Growth in Animals (eBook)

Front Cover 1
Growth in Animals 4
Copyright Page 5
Table of Contents 8
PREFACE 6
CHAPTER 1. DEFINITIONS OF GROWTH 10
Introduction 10
Growth of cells, organs and tissues 10
Growth of the whole body 14
Growth after birth 16
References 18
CHAPTER 2. THE BIOCHEMICAL AND GENETICAL DETERMINANTS OF SELECTION FOR GROWTH 20
Introduction 20
The questions we can ask 20
Biochemical studies on animals selected for growth rate 21
Replicated selection for body weight 22
Metabolite flux analysis and selection for growth 25
Immunogenetics and selection for growth 30
The relationship between genes, enzymes and growth 30
Conclusions 31
Acknowledgements 31
References 31
Chapter 3. THE HORMONAL CONTROL OF GROWTH AT PUBERTY 34
References 52
CHAPTER 4. GROWTH AND THE THERMAL ENVIRONMENT 56
Introduction 56
Thermal environment and metabolism 56
The new-born animal 59
Behavioural effects 68
Morphology and heat exchange 68
References 69
CHAPTER 5. INTERRELATIONSHIPS BETWEEN IMMUNITY AND GROWTH 74
Introduction 74
Infection, growth and immunity 75
Impairment of active immunity by malnutrition 76
Passive immunity 79
Relationships between growth and immunity in the gut 81
Immunological disorders 83
The effects of adrenocortical hormones on immunity and growth 84
Conclusions 86
References 87
CHAPTER 6. BONE GROWTH AND MODELLING 92
Introduction 92
Development of bone 93
Apposition of new bone 98
Resorption of bone 100
Factors controlling bone growth and modelling 103
Conclusion 106
References 106
CHAPTER 7. GROWTH CURVES IN MUSCLE NUCLEIC ACID AND PROTEIN: PROBLEMS OF INTERPRETATION AT THE LEVEL OF THE MUSCLE CELL 110
Introduction 110
Muscle growth as involving the replication of cells and the growth of individual cells 114
Growth curves in muscle nucleic acid and protein 117
Comments on rates of protein turnover in muscle 121
Exercises in computer-simulated growth 121
The significance of protein/nucleic acid ratios when altered in response to physiological variables 134
Some factors other than protein turnover that may restrict muscle growth 136
Summary 139
Acknowledgement 141
References 141
CHAPTER 8. FUNDAMENTAL ASPECTS OF ADIPOSE TISSUE GROWTH 146
Introduction 146
Distribution of adipose tissue 146
Histogenesis of the fat cell 148
Gross development of adipose tissue 159
Cellular aspects of development in various species 167
Other factors affecting the cellularity and growth of adipose tissue 171
Depletion of adipose tissue 175
Chemical composition of adipose tissue 178
Acknowledgement 179
References 179
CHAPTER 9. THE GUT MICROFLORA AND GROWTH 184
Introduction 184
Effects of the gut micro-organisms on nutrient metabolism 186
Effects of micro-organisms on physiology and function of the gut 190
Microbiological aspects of growth depression 193
Summary 195
References 195
CHAPTER 10. MECHANISMS OF ACTION OF GROWTH-PROMOTING AGENTS IN RUMINANT ANIMALS 198
Introduction 198
Agents increasing quantity or quality of nutrients available to animal tissues 198
Increasing efficiency of nutrient utilization in animal tissues 208
Summary and conclusions 211
CHAPTER 11. MECHANISMS OF GROWTH PROMOTERS IN SINGLE-STOMACH ANIMALS 216
Introduction 216
The nutrient-sparing effect 219
Absorption of nutrients 221
The microflora 222
Physiological effects of antimicrobials 226
Relationship of 'non-pathogenic' microflora to disease 227
Conclusions 228
References 230
CHAPTER 12. GROWTH AND BREEDING PERFORMANCE IN ANIMALS AND BIRDS 238
Introduction 238
Factors confounding the study of the relationship between growth and reproductive activity 239
Experimental evidence for growth-mediated effects on breeding performance 241
The physiological mechanisms mediating the effects of growth on reproduction 251
Conclusions 252
References 253
CHAPTER 13. GROWTH IN MAMMALS FOR MEAT PRODUCTION 258
Introduction 258
Mature size and efficiency 259
Interrelationships between mature size, growth rate and efficiency of the growing pig 260
Brody's equation and lean tissue gain in animals of different genetic potential 263
Changes in body composition and feed intake during growth 265
Choosing selection objectives for more efficient meat production 267
Conclusions 269
References 270
CHAPTER 14. GROWTH IN BIRDS FOR MEAT PRODUCTION 274
The structure of the UK poultry meat industry 274
The nature of poultry meat production 275
The development of birds for meat production 276
The characteristics of poultry growth 278
Manipulation of growth in meat poultry 279
References 281
CHAPTER 15. GROWTH IN FISHES 282
Introduction 282
Food 286
Temperature 287
Sex 287
Social interaction and genetics 288
Conclusion 293
References 293
CHAPTER 16. GROWTH AND MEAT QUALITY IN ANIMALS 296
Introduction 296
Carcass and meat quality 296
General aspects of growth and meat quality 296
The effect of the post-slaughter environment 298
The nature of individual variations in meat quality 298
Halothane sensitivity, body type and meat quality in pigs 300
The extent of acidification of muscles 301
Conclusions 302
References 302
LIST OF PARTICIPANTS 306
INDEX 312