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This study was supported by the Agricultural Research Service of the U.S. Department of Agriculture, under Agreement No. 59-32U4-5-6, and by the Center for Veterinary Medicine, Food and Drug Administration of the U.S. Department of Health and Human Services, under Cooperative Agreement No. FD-U-000006-10. Additional support was provided by the American Feed Industry Association, Monsanto Company, American Cyanamid Company, and Pitman-Moore, Inc. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authoring subcommittee and do not necessarily reflect the views of the sponsors.
Library of Congress Cataloging-in-Publication Data
Metabolic modifiers: effects on the nutrient requirements of food -producing animals / Subcommittee on Effects of Metabolic Modifiers on the Nutrient Requirements of Food-Producing Animals, Committee on Animal Nutrition, Board on Agriculture, National Research Council
p. cm.
Includes bibliographical references (p. ) and index.
ISBN 0-309-04997-0
1. Somatotropin in animal nutrition. 2. Adrenergic beta agonists in animal nutrition. 3. Anabolic steroids in animal nutrition. 4. Livestock—Metabolism. 5. Feed utilization efficiency. 6. Livestock—Nutrition—Requirements. I. National Research Council (U.S.). Subcommittee on Effects of Metabolic Modifiers on the Nutrient Requirements of Food-Producing Animals.
SF98.S65M47 1994
636.08'52—dc20 94-13922
CIP
©1994 by the National Academy of Sciences. All rights reserved.
Printed in the United States of America
SUBCOMMITTEE ON EFFECTS OF METABOLICMODIFIERS ON THE NUTRIENTREQUIREMENTS OFFOOD-PRODUCING ANIMALS
TERRY D. ETHERTON, Chair,
The Pennsylvania State University
DALE E. BAUMAN,
Cornell University
DONALD H. BEERMANN,
Cornell University
R. DEAN BOYD,
Pig Improvement Company, Franklin, Kentucky
PETER J. BUTTERY,
University of Nottingham, United Kingdom
ROGER B. CAMPBELL,
Bunge Meat Industries, Ltd., Corowa, Australia
WILLIAM V. CHALUPA,
University of Pennsylvania
KIRK KLASING,
University of California, Davis
GERALD T. SCHELLING,
University of Idaho
NORMAN C. STEELE,
Nonruminant Animal Nutrition Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, Maryland
COMMITTEE ON ANIMAL NUTRITION
HAROLD F. HINTZ, Chair,
Cornell University
DONALD C. BEITZ,
Iowa State University
GARY L. CROMWELL,
University of Kentucky
DANNY G. FOX,
Cornell University
ROGER W. HEMKEN,
University of Kentucky
LAURIE M. LAWRENCE,
University of Kentucky
LARRY P. MILLIGAN,
University of Guelph, Canada
OLAV T. OFTEDAL,
National Zoological Park, Washington, D.C.
JERRY L. SELL,
Iowa State University
ROBERT P. WILSON,
Mississippi State University
Staff
MARY I. POOS, Project Director
JANET OVERTON, Editor
DENNIS BLACKWELL, Senior Project Assistant
KAMAR PATEL, Senior Project Assistant through February, 1992
BOARD ON AGRICULTURE
DALE E. BAUMAN, Chair,
Cornell University
PHILIP H. ABELSON,
American Association for the Advancement of Science
JOHN M. ANTLE,
Montana State University
WILLIAM B. DELAUDER,
Delaware State University
SUSAN K. HARLANDER,
Land O'Lakes, Inc., Minneapolis, Minnesota
RICHARD R. HARWOOD,
Michigan State University
T. KENT KIRK,
U.S. Department of Agriculture, Madison, Wisconsin
JAMES R. MOSELEY,
Jim Moseley Farms, Inc., Clarks Hill, Indiana, and Purdue University
NORMAN R. SCOTT,
Cornell University
GEORGE E. SEIDEL, JR.,
Colorado State University
CHRISTOPHER R. SOMERVILLE,
Carnegie Institute of Washington
PATRICIA B. SWAN,
Iowa State University
JOHN WELSER,
The Upjohn Company, Kalamazoo, Michigan
Staff
SUSAN E. OFFUTT, Executive Director
JAMES TAVARES, Associate Executive Director
CARLA CARLSON, Director of Communications
JANET OVERTON, Editor
Preface
Animal scientists have long sought economical ways to improve the productivity of commercially important domestic animals, to enhance their productive efficiency, and, in the case of meat animals, increase muscle mass and concurrently decrease carcass fat. Remarkable scientific advances during the past 10 years have led to the discovery of two new technologies that achieve these goals—the administration of (1) recombinantly derived somatotropin (ST) (growth hormone) and (2) β-adrenergic agonists (synthetic catecholamine-like analogs). Administration of ST to cows increases both milk production and productive efficiency (milk/unit feed). In meat animals, administration of ST or β-adrenergic agonists improves productive efficiency and carcass leanness. Administration of anabolic steroids enhances growth performance in sheep and beef cattle.
In 1989, under the auspices of the Board on Agriculture's Committee on Animal Nutrition, the Subcommittee on Metabolic Modifiers was appointed to summarize our present understanding of the mechanisms by which ST and β-adrenergic agonists act and to determine, where possible, what effects administration of these metabolic modifiers have on nutrient requirements of domestic livestock.
