Abstract
The effects of whey mineral complexes (WMC1 and WMC2) on bone metabolism were studied in male growing rats. The contents of Ca, P, and protein in WMC 1 were 18.2, 8.4, 2.3%, respective-ly, whereas those of WMC2 were 26.4, 14.6, and 10.5%, respectively. WMCs were added to diets as a sole source of Ca: the levels of dietary Ca were 0.3 and 0.6%. CaCO3 was used as a reference. There was no difference in body weight gain and quantitative values for Ca balance among the groups at the same level of dietary Ca. Rats fed WMC2 had a higher femoral Ca and bone density of humerus. The bone properties in rats fed WMC 1 were not as high as those in rats fed WMC2. The P absorption and absorption rate were affected significantly by the type of dietary Ca source as well as the levels of dietary Ca. The percent of tubular reabsorption of P of rats fed WMC1 or WMC2 had a tendency to be higher than that of rats fed CaCO3 at each dietary Ca level. The results of urinary cAMP excretion showed that the parathyroid hormone func-tion in rats fed WMC2 was relatively lower. The differences in minerals and other constituents between WMC1 and WMC2 are discussed from the viewpoint of bone metabolism.
