The Microbiota-Gut-Brain Axis During Heat Stress in Chickens: A Review

Abstract

Heat stress is a global issue for the poultry industries with substantial annual economic losses and threats to bird health and welfare. When chickens are exposed to high ambient temperatures, like other species they undergo multiple physiological alterations, including behavioral changes, such as cessation of feeding, initiation of a stress signaling cascade, and intestinal immune, and inflammatory responses. The brain and gut are connected and participate in bidirectional communication via the nervous and humoral systems, this network collectively known as the gut-brain axis. Moreover, heat stress not only induces hyperthermia and oxidative stress at the gut epithelium, leading to impaired permeability and then susceptibility to infection and inflammation, but also alters the composition and abundance of the microbiome. The gut microflora, primarily via bacterially derived metabolites and hormones and neurotransmitters, also communicate via similar pathways to regulate host metabolic homeostasis, health, and behavior. Thus, it stands to reason that reshaping the composition of the gut microbiota will impact intestinal health and modulate host brain circuits via multiple reinforcing and complementary mechanisms. In this review, we describe the structure and function of the microbiota-gut-brain axis, with an emphasis on physiological changes that occur in heat-stressed poultry.

Biological aspects of phage therapy versus antibiotics against Salmonella enterica serovar Typhimurium infection of chickens

“…Gut microbiota plays a crucial role in the physiology of chickens and disturbances in the composition of the gut microbiome may cause serious disorders ( Zhou et al., 2021 ), not only withing the gastrointestinal tract but also in other organs, including the central nervous system ( Cao et al., 2021 ). In fact, although previous works on the use of phage therapy in chickens focused solely on testing the presence of certain pathogenic bacteria and/or specific symptoms in birds, recent studies indicated the importance of investigating microbiomes during and after specific treatment procedures ( Clavijo et al., 2022 ; Lorenzo-Rebenaque et al., 2022 ).…”

Effects of Dietary Macleaya cordata Extract on Growth Performance, Biochemical Indices, and Intestinal Microbiota of Yellow-Feathered Broilers Subjected to Chronic Heat Stress

“…The composition and function of the gut microbiota are critical to host health [ 8 ]. The gut microbiota can also influence the brain–gut axis to regulate host metabolic homeostasis, health, and behavior through microbiota-derived metabolites, hormones, and neurotransmitters [ 9 ]. Therefore, the regulation of gut microbiota homeostasis by inhibiting oxidative stress and/or inflammation in organisms is important for preventing and/or treating HS.…”

Heat Stress Affects Jejunal Immunity of Yellow-Feathered Broilers and Is Potentially Mediated by the Microbiome

“…Gut microbiota homeostasis is critical for eliminating pathogens, maintaining intestinal epithelial integrity, and regulating mucosal immunity in the GIT ( Cao et al, 2021 ). Existing studies have primarily focused on the effect of HS on the hindgut microbiota of broilers and analyzing the role of microbiota in mediating small intestinal health ( Patra and Kar, 2021 ; Yadav et al, 2021 ).…”