Nutritional regulation of gut health through the gastrointestinal tract microbiota in weaning piglets

Piglets experience stresses that impact intestinal homeostasis and result in a high incidence of diarrhoea and reduced growth performance during weaning. Recent studies have indicated that gastrointestinal tract microbiota can be nutritionally regulated in ways that can benefit and promote gut health in weaning piglets. In this review, we discuss different components of nutrition and their effects on microbial populations, diversity, and activity and, in turn, how these altered microbial structures and activities affect gut health in weaning piglets. In addition, we discuss some of the inner mechanisms through which microbiota regulate and exert their effects on gut health, focusing particularly on adaptive and innate immunity, inflammatory responses and intestinal barrier integrity. Most of the mechanisms involve the TLR and NF-kB signalling pathways, and miRNA regulation. An understanding of the effects of nutritional regulation of microbiota on gut health and its underlying mechanisms can be applied in developing nutritional regimens that promote beneficial microbial structures for gut health.