BIOAVAILABILITY OF MAGNESIUM CONTAINED IN PURPLE LAVER (ASAKUSA-NORI)BY RATS WITH SCARCE MAGNESIUM, BEING EVALUATED FROM SERUM MAGNESIUM, KIDNEY CALCIFICATION, AND BONE MAGNESIUM CONTENTS

An experiment was designed to evaluate the bioavailability of purple l aver (Asakusa-Nori, Porphyra tenera Kjellman) magnesium (Mg) in Mg-sca rcity Fischer 344 male rats from serum Mg level, kidney calcification and bone Mg contents. Male rats of 4 weeks of age were divided into fo ur groups of six rats. The four groups were control (20SC), Mg-restric ted (-Mg20SC), -Mg20SC plus purple laver (-Mg20SCP), and 20SC plus pur ple laver (20SCP) group respectively. To -Mg20SC, 1/10 Mg of the 20SC diet was added. -Mg20SCP diet was prepared to contain equal amount of Mg as in the 20SC diet with purple laver as a Mg source. 20SCP diet wa s designed to contain double amount of Mg. After a 3-week experimental period, rats were decapitated. Blood serum, right kidney, and right f emur were collected and Mg, calcium (Ca), phosphorus (P) were determin ed. Serum Mg concentration of the -Mg20SC was 1/3 of the 20SC, indicat ing apparent hypomagnesemia. Serum P also showed lowered concentration . On the other hand, the serum Ca indicated higher value than the othe r groups, indicating hypercalcemia. Addition of purple laver to -Mg20S C diet resulted in a normal serum Mg, Ca, and P level. The Mg-scarcity (-Mg20SC) rats accumulated much amount of kidney Ca. Whereas, there w as no significant difference in kidney Ca between control (20SC) group and purple laver-supplemented (-Mg20SCP) rat group. The -Mg20SC rats showed lowered ash content and reduced Mg and P concentrations in the femur. Purple laver supplementation increased the ash, Mg, and P. All of the results indicated that the purple laver Mg was used as a Mg sou rce.