Abstract

Clinical and biochemical signs of vitamin D deficiency and secondary hyperparathyroidism were identified in a colony of emperor tamarins (Saguinus imperator) housed at St. Paul’s Como Zoo. Suggestive clinical signs occurring over a 2-year period, including the death of three juveniles with identification of skeletal abnormalities upon necropsy in two of the juveniles and the clinical presentation of a mature male with limb bowing, thoracolumbar scoliosis, and altered gait (stiffness and difficulty climbing) prompted clinical, radiographic, and biochemical evaluation of all colony members.

At the time of initial evaluation, the tamarin colony consisted of seven adults (4.3) and one juvenile (0.1). Animals were housed indoors without access to direct sunlight or an artificial UVB light source. They were fed a morning meal of mush (ZuPreem Marmoset Diet; Premium Nutritional Products, Mission, KS, USA), bananas, Mazuri® Leaf Eater Primate Diet (PMI Nutrition International, Brentwood, MO, USA), wheat germ, calcium, vitamin C, honey, water and an afternoon meal of fruits, vegetables, a mealworm or cricket, and Mazuri® Marmoset Jelly (PMI Nutrition International, Brentwood, MO, USA).

Animals were anesthetized with injectable ketamine HCl (8–12 mg/kg IM) for physical examination, whole body radiography, and collection of blood for serum 25-hydroxyvitamin D₃ (25[OH]D₃), ionized calcium (iCa), and intact parathormone (iPTH) measurements. All animals, except an adult male who was euthanatized shortly after evaluation, were in good body condition and exhibited no abnormal clinical signs. However, radiographic lesions, including variable degrees of limb bowing (varus deviation distal to the elbow with separation of the radius and ulna), physeal abnormalities, radiolucency, and apparent pathologic fractures were identified in six of eight animals. Initial serum concentrations of 25[OH]D₃, iPTH, and iCa revealed seven of eight animals with low 25[OH]D₃, compared to levels reported in healthy wild-caught callitrichids,^1,2 and seven of eight with apparent high iPTH and normal iCa levels based on human “normals” used by the reporting laboratory (Minnesota State Diagnostic Laboratory, Animal Health Diagnostic Laboratory, Lansing, MI, USA). Changes were the most severe in older animals (>11 years of age).

Based on these results, a series of environmental and dietary manipulations were initiated. During the first 3-month period, all males were moved into a screened, outdoor enclosure for the summer, while the females remained indoors. At the end of this period, 25[OH]D₃ concentrations changed little in either group. However, iPTH concentrations decreased in the males with little change in females. During the second 3-month period, all animals were provided access to an artificial UVB light source (ReptiSun 5.0, Zoo Med Laboratories, San Luis Obispo, CA, USA) and are scheduled for repeat serum evaluation. Regular evaluation and management modification will continue over the next 6 months in this colony. This study provides baseline values for 25-[OH]D₃, intact parathormone, and ionized calcium levels in a colony of emperor tamarins. It also provides information about the clinical and biochemical impact of specific sequential dietary and environmental modifications that are practical and feasible in a zoo setting.

Literature Cited

1.  Power ML, OT Oftedal, A Savage, ES Blumer, LH Soto, TC Chen and MF Holick. 1997. Assessing vitamin D status of callitrichids: baseline data from wild cotton-top tamarins (Saguinus oedipus) in Columbia. Zoo Biol. 16:39–46.

2.  JS Adams, MA Gacad, AJ Baker, B Gonzales, RK Rude. 1985. Serum concentrations of 1,25-dihydroxyvitamin D₃ in Platyrrhini and Catarrhini: a phylogenetic appraisal. Am. J. Primatol. 9:219–224.