Abstract
Many reports on the effect of condensed inorganic phosphates fed to growing rats at the P/Ca ratio of above 1.5.
The experiment was conducted by feeding weanling male rats (Fisher strain, 4 weeks old) a diet containing phosphorus at P/Ca ratio of 0.7 using only Na2HPO4 as orthophosphate or Na5P3O10 as a phosphorus source and the following result was obtained.
1) Phosphorus of tripolyphosphate was utilized almost equally to that of orthophosphate.
2) Mean feed intake and body weight gain of rats fed tripolyphosphate were lower (p<0.05) than the control group fed orthophosphate. No difference was observed between the two groups in the feed efficiency and the protein efficiency ratio.
3) The mean lung weight was lower (p<0.05) in the group fed tripolyphosphate than in the control group, but no inter-group difference was observed in the mean weight of thymus, heart, liver, spleen, kidney, adrenal gland and testis respectively.
4) There were no inter-group differences in the mean weight of femur as well as that of tibia and fibula.
5) Calcium excretion (p<0.05) in the feces and urine in the group fed tripolyphosphate was greater than in the control group, resulting in a lower calcium retention (p<0.05) in the treated group.
6) No significant inter-group differences were observed in the apparent absorption of calcium, magnesium and iron, even though it was lower in the treated group than the control group.
