Abstract: Objective: To investigate the effects of yak bone powder on the bone density, bone calcium content and bone calcium apparent absorption rate in rats. Method: Seventy female SD rats were divided into 7 groups. The low calcium control group was fed with 1180 mg Ca/kg in diet. The three experiment groups were fed three dosage of yak bone powder, corresponding to 5, 10, 20, times of the recommended dosage for human body. Ca contents in the three groups are respectively 1437, 1852, 2778 mg/kg of diet. For another three groups, Ca contents in the diet were the same as the experiment groups, but using calcium carbonate as control. At the end of the fourth week, calcium metabolic experiment was performed for 3 days. Food intake was recorded and feces were collected for calcium contents assay. Calcium apparent absorption rate was also assayed. Twelve weeks later, bone calcium, bone density, bone length and femur bone weight were all assayed. Result: The results showed that yak bone powder shows higher calcium apparent absorption rate than calcium carbonate. Bones Ca content and bone density in yak bone powder groups are significant and higher than those in the low Ca control group. However, there are no significant differences between yak bone powder group and calcium carbonate group. Conclusion: Yak bone powder may improve bone density and have a higher apparent absorption rate than calcium carbonate.

Key words: yak bone powder, bone calcium, bone density, calcium apparent absorption rate, rat test