title: Relationships between cholecalciferol metabolism and growth in chicks as modified by age, breed and diet.
abstract: Fast-growing heavy (White Rock) chicks, fed a vitamin D-deficient diet, exhibited a higher activity of kidney 25-hydroxycholecalciferol-1-hydroxylase (1-hydroxylase) than slow-growing light (White Leghorn x Rhode Island Red) chicks fed the same diet. 1-Hydroxylase and duodenal calcium-binding protein (CaBP) declined with age. Feeding of low energy diets with or without vitamin D resulted in a slower rate of growth and reduced 1-hydroxylase activity and CaBP concentration. Severe dietary restriction of either calcium or phosphorus resulted in a lower growth rate as well as a duodenal CaBP as compared to a moderate mineral restriction. The severe dietary calcium restriction also resulted in a lower 1-hydroxylase activity than that resulting from a moderate restriction. The results clearly indicate that high 1-hydroxylase activity and a high intestinal CaBP are associated with a high growth rate.
mesh_terms: D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase / Q000378:metabolism; D000375:Aging; D000818:Animals; D002118:Calcium / Q000172:deficiency; D002645:Chickens / Q000254:growth & development* / Q000378:metabolism; D002762:Cholecalciferol / Q000378:metabolism*; D004032:Diet; D004386:Duodenum / Q000378:metabolism; D004734:Energy Metabolism; D007668:Kidney / Q000201:enzymology; D008297:Male; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D013045:Species Specificity; D014808:Vitamin D Deficiency / Q000378:metabolism
chemical_list: D064030:S100 Calcium Binding Protein G; D002762:Cholecalciferol; D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase; D002118:Calcium