The Symbiosis Between Nutrition, Intestinal Microbiota and Host Immunity for Animal Health and Production

Within an animal’s interactive physiological networks, the complexity of nutritional interactions is not solely confronted by the host but is made substantially greater since the animal plays host to entire communities of commensal and symbiotic microbes that derive nutrients from the host diet and provide vital nutrients to the host. The gut microbiome is involved in the development, function, and maturation of the host immune cells locally and systemically. Under the influence of diet, the composition of the gut microbiome, as well as the commensal-derived nutrients and metabolites, are altered. These diet-induced shifts in microbiome composition and commensal-derived nutrients and metabolites have profound direct effects on host immunity. Until recently, the interaction between nutrition/diet host immunity has virtually ignored the effect of the gut microbiome. Many studies have concluded a direct effect of a specific nutrient on the immune system without determining the effect on the gut microbiome. Therefore, knowing that diet and commensal microbiota interaction has a remarkable influence on the host immune response, many studies indicating poultry diets and their components directly affect the avian immune response may have to be re-evaluated, since the role of the gut microbiota was not considered. Although much is still to be learned about the microorganisms that comprise the avian gut microbiota, it is paramount that avian nutritionists and immunologists consider the role of the gut microbiota when investigating the role of the diet and dietary components on avian immune function and their effects on health and production.