Abstract:[Background] In recent years, efforts have been made to protect wildlife and improve the eco-environment. Accordingly, the number of wild boars has been increasing year by year, and it has even exceeded the number of protection in some areas, which has caused a certain impact on agricultural production. Wild boars have strong disease resistance, environmental adaptability, and rich gut microbiota, demonstrating a potential value of improving the quality of domestic pigs. However, there are few reports on the research and development of gut microbiota of wild boars in China. [Objective] To explore the diversity of gut microbiota in wild boars and isolate strains with good probiotic performance from the gut based on the omnivorous habit and disease resistance of wild boars. [Methods] Five feces samples were collected from wild boars, foreign three-way cross hybrid pigs, and commercial pigs of new American pig lines, respectively. Bacillus strains with cellulase activity were isolated from the guts of wild boars and tested for their probiotic properties such as acid tolerance and enzyme production. [Results] The alpha diversity of gut microbiota in wild boars and foreign three-way cross hybrid pigs was higher than that in the pigs of new American pig lines, and the richness of gut microbiota was the highest in wild boars. At the phylum level, Firmicutes, Bacteroidota, and Fusobacteriota had the highest abundance in the guts of wild boars, foreign three-way cross hybrid pigs, and pigs of new American pig lines, respectively. At the genus level, unclassified_f_Lachnospiraceae, UCG-005, Prevotelaceae_NK3B31_group, and Ruminococcus had high abundance in the guts of wild boars. The β diversity clustering analysis results showed that the similarity of gut microbiota between the wild boar samples was the lowest among the three groups of samples. Several strains of Bacillus velezensis isolated from the guts of wild boars exhibited high cellulase and amylase activities and acid tolerance. [Conclusion] The richness of gut microbiota in wild boars is higher than that in commercial pigs, and several strains of B. velezensis isolated from the guts of wild boars have the potential to be developed as probiotic preparations.