The concentrations of TRAP by ELISA detection. In the group B, the concentrations of TRAP were mounting steadily during the experimental periods. Compared with the group N, the concentrations increased significantly in the group B, but no significant in the group A. There were significant difference between group A and B. (P < 0.05: # vs. group N; ★ vs. group A; P < 0.01: * vs. group N; Δvs. group A).