Preharvest Food Safety – Potential Use of Plant-derived Compounds in Layer Chickens

With concerns in the use of antibiotic growth promoters in poultry agriculture, alternative strategies that ensure sustainability of the industry in producing safe poultry meat and eggs are important. Among the food-borne pathogens transmitted through poultry products, Salmonella poses a significant health hazard, with contaminated eggs serving as a major vehicle of the pathogen in causing human infections. Egg-laying chickens serve as an important reservoir of Salmonella, where it can colonize various parts of the intestinal tract and other vital organs, thereby underscoring the need for controlling the bacterium in birds. Plant-derived compounds (PDCs), an emerging class of natural and environmentally friendly antimicrobials have been investigated for their antimicrobial benefits in animal-derived foods, including eggs. However, their use as feed supplements in live chickens for controlling pathogens and improving gut health has gained momentum only recently. This chapter focuses on the potential use of PDCs in layer chickens for improving preharvest food safety. Scientific data on existing, new, and/or emerging PDCs that have potential use in layers for controlling Salmonella are discussed along with their classification, sources, and possible mechanisms of action. A discussion of in vivo studies on the effects of PDCs on layer performance, intestinal health, and gut microbiome is also included. In addition, challenges in experimental research involving PDCs and factors affecting the applicability of PDCs in commercial layer diets, including economic viability and palatability issues, with suggested mitigation methods are presented.