Lee Russell McDowell Vitamins in Animal and Human Nutrition S E C O N D E D I T I O N Iowa State University Press / Ames V I TA M I N S I N A N I M A L A N D H U M A N N U T R I T I O N Lee Russell McDowell Vitamins in Animal and Human Nutrition S E C O N D E D I T I O N Iowa State University Press / Ames Lee Russell McDowell,PhD,is a professor of animal science in the Department of Animal Science, University of Florida, Gainesville. His research interests center pri- marily on minerals for grazing livestock, vitamins for livestock, and feed composition. Dr. McDowell also collaborates with numerous animal nutritionists in tropical coun- tries of Latin America, Africa, and Southeast Asia. ©2000 Iowa State University Press; 1989 Academic Press All rights reserved Iowa State University Press 2121 South State Avenue, Ames, Iowa 50014 Orders: 1-800-862-6657 Office: 1-515-292-0140 Fax: 1-515-292-3348 Web site: www.isupress.edu Authorization to photocopy items for internal or personal use, or the internal or per- sonal use of specific clients, is granted by Iowa State University Press, provided that the base fee of $.10 per copy is paid directly to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA01923. For those organizations that have been granted a photocopy license by CCC, a separate system of payments has been arranged. The fee code for users of the Transactional Reporting Service is 0-8138-2630-6/2000 $.10. Printed on acid-free paper in the United States of America First edition, 1989 (©Academic Press) Second edition, 2000 Library of Congress Cataloging-in-Publication Data McDowell, L. R. Vitamins in animal and human nutrition/Lee Russell McDowell—2nd ed. p. cm. Includes bibliographical references and index. ISBN 0-8138-2630-6 1. Vitamins in human nutrition. 2. Vitamins in animal nutrition. 3. Avitaminosis. I. Title. QP771.M396 2000 613.2′86—dc21 00-027082 The last digit is the print number: 9 8 7 6 5 4 3 2 1 This book is dedicated, with appreciation, to my parents; my wife, Lorraine; my daughters, Suzannah, Joanna, and Teresa and their husbands and children; and to Tony J. Cunha (deceased), the former head of the Depart- ment of Animal Science at the University of Florida, for his practical knowledge of the livestock in- dustry and for his support and encouragement to write books. C O N T E N T S Preface, xv 1. Introduction and Historical Considerations Definition of Vitamins,3 Classification of Vitamins, 4 Vitamin Nomenclature, 5 Vitamin Requirements, 6 Vitamin Occurrence, 7 History of the Vitamins, 7 References, 13 2. Vitamin A Introduction, 15 History, 16 Chemical Structure and Properties, 18 Analytical Procedures, 21 Metabolism, 22 Functions, 28 Requirements, 39 Natural Sources, 43 Deficiency, 48 Supplementation, 69 β-Carotene Function Independent of Vitamin A, 75 Toxicity, 78 References, 82 3. Vitamin D Introduction, 91 History, 91 Chemical Structure, Properties, and Antagonists, 94 Analytical Procedures, 95 vii CONTENTS Metabolism, 97 Functions, 103 Requirements, 111 Natural Sources, 115 Deficiency, 117 Supplementation, 134 Toxicity, 140 References, 147 4. Vitamin E Introduction, 155 History, 155 Chemical Structure and Properties, 157 Analytical Procedures, 160 Metabolism, 161 Functions, 164 Requirements, 170 Natural Sources, 174 Deficiency, 178 Supplementation, 207 Toxicity, 216 References, 217 5. Vitamin K Introduction, 227 History, 227 Chemical Structure, Properties, and Antagonists, 229 Analytical Procedures, 231 Metabolism, 232 Functions, 235 Requirements, 239 Natural Sources, 242 Deficiency, 244 Supplementation, 254 Toxicity, 258 References, 259 6. Thiamin Introduction, 265 History, 265 Chemical Structure, Properties, and Antagonists, 267 Analytical Procedures, 269