Effects of tuna bone and herbal extract on bone metabolism in ovariectomized rats

This study was conducted to examine the effects of herb extract addition on bone metabolism of ovariectomized (OVX) rats fed a diet with tuna bone as a source of calcium. The experimental groups were sham-control (CaCO3 [CC]), OVX-CC (OVX-control), OVX-CC + herb extract, OVX-tuna bone powder (TB), OVX-tuna bone powder + herb extract, OVX-citrated tuna bone powder (CTB), and OVX-citrated tuna bone powder + herb extract (CTBH). The herb extract included Rehmanniae radix and Angelicae gigantis radix, following the prescribed theories of Oriental herb medicine. In the OVX-CTBH group, the level of fecal (33.6%) and urinary calcium excretion (45.8%) greatly decreased compared with the TB groups. Osteocalcin concentrations were significantly lower in the OVX-CC group and higher in the OVX-CTB group. The deoxypyridinoline value was significantly influenced by ovariectomy. It was elevated in all OVX groups compared with the sham group, and it was reduced by 12.8% in rats supplemented with the herb extract. The bone density value per 100-g body weight was lowest in the TB group, and it was higher in the tuna bone powder + herb extract, CTB, and CTBH groups. We concluded that TB can be a good calcium source, and it was effective in maintaining skeletal metabolism of OVX rats when it was fed in the form of citrated or herb extract-supplemented diets.