Direct-Fed Microbials and Prebiotics for Animals : Science and Mechanisms of Action

In this exciting update, readers will learn how feeding direct-fed microbials (including eubiotics, postbiotics, prebiotics, and synbiotics) is becoming increasingly widespread during food animal production. Animal production must improve efficiency of growth, and the use of direct-fed microbial and prebiotic additives to domestic animals has become widely accepted and utilized. The benefits of probiotic-type approaches in cattle, pigs, fish, and poultry, include improved general animal health, reduced foodborne pathogen populations, increased growth rate and feed efficiency, improved milk and egg production, and have been reported world-wide. Successes from probiotic approaches in multiple species have ensured their adoption; however, several fundamental questions remain. Early establishment and retention of an ecological balance in the gastrointestinal tract is an important first step for an external biological additive to be effective in young animals, suggesting that some of the benefits of direct-fed microbials may be due to an early establishment of a "normal" native gut microbial population. Research has indicated that the establishment of a normal population can enhance gut epithelial integrity, preventing inflammation and improving animal health. Thus, it is important that we understand the key processes that occur during the establishment of the gut microbial population that can impact gastrointestinal fermentation and provide protection against pathogens of the animals and of human consumers. Knowing how these processes work and how they impact animal energy and protein expenditures can guide further improvements of available and future commercial products. Exciting research opportunities are discussed in this book, examining different characteristics of DFMs that are fed to animals to meet different production demands in different production scenarios (e.g., beef versus dairy versus swine versus fin fish). The advent of molecular and next-generation sequencing offers methods of developing tailored DFMs, and of early detection of successful DFM establishment in the gut. These techniques will further deepen our insight into understanding the microbial population of the gut and how these populations impact animal health, food safety, and sustainability of animal-derived protein production. Preface 5 Definitions 6 References 7 Contents 10 About the Editors 12 Part I: The Gastrointestinal Tract of Food Animals and Impact of Feed Additives 14 Chapter 1: Commensal Gastrointestinal Microbiota as a Complex Interactive Consortia 15 1.1 Introduction 15 1.2 The Diversity of Microbial Communities in the Gastrointestinal Tract 16 1.3 Temporal Colonization of the Intestinal Tract 18 1.3.1 Postnatal Programming 18 1.4 Upsetting the Balance: The Effect of Stressors on the Intestinal Microbiota 20 1.5 Upsetting the Balance: Lactic Acidosis and Rumen Microbiota 21 1.6 Upsetting the Balance: Feed Withdrawal and Intestinal Microbiota 22 1.7 Development of Intestinal Microbiota in the Early Life of the Host 23 1.8 Conclusions 26 References 27 Chapter 2: The Poultry Gastrointestinal Tract: An Overview of Microbial Ecology 33 2.1 Introduction 33 2.2 The Poultry Gastrointestinal Tract: Anatomy and Physiology 35 2.3 Poultry Gastrointestinal Microbiota 38 2.4 Bacterial Ecology in the Poultry Gastrointestinal Tract 38 