Revealing the combined effects of lactulose and probiotic enterococci on the swine faecal microbiota using 454 pyrosequencing.

Demand for the development of non-antibiotic growth promoters in animal production has increased in recent years. This report compared the faecal microbiota of weaned piglets under the administration of a basal diet (CON) or that containing prebiotic lactulose (LAC), probiotic Enterococcus faecium NCIMB 11181 (PRO) or their synbiotic combination (SYN). At the phylum level, the Firmicutes to Bacteroidetes ratio increased in the treatment groups compared with the CON group, and the lowest proportion of Proteobacteria was observed in the LAC group. At the family level, Enterobacteriaceae decreased in all treatments; more than a 10-fold reduction was observed in the LAC (0.99%) group compared with the CON group. At the genus level, the highest Oscillibacter proportion was detected in PRO, the highest Clostridium in LAC and the highest Lactobacillus in SYN; the abundance of Escherichia was lowest in the LAC group. Clustering in the discriminant analysis of principal components revealed distinct separation of the feeding groups (CON, LAC, PRO and SYN), showing different microbial compositions according to different feed additives or their combination. These results suggest that individual materials and their combination have unique actions and independent mechanisms for changes in the distal gut microbiota.