Conclusion: SYN exerted a synergistic effect on bone mineralization, presumably due to changes in gut microbiota and ecology associated with large bowel digesta weight (most likely reflecting microbial mass) and with large bowel weight (reflecting absorptive area), while bone turnover tended to be reduced as indicated by BAP.© 2016 The Authors. Published by Elsevier GmbH. This is an open access article under the CC BY-NC-ND license