Early growth and bone mineralization of the iguanid lizard, Sceloporus occidentalis in captivity: Is vitamin D3 supplementation or ultraviolet B irradiation necessary?

Abstract

AbstractThe insectivorous, heliophilic iguanid lizard, Sceloporus occidentalis, was used in this study. Eight groups of field‐collected juveniles were subjected to different doses of ultraviolet‐B radiation or were fed crickets maintained on different diets with varying amounts of vitamin D3 and other nutrients. The crickets fed to all groups were dusted with calcium carbonate powder. Snout‐vent lengths and body masses were significantly greater within each group at the end of 10 weeks; however, there were no significant among‐group differences in growth. There were no differences among treatment groups regarding plasma calcium concentration or bone calcium, phosphorus or magnesium concentrations. However, compared to length‐matched field controls, individuals from treatment groups had significantly greater body masses, greater bone calcium concentrations, and lower bone magnesium concentrations. Lizards exposed to ultraviolet radiation exhibited lower plasma phosphorus concentrations relative to several other treatment groups and field controls. In the field sample, bone calcium concentration was positively correlated with body size while bone magnesium and phosphorus concentrations were negatively correlated with body size.