Cutaneous concentrations of 7-dehydrocholesterol in Hoffmann's two-toed sloths (Choloepus hoffmanni) in managed care

Hoffmann's two-toed sloths (Choloepus hoffmanni) are unique animals popular in zoological settings. The role of vitamin D in the maintenance of calcium homeostasis in this species is unexplored, although disorders of calcium homeostasis have been reported in managed sloths, including urolithiasis and soft tissue mineralization. This study assessed cutaneous concentrations of 7-dehydrocholesterol (7-DHC) in nine indoor-housed Hoffmann's two-toed sloths, as a means of evaluating the potential for cutaneous photobiosynthesis of vitamin D₃. Samples were obtained from both abdominal and lumbar regions of the skin to assess for regional variation in 7-DHC concentration. The average concentration of 7-DHC in the sloth skin was low (0.197 ± 0.02 nmol/cm²). Location had a significant effect on 7-DHC level only when concentrations were expressed based on the wet weight of the sample (ng/g), but levels were similar when values were normalized to biopsy surface area (nmol/cm²).