Rafaela S. C. Takeshita

Hematological, hepatic, and renal evaluation in Aotus azarai infulatus

Background  Knowing the physiological ranges of certain hematological and biochemical parameters is necessary for understanding the alterations caused by pathogenic agents and establishing differences between states of health and disease. Hematological evaluations and clinical chemistry were performed on livers and kidneys from owl monkeys with different sexes and age ranges.

Environmental, biological, and social factors influencing fecal adrenal steroid concentrations in female Japanese macaques (Macaca fuscata)

The ability to determine hormonal profiles of primate populations using non‐invasive techniques can help to monitor physical fitness, stress, and physiological responses to environmental changes. We investigated fecal glucocorticoids (fGC) and DHEAS concentrations in captive Japanese macaques (Macaca fuscata) in relation to environmental, biological, and social factors. The subjects were female Japanese monkeys from 4 months to 31 years old housed in captivity (27 in social groups and 12 in single cages). Fecal samples were collected from all females, and behavioral data from the social groups during the mating season and the following birth season. Hormonal concentrations were analyzed by enzyme immunoassay. Our results revealed that both fGC and fecal DHEAS concentrations are higher in females housed indoors in single cages than in those living outdoors in social groups. We also found that fGC concentrations were higher in the cycling females during the mating (winter) season than the lactating females in the birth (spring) season. Age was negatively associated to both fGC and fecal DHEAS levels, but the relationship between age and fecal DHEAS was more evident in females housed indoors in single cages than in females housed in outdoor social groups. We did not observe any association of dominance rank with either fecal DHEAS or fGC. This study showed that measurement of fecal DHEAS and fGC can be a good method to assess stress in Japanese macaques. These findings provide insights about the physiology of these two adrenal hormones in female Japanese macaques, which can be applied to wild populations and is fundamental for captive management and conservation biology. Am. J. Primatol. 76:1084–1093, 2014.

The influence of age and season on fecal dehydroepiandrosterone-sulfate (DHEAS) concentrations in Japanese macaques (Macaca fuscata).

Dehydroepiandrosterone (DHEA) and its sulfate, DHEAS, are the most abundant steroid hormones in primates, providing a large reservoir of precursors for the production of androgens. DHEAS levels decline with age in adult humans and nonhuman primates, prompting its consideration as a biomarker of senescence. However, the mechanisms responsible for this age-related decrease and its relationship to reproduction remain elusive. This research investigated DHEAS concentrations in fecal samples in order to determine age-related changes in captive Japanese macaques, as well as to assess the possible influence of seasonality. The subjects were 25 female Japanese macaques (2weeks to 14years-old) housed outdoors in social groups at the Primate Research Institute. We collected three fecal samples from each animal during the breeding season (October to December) and three additional samples from adult females during the non-breeding season (May to June). The hormonal concentrations were determined using enzyme immunoassay. DHEAS concentration was negatively correlated with age, but we did not find a significant difference between breeding and non-breeding seasons. Neonatal macaques had the highest DHEAS concentrations of all age groups. We suggest that elevated neonatal DHEAS is possibly a residue from fetal adrenal secretion and that, as in humans, it might assist in neurobiological development.

Effect of age and number of parturitions on uterine and ovarian variables in owl monkeys

Background  We aimed to evaluate the uterine and ovarian volumes of owl monkeys in different age groups with different numbers of live births and to analyze the interaction between both.

