LAUSR

Simple Summary The aim of this study is to investigate the relationship between fecal microbiota and the backfat thickness of pigs by 16S rRNA gene sequencing. Our study found that there were significant differences in the composition of microbiota at the species level, characterized by a higher abundance of Lactobacillus reuteri (L. reuteri) in pigs with low-backfat thickness. Additionally, functional profiling of microbial communities indicated that the isoquinoline alkaloid biosynthesis, arachidonic acid metabolism, and styrene degradation were significantly different between low- and high-backfat thickness groups. Furthermore, feeding L. reuteri reduced the intake-to-gain ratio and had the potential to reduce backfat thickness. These findings show that microbiota could alter the production performance of pigs. Abstract The backfat thickness of pigs not only affects the physical properties and taste of meat, but it also closely relates to the reproduction performance of sows. Accumulating evidence indicates that, apart from genetic factors, gut microbiota can also modulate the fat deposition and muscle growth. However, the differential microbiota in pigs with different backfat thickness, and whether microbiota affects backfat thickness, remains elusive. Firstly, 16S ribosomal RNA (16S rRNA) gene sequencing was performed on 62 fecal samples from pigs with different backfat thicknesses, and the compositions of microbiota among different groups with different backfat thicknesses were different. The abundance of Lactobacillus. reuteri (L. reuteri) and Prevotella sp RS2 was significantly higher in pigs with low-backfat thickness than that in pigs with middle and high-backfat thickness; meanwhile, the abundance of Desulfovibrio piger was significantly lower (p < 0.05) in pigs with low-backfat thickness. Furthermore, the functional profiling of microbial communities suggested that the abundance of isoquinoline alkaloid biosynthesis and styrene degradation were significantly lower (p < 0.05) in the low-backfat thickness group than that in middle and high-backfat thickness groups. Finally, L. reuteri fed to Meishan piglets was capable of improving the production performance and had the potential to reduce backfat thickness. This study provides new evidence that microbiota can regulate the phenotype of the host, and dietary supplementation with L. reuteri can improve the production performance of piglets.