Livestock production is changing worldwide. Amongst the changes are those instigated by legislation such as restrictions on antibiotics and antibiotic growth promoters, well fare regulations, etc., all forcing livestock producers to adapt to new husbandry, management, nutrition and healthcare techniques. Food safety is an explosive political issue. The expectations and demands of the informed consumer have altered perceptions of risk and brought food safety to the very front and centre of politics. The gastrointestinal tract is essential in the maintenance of health, wellbeing and production in livestock. The above changes impact feed formulation. The industry looks for alternatives to maintain intestinal health and maximise animal performance, whilst complying with increasingly stringent legislation. This requires a good understanding of the physiological processes involved.In this book, the current knowledge in the major monogastric production species (pigs and chicken) is reviewed by renowned experts in the field. It describes infectious and non-infectious challenges as well as the complex interaction between innate, cellular and humoral immunity and performance. The problems that this complexity poses concerning the identification of important factors for intestinal health are discussed. 'Intestinal health' also reviews promising new approaches such as the use and development of validated biomarkers, and the application of omics techniques and systems biology.