https://repository.dl.itc.u-tokyo.ac.jp/record/2000461/files/CMS440101.pdf |
_version_ |
1766378005346648064 |