Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 9/18/2023
Publication Date: N/A
Interpretive Summary: Stress management is a ubiquitous challenge across the diverse production environments of food animals in the 21st century. That monogastric and ruminant producers often share concern regarding the effect of the same environmental stressor on animal gut health highlights conserved pathways of stress adaptation across both mammalian and avian food animal species. The remarkable integration of an animal’s physiology and its microbiota, which are the collection of bacteria in the animal's gut, produce and respond to key stress-related neuroendocrine hormones once thought exclusive to the host, presents the novel understanding that host stress response relies on interaction between microbe and host (i.e. the animal). As a result, stress reduction strategies used in poultry and livestock production systems are increasingly designed to target the animal’s microbiota. Likewise, feeding and nutrition are now seen as important not only to animal gut health but also to cultivating and maintaining a beneficial microbiota Yet, much remains to be understood regarding the mechanisms of neuroendocrine bi-directional communication that govern, in part, the food animal microbiota-gut-brain and other physiological axes that intimately link the microbiota and animal physiology. Neurophysiological mechanisms of host-microbe interaction that are immediately relevant to aspects of the host stress response hold promise for the improvement of gut health in food animal species. Likewise, the extent to which the tight association between host and microbe mediates stress response to alter stress-induced changes in host behavior may hold implications for food animal welfare. In this chapter, we discuss the role of neurochemical-based host-microbe cross communication in mediating the effects of environmental stress on food animal gut health, with special attention towards poultry, and present suggestions how this may inform the development of next-generation feed and microbiota strategies in food animal production.
Technical Abstract: Environmental pressures due to climate change represent an omnipresent threat across the diverse production phases of food animals in the 21st century. Research directed at mitigating the deleterious effects of environmental stress, including heat stress, on the gastrointestinal tract, necessitates the identification of mechanistic pathways amenable to modulation by the producer. The research approach we have employed has its basis in common mechanistic pathways that are shared among diverse forms of environmental stressors. Those pathways principally involve the host’s neurophysiological response to stress as well as the response of the gut microbiota whose composition and function are critical to gut homeostasis and animal well-being. Most critically, it is the intersection of these two seemingly disparate fields, neurophysiology and microbiology, and the bi-directional communication between both, that is at the core of our approach to devising new strategies to combat environmental stressors in food production animals. The remarkable integration of an animal’s neurophysiology and its microbiota is due to the evolutionary-based fact that each shares a range of neurochemicals, principally those related to the stress response, that permit bi-directional communication between the two that ultimately influences host gut function. This bi-directional communication is facilitated, in part, by the enteric nervous system which is composed of neurons that innervate the intestinal wall producing neurochemicals and sensing the microbiota. This chapter will focus on the gut of the animal as the anatomical region where the host and microbiota interact and represents the area that can most easily be leveraged to deal with environmental stressors. As will be discussed, the design of new feed formulations that seek to manage the intersection of the host neurophysiology and microbiota is one of the most promising avenues for dealing with the negative effects of environmental stress on food production animal health.