2.5 Conclusions and Future Directions 41 References 42 Chapter 3: Current Understanding of the Crosstalk Between Direct-Fed Microbials and Indigenous Microbiome in the Gastrointestinal Tract: Applications and Challenges in Food-Producing Animals 47 3.1 Introduction 48 3.2 Recent Advances in Researching the GIT Microbiome of Food-Producing Animals 49 3.2.1 Core Microbiota 49 3.2.1.1 Taxonomic Core Microbiota in the GIT of Food-Producing Animals 49 3.2.1.2 Functional Core Microbiota in the GIT of Food-Producing Animals 51 3.2.2 Mucosa-Associated Versus Digesta-Associated Microbiomes 52 3.3 Challenges for the Application of DFMs in Food-Producing Animals 56 3.3.1 Lack of In-Depth Understanding of the GIT Microbiome 56 3.3.2 Lack of Understanding of the Interaction Between DFMs and the GIT Microbiome 58 3.3.3 Individualized Microbiomes Pose Challenges for Application of DFMs 59 3.4 Future Directions for Effective Use of DFMs in Food-Producing Animals 60 3.5 Conclusion 63 References 63 Chapter 4: Advancements in Poultry Nutrition and Genetics, the Role of Antibiotic Growth Promoters, and the Introduction of Feed Additive Alternatives 70 4.1 Introduction 70 4.2 Broiler Performance and Genetics 72 4.3 Nutritional Advancements in the Poultry Industry 73 4.4 Feed Additives 77 4.5 Antibiotic Growth Promoters 77 4.6 Alternatives to Antibiotic Growth Promotors 81 4.7 Conclusions and Future Directions 82 References 83 Chapter 5: Prebiotics with Plant and Microbial Origins 91 5.1 Introduction 92 5.2 Nondigestible Oligosaccharides and Fermentation 92 5.3 Health Benefits and Industrial Use of Prebiotics 93 5.4 Methods of Manufacture 94 5.5 Established Prebiotics 95 5.5.1 Fructans 95 5.5.2 Galactooligosaccharides 97 5.5.3 Lactulose 98 5.6 Candidate Prebiotics 99 5.6.1 Lactosucrose 99 5.6.2 Isomaltooligosaccharides 100 5.6.3 Xylooligosaccharides 100 5.6.4 Polydextrose 101 5.6.5 Bovine- and Human-Milk Oligosaccharides 102 5.7 Prospective Carbohydrate-Based Prebiotics 102 5.7.1 Resistant Starches and Dextrins 103 5.7.2 β-Glucans and Arabinoxylan-oligosaccharides 104 5.7.3 Mannanoligosaccharides 104 5.8 Prospective Noncarbohydrate Prebiotics 105 5.9 Conclusions 105 References 106 Chapter 6: Prospects for Prebiotic and Postbiotic Applications in Poultry 113 6.1 Introduction 114 6.2 Prebiotics: General Concepts 114 6.3 Fructooligosaccharides 115 6.4 Galactooligosaccharides 117 6.5 Xylooligosaccharides 119 6.6 Yeast Cell Wall Components: Prebiotics/Microbiota 120 6.6.1 Chitins 121 6.6.2 β-glucans 121 6.6.3 Mannans 122 6.7 Yeast Fermentation Products as Postbiotics 122 6.8 Conclusions and Future Directions 126 References 127 Part II: Probiotics: Current Status and Future Challenges of Practical Applications 135 Chapter 7: Probiotics in Poultry Preharvest Food Safety: Historical Developments and Current Prospects 136 7.1 Introduction 137 7.2 Foodborne Pathogens Associated with Poultry 137 7.3 Preharvest Control Strategies 138 7.4 Chicken GIT Microbiota 139 7.4.1 Microbiota Changes in Adult Chickens 142 7.5 Probiotics 144 7.5.1 Historical Background 144 7.5.2 Regulatory Considerations of Probiotics 144 7.5.3 Selection Criteria of Probiotic Strains 146 7.6 Potential Mechanisms of Action of Probiotics in Poultry 146 7.6.1 Immune System Stimulation 147 7.6.2 Competitive Exclusion (CE) 147 7.6.3 Alter the Intestinal pH 148 7.6.4 Colonizing Ability 148 7.6.5 Maintenance of Epithelial Barrier Integrity 149 7.7 Applications