Interrelationships between blood, erythrocyte and dietary Zn levels, in rats

DE PORTELA ML; WEISSTAUB A; RONAYNE P; ZENI SN

Irlanda

Simposio; 12th. International Symposium on Trace Elements in man and animals; 2005

Blood Zn levels relationship with Zn erythrocyte levels was evaluated in female Wistar rats (280-350 g) fed during pregnancy and lactation with a diet (AING) prepared according to the American Institute of Nutrition (AIN-93) recommendations (casein: 20.0 g/100g; Zn: 35 mg/g). A second group, fed the usual commercial diet (CG), (protein: 26 g/100g; Zn: 116 mg/g) was run simultaneously. Maternal blood samples were drawn from the tail before mating (To), at delivery (Td) and at weaning (Tw). Zn and Haemoglobin (Hb) were assessed in whole blood (WB) and in washed and haemolysed erythrocytes (RBC). Zn was determined by Atomic Absorption Spectrometry. The results (mean±SEM) were: WBZn (mg/dL): To: 470±23; CG: Td: 553±36; Tw: 604±38; AING: Td: 349±19; Tw: 373±37. WB Zn/Hb:(mg/g): To: 32.6±1.5; CG: Td: 51.1±2.6; Tw: 45.1±3.0; AING: Td: 32.8±1.1; Tw: 29.8±2.2. RBC Zn/Hb:(mg/g): To: 29.5±2.1; CG: Td: 48.1±3.5; Tw: 41.9±3.0; AING: Td: 30.1±1.2; Tw: 31.7±2.5. In CG, WB Zn and WB Zn/Hb increased significantly at Td and Tw, regarding To. In AING, WB Zn decreased but WB Zn/Hb and RBC Zn/Hb did not change. Taking into account the whole data, WB Zn/Hb correlated significantly with RBC Zn/Hb (r=0.98; p=0.005). The different patterns of Zn change in both groups indicate the need of a reformulation of the commercial diet. Partially supported by UBACYT B063 and B103