Hopper, K., Morales, P. R., Wagner, J. L. 2010. Effects of caging on bone metabolism in cynomolgus monkeys (Macaca mulatta). American Association for Laboratory Animal Science [AALAS] Meeting Official Program, 735 (Abstract #P173).

Juvenile cynomolgus monkeys are frequently used in drug pharmacokinetic and toxicology testing where they are cage housed for extendeded periods of time. In this study measures of body mass, bone metabolism, and turn over were compared between 2 groups of age and sex-matched, male juvenile cynomolgus macaques. The test group had been pair-housed in standard primate caging for 1 y. The control group was housed in large outdoor cages in peer groups for the same period of time. Bone densities were determined by dual energy X-ray absorptiometry (DXA). Markers of bone turnover included serum levels of osteocalcin, C-terminal telopeptide, and bone specific alkaline phosphatase. Creatinine, vitamin D3, calcium, phosphorous, parathyroid hormone levels and hematocrit were also compared between groups. Two sample t tests were applied to compare parameters between groups. A difference in body mass was found between groups, with the outdoor-housed animals being significantly heavier. The outdoor-housed animals also had significantly more bone mineral density in the pelvis, legs, and trunk. Significant differences were found between total vitamin D and parathyroid hormone between groups, both being higher in the outdoor-housed animals. This study suggests that long-term caging has an effect on body mass and bone metabolism in juvenile cynomolgus macaques, and in drug studies these alterations need to be considered when evaluating test results.