Dietary zinc effects on zinc, calcium, and magnesium content in bones of growing rats.

The aim of the present study was to assess dietary zinc effects on femur weight and mineral content in growing rats. For this purpose, 70 weanling Sprague-Dawley rats were divided into four groups. Each group was subject to a diet containing 2 (BZ), 5 (DZ), 10 (MZ), and 30 (CZ) ppm zinc. The calcium and magnesium content in all diets was 5 g/kg and 507 mg/kg, respectively. The animals were kept on this regime for 28 d and then sacrificed and their femurs were removed for analysis using atomic absorption spectrophotometry. The weights of the BZ and DZ groups were significantly different from the MZ and CZ groups (38.5+/-10.5, 89.9+/-13.7, 118.6+/-13.6, and 134+/-19.9 g, p<0.01) respectively. There were no differences between the MZ and CZ groups. Femur weight also varied with dietary zinc, as it was significantly different among all groups (BZ, 265+/-49 mg; DZ, 380+/-40 mg; MZ, 452+/-54 mg; CZ, 735+/-66 mg; p<0.01). The femur zinc content varied with diets, following a different pattern than the above parameters. Femur zinc from the BZ group (51.5+/-5.4 ppm) was significantly different from the MZ and CZ groups (115.9+/-14.2 and 175.0+/-13.5 ppm, respectively), whereas the DZ group (62.5+/-11.3 ppm) did not differ from the other three groups. The femur content of calcium (BZ, 83.2+/-9.8 mg/g; DZ, 88.0+/-9.2 mg/g; MZ, 90.2+/-13.6 mg/g; CZ, 83.1+/-14.7 mg/g) and magnesium (BZ, 1.82+/-0.13 mg/g; DZ, 1.98+/-0.09 mg/g; MZ, 1.93+/-14 mg/g; CZ, 1.83+/-0.19 mg/g) were not significantly different among the groups, nor was the calcium-magnesium ratio. These results suggest that although dietary zinc deficiency retards growth and causes bone fragility, bone deposition of calcium and magnesium and its ratio are not affected.

Iron bioavailability from fortified petit suisse cheese determined by the prophylactic-preventive method.

In this research, we measured the iron bioavailability of ferrous gluconate stabilized with glycine (SFG) when it is used to fortify petit suisse cheese using the prophylactic-preventive method in rats. Three groups of male, weaned rats received a basal diet (control diet; 5.2 ppm Fe), a reference standard diet (SO4Fe; 9.2 ppm Fe), and a basal diet using iron-fortified petit suisse cheese as the iron source (cheese diet; 8.8 ppm Fe) for 22 d. The iron bioavailability was calculated as the ratio between the mass of iron incorporated into hemoglobin and the total iron intake per animal during the treatment. These values (BioFe) were 68% and 72% for SFG and ferrous sulfate, respectively. The value of the Relative Biological Value (RBV) was 95% for SFG in petit suisse cheese. These results show that according to this method, the iron bioavailability from industrial fortified petit suisse cheese can be considered as a high bioavailability rate.