Metabolism of calcium, phosphorus and magnesium during pregnancy was investigated with 20 primigravida albino rats about 170g body weight of Wister Imamichi strain fed with diets containing Ca 0.534 and 1.077% respectively.
The animals were divided into four groups (A, B, C and D), and in the early period of pregnancy, A and B group were fed with low-Ca diet and C and D group were fed high-Ca diet. In the middle period, A and D group fed with low, and B and C group with high, then in the last period A and B fed with high, and C and D with low Ca diet.
In the early period, calcium retention increased with the amount of calcium intake, therefore the absorption and the utilization of calcium were better in high calcium groups. In the middle and last period, the absorption rate was decreased and the amount of calcium retention of group C was smaller than that of calcium requirement for growth of fetuses.
It seemed that the calcium need to fetuses was removed from the calcium stored in mother rat during the early period of pregnancy.
From these results, it is considered that high calcium feeding in the middle or in the last period of pregnancy have no effect on calcium utilization, therefore it is preferable to feed high calcium diet from the beginning of pregnancy.
Absorption and utilization of phosphorus in diet are affected by it Ca/P ratio, and the rats of high-Ca group utilized P better than that of the low-Ca group
Metabolism of magnesium resembles to that of phosphorus, and high Ca/Mg ratio in diet seems to have good effect on magnesium utilization.
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