Effects of ascorbic acid on the skeletal response of chicks to vitamin D deficiency

The skeletal response of vitamin D-deficient chicks to dietary ascorbic acid was tested. 2. The epiphyseal cartilaginous plate width, which was increased by the vitamin D deficiency, was further increased when ascorbic acid was added and the effect appeared sooner. 3. Absence of vitamin D was associated with a reduction in the relative amount of cancellous to compact bone ash in the tibia. Dietary ascorbic acid intensified this effect to a significant degree. 4. Plasma ascorbic acid levels in rachitic chicks were approximately 25% less than in controls. This observation may explain the skeletal response to added vitamin C and suggests that avian bone tissue has a particularly high requirement for this vitamin.