Correlation between fat accumulation and fecal microbiota in crossbred pigs.

Backfat thickness (BF) is an important indicator of fat deposition capacity and lean meat rate in pigs and is very important in porcine genetics and breeding. Intestinal microbiota plays a key role in nutrient digestion and utilization with a profound impact on fat deposition of livestock animals. To investigate the relationship between the pig gut microbiome and BF, 20 low-BF (L-BF) and 20 high-BF (H-BF) pigs were selected as two groups from Yunong Black pigs in the present study. Fecal samples from pigs were analyzed for microbial diversity, composition, and predicted functionality using 16S rRNA gene sequencing. The results showed that there were significant differences in microbial β diversity between the two groups. LEfSe analysis revealed a number of bacterial features being differentially enriched in either L-BF or H-BF pigs. Spearman correlation analysis identified the abundance of Oscillospira, Peptococcus, and Bulleidia were significantly positive correlations with BF (P < 0.05), while Sutterella and Bifidobacterium were significantly negatively correlated with BF (P < 0.05). Importantly, the bacteria significantly positively correlated with BF mainly belong to Clostridium, which can ferment host-indigestible plant polysaccharides into short-chain fatty acid (SCFA) and promote fat synthesis and deposition. Predictive functional analysis indicated that the pathway abundance of cell motility and glycan biosynthesis were significantly widespread in the microbiota of the H-BF group. The results of this study will be useful for the development of microbial biomarkers for predicting and improving porcine BF, as well as for the investigation of targets for dietary strategies.