of Probiotics in Poultry Preharvest Food Safety 150 7.7.1 Introduction 150 7.7.2 Bacteria 150 7.7.3 Yeasts 152 7.7.4 Probiotics and Poultry Management 153 7.7.5 Role of Probiotics: Beneficial Effects 158 7.7.6 Commercial Probiotic Supplements 158 7.7.7 Probiotics’ Inconsistent Responses 160 7.8 Future Directions 160 7.9 Conclusions 161 References 162 Chapter 8: Probiotics and Prebiotics: Application to Pets 176 8.1 Introduction 176 8.2 Probiotics 177 8.2.1 Application of Probiotics in the Pet Industry 177 8.2.2 Probiotic Evaluation In Vitro 178 8.2.3 Probiotic Use in Dogs and Cats 180 8.3 Prebiotics 196 8.3.1 Prebiotic Evaluation In Vitro 196 8.3.2 Prebiotic Use by Dogs and Cats 196 8.4 Synbiotics 228 8.4.1 Synbiotic Evaluation In Vitro 228 8.4.2 Synbiotics in Dogs and Cats 229 8.5 Conclusions 230 References 231 Chapter 9: Direct-Fed Microbial Supplementation and the Swine Gastrointestinal Tract Microbial Population: Current Challenges and Future Prospects 237 9.1 Introduction 238 9.2 Influence of Swine Management Practices on the Gastrointestinal Microbiota 238 9.3 Host–Microbe Interactions 241 9.4 Nutritional Impacts on Swine Gut Microbial Populations 244 9.5 Direct-Fed Microbials and Swine Response 246 9.6 Probiotics as Protection Against Gastrointestinal Pathogens in Swine 249 9.7 The Future of Direct-Fed Microbial Use in Swine Production 251 References 251 Chapter 10: Finfish Microbiota and Direct-Fed Microbial Applications in Aquaculture 256 10.1 Introduction 256 10.2 Current Understanding of the Homeostatic Microbiota of Fishes 258 10.2.1 Physiological Function of Fish Microbiota 259 10.2.2 Factors Influencing the Fish Microbiota 261 10.2.2.1 Host-Associated Factors 262 Host Phylogeny 262 Host Ontogeny 262 Host Body Site 264 Host Immunity 264 Host Trophic Level 266 10.2.2.2 Environmental Factors 267 Diet and Feeding Pattern 267 Environmental Microbiota 268 Physiochemical Properties 269 Interindividual Variations 270 10.3 Manipulating Fish Microbiota: Current Status of DFMs in Aquaculture 271 10.3.1 Bibliometric Analysis of Aquaculture Finfish Probiotic Literature 272 10.3.2 Probiotics Used in Aquaculture 274 10.3.2.1 Gram-Positive Bacteria 274 10.3.2.2 Gram-Negative Bacteria 280 10.3.2.3 Synbiotics 280 10.3.2.4 Yeast 281 10.3.3 Known Effects of Probiotics on Fish Performance 282 10.3.4 Important Considerations for the Future Selection of Probiotics for Aquaculture 286 10.3.4.1 Safety of the Host and the Environment 286 10.3.4.2 Route of Delivery 287 10.3.4.3 Host Colonization and Persistence 289 10.4 Future Directions for DFM Strategies in Aquaculture 290 10.5 Conclusion 293 References 294 Chapter 11: Practical Applications of Probiotics in Beef Cattle Production 308 11.1 Introduction 309 11.2 Challenges Facing Beef Production 310 11.3 Direct-Fed Microbials/Probiotic-Type Approaches: Definitions 312 11.4 Pathogen Reduction 316 11.5 Other Pathogen Issues 317 11.6 Focusing on Carcass Quality 318 11.7 Conclusions 319 References 320 Chapter 12: Current Status of Practical Applications: Probiotics in Dairy Cattle 330 12.1 Introduction 330 12.2 Why Are DFMs Used in Cattle? 331 12.3 Which DFMs Are Used in Dairy Cattle? 332 12.4 How Does DFM Feeding Benefit Dairy Cattle? 334 12.5 Effects of DFMs on Dairy Cattle Production and Performance 335 12.6 Health Benefits of DFMs 337 12.7 Food Safety Benefits of DFMs 339 12.8 DFM Modes of Action 339 12.9 Conclusions 340 References 341 Index 353