ABSTRACT: Fully understanding the dynamic distribution of the gut microbiota in pigs is essential, as gut microorganisms play a fundamental role in physiological processes, immunity, and the metabolism of nutrients by the host. Here, we first summarize the characteristics and the dynamic shifts in the gut microbial community of pigs at different ages based on the results of 63 peer-review publications. Then a meta-analysis based on the sequences from 16 studies with accession numbers in the GenBank database is conducted to verify the characteristics of the gut microbiota in healthy pigs. A dynamic shift is confirmed in the gut microbiota of pigs at different ages and growth phases. In general, Bacteroides, Escherichia, Clostridium, Lactobacillus, Fusobacterium, and Prevotella are dominant in piglets before weaning, then Prevotella and Aneriacter shift to be the predominant genera with Fusobacterium, Lactobacillus, and Miscellaneous as comparative minors in postweaned pigs. A number of 19 bacterial genera, including Bacteroides, Prevotella, and Lactobacillus can be found in more than 90% of pigs and three enterotypes can be identified in all pigs at different ages, suggesting there is a "core" microbiota in the gut of healthy pigs, which can be a potential target for nutrition or health regulation. The "core" members benefit the growth and gut health of the host. These findings help to define an "optimal" gut microbial profile for assessing, or improving, the performance and health status of pigs at different growth stages. IMPORTANCE The ban on feed antibiotics by more and more countries, and the expected ban on ZnO in feed supplementation from 2022 in the EU, urge researchers and pig producers to search for new alternatives. One possible alternative is to use the so-called "next-generation probiotics (NGPs)" derived from gastrointestinal tract. In this paper, we reveal that a total of 19 "core" bacterial genera including Bacteroides, Prevotella, and Lactobacillus etc., can be found in more than 90% of healthy pigs across different ages. These identified genera may probably be the potential candidates of NGPs or the potential target of microflora regulation. Adding substrates preferred by these target microbes will help to increase the abundance of specific symbiotic species and benefit the gut health of pigs. Further research targeting these "core" microbes and the dynamic distribution of microbiota, as well as the related function is of great importance in swine production.