Renal Evaluation of Aotus azarai infulatus by Ultrasonography and Serum Chemistry Profile

This study aimed to characterize anatomical and biochemical properties of owl monkey kidneys in order to provide normal reference values. Sixty‐nine Aotus azarai infulatus (45 males and 24 females) were divided into four different age groups (AG1: 3 months–1 year; AG2: 2–3 years; AG3: 4–6 years; and AG4: over 7 years old). The monkeys were evaluated with a serum chemistry profile, focusing on serum creatinine (SCr) and blood urea nitrogen (BUN) and with ultrasound. Mean body mass differed among the age groups. This significance was attributed to AG1 body mass being significantly lower than in AG2 and that in both AG2 and AG3 being significantly lower than in the two older age groups (AG3 and AG4). SCr and BUNconcentrations differed significantly between the sexes and SCr level correlated positively with age. In contrast, renal measurements did not differ between males and females. Left and right renal volumes did not differ significantly within age groups, or among AG2, AG3, and AG4. Renal volumes in AG1, however, while not differing from those in AG2, did differ significantly from those in AG3 and AG4. In conclusion, this study provides ultrasonographic reference values for the morphology the kidneys in A. a. infulatus. Evidence is also provided that SCr and BUNlevels in owl monkeys are influenced by the sex and age of the individual, factors that should be considered when interpreting test results. Am. J. Primatol. 74:482‐490, 2012.

Beneficial effect of hot spring bathing on stress levels in Japanese macaques

The ability of animals to survive dramatic climates depends on their physiology, morphology and behaviour, but is often influenced by the configuration of their habitat. Along with autonomic responses, thermoregulatory behaviours, including postural adjustments, social aggregation, and use of trees for shelter, help individuals maintain homeostasis across climate variations. Japanese macaques (Macaca fuscata) are the world’s most northerly species of nonhuman primates and have adapted to extremely cold environments. Given that thermoregulatory stress can increase glucocorticoid concentrations in primates, we hypothesized that by using an available hot spring, Japanese macaques could gain protection against weather-induced cold stress during winter. We studied 12 adult female Japanese macaques living in Jigokudani Monkey Park, Japan, during the spring birth season (April to June) and winter mating season (October to December). We collected faecal samples for determination of faecal glucocorticoid (fGC) metabolite concentrations by enzyme immunoassay, as well as behavioural data to determine time spent in the hot springs, dominance rank, aggression rates, and affiliative behaviours. We used nonparametric statistics to examine seasonal changes in hot spring bathing, and the relationship between rank and air temperature on hot spring bathing. We used general linear mixed-effect models to examine factors impacting hormone concentrations. We found that Japanese macaques use hot spring bathing for thermoregulation during the winter. In the studied troop, the single hot spring is a restricted resource favoured by dominant females. High social rank had both costs and benefits: dominant females sustained high fGC levels, which were associated with high aggression rates in winter, but benefited by priority of access to the hot spring, which was associated with low fGC concentrations and therefore might help reduce energy expenditure and subsequent body heat loss. This unique habit of hot spring bathing by Japanese macaques illustrates how behavioural flexibility can help counter cold climate stress, with likely implications for reproduction and survival.

Effect of castration on social behavior and hormones in male Japanese macaques (Macaca fuscata)

Population control is essential for animal welfare and human safety in free-ranging or captive settings, especially when resources are limited. As an alternative to lethal control, contraceptive methods such as castration in males can be a practical solution, because the testicles are a visual cue to determine which males have been sterilized. However, careful analyses should be carried out to ensure no disruption in the social structure of the population. Japanese macaques (Macaca fuscata) live in a society centered around dominance rank and matrilineal kin relationships. Testosterone and glucocorticoids have been correlated with dominance rank in humans and other species, but previous studies in Japanese macaques were inconclusive. This study aimed to investigate behavioral and physiological differences between castrated and intact male Japanese macaques, and to examine the effect of season and behavior in hormonal concentrations in intact males. Our subjects were six intact males from Jigokudani Monkey Park (Japan) and 13 castrated males from Born Free Primate Sanctuary (USA). We collected behavioral data using both focal and ad libitum sampling, and fecal samples for determination of testosterone (fT) and glucocorticoids (fGC) by enzyme immunoassay. We found that castrated males exhibited a social hierarchy, but not a linear hierarchy, as was the case in intact males. Castrated males were less aggressive than intact males, probably because fT concentrations were lower in the castrated males. Age was positively correlated with fGC levels, while fT concentrations were lower in old males than younger adult males. Fecal T levels correlated with both rank and atmospheric temperature. In intact males, both fGC and fT levels were elevated during the mating season. We found a negative correlation between fGC levels and the amount of grooming received. Our findings indicate that castration had a minimal impact on sociality, with season, temperature, and rank all influencing male sex steroid levels in intact males. Our study indicates that castration can be adopted as a population control mechanism without drastically altering the social relationships of males.

