カキ肉エキスを投与したラットの血清亜鉛濃度の変化

抄録

The availability of zinc contained in oyster extracts was investigated. In the first experiment, after being given a zinc-adequate diet (20 μg Zn/g) for 1 week, 10-week-old male Wistar rats were divided into two groups. One group was given a zinc-deficient diet (0.6 μg Zn/g) for 5 days and the other group was given a zinc-adequate diet for 4 days followed by a zinc-deficient diet for one day. Then, the rats were orally administered diets supplemented with zinc (1 mg/kg body weight) as zinc sulfate or oyster extract. Before the oral administration, the rats given the zinc-deficient diet for 5 days showed lower serum zinc concentrations than those given zinc-adequate diets. After the oral administration, the rats given a zinc-deficient diet showed higher serum zinc concentration than those given zinc-adequate diets at 1, 2 and 4 hours irrespective of the source of zinc supplementation. Similarly, the area under the curve at 4 hours (AUC4) calculated from serum zinc concentration in rats given a zinc-deficient diet was larger than that of those given a zinc-adequate diet.

In the second experiment, three groups of zinc-deficient rats were orally administered three kinds of commercial oyster extracts, respectively, and the effects on serum zinc concentrations were examined. The serum zinc concentrations in all rats were elevated after administration. The extent of elevation and AUC4 values were strongly associated with the zinc content in the oyster extracts administered. These results indicate that a low zinc status induces higher zinc absorption in the gastrointestinal tract and that the zinc contained in oyster extract is utilized effectively.