SUMMER AND WINTER VITAMIN D3 LEVELS IN SEVEN PLATYRRHINE SPECIES HOUSED AT A BRITISH ZOO, WITH REFERENCE TO NATURAL UVB LEVELS.

Serum samples were collected from 24 platyrrhines of seven diurnal species housed with outdoor access at Bristol Zoo Gardens (United Kingdom) to test 25-hydroxyvitamin D3 (25OHD3) levels as part of the veterinary department's preventative health care program. Samples were collected in August 2008 (summer) and January 2009 (winter) to examine the effect of season on 25OHD3 levels. Dietary levels of vitamin D3 remained the same throughout the study period and fell within the range of 2000-4000 IU/kg dry matter, in accordance with current primate guidelines. Statistical analysis showed that there was no significant difference between the platyrrhines' summer 25OHD3 values (range, <4.0->150.0 µg/L) and winter 25OHD3 values (range, <4.0-80.1 µg/L). However, ultraviolet B (UVB) measurements taken at the zoo during the study period confirmed that UVB levels were significantly higher in summer (mean reading for 1200-1300 hours GMT time period, 153.8 µW/cm2) compared with winter (mean reading for 1200-1300 hours GMT time period, 19.4 µW/cm2). The 25OHD3 levels measured were generally found to be low compared with previously published values from healthy captive and wild platyrrhines.