Hormonal and behavioral variation in pied tamarins housed in different management conditions.

Pied tamarins are an endangered Amazonian primate that has limited breeding success in zoos. Unfortunately, little is known about their reproductive biology and adrenocortical activity. Objectives were: (1) determine if fecal hormones could be utilized to monitor gonadal and adrenocortical activity; (2) characterize male and female gonadal and adrenocortical hormones; and (3) determine if there were differences between adrenocortical activity and behavior in a nonbreeding, on-exhibit (NB-ON) pair compared to a breeding, off-exhibit (B-OFF) pair. Fecal samples were collected from four (two males; two females) individuals. Hormones were analyzed for fecal progesterone (FPM), androgen (FAM), and glucocorticoid (FGM) metabolites by enzyme immunoassay. Behavioral observations were conducted for 6 months. Data were collected on instantaneous behavior, location, and all occurrences of intraspecific behaviors. Fecal progesterone metabolites were validated by pregnancy (mean ± SE, pregnant: 28.47 ± 1.60 µg/g; nonpregnant: 8.63 ± 0.89 µg/g). Fecal androgen metabolites were higher (T = 31,971, P < 0.05) in the B-OFF male (863.66 ± 46.30 µg/g) than the NB-ON male (838.63 ± 60.70 µg/g). Fecal glucocorticoid metabolites were validated by response to veterinary procedure with elevated values (7.31 ± 1.48 µg/g) seven times the baseline (0.37 ± 0.04 µg/g) at 24-hr postphysical. Females had higher baseline FGM than the males (P < 0.05). Baseline FGM were higher (P < 0.05) in the NB-ON female (0.93 ± 0.03 µg/g) compared to the B-OFF female (0.38 ± 0.02 µg/g). Similarly, the NB-ON male's FGM baseline (0.71 ± 0.03 µg/g) were higher (P < 0.05) than the B-OFF male (0.21 ± 0.01 µg/g). Behavioral data revealed stereotypical behaviors in the NB-ON pair but no stereotypical behaviors in the B-OFF pair. Fecal hormone monitoring and behavioral analysis may provide insight on the limited breeding success of pied tamarins in zoos.

Variation in oxytocin is related to variation in affiliative behavior in monogamous, pairbonded tamarins.

Oxytocin plays an important role in monogamous pairbonded female voles, but not in polygamous voles. Here we examined a socially monogamous cooperatively breeding primate where both sexes share in parental care and territory defense for within species variation in behavior and female and male oxytocin levels in 14 pairs of cotton-top tamarins (Saguinus oedipus). In order to obtain a stable chronic assessment of hormones and behavior, we observed behavior and collected urinary hormonal samples across the tamarins' 3-week ovulatory cycle. We found similar levels of urinary oxytocin in both sexes. However, basal urinary oxytocin levels varied 10-fold across pairs and pair-mates displayed similar oxytocin levels. Affiliative behavior (contact, grooming, sex) also varied greatly across the sample and explained more than half the variance in pair oxytocin levels. The variables accounting for variation in oxytocin levels differed by sex. Mutual contact and grooming explained most of the variance in female oxytocin levels, whereas sexual behavior explained most of the variance in male oxytocin levels. The initiation of contact by males and solicitation of sex by females were related to increased levels of oxytocin in both. This study demonstrates within-species variation in oxytocin that is directly related to levels of affiliative and sexual behavior. However, different behavioral mechanisms influence oxytocin levels in males and females and a strong pair relationship (as indexed by high levels of oxytocin) may require the activation of appropriate mechanisms for both sexes.

Carcinoembryonic antigen family of adhesion molecules in the cotton top tamarin (Saguinus oedipus).

Humans and the cotton top tamarin, a model for colitis and colorectal cancer, share carcinoembryonic antigen (CEA) moieties. We quantified CEA in colonic washings and extracts in both, and CEA bands were confirmed by Western blot. We compared CEA-family expression in tissues and serum in the tamarin with that of the common marmoset, which develops colitis but not cancer. CEA levels are higher in tamarin washings compared with humans, and higher than in marmosets extracts (P<0.005). CEA molecular species appear to be specific, and human CEA-family member epitopes are also found in these primates. The higher CEA levels in the tamarin may reflect the overall higher cancer prevalence.

