Weaning Induced Gut Dysfunction and Nutritional Interventions in Nursery Pigs: A Partial Review

SIMPLE SUMMARY: The beneficial and functional roles of the gut microbiota in maintaining host health are becoming clearer. In general, the swine intestinal bacterial population is predominated by two phyla, Firmicutes and Bacteroidetes, followed by Proteobacteria, Actinobacteria, and Spirochaetes, among others. This general profile is relatively stable, although variations exhibit below the phylum level when the gut microbiota experiences dysbiosis. At weaning, dietary and environmental changes often result in gut microbiota dysbiosis, which is frequently associated with post-weaning diarrhea and enteric infections. A healthy gut microbiota possesses specific capacities involving nutrient metabolism, immunomodulation, controlling inflammation, and maintaining intestinal barrier function and structure. Manipulating the gut microbiota through diet is a useful strategy to attenuate weaning stress and restore microbiota homeostasis. Understanding the interaction between feed additives and gut microbiota would facilitate the development of effective feeding strategies to improve the gut health, growth performance, and well-being of nursery pigs. This review summarizes certain feed additives, which are used to modulate gut microbiota with some success. ABSTRACT: Weaning is one of the most stressful events in the life of a pig. Unsuccessful weaning often leads to intestinal and immune system dysfunctions, resulting in poor growth performance as well as increased morbidity and mortality. The gut microbiota community is a complex ecosystem and is considered an “organ,” producing various metabolites with many beneficial functions. In this review, we briefly introduce weaning-associated gut microbiota dysbiosis. Then, we explain the importance of maintaining a balanced gut microbiota. Finally, we discuss dietary supplements and their abilities to restore intestinal balance and improve the growth performance of weaning pigs.