This collection features five peer-reviewed reviews on dietary supplements in poultry nutrition. The first chapter reviews latest research on feed enzymes focussing on identifying the key challenges researchers face in terms of current trends in enzyme development, mechanism(s) of action and enzyme efficacy. The second chapter considers the role of probiotics in optimising gut function in poultry. It reviews the development of novel, cost-effective, feed-stable, direct-fed microbials with potential for widespread utilisation and improved production. The third chapter discusses the role of essential oils and botanicals in improving gut function in poultry, focussing on four major functions of phytobiotics that could potentially contribute to gut health: digestive conditioning, antimicrobial property, immunomodulation and gut microbiota modulation. The fourth chapter considers the development of alternative protein sources for poultry nutrition, including grain by-products, pulses and algae. It also reviews best practices for improving the nutritive value of these alternative protein sources. The final chapter reviews the effects of supplemental full- or de-fatted microalgal biomass in poultry diets on animal production and performance, meat and egg qualities, as well as nutrient metabolism and molecular responses.

This collection features three peer-reviewed literature reviews on pre- and probiotics in poultry production. The first chapter summarises the safety and efficacy of individual monocultures for prophylactic and/or therapeutic efficacy against Salmonella infections in poultry under both laboratory and field conditions. The chapter also considers the development of novel, cost-effective, feed-stable, direct-fed microbials with potential for widespread utilisation and improved production, delivery and clinical efficacy for animal use. The second chapter discusses the establishment of prebiotics as a series of feed compounds that serve as specific substrates for gastrointestinal tract (GIT) bacteria. The chapter reviews the impact of prebiotics on bird health, GIT function, and prevention of foodborne pathogen GIT colonization. Particular attention is drawn on the impact of prebiotics on the avian intestinal microbiome, cecal microbiome and the avian upper GIT. The final chapter considers current concerns surrounding the application of probiotics in poultry production, primarily due to mixed experiences of their effectiveness and lack of knowledge regarding the scientific basis for their modes of action. In contrast, prebiotics have been readily accepted by the sector. This chapter summarises recent research on the effects of both types of treatment, their possible modes of action, as well as the strengths and limitations of their use.