Development of the Avian Embryo Development of the Avian Embryo A Behavioural and Physiological Study B. M. FREEMAN Houghton Poultry Research Station, Houghton, Huntingdon and Margaret A. VINCE Psychological Laboratory, Downing Street, Cambridge LONDON CHAPMAN AND HALL First published 1974 by Chapman and Hall Ltd 11 New Fetter Lane, London EC4P 4EE © 1974 B. M. Freeman and Margaret A. Vince Soj'tcover reprint of the hardcover 1st edition 1974 All rights reserved. No part of this book may be reprinted, or reproduced or utilized in any form or by any electronic, mechanical or other means, now known or hereafter invented, including photocopying and recording, or in any information storage and retrieval system, without permission in writing from the Publisher. Distributed in the U.S.A. by Halsted Press, a Division of John Wiley & Son, Inc., New York Library of Congress Catalog Card Number 74-4340 ISBN -13: 978-94-009-5712-1 e-ISBN-13:978-94-009-571 0-7 DOT: 10.1007/978-94-009-5710-7 Contents Preface page xiii Acknowledgements xiv List of Generic and Specific Names xv PART ONE: BEHAVIOUR by Margaret A. Vince 1. Incubation Requirements 3 1.1 Introduction 3 1.2 Requirements of the embryo of the domestic fowl 4 Heat - Humidity - The gaseous environment - Egg position and change of position 1.3 Incubation requirements of other domestic species 5 1.4 Incubation in wild birds 6 Introduction - Incubation sites - Warming of the eggs - The problem of cooling - The continuity of attentiveness - Humidity - The gaseous environment - Egg shifting or turning - Hatching success 2. General Development, Postural Changes, Activity and Relationship between the Embryo and Other Structures within the Shell 20 2.1 Changes in size, posture and position in the domestic fowl embryo during incubation 20 2.2 Embryonic activity during incubation in the domestic fowl 25 embryo Passive movements - Active, spontaneous movements - Significance of spontaneous activity 2.3 Hatching and emergence in the fowl 30 2.4 Structural and behavioural development in species other than the fowl 32 Structural and behavioural development during the first two thirds of incubation - Pre-hatching and hatching behaviour in species other than the fowl v CONTENTS 2.5 The characterization and scoring of embryonic movements 36 Terms used to describe embryonic activity - The quantifica- tion of embryonic motility 3. Vocalization and Communication in the Natural Situation 38 3.1 Species which can vocalize before hatching 38 3.2 Prerequisites for the onset of vocalization 38 3.3 Types of stimulation followed by embryonic vocalization 39 3.4 Effects of embryonic vocalization on the parent 40 3.5 Long-term effects of embryo/parent interaction 40 3.6 The earliest stage at which embryos become responsive to parental calls 42 4. Effects of External Stimulation on Embryonic Activity, Rate of Development and Time of Hatching 43 4.1 Introduction 43 4.2 The synchronization of hatching in quail 43 Effects of stimulation on the time of hatching - Problems arising from changes in hatching time - Signals which have accelerating or retarding effects on neighbouring eggs - Effects ofa ccelerating and retarding signals on the rate of development 4.3 Effects of accelerating and retarding stimulation in domesticated species 55 4.4 Effects of light in the fowl 56 4.5 Embryonic interactions in wild species 57 4.6 The embryonic response to stimulation 59 5. The Nervous System 62 5.1 Introduction 62 5.2 Development of activity in different parts of the nervous system 62 Spontaneous activity - Responses of the brain to stimulation 5.3 Neural mechanisms mediating early motility in the embryo of the domestic fowl 66 The development of motor and sensory areas in the spinal cord -The part played by the brain in controlling periodic, random motility - Independence of periodic, random motility from sensory input - Areas of the brain which influence periodic random motility vi CONTENTS 5.4 Neural mechanisms mediating pre-hatching and hatching behaviour 71 Introduction - The spinal cord and pre-hatching behaviour - The midbrain and pre-hatching behaviour - The fore- brain and hatching - The cerebral EEG during hatching 5.5 Neural correlates of embryonic motility 73 Nervous activity in the spinal cord between 15 and 19 days- The polyneuronal burst discharge between days 5 and 20 - Neural correlates of motility - Communication between different parts of the spinal cord 5.6 Inhibition 78 5.7 Sleep and arousal 80 6. The Development of Sensory Systems 84 6.1 Introduction 84 6.2 The non-visual response to light 85 Introduction - Evidence for a non-visual response to light in newly hatched pigeons - Evidence for a non-visual response to light in pigeon embryos 6.3 Tactile sensitivity 86 The onset of sensitivity - The type of movement evoked by tactile stimulation - Response decrements with repeated stimulation 6.4 Vestibular sensitivity 89 6.5 Proprioception 90 6.6 Hearing 91 Development of the auditory system - The age of onset of auditory sensitivity - The development of auditory sensitivity - The ontogeny of auditory discrimination 6.7 Taste 96 The sense of taste in birds - Development of a taste sense in the embryo 6.8 Vision 98 Development of the visual system - Response to light in the domestic fowl - Colour vision - The behavioural response to light - Effects of previous experience on the responsiveness of the visual system - A comparative view of the onset of visual function - Effects of light on the embryo in ovo 6.9 Olfaction 102 The olfactory sense in birds - Development of olfaction in the embryo vii CONTENTS 7. Conditioning of the Chick Embryo and Conclusions to 104 Chapters 1-7 8. The Newly Hatched Bird 108 8.1 Introduction 108 8.2 Requirements of the neonate 109 Warming and cooling - Righting and standing - Social attachments in young birds - Feeding behaviour - Oiling and preening 8.3 What is new in the life of the neonate? 