Gut Microbiota, Immune System, and Health in Animals

Dear Colleagues,

The gastrointestinal (GI) tract is the largest immunological organ; it plays a central role in regulating the host immune system and homeostasis. The gut microbiota (GM) refers to all of the commensal, symbiotic, and pathogenic microorganisms inhabiting the GI tract, including bacteria, archaea, fungi, viruses, and phages. Interactions between the commensal GM and the host contribute to the maturation of the host immune system, thus modulating its systemic response. Alongside local immune responses in the gut, the GM can interact with non-enteral cells such as immune cells (including immunosuppressive and inflammatory cells), myocytes, and hepatocytes. These cells can express different receptors for GM metabolites. Alterations of the gut microbiota—induced by metabolites such as short-chain fatty acids (SCFAs), bile acids (BAs), and tryptophan (Trp)—have been found in many immune-related diseases.

Further, nutrition (i.e., the diet) can impact the composition of the GM and the immune system; thus, we acknowledge the intricate interactions between nutrition, GM, the immune system, and host health. On this basis,  using antibiotics as feed growth promoters in livestock is forbidden; this ruling is crucial for ensuring the immunity of farm animals (including but not limited to pigs, broilers, sheep, and cattle).

The main aim of this Special Issue is to collate high-quality submissions that highlight emerging findings related to nutrition, GM, host immunity, and animal health, as well as the intricate interplay of diets, GM, and host homeostasis.

Topics of interest include but are not limited to the following:

• Nutrition–GM interactions: diet alterations, gut microbiota composition and function;
• Diet alterations, changes in GM metabolites, and the host–GM metabolite axis;
• GM metabolites and host metabolism;
• GM metabolites and host immunity/immune responses;
• Swine health: piglet weaning, regulation and healthy breeding;
• Broiler health: nutritional/environmental factors, intestinal health, and regulation of the host metabolism;
• Healthy breeding of livestock animals and enhancing immunity.

Dr. Bao Yi
Dr. Ruqing Zhong
Dr. Yue Hao
Dr. Wei Si
Guest Editors

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• gut microbiota
• animal health
• immunity
• nutrition
• metabolites
• short-chain fatty acids
• bile acids
• immune cells
• inflammation