Comparative analysis of fecal microbial communities and growth traits among Duroc, Landrace and Yorkshire pigs through 16S rRNA gene pyrosequencing

Abstract: Intestinal microorganisms have been shown to be important factors that affect the growth performance of different pig breeds regardless of their genetic background. Therefore, to investigate the effect of the intestinal microflora structure on the growth performance of different pig breeds, samples from Duroc (n=10), Landrace (n=9) and Yorkshire (n=5) pigs under the same diet and feeding conditions were collected. The fecal microbial composition was profiled via 16S ribosomal RNA (rRNA) gene sequencing. At the phylum level, Firmicutes and Bacteroidetes dominated the majority of the fecal microbiota regardless of breed, but the bacterial community compositions differed among these distinct breeds. At the genus level, there were significant differences in 18 bacterial communities between the Duroc and Landrace pigs (P<0.05), 8 communities between Duroc and Yorkshire pigs (P<0.05), and 5 communities between Landrace and Yorkshire pigs (P<0.05). Landrace and Yorkshire pigs harbored similar intestinal flora, whereas Landrace and Duroc pigs were significantly different. The functional prediction results indicated that intestinal microbial species may lead to higher growth and an increased fat accumulation capacity in Landrace pigs than in Duroc pigs. In addition, the results of this study showed that many bacteria had strong interactions with each other. For example, a strong positive correlation between Bacteroidetes and Proteus was observed, which are closely associated with the generation of fat. These results indicate that interactions between bacteria are likely to be important factors leading to phenotypic differences. Finally, it is worth noting that we identified Salinispira as a unique species in the intestinal tract of Duroc pigs. Because few studies on this bacterial genus have been performed, further studies on the function of these bacteria are still needed. The results of the present study provide specific references for follow-up studies on the relationship between intestinal flora and phenotypic traits in pigs. Moreover, the study of the interactions between bacteria provides new directions for subsequent research on the regulation of host phenotypic traits that are influenced by interactions between bacteria.