Archivos Latinoamericanos de Nutrición (Jun 2003)
Efecto del nivel de calcio de la dieta consumida durante gestación y lactancia sobre el zinc en sangre y hueso, en ratas
Abstract
RESUMEN. Se estudió la influencia del nivel de calcio (Ca) de la dieta, durante preñez y lactancia, sobre el contenido materno de zinc (Zn) en hueso y en sangre. Ratas Wistar, hembras, entre 250 a 350 g de peso, se alimentaron desde el comienzo de la preñez hasta el destete con una dieta conteniendo/100 g: 0.2, 0.6 ó 0.9 g Ca (grupos BAJO, NORMAL y ALTO respectivamente). Al parto y al destete se determinó Zn en sangre (ZnS). Al destete se determinó en fémur Zn (ZnF) y Ca (CaF). Los resultados promedio ± ESM fueron : para ZnS (my g/ml), al parto y al destete respectivamente: BAJO: 8.73 ± 1.05; 12.8 ± 2.02; NORMAL: 3.49 ± 0.19; 3.73 ± 0.37; ALTO: 3.21 ± 0.19; 3.85 ± 0.27. Al destete para ZnF (my g/100 mg): BAJO: 30.2 ± 0.9; NORMAL: 24.1 ± 0.3; ALTO: 24.1 ± 0.9; CaF (mg/100 mg): BAJO:19.2 ± 0.8; NORMAL: 21.4 ± 0.6; ALTO: 20.4 ± 1.1. ZnS en BAJO fue estadísticamente mayor (pSUMMARY. Influence of dietary calcium during prenormalancy and lactation on zinc levels in maternal blood and bone, in rats. The effect of dietary calcium (Ca) level on maternal zinc (Zn) nutritional status was studied. Female Wistar rats, weighing 250-350 g, were fed during pregnancy and lactation with an experimental diet containing/100g different levels of calcium: 0.2 g (low calcium: LCa), 0.6 g (normal calcium: NCa) or 0.9 (high calcium: HCa). Maternal blood samples were drawn from the tail at delivery and at the end of lactation. Laboratory determinations were: Zn in whole blood (WB) at delivery and weaning; Zn (ZnF) and Ca (CaF) in the ashed femur at weaning. The results (mean ± SEM) were: ZnWB (mu g/ml) at delivery and weaning: LCa: 8.73 ± 1.05; 12.8 ± 2.02; NCa: 3.49 ± 0.19; 3.73 ± 0.37; HCa: 3.21 ± 0.19; 3.8 5± 0.27. CaF (mg/100 mg): LCa: 19.2 ± 0.8; NCa: 21.4 ± 0.6; HCa: 20.4 ± 1.1. ZnF (mu g/100 mg): LCa: 30.2 ± 0.9; NCa: 24.1 ± 0.3; HCa: 24.1 ± 0.9. ZnWB was significantly higher in LCa (p<0.0001) regarding NCa and Hca. ZnF showed an increase and CaF a decrease in LCa regarding NCa and HCa (p<0.0001). There were no significant differences in ZnWB, ZnF and CaF between NCa and HCa These results show that: there was no detrimental effect when dietary Ca content was increased by 50 % above the normal requirements of the rat.; low dietary Ca during pregnancy and lactation produced an increase of Zn utilization, reflected in maternal blood Zn and in ZnF content.
