Study on the microbial diversity and composition at different regions of stomach in adult pigs.

To investigate the microbial composition and diversity across distinct anatomical regions of the porcine stomach, this study took adult "Landrace×Yorkshire" hybrid pigs as the research subjects. Mucosal samples were collected from eight regions, including gastroesophageal groove, gastric fundus, lesser curvature of the gastric body, greater curvature of the gastric body, middle antrum of the gastric antrum, gastric diverticulum, round pillow of the pylorus, and pylorus, and subjected by high-throughput sequencing targeting the microbial 16S rRNA V3-V4 hypervariable regions. The results showed obvious difference in microbial diversity among the eight stomach regions. The gastric fundus and gastric body greater curvature exhibited higher microbial diversity and richness, while the esophageal groove, gastric body lesser curvature, gastric antrum middle section, gastric diverticulum, pyloric bulge, and pylorus showed lower diversity and richness. Firmicutes and Proteobacteria constituted the predominant phyla across all eight regions of the pig stomach. A` relatively high abundance of Cyanobacteria was also detected in the esophageal groove and gastric antrum middle section. However, the dominant genera varied substantially across regions. <i>Lactobacillus</i> predominated in the esophageal groove, fundus, lesser curvature, and greater curvature. <i>Delftia</i> and <i>Chryseobacterium</i> were dominant in the mid-antrum. <i>Bacteroides</i> dominated in the gastric diverticulum and pylorus. <i>Proteus</i> was the dominant genus in the pyloric torus. Further functional analysis of stomach microbiome indicated the regions with the most active metabolic processes and cellular activity within the stomach were the esophageal groove and lesser curvature of the gastric body. These findings provide valuable reference data for future research on the physiological structure and function of the stomach.