Effect of Phytic Acid and Microbial Phytase on Cd Accumulation, Zn Status, and Apparent Absorption of Ca, P, Mg, Fe, Zn, Cu, and Mn in Growing Rats

Abstract

Three groups of individually housed albino rats (n = 6, initial average weight = 47 g) were fed diets based on egg white and cornstarch (basal diet 8 g Ca, 5.2 g P, 0.76 g Mg, 100 mg Zn, 100 mg Fe, 50 mg Mn, 7 mg Cu, and 5 mg Cd per kilogram diet) over a 4-week period. Group I (controls) was fed the basal diet free of phytic acid (PA) and microbial phytase. In groups II and III cornstarch was replaced by 0.5% PA from NaPA (molar PA/Zn ratio ∼ 5). In group III, 2,000 U of microbial phytase from Aspergillus niger per kilogram diet was added. Live weight gain, zinc status (zinc in plasma, femur, liver, and testes; activity of the plasma alkaline phosphatase), and apparent absorption of zinc, iron, copper, and manganese remained unchanged by the different dietary treatments. The apparent phosphorus absorption was highest in the phytase group. PA decreased and microbial phytase improved thv apparent absorption of calcium and magnesium. Liver cadmium concentration, total liver and kidney cadmium content, as well as fractional liver and kidney cadmium accumulation in rats fed the diet containing PA were significantly higher than those in the controls. Phytase supplementation lowered liver and kidney cadmium accumulation. Differences in calcium and magnesium bioavailability due to PA and microbial phytase may be one factor in the alteration of tissue cadmium accumulation.

Phytate in foods and significance for humans: Food sources, intake, processing, bioavailability, protective role and analysis

“…These results show that the high cadmium accumulation in liver and kidneys were due to the sodium phytate added as after phytate degradation by phytases the high cadmium accumulation was reduced [251]. The results were confirmed by the same authors in another rat study, showing also significantly higher cadmium liver and kidney accumulation after application of a sodium phytate containing diets (0.5%) and also a reduction of the accumulated cadmium by supplementation of microbial phytases (2000 U/kg) [252]. A later rat study by Rimbach and Pallauf [253] showed, however, only a slight increase in the cadmium accumulation in the kidneys and no significant alteration of the liver cadmium content with increasing dietary phytate up to 1.4% (3.5 -14.0 g Na -phytate/kg).…”

Colitis-Induced Changes in the Level of Trace Elements in Rat Colon and Other Tissues

“…The liver, on the other hand, is rich in free radical scavenging systems, therefore, a reduction in Se may be due to enhanced synthesis of selenoproteins by this organ. The concentrations of the trace elements in the control animals reported in this study are comparable to those reported earlier [19,20].…”

Bioavailability of zinc sources and their interaction with phytates in broilers and piglets

“…In contrary to ZN N , PP NH was not an antagonist for ZN I bioavailability in piglets (Analysis II). This finding is in contradiction with the reduced Zn absorbability, Zn status or growth from experiments having studied the effect of supplemental phytate (mostly as sodium phytate, C 6 H 6 Na 12 O 24 P 6 ) in semi-synthetic diets containing or not containing supplemental Zn (O'Dell and Savage, 1960;Oberleas et al, 1962;Rimbach and Pallauf, 1992;Rimbach et al, 1995;Windisch and Kirchgessner, 1999). As phytate from sodium phytate is easily ionizable under a wide pH range, ionized Zn from supplemental sources may rapidly bind to phytic acid (Davies and Nightingale, 1975).…”