Submitted to: Journal of Applied Poultry Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/16/2013
Publication Date: 9/1/2013
Citation: Kogut, M.H. 2013. The gut microbiota and host innate immunity: Regulators of host metabolism and metablic diseases in poultry? Journal of Applied Poultry Research. 22:637-646.
Interpretive Summary: The development of the immune response in baby chicks is controlled by the animal’s gut. This is because the gut is exposed to not only nutrients, but also many germs that can make the baby animals sick. What has been found over the last 20 years is that bacteria that do not cause disease, but normally grow in the gut, can work together to make the baby animals' immune system work better and prevent the bad germs from growing. Changes in the bacteria that grow in the gut of chicks can affect the overall health of the baby chick by affecting the way nutrients are broken down and used by the body. These negative effects on nutrients prevent the normal growth of the baby chick and result in poor growth and reduced egg and meat production. This paper would be beneficial to chicken growers, microbiologists, and nutritionists and will help make better animal feeds that encourage the growth of the normal bacteria in the gut.
Technical Abstract: The gut microbiota represents the multitudes of microbes residing in the intestine and is integral in multiple physiological processes of the host. The endogenous intestinal microflora together with other environmental factors, such as diet, play a central role in immune homeostasis. Moreover, the gut microbiome has been shown to be a key factor involved in host metabolism, body weight, and energy homeostasis. Any immune alteration, specifically inflammation and can cause disturbances in metabolism. Mechanistically, the gut microbiota affects metabolic disorders by two major methods: 1) a chronic innate immune response to the structural components of bacteria, such as lipopolysaccharide, resulting in inflammation, and 2) bacterial metabolites of dietary compounds, such as short chain fatty acids (SCFA), which have biological activities that regulate host functions. Gut microbiota have evolved with the host as a mutualistic partner, but dysbiosis in a form of altered gut metagenome and gut microbial activities, as well as environmental factors, may promote the development of metabolic disorders of poultry. Metabolic systems are integrated with pathogen sensing and immune responses, and these pathways are evolutionarily conserved. Several important networks sense and manage nutrients and integrate with immune and inflammatory pathways to influence the physiological and pathological metabolic states in poultry. Toll-like receptors (TLRs) of the innate immune system, which are found on immune cells, intestinal cells, and adipocytes, play an essential role in the complex balance ensuring immune and metabolic health. This review will provide a hypothesis based on human studies as a model on how nutrient-derived factors (mostly focusing on fatty acids and glucose) could impact the avian innate immune system, including the gut immune system and its associated gut microbiota and how the functional and molecular integration of the immune and metabolic systems may be a crucial homeostatic mechanism for host metabolism, the dysfunction of which may trigger many metabolic disorders of poultry.