title: Vitamin A toxicity: comparative changes in bone of the broiler and leghorn chicks.
abstract: Severe skeletal lesions were produced in both broilers and leghorns orally administered toxic levels of vitamin A (330 or 660 IU vit. A/g body weight X day) for 21 consecutive days. Hypervitaminosis A in broilers produced an osteodystrophy characterized by abnormal thickening of the proliferative-maturation zone, metaphyseal sclerosis, hyperosteoidosis, decreased number of osteoclasts, and parathyroid gland hyperplasia. In leghorns, the osteodystrophic lesions were characterized by a thin proliferative-maturation zone, a relatively thickened hypertrophy zone, flattened spindle-shaped osteoblasts, and osteoporosis. In both broilers and leghorns given excessive vitamin A, the osteogenic layer of periosteum in all bones was thin.
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D001847:Bone Diseases / Q000139:chemically induced / Q000473:pathology / Q000662:veterinary*; D001842:Bone and Bones / Q000187:drug effects* / Q000473:pathology; D002645:Chickens / Q000235:genetics*; D011201:Poultry Diseases / Q000139:chemically induced* / Q000473:pathology; D014801:Vitamin A / Q000633:toxicity*
chemical_list: D014801:Vitamin A