STUDIES ON MILK-SUBSTITUTES Ⅵ Absorption and Retention of Nitrogen, Calcium, and Phosphorus of Soybean Milk-substitute by Infants / 营养学报

ABSTRACT

Previous feeding experiments on infants have shown that the growth promoting effect of the milk-substitute 5410 was comparable to that of hu- man milk or a milk powder diet. In order to know more about the biochemical and physiological properties of this mixture, nine male infants were put in serial metabolic studies with respect to the digestion, nitrogen, calcium and phosphorus utilization of this soybean product.The age of the infants were 37-77 days at the beginning of the experiment, and 6-7 months at the end. The infants were fed with the milk-substitute and a milk powder diet in alternative periods each of which lasted 2-4 weeks. In the first and second periods the infants were fed milk powder or milk-substitute alone, while in the third and forth periods the same diets were supplemented with concentrated cod liver oil, and in the fifth period the infants were fed with another soybean product similar to mixture 5410 but with higher protein content.The digestibility of protein and the absorption of nitrogen, calcium and phosphorus of mixture 5410 were significantly lower than those of the milk powder diet. However, the nitrogen retention were the same during these two dietary periods (191 and 196 mg per kilo per day). The calcium and phosphorus retention were signigicantly lower during periods without cod liver oil (24 and 24 mg per kilo per day) but improved markedly after supplementation (58 and 36 mg per kilo per day).On the average, each infant received from the milk-substitute 4.3g of protein per kilo per day. The amount of calcium ingested was 850 mg per day; it seems to be that supplementation with cod liver oil is necessary for adequate calcium retention at this level of intake.Raising the protein content of the milk-substitute by further addition of soybean powder may increase the nitrogen retention, but it tends to lower the absorption and retention of calcium and phosphorus due to increased amount of fecal excretion.