engleski

Effect of calcium supplementation in sucklings on bone mineral density in adolescent rats

Importance of adequate calcium intake on formation of bone mass has been proved for children and teenagers, but the effect of calcium supplementation during infancy is yet to be established. An increase in peak bone mass by calcium supplementation during skeletal formation may contribute to osteoporosis prevention. We evaluated the effect of calcium supplementation in suckling rats on bone calcium content and essential element concentrations immediately after supplementation period and on bone mineral density (BMD) at the age of 2 months. Forty-eight female suckling rats (Wistar) were artificially fed on cow's milk or on cow's milk supplemented with 6% calcium (as Ca-hydrogen phosphate) to increase the daily calcium intake about 3 times above control values. Treatment lasted 7 hr a day for nine consecutive days, from day 6 through 14 after birth. At the end of supplementation period, 18 sucklings (9 non-supplemented and 9 calcium- supplemented) were killed and calcium concentration in the carcass (whole body after removal of the organs, total gastrointestinal tract, and skin) was analysed by atomic absorption spectrometry. Calcium supplementation was associated with an increase in carcass calcium concentration by about 17% compared to non-supplemented pups. Growth and concentrations of trace essential elements in carcass and organs were not affected. Other 30 suckling rats (15 non-supplemented and 15 calcium-supplemented) weaned on feed with marginal calcium (0.33%) and were fed on the same test diet during 7 weeks. At the end of this period, total body BMD was measured in 2-month- old rats by densitometry using dual energy X-ray absorptiometry (Lunar DPX, Madison, WI, USA) in ketamine and xylazine anesthesia. No difference was found between groups in relation to calcium supplementation during the suckling period. These results confirm findings from our previous investigation in which calcium supplementation during the suckling period had no effect on BMD in 3-month-old female rats fed on either 1% or 0.45% calcium diet. It is concluded that calcium supplementation during the suckling period increases the calcium concentration in bones, but it has no influence on bone mineral density in adolescence, even under condition of marginal calcium intake.

calcium supplementation; suckling rat; bone density

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