This collection features four peer-reviewed reviews on developing immunity in poultry. The first chapter discusses the advances in genetic, genomic and functional genomic studies of immune and disease resistance in chickens. The chapter reviews multi-trait selection experiments and considers the potential trade-offs between production and immunocompetence in response to disease. The second chapter reviews the importance of the gut microbiome in optimising animal health and reducing susceptibility to major diseases affecting poultry production. The chapter examines intestinal immunity, as well as the microbiota interactions which occur within the poultry immune system. The third chapter addresses the nutritional strategies which can be implemented to boost immune function in poultry. The chapter considers the process of nutritional modulation and reviews the use of vitamins, minerals and amino acids to enhance, suppress and balance poultry immune systems. The final chapter provides an overview of the avian defence system and its role in tackling some of the major pathogens affecting global poultry production, such as coccidiosis. The chapter reviews the various elements of the host defence system and considers how supplements can modulate the immune system and its responses to specific challenges.

This work sheds new light on the interplay between the gut, gut microbiota, and host physiological processes in production animals. The gut microbiome shapes health and susceptibility to disease and has become a leading area of research in the animal sciences. Gut health encompasses a number of physiological and functional features. Nutrient digestion and absorption, host metabolism and energy generation, a stable microbiome, mucus layer development, barrier function, and mucosal immune responses; all of which are required to interact to make an animal perform physiologically and according to its greatest genetic potential. This carefully presented book broadens our vision, approach and results on gut health and the ability to regulate animal production. Understanding the chemistry of microbiomes has broad implications, including providing functional annotations for the microbial genomes, insights into the chemical languages that link microbes to each other and to their host, and translational implications for precision veterinary medicine, environmental health, and sustainable animal agriculture and welfare. Experts working in microbiome research, host immunity, and animal production, veterinarians and researchers in livestock science will understand the great importance of this volume.