Colonic Microbiota Improves Fiber Digestion Ability and Enhances Absorption of SCFAs in Hainan Local Pigs

Abstract Background Compared to commercial breeds, Chinese local pig breeds have a greater ability to digest dietary fiber, which may be due to differences in intestinal microbiota. Previous studies on the adaptation of dietary fiber either considered only feed factors or breed factors. Therefore, this study took both of these factors into consideration for the experimental design in order to explore the potential causes of high dietary fiber adaptation of Ding’an pigs. Results Compared with commercial pigs, Ding’an pigs have a stronger ability to digest dietary fiber. Prevotella was more prevalent in Ding’an pigs than in DLY pigs, which may be an important reason for the stronger ability of fiber degradation in Ding’an pigs. When the effects of feed and breed factors are considered, differences in abundance of 31 species and 14 species, respectively, may result in a greater ability of fiber degradation in Ding’an pigs. Among them, Prevotella. sp. CAG:520 may be a newly discovered bacterium related to fiber degradation, which positively correlated with many fiber-degrading bacteria. We also found that the concentration of plant metabolites with anti-inflammatory and antioxidant effects was higher in the colonic chyme of Ding’an pigs after increasing the fiber content, which resulted in down-regulated expression of inflammatory factors in colonic mucosa. Spearman’s correlation coefficient revealed a strong correlation between microbiota and apparent digestibility of dietary fiber. The mRNA expressions of SLC16A1 , PYY and GCG were significantly increased in the colonic mucosa of Ding’an pigs fed on high-fiber diets, which indicates that Ding’an pigs have an enhanced absorption of SCFAs. Conclusions Our results suggested that an appropriate increase in dietary fiber content can reduce the inflammatory response and improve feed efficiency in Ding'an pigs, and differences in the intestinal microbial composition may be an important reason for the difference in the fiber degradation capacity between the two breeds of pigs.