Close Proximity of the Heterosexual Partner Reduces the Physiological and Behavioral Consequences of Novel-Cage Housing in Black Tufted-Ear Marmosets (Callithrix kuhli)

The present studies assessed the extent to which heterosexual pairmates could buffer marmosets (Wied's black tufted-ear marmoset,Callithrix kuhli)against stress. Six male and six female marmosets from established groups were exposed to two experimental manipulations together with a control condition. Each condition lasted a total of 4 days. For the two experimental conditions, animals were removed from the family group and housed in a novel cage for 48 h in either the presence or the absence of the heterosexual pairmate. During the 48-h novel-cage housing period and for 48 h upon reunion of the subjects with the family group, concentrations of urinary cortisol were measured in the first void sample of the day and behavioral observations were conducted. When animals were housed alone in a novel cage they exhibited significant elevations in levels of urinary cortisol after 24 and 48 h of novel-cage exposure. In contrast, when marmosets were housed in the novel cage in the presence of the pairmate, levels of urinary cortisol did not change across the 4-day period. The presence of the social partner also reduced the behavioral manifestations of exposure to novelty. Upon reunion with the family group, animals that had been housed in the novel cage alone spent significantly more time in close proximity to the pairmate than animals that had been housed with the partner. A second experiment was conducted to determine the effect that separation from the pairmate, only (independent of any effects of novelty), had on levels of cortisol. Concentrations of urinary cortisol were measured in subjects housed in the familiar home cage, but in the absence of the pairmate, over a 48-h period and compared to concentrations of excreted cortisol immediately prior to separation. Separation from the pairmate did not elevate cortisol levels when the subject was housed in the home cage, suggesting that elevated cortisol levels in animals housed alone in the novel cage were in response to novelty exposure rather than to separation from the pairmate. Since the physical presence of the heterosexual partner reduced the physiological and behavioral effects of novel-cage housing, social attachments might function as homeostatic regulators of HPA function in marmosets.     

Species and subspecies specificity in urine and scent marks of saddle-back tamarins (Saguinus fuscicollis)

Saguinus fuscicollisproduces scent marks which consist mainly of a mixture of urine and the secretions of circumgenital scent glands. The present study investigates the ability of saddle-back tamarins to discriminate between scent material from conspecifics and corresponding material from other species and to differentiate material from two subspecies of Saguinus fuscicollis.When choices between urine samples from conspecifics and from guinea pigs and choices between urine samples from conspecifics and from common marmosets were offered, the tamarins investigated samples from conspecifics more frequently. Similar responses were obtained when choices between scent marks from saddle-back tamarins and from common marmosets and between scent marks from saddle-back and red-chested moustached tamarins were offered. The tamarins also discriminated between scent marks and between extracts of scent marks from Saguinus f. fuscicollisand Saguinus f. illigeri.In these choice tests, subjects of both subspecies tended preferentially to investigate material from Saguinus f. fuscicollis.The results of these studies show that urine and scent marks contain chemical cues on which recognition of conspecifics can be based. Moreover, the scent marks of closely related subspecies also offer cues which could enable the tamarins to discriminate between them.     

Parameters of haematology, clinical chemistry and lipid metabolism in the common marmoset and alterations under stress conditions

Common marmosets are suitable non-human primate models for many human diseases. Standard values for blood parameters are required to evaluate physiological and pathological situations. Two studies were conducted: study I to determine standard values and study II to examine these under changed housing conditions. In study I, all parameters for clinical chemistry were similar in range for both genders with these specifics: male marmosets had significantly higher total and LDL cholesterol levels than females, whereas the mean corpuscular volume and the mean corpuscular haemoglobin were significantly lower than in females. In study II, glucose, lymphocytes and salivary cortisol were significantly lower, and faecal cortisol was increased during the change of housing conditions. In conclusion, standard values for haematology and clinical chemistry for the common marmoset were determined. Further on, parameters that are influenced by relocation stress and its importance for experimental results are described.     

