Review: Microbial endocrinology: intersection of microbiology and neurobiology matters to swine health from infection to behavior

Abstract

From birth to slaughter, pigs are in constant interaction with microorganisms. Exposure of the skin, gastrointestinal and respiratory tracts, and other systems allows microorganisms to affect the developmental trajectory and function of porcine physiology as well as impact behavior. These routes of communication are bi-directional, allowing the swine host to likewise influence microbial survival, function and community composition. Microbial endocrinology is the study of the bi-directional dialogue between host and microbe. Indeed, the landmark discovery of host neuroendocrine systems as hubs of host-microbe communication revealed neurochemicals act as an inter-kingdom evolutionary-based language between microorganism and host. Several such neurochemicals are stress catecholamines, which have been shown to drastically increase host susceptibility to infection and augment virulence of important swine pathogens, including Clostridium perfringens. Catecholamines, the production of which increase in response to stress, reach the epithelium of multiple tissues, including the gastrointestinal tract and lung, where they initiate diverse responses by members of the microbiome as well as transient microorganisms, including pathogens and opportunistic pathogens. Multiple laboratories have confirmed the evolutionary role of microbial endocrinology in infectious disease pathogenesis extending from animals to even plants. More recent investigations have now shown that microbial endocrinology also plays a role in animal behavior through the microbiota-gut-brain axis. As stress and disease are ever-present, intersecting concerns during each stage of swine production, novel strategies utilizing a microbial endocrinology-based approach will likely prove invaluable to the swine industry.

Maternal Microbiota Transfer Programs Offspring Eating Behavior

“…which was significantly more abundant in the F-OR group at weaning and the total fat consumption during taste preference tests is of particular interest given the immunomodulatory potential of some species belonging to this genus (Delgado et al, 2020). Similarly, the correlation that we observe for females between the abundance of cluster 10 (affiliated to Enterobacteriaceae) at PND21 and z-score is intriguing since E. coli synthetize dopamine (see Lyte and Lyte, 2019 for review) while this property is present in less than 5% of the bacterial genomes representative of the human intestinal microbiota (Valles-Colomer et al, 2019). Further investigation of these tracks requires more precise bacterial identification, if possible at the strain level, since differences in physiological effects have been observed at this taxonomic scale, particularly in the case of appetite regulation by the intestinal microbiota (Chagwedera et al, 2019).…”

A Glance at Neurofitness in Nutrition Perspective

“…This two way pathway plays an important role in balancing between neural, hormonal, immunological responses, such as producing cytokines by mucosal immune cells [23]. Nutrients present in the lumen of GI tract and the ecosystem of microbes in the GI tract influences the entero-endrocrine cells responses which designated as the largest endocrine organ in the human body [24]. Figure 2 explains the process of how microbiota interacts with the metabolites to cause CNS disorders [25].…”

Insights into host-microbe interaction: What can we do for the swine industry?

“…Another example in the lexicon of host-microbial cross-talk is tryptophan because of the important physiological implications of microbial metabolism of tryptophan both in the gut and brain ( Lee et al., 2015 ; Roager and Licht, 2018 ). As meat quality and product safety are the priority of the swine industry, the health and welfare of pigs are of universal importance for all swine producers ( Lyte and Lyte, 2019 ). Interestingly, a stable and diverse flora structure is essential for the health and welfare of pigs.…”