Vitamin D and Winter Reproduction in the Collared Lemming, Dicrostonyx Groenlandicus

Abstract

Collared lemmings D. groenlandicus Traill were maintained and bred on vitamin D replete and deplete diets. Vitamin D deficient female lemmings had reduced fertility and their young exhibited lower post-weaning body weight and mineral content of bone than had vitamin D replete females and their young. Weaned young of D replete females maintained on vitamin D replete and deplete diets were not significantly different with respect to body weight and bone mineral content. Maternal vitamin D status is more important in influencing the pattern of post-weaning growth than the presence of vitamin D in the post-weaning diet. During the arctic summer when the sun is above the horizon 24 h a day, collared lemmings have nearly equal levels of vitamin D2 and D3 in plasma. UV radiation is required for the manufacture of vitamin D3 in mammalian skin, and vitamin D2 in plants. In the absence of solar UV during the arctic winter, lemmings are unlikely to manufacture vitamin D3 in the skin. Considering that vitamin D is needed for reproduction, it is proposed that the collared lemming must utilize dietary vitamin D2 to support winter reproduction.