In this report, we have discussed the current understanding of the mechanisms by which metabolic modifiers alter nutrient partitioning and productive efficiency and what is known about their effects on the nutrient requirements of food-producing animals. In Chapter 1, the subcommittee underscores the role agricultural scientists play to provide optimal nutrition and productive efficiency for food-producing animals to meet the changing needs of consumers and the increasing demands of a growing world population. Chapter 2 addresses our growing knowledge of biology, chemistry, and mechanisms of action of metabolic modifiers that make it possible to alter carcass composition, improve feed efficiency, and enhance growth rate in poultry, sheep, pigs, and cattle, and increase milk yield in dairy cattle. Chapter 3 examines the nutrient requirements and production responses of dairy cattle supplemented with bovine ST (bST) with respect to the yield and composition of milk in relation to breed and genotype, parity, management, environment, and feed intake. Chapter 4 addresses nutritional implications in swine, including constraints to lean growth, and nutrient requirements with respect to intake, digestion, maintenance, and efficiency of nutrient use. Discussion includes estimates of amino acid, mineral, and vitamin requirements in growing swine. In Chapter 5, strategies for administering metabolic modifiers to poultry are discussed, including exogenous ST administration and in ovo manipulations. Nutrient intake recommendations are given along with modeling approaches and empirical predictions. Chapter 6 discusses the effects of metabolic modifiers on growing cattle and growing lambs.
In summary, the subcommittee believes that the full spectrum of advantages available from these technologies can only be realized by increasing our understanding of the effects these metabolic modifiers have and the biological mechanisms and nutritional requirements that account for the changes in performance and productive efficiency.
TERRY D. ETHERTON, Chair
Subcommittee on Effects of Metabolic Modifiers on the Nutrient Requirements of Food-Producing Animals
Acknowledgments
The Subcommittee on Metabolic Modifiers is particularly grateful to Harry Mersmann, Children's Nutrition Center of the U.S. Department of Agriculture, Houston, Texas. We also acknowledge the contributions of Gary Hartnell, Monsanto Company and Mary Beth Rymph, Alice Pell and Mark McGuire, Cornell University for their review of Chapter 3. We are also indebted to Sandy Gunsallus, at The Pennsylvania State University, for her secretarial support during the preparation of this report. The subcommittee also appreciates the ideas and contributions of a number of individuals throughout the course of the study. We acknowledge the assistance of Board on Agriculture staff members Sharon Giduck, who served as our first staff officer; James Tavares, who on an interim basis assumed her responsibilities; Mary Poos, our most recent staff officer, who helped guide this report to its completion; Janet Overton, editor, who guided this report throughout the editorial and production stages; Kamar Patel, the senior project assistant, through February 1992; and Dennis Blackwell, our most recent project assistant.
Contents
Tables and Figures
TABLES
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2-1 |
Effects of Porcine Somatotropin (pST) on Pig Growth Performance |
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2-2 |
Effects of Chicken Somatotropin (cST) on Chicken Growth Performance |
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2-3 |
Increase in Milk Yield (kg milk/day above controls) in Response to Bovine Somatotropin (bST) |
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2-4 |
Effects of Somatotropin on Animal Tissue and Systems during Growth or Lactation |
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2-5 |
Representative Responses in Farm Animal Species to Dietary Administration of β-Adrenergic Agonists |
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3-1 |
Comparison of Bovine Somatotropin (bST)-Treated to Genetically Superior Cows Producing the Same Quantity of Milk |
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4-1 |
Representative Data of the Effects of Somatotropin (ST) on Growth Performance and Composition of Cattle and Lambs |
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5-1 |
Responses of Swine Administered Porcine Somatotropin (pST) during Two Phases of Growth |
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5-2 |
Factorial Estimation of Dietary Protein and Lysine Requirement in Control and Porcine Somatotropin (pST)-Treated Pigs (50-100 kg) Exhibiting Different Protein Accretion Rates |
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5-3 |
Expected Field Responses to Porcine Somatotropin (pST) and the β-Agonist Ractopamine |
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6-1 |
Regression Equations Used to Predict Nutrient Requirements (mg/kcal) for Broilers at Accelerated Growth Rates |
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6-2 |
Theoretical Percent of Nutrient Levels for Broiler Chicks, by Age (weeks), Growing at Normal and Augmented Rates |
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6-3 |
Formulation of a Practical Reference Diet for Broiler Chicks Growing at 120 Percent of Normal Rates |
FIGURES
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1-1 |
Accretion rates for protein and fat in pigs over the body weight range from 45 kg to 100 kg (market weight) |
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1-2 |
Effects of a maximally effective dose of pST on nutrient partitioning in growing pigs |
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1-3 |
The effect of bST on the quantity of energy used for milk production and maintenance in lactating cows |
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2-1 |
Comparison of amino acid sequences for somatotropin from different species |
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2-2 |
The dose-response relationship between pST and different parameters of pig growth performance |
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2-3 |
Chemical structures of the endogenous catecholamines dopamine, norepinephrine, and epinephrine and of select synthetic β-adrenergic agonists |
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2-4 |
Chemical structures of the endogenous steroids estradiol, progesterone, and testosterone and of synthetic anabolic steroids |
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5-1 |
Interrelationship between protein deposition and protein (amino acid) intake in swine |
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5-2 |
Hypothetical model showing the relationship between dietary energy intake and deposition of muscle and fat tissues |
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5-3 |
Differential response of female and intact male pigs to pST treatment and dietary energy intake |
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5-4 |
Theoretical protein (amino acid) dose-response curves for metabolic modifiers |
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5-5 |
Dose-response curve for control and pST-treated castrate male and female pigs |
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5-6 |
Dose-response curve for control and pST-treated intact male pigs |
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5-7 |
Carcass protein deposition response of castrate male pigs |
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5-8 |
Effect of digestible energy intake on total energy retained as protein and maintenance energy required for control and pST-treated pigs |
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5-9 |
Temporal pattern of the growth response of pigs administered the β-adrenergic agonist L-644,969 for 7 weeks |
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5-10 |
Protein deposition response of castrate pigs |
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5-11 |
Relationship between empty-body protein deposition and dietary protein intake in restrictively fed female pigs |
