Publications by authors named "Nobuyuki Kashiwagi"

In this study, we examined the usefulness of a simpler and more feasible method for determining the optimal timing of artificial insemination and the conditions for its success in six female common bottlenose dolphins. Pregnancy was successfully achieved in five dolphins by performing intrauterine insemination, using chilled semen stored for less than 3 days or frozen semen within 24 hr of exhibiting a peak serum estradiol (E) level of 100 pg/mL or higher or on the day with a serum E level of approximately 100 pg/mL, measured with a simple measuring device. We concluded that the determining the optimal timing of intrauterine insemination by measuring serum E levels is a simpler and more useful method compared with the conventional approach.

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With the shift in their social roles, modern zoos and aquariums are required to develop scientific research. Although zoos and aquariums worldwide have reported an increase in the number of papers they publish and the diversification of their fields in recent decades, the specific circumstances in Japan are slightly unclear. We listed peer-reviewed papers authored by Japanese zoos and aquariums using search engines and quantitatively evaluated the changes in the number of papers published over 62 years.

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Assisted reproduction techniques are required to maintain a genetically diverse captive population of bottlenose dolphins. These techniques include semen preservation, and liquid storage has been proposed as a suitable alternative to cryopreservation, but the optimum conditions, in terms of temperature, duration, and media, have yet to be fully established. The aim of this study, therefore, was to determine the optimum temperature for the liquid storage of dolphin semen during a 14-day period and the usefulness of carboxylated poly-L-lysine (CPLL) as an additive to the semen extender used for the liquid storage.

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Post-conflict affiliations initiated by bystanders (bystander affiliation) toward aggressors or victims have been suggested to represent the function of conflict management in some social living species. However, the function of bystander affiliations toward aggressors and victims has not been examined in marine mammals. In the present study, we investigated the function of bystander affiliations to aggressors and victims in bottlenose dolphins: self-protection, the substitute of reconciliation, social facilitation and tension relief of opponents.

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In comparison with terrestrial animals, such as primates, there is limited empirical evidence for cooperative behavior in marine mammals under experimental conditions. In this study, we used a cooperative rope-pulling task to investigate how bottlenose dolphins () coordinate their behavior with a partner. Dolphins successfully learned and were able to perform the task, even when one subject started after the other.

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Lobomycosis is a chronic fungal disease caused by the etiologic agent, Lacazia loboi, in the skin and subcutaneous tissues in humans and dolphins in tropical and transitional tropical climates. An Indo-Pacific bottlenose dolphin (Tursiops aduncus) stranded in Kagoshima, Japan, had severe skin lesions characterized by granulomatous reactions and hyperkeratosis that were similar to those of the lobomycosis, but no fungal organism was observed in the skin lesion. In this paper, we report a stranded Indo-Pacific bottlenose dolphin with lobomycosis-like lesions based on pathological examinations in Japan.

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We describe here a case of accidental electrocution. A 48-year-old male was found dead in his room. At autopsy, there was a current mark on the right thumb and big toe.

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