Cholesterol metabolism in New World primates: comparative studies in two tamarin species (Saguinus oedipus and Saguinus fuscicollis) and the squirrel monkey (Saimiri sciureus).

1. Cholesterol metabolism has been characterized in three species of New World primates, the cotton-top tamarin, the saddle-back tamarin, and the squirrel monkey. 2. When fed a diet containing cholesterol, the three species exhibited differing responses of plasma cholesterol levels. 3. Dietary cholesterol absorption was determined and plasma cholesterol die-away kinetics were analyzed in terms of a two-pool model. 4. The results of the analyses of cholesterol turnover are consistent with the observed species-specific differences in plasma cholesterol values and cholesterol absorption. 5. Cholesterol metabolism differs between the two tamarin species, as well as between the tamarins and the squirrel monkey. 6. Implications of species-specific differences between tamarin species are discussed in terms of the use of tamarin species as animal models for comparative studies of cholesterol metabolism and the etiology of cancer and cardiovascular disease.

Maintenance of cotton-top tamarins fed an experimental pelleted diet versus a highly diverse sweetened diet.

The future study of colon disease in captive callitrichid colonies may require manipulation of diets. The limited knowledge of the nutritional requirements for these species and the varied diets and supplementations fed to these animals in various colonies suggest the importance of testing the palatability and acceptability of diets for these primates. Individually housed cotton-top tamarins (Saguinus oedipus) were given either the regular Oak Ridge Associated Universities (ORAU) diet (monkey chow slurry, canned diet and supplements), a similar slurry using an experimental natural ingredient diet plus supplements, or the experimental diet without supplements. Neither dry food consumption, body weight, fecal output, nor the histological evaluation of the colons were affected by these diets. Daily intake of protein and calories were higher than previously reported estimates for the species. These results demonstrate that a natural ingredient non-sweetened pelleted diet is palatable for cotton-top tamarins for a period of 3.5 months, however, further testing over longer time periods is necessary. The nonnutritional (e.g. psychological) advantages of providing a highly diverse diet to primates housed in a relatively monotonous environment should be considered before adopting such a diet for an entire colony.

Diminished internalization and action of 1,25-dihydroxyvitamin D3 in dermal fibroblasts cultured from New World primates.

We investigated the occurrence of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3]-resistant osteomalacia in the New World primate colony of Saguinus imperator at the Los Angeles Zoo. The mean serum concentration of 1,25-(OH)2D3 was elevated 5-fold in the New World primates compared to that in their Old World counterparts. The specific internalization of 0.6 nM [3H]1,25-(OH)2D3 by cultured dermal fibroblasts from New World primates was reduced 75% compared to that by cells from Old World primates or man. The decrease in hormone uptake resulted from a decrease in the number of high affinity intracellular binding sites for 1,25-(OH)2D3 and apparently caused a 90-95% reduction in 1,25-(OH)2D3-induced 25-hydroxyvitamin-D3-24-hydroxylase activity. There was no alteration in the capacity or avidity of New World primate serum for 1,25-(OH)2D3 compared to that of serum from Old World primates. These data suggest that the occurrence of vitamin D-resistant osteomalacia in New World primates is the result of decreased high affinity, receptor-mediated uptake of 1,25-(OH)2D3 by the target cell.

Low affinity of the receptor for 1 alpha,25-dihydroxyvitamin D3 in the marmoset, a New World monkey.

Circulating levels of 1,25-dihydroxyvitamin D are 10-fold higher in the marmoset, a New World monkey, than in man; to assess hormone receptors, we evaluated interactions of 1,25-dihydroxyvitamin D3 with virus-transformed lymphocytes. Soluble extracts of transformed lymphocytes from humans showed hormone binding with affinity and capacity similar to that of receptors for 1,25-dihydroxyvitamin D from other human tissues. However, soluble extracts of transformed lymphocytes from the marmoset showed a strikingly lower affinity for 1,25-dihydroxyvitamin D (Kd 2.2 vs 0.27 nM in marmoset vs human) and a mildly lower binding capacity (6.9 vs 16 fmol/mg protein). A defective receptor for 1,25-dihydroxyvitamin D3 could account for resistance of target tissues to this hormone in the marmoset.