Qualitative analysis of preputial and vaginal bacterial microbiota in owl monkeys (Aotus azarai infulatus) raised in captivity

The aim of this study was to identify the aerobic bacteria of the preputial and vaginal microbiota in owl monkeys that have been raised in captivity and to evaluate the antimicrobial susceptibility of these bacteria by gender and social organization.

Dead or alive? Predicting fetal loss in Japanese macaques (Macaca fuscata) by fecal metabolites

Dehydroepiandrosterone-sulfate (DHEAS) is the main steroid product of the primate fetal adrenal during mid to late gestation and it plays a major role in providing estrogens needed for parturition. We tested the hypothesis that this hormone can indicate fetal health status and attempted to use fecal DHEAS (fDHEAS) to predict pregnancy outcome in Japanese macaques. The subjects were 16 adult females and 3 neonatal Japanese macaques living in captivity at the Primate Research Institute, Kyoto University. We classified females that gave birth to healthy infants as successful and females that gave birth to dead infants as stillbirth (late fetal loss) and miscarriage (early fetal loss). The remaining females did not become pregnant and were used as controls. We collected fecal samples from all cycling, pregnant, and post-pregnant females as well as the three neonates for analysis of fDHEAS, fecal estrogen (fE) and fecal progesterone (fP) by enzyme immunoassay. We found that fE and fP increased during gestation in both successful and stillbirth groups, but increased only during the first two months in the female that had a miscarriage. Levels of fDHEAS only increased in the second half of gestation in successful pregnancies. Neonates had extremely elevated concentrations of fDHEAS in comparison to post-parturition females, which confirms that DHEAS metabolites are a product of the fetal adrenal. Low DHEAS levels could be a marker of an unsuccessful pregnancy in primates. Monitoring fDHEAS levels can be useful in zoos and institute management and can be applied to wild and free-ranging populations.

Development and Validation of an Enzyme Immunoassay for Fecal Dehydroepiandrosterone Sulfate in Japanese Macaques (Macaca fuscata)

Measuring hormonal profiles is important in monitoring stress, physical fitness, and reproductive status in primates. Noninvasive methods have been used to measure several steroid hormones in primates without causing them stress. However, few studies have used feces or urine to measure dehydroepiandrosterone sulfate (DHEAS), an important precursor of sex steroids that has been studied as a biomarker of aging, pregnancy, and stress in humans and nonhuman primates. We developed an enzyme immunoassay to detect DHEAS in the feces of Japanese macaques (Macaca fuscata). Our subjects included eight singly housed Japanese macaques. To validate the assay, we administrated oral DHEA to one male and one female macaque, collected their feces, and measured DHEAS levels over time. Given that DHEAS is related to gonadal steroids and the stress response, we also measured DHEAS concentrations in response to adrenal (adrenocorticotropic hormone [ACTH]) and gonadal (human chorionic gonadotropin [hCG]) stimulation. Our assay successfully detected DHEAS in Japanese macaque feces, and levels of DHEAS were associated with the amount of DHEA ingested. Parallelism and accuracy tests revealed that fecal extracts were reliable measures of DHEAS. Neither ACTH nor hCG challenge appeared to affect DHEAS levels. The method we describe is less expensive than that using the commercially available kits and is applicable to investigations involving aging, stress, and reproduction in Japanese macaques.