The Role of Phytogen Supplementation on the Intestinal Health and Immunity

Antibiotic resistance in livestock production emerges as a significant concern for global public food security. Traditionally antibiotics served as antibiotic growth promoters (AGPs) and prophylactic treatments in animal husbandry. The risk of transmitting antibiotic resistance from animals to humans presents severe health challenges. In response to growing concerns, the search for natural antibiotic alternatives has intensified aiming to overcome the issues of resistance and residue, thus addressing a global health challenge. This thesis investigates the efficacy of Phytogenic Feed Additives (PFAs) as sustainable natural alternatives to antibiotics in livestock production focusing on gut health and its influence on the overall wellbeing of monogastric animals. 

Chapter 1 provides a literature review on current molecular techniques used to study the gut microbiota's role in host health and disease. This chapter investigates how these molecular sequencing techniques have advanced our understanding of the gut microbiota's impact on animal health and evaluates the effectiveness of PFAs in poultry and swine. This chapter aims to give a broad overview of recent research findings, showcasing the potential of PFAs as natural alternatives to antibiotics in livestock production and sets the foundation for the thesis by discussing the relevance of gut health in monogastric animals. In a trial involving 20,000 layer birds, our research documents how PFAs contribute to reducing mortality and enhancing productivity against heat stress and disease challenges (Chapter 2). Similarly, a trial with 200 piglets during the critical weaning phase (weeks 3 to 8) in Chapter 4 and a subsequent study on 400 pigs in the growth-finisher phase (weeks 8 to 17) in Chapter 5 highlights PFAs' role in improving gut health, microbial diversity, and metabolic health. Despite the trials' diverse conditions, PFA-treated animals consistently showed improved health outcomes, such as lower mortality rates in poultry and better weight gain in weaning piglets, alongside a richer microbial diversity and potential metabolic benefits in the growth-finisher pigs. The genomic analysis across these studies in Chapters 3 and 6 reveals PFAs' broad molecular advantages, suggesting their capacity to significantly influence cancer, obesity, diabetes, high blood pressure, tissue repair, liver functionality, and muscle growth. This thesis underlines the potential for promoting sustainable health practices in livestock. It presents a viable way to lessen global health risks and boost animal welfare and productivity.