NUTRITION AND HEALTH: COMPANION ANIMAL APPLICATIONS: Functional nutrition in livestock and companion animals to modulate the immune response

Advances in the understanding of how the immune system functions in response to diet have altered the way we think about feeding livestock and companion animals on both the short (weeks/months) and long-term (years) timelines; however, depth of research in each of these species varies. Work dedicated to understanding how immune function can be altered with diet has revealed additional functions of required nutrients such as vitamins D and E, omega-3 polyunsaturated fatty acids (PUFA), and minerals such as zinc, while feed additives such as phytogenics and probiotics add an additional layer of immunomodulating potential to modern diets. For certain nutrients such as vitamin D or omega-3 PUFA, inclusion above currently recommended levels may optimize immune function and reduce inflammation, while for others such as zinc, additional pharmacological supplementation above requirements may inhibit immune function. Also to consider is the potential to over-immunomodulate, where important functions such as clearance of microbial infections may be reduced when supplementation reduces the inflammatory action of the immune system. Continued work in the area of nutritional immunology will further enhance our understanding of the power of nutrition and diet to improve health in both livestock and companion animals. This review collects examples from several species to highlight the work completed to understand how nutrition can be used to alter immune function, intended or not.