Comparative analysis of sperm motility in liquid and seminal coagulum portions between Bornean orangutan (Pongo pygmaeus) and chimpanzee (Pan troglodytes).

Coagulum in the semen of some primates plays different roles, depending on the species. In the present study, we examined sperm motility in the coagulum and liquid portions of semen collected from captive individuals from two great ape species: two adult Bornean orangutans (Pongo pygmaeus) (n = 27) and three adult chimpanzees (Pan troglodytes) (n = 14). The results revealed that orangutan sperm remained motile for significantly longer in the coagulum than in the liquid portion (> 18 h). By contrast, chimpanzee sperm motility did not differ significantly over time between the two portions of the semen, although motility was slightly higher in the liquid portion than in the coagulum. The evolution of the seminal coagulum is thought to be related to postcopulatory sperm competition; however, functions of seminal coagulum have not been completely elucidated. Our data from the orangutan semen suggest that in this species, seminal coagulum may strengthen own-sperm survival. This report is the first to provide evidence for this distinctive function of the seminal coagulum. This unique property of orangutan seminal coagulum might be attributable to their reproductive traits, e.g., difficulty in predicting ovulation due to a lack of genital swelling during estrus. The orangutan is a Critically Endangered species, and captive breeding, including artificial insemination (AI), is expected. However, worldwide, only one case of orangutan AI has been successful. Our findings may contribute to an understanding of their basic semen characteristics and help improve the AI method.

Supplemental feeding of captive neonatal koalas (Phascolarctos cinereus).

Koalas (Phascolarctos cinereus) are cautious animals, making supplemental feeding of neonates challenging because of disturbances to the normal routine. However, supplemental feeding is beneficial in improving juvenile nutrition using less formula than required for hand-rearing, and allowing maternal bonding to continue through suckling. In this study, two neonatal koalas, delivered by the same mother in 2 years, exhibited insufficient growth post-emergence from the pouch; supplemental feeding was therefore initiated. The amount of formula fed was determined according to the product instructions, and offspring weight was monitored. Slower than normal growth was not initially noticed in the first offspring. This caused delayed commencement of supplemental feeding. An attempt was made to counteract this by providing more formula for a longer period; however, this meant No. 1 was unable to eat enough eucalyptus when weaning. Supplemental feeding was started earlier for the second offspring than for the first, and was terminated at weaning; this juvenile showed a healthy body weight increase. Furthermore, it was able to eat eucalyptus leaves at an earlier stage than No. 1. Although No. 1 showed delayed growth, both koalas matured and are still living. This study showed that supplemental feeding is useful for koalas, if the mother will accept human intervention. The key factors for successful supplemental feeding of koalas identified by comparing the two feeding systems observed in this study are that: (1) it should be initiated as soon as insufficient growth is identified; and (2) it should be terminated before weaning age. Zoo Biol. 36:62-65, 2017. © 2016 Wiley Periodicals, Inc.

Detection of urinary estrogen conjugates and creatinine using near infrared spectroscopy in Bornean orangutans (Pongo Pygmaeus).

For promoting in situ conservation, it is important to estimate the density distribution of fertile individuals, and there is a need for developing an easy monitoring method to discriminate between physiological states. To date, physiological state has generally been determined by measuring hormone concentration using radioimmunoassay or enzyme immunoassay (EIA) methods. However, these methods have rarely been applied in situ because of the requirements for a large amount of reagent, instruments, and a radioactive isotope. In addition, the proper storage of the sample (including urine and feces) on site until analysis is difficult. On the other hand, near infrared (NIR) spectroscopy requires no reagent and enables rapid measurement. In the present study, we attempted urinary NIR spectroscopy to determine the estrogen levels of orangutans in Japanese zoos and in the Danum Valley Conservation Area, Sabah, Malaysia. Reflectance NIR spectra were obtained from urine stored using a filter paper. Filter paper is easy to use to store dried urine, even in the wild. Urinary estrogen and creatinine concentrations measured by EIA were used as the reference data of partial least square (PLS) regression of urinary NIR spectra. High accuracies (R(2) > 0.68) were obtained in both estrogen and creatinine regression models. In addition, the PLS regressions in both standards showed higher accuracies (R(2) > 0.70). Therefore, the present study demonstrates that urinary NIR spectra have the potential to estimate the estrogen and creatinine concentrations.