Comparative study of heat stress responses in chickens and fish: elucidation of cross-species mechanisms of immunity and metabolism

As the global population continues to grow, the demand for protein is increasing correspondingly. However, increasing ambient temperatures affect the performance of temperature sensitive animals, such as broiler chickens and fish, and persistent high temperatures may cause heat stress (HS). HS represents an abiotic constraint on high-efficiency poultry and aquaculture systems,. The intestine is the first organ to be irreversible damaged by HS in both broilers and fish. HS-induces increased mucosal permeability and subsequently, facilitates translocation of pathogenic bacteria, bacterial components and their metabolites, followed by systemic inflammation. The mechanism behind the HS induced effects on the host intestine and gut microbiota are still unknown, as is the relationship between the changed microbiota composition (dysbiosis) and the intestinal function of the host. To address these gaps, our study aims to 1) clarify how HS compromises the gut barrier function and host–microbe crosstalk in both broilers and fish at the molecular and cellular level; 2) how HS induced changes affect the subsequent immune response and metabolism; 3) identify probiotic strains and their key bioactive metabolites capable of restoring microbial homeostasis, reinforcing epithelial integrity, and ameliorating HS-induced performance losses; 4) identify the signalling pathways of the key bioactive metabolites on improving intestinal function and maintaining gut microbiota. In this project, in vivo models (conventional and germ-free animals models), will be employed in combination with omics technologies to investigate the HS induced effect on the immune response and metabolism of the host. Besides, intestinal structure and function, accompanied with 16S rRNA sequencing data, will be used to determine the correlation. Subsequently, the causation between intestinal dysfunction and immune response/metabolism will also be determined through germ-free model. Finally, potential probiotic and its bioactive metabolites will be screened, characterized, and validated for their effects in ameliorating HS in vivo.