Estimation of immunoreactive testicular androgen metabolites in the urine of saddle-back tamarins

Hydrolysis, extraction, and radioimmunoassay techniques for the estimation of excreted testosterone metabolites in the urine of saddle-back tamarins have been validated and are described. The steroids measured with the testosterone antiserum used are mostly present as glucuronides and sulfates. Immunoreactivity in high-performance liquid chromatography (HPLC) fractions of urinary extracts and in a standard mixture of cortisol, testosterone, and dihydrotestosterone (DHT) were compared. The fractions with the same retention data as testosterone accounted for the major part of the immunoreactivity. Several other immunoreactive compounds of unknown identity were present in low concentrations. These results suggest that testosterone conjugates are the major steroid metabolites measured with this method in Saguinus fuscicollis. Urinary testosterone levels of castrated males were much lower than those of intact males. Testosterone treatment of castrated males resulted in a temporary superphysiological increase in the levels of urinary testosterone and in an individually variable increase in the levels of the minor immunoreactive compounds. These results suggest that estimation of testosterone metabolite levels in urine is a valid method for the assessment of testicular activity in Saguinus fuscicollis.     

Annual variation in plasma cortisol levels in common marmosets, Callithrix jacchus

In contrast to numerous studies showing breeding seasonality for animals living in temperate zones, few have addressed the effect of annual environmental changes on hormones and behavior related to reproduction for animals living in tropical and equatorial regions. In order to expand information on other primates living near the equator, we used 13 adult common marmosets, eight males and five females living under natural climatic conditions in a colony located in North-Eastern Brazil. Blood samples were collected monthly from July 2002 to June 2004. Cortisol assays were performed by ELISA. Cortisol levels varied according to environmental temperature and rainfall but were not significantly affected by photoperiod. After separating out these environmental effects through an analysis of covariance for repeated measurements, a marginal significant difference in cortisol levels according to the seasons of the year was detected. A significant difference in cortisol levels between females and males was also observed. The results suggest that annual variation in cortisol in common marmosets is influenced by temperature and rainfall and might be associated with the mating season.     

Behavioral and adrenocortical responses to environmental changes in leopard cats (Felis bengalensis)

Indicators of environmental adequacy relevant to the well-being of small felids are developed by examining, in 4 captive leopard cats, interrelationships between behavioral and adrenocortical responses to changes in housing conditions. Singly housed cats were moved from their barren home cage (Cage 1, baseline) sequentially to 2 new, barren housing situations (Cages 2 and 3; ≈ 10 weeks/cage). Urinary cortisol concentrations, stereotypic pacing, and hiding frequencies were transiently increased for 1 week after translocation to Cage 2. After translocation to Cage 3, cortisol concentrations and hiding also were increased for the first week. However, conditions in Cage 3 were determined to be aversive to the cats, as evidenced by cortisol concentrations that remained chronically elevated for the entire 10-week period. Exploratory behavior was suppressed during this period. When Cage 3 was enriched with a complex of branches and hiding places, urinary cortisol concentrations and stereotypic pacing decreased, and exploration increased. Concealment locations that camouflage were more often used for lying down when urinary cortisol was elevated. These results suggest that reduced exploratory behavior is an indicator of chronic exposure to aversive environmental conditions. Stereotypic pacing may not necessarily increase when adrenocortical activity increases. The results also suggest that enrichment facilitates coping with aversive stimulation by providing behavioral options to confined felids. To promote the welfare of small felids, appropriate camouflaged hiding places should be provided and enrichment programs developed to stimulate exploratory behavior. © 1993 Wiley-Liss, Inc.     

Negative relationships in the family-of-origin predict attenuated cortisol in emerging adults

Negative childhood family environments have been associated with stress-related physical and psychological health consequences across the lifespan. The present study examined the relation between adverse relationships in the family of origin and physiological stress response, as measured by salivary cortisol, in emerging adulthood. Seventy-six university students (age range = 18-22) selected from intact married families-of-origin characterized by either negative (n = 39) or positive (n = 37) relationship quality engaged in a challenging role play task. Results from multilevel models indicated that those from negative families exhibited significantly lower salivary cortisol across the task than those from positive families. This relation did not change in strength or direction after controlling for experiences with abuse or recent anxiety or depressive symptoms. These findings suggest the significance of early family relationships on the long-term activity of the HPA axis.