Effects of ultraviolet radiation on plasma 25-hydroxyvitamin D₃ concentrations in corn snakes (Elaphe guttata)

Objective - To determine whether corn snakes exposed to UVB radiation have increased plasma 25-hydroxyvitamin D₃ concentrations, compared with control snakes. Animals - 12 corn snakes (Elaphe guttata). Procedures - After an acclimation period in individual enclosures, a blood sample was collected from each snake for assessment of plasma 25-hydroxyvitamin D₃ concentration. Six snakes were provided with no supplemental lighting, and 6 snakes were exposed to light from 2 full-spectrum coil bulbs. By use of a radiometer-photometer, the UVA and UVB radiation generated by the bulbs were measured in each light-treated enclosure at 3 positions at the basking surface and at 2.54 cm (1 inch) below each bulb surface; the arithmetic mean values for the 3 positions at the basking surface and each individual bulb surface were calculated immediately after the start of the study and at weekly intervals thereafter. At the end of the study (day 28), another blood sample was collected from each snake to determine plasma 25-hydroxyvitamin D₃ concentration. Results - Mean ± SD plasma concentration of 25-hydroxyvitamin D₃ in snakes that were provided with supplemental lighting (196 ± 16.73 nmol/L) differed significantly from the value in control snakes (57.17 ± 15.28 nmol/L). Mean exposure to UVA or UVB did not alter during the 4-week study period, although the amount of UVA recorded near the bulb surfaces did change significantly. Clinical Relevance - These findings have provided important insight into the appropriate UV radiation requirements for corn snakes. Further investigation will be needed before exact husbandry requirements can be determined.