113 8.4 Effects of new environmental stimuli on neural mechanisms 114 8.5 Conclusions 116 PART TWO: PHYSIOLOGY by B. M. Freeman 9. Gaseous Exchange and Oxygenation of the Embryo 119 9.1 Gross oxygen consumption and carbon dioxide production 119 9.2 The shell and the chorio-allantois 123 Structure of the shell - Development and structure of the chorio-allantois 9.3 Physical aspects of gaseous exchange 130 Oxygen - Carbon dioxide - The air space - Maximum gaseous flux during incubation 9.4 The blood and vascular system 138 Red blood cells - Blood volume and pressure - The heart Haemoglobins - Oxygen affinity of haemoglobins - Blood gases 9.5 Efficiency of the chorio-allantois as a surface for gaseous exchange 154 9.6 Effects of altitude 156 10. Nutrition and Utilization of Albumen and Yolk 160 10.1 Nutrition of the developing bird 160 Essential amino acids - Carbohydrate - Essential fatty acids - Minerals, trace elements and vitamins - Energy sources 10.2 Gross composition of the egg and the changes during incubation 163 10.3 The albumen and its utilization 164 Composition - Absorption - Functions viii CONTENTS 10.4 The yolk and its utilization 168 Composition - The yolk sac membrane - Utilization of yolk 10.5 Energy metabolism 183 10.6 The sub-embryonic fluid 184 11. Acid-base Balance 186 11.1 Blood pH and P 186 C02 11.2 Plasma bicarbonate 186 11.3 The compensation of respiratory acidosis 187 The sources of bicarbonate - The possible role of the kidney in excreting bicarbonate 12. Excretion and Water Balance 191 12.1 Introduction 191 12.2 The development of the excretory system 191 The pronephros - The mesonephros - The metanephros 12.3 Synthesis of nitrogenous excretory products 194 Metabolism of the amino group - Urea - Uric acid 12.4 The pattern of excretion during development 198 Excretory products - The organs of excretion 12.5 The allantoic sac 200 Storage of excretory products - Active transport by the allantoic endoderm 12.6 Water balance 204 Sources of water - Factors affecting water loss - Gross movements of water within the egg - Conservation of water 13. Hormones in Development 208 13.1 General introduction 208 13.2 Thyroid hormones 208 Development of the thyroid glands - Synthesis and secretion of hormones - Metabolic effects of the thyroid hormones- The thyroid and hatching 13.3 Parathyroid hormone and calcitonin 213 Introduction - Development oft he parathyroids and ultimo branchial bodies - Secretion of parathormone and calcitonin - Significance in development 13.4 Adrenal hormones 216 Development of the adrenal glands - Synthesis and secretion of adrenal hormones - Significance of adrenal cortical hor mones in development - Significance of adrenal medullary hormones in development * ~ CONTENTS 13.5 Pancreatic hormones 223 Introduction - Development of the endocrine pancreas - Structure and secretion of insulin and glucagon - Role of insulin in development - Role of glucagon in development 13.6 Gonadal hormones 226 Development of the genital system - Synthesis and secretion of gonadal hormones - Significance in development 13.7 Hypophyseal hormones 232 Introduction - Development of the hypophysis - Secretion of hormones by the pars distalis - Significance of hypo- physeal hormones in development 13.8 Glands of uncertain endocrine status 235 Introduction - Bursa of Fabricius - The pineal gland 14. Mobilization and Utilization of Calcium Stores 237 14.1 Physiological aspects of calcium transport 237 14.2 The sources of calcium and gross changes during incubation 237 14.3 The role of the chorio-allantois in calcium transport 239 Solubilization of calcium - Active transport by the chorionic ectoderm 14.4 Changes following calcium resorption 246 The shell - Plasma calcium 14.5 Mineralization of the bones 247 15. Physiology of Hatching 249 15.1 General introduction 249 15.2 Pulmonary respiration 249 Introduction - The respiratory system - The onset of breathing: the pulmonary stimulus - The development of the breathing pattern 15.3 Circulatory and associated changes 254 15.4 Pipping 256 15.5 Active hatching 257 15.6 Withdrawal and fate of the yolk sac 258 15.7 Oxygenation and energy metabolism during hatching 258 16. The Neonate 261 16.1 Introduction 261 16.2 Thermoregulation 261 Ontogeny of thermoregulation - Mechanisms of thermo regulation x CONTENTS 16.3 The alimentary tract 263 16.4 Immunological competence 264 16.5 Concluding remarks 265 Appendix 1: Chronology of development in the domestic fowl 269 Appendix 2: Development of the chick embryo in relation to the shell, yolk, albumen and extra-embryonic membranes by Beryl Tolhurst 277 References 295 Index 351 xi