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

Abstract

An experiment was designed to evaluate the bioavailability of purple laver (Asakusa-Nori, Porphyra tenera Kjellman) magnesium (Mg) in Mg-scarcity Fischer 344 male rats from serum Mg level, kidney calcification and bone Mg contents. Male rats of 4 weeks of age were divided into four groups of six rats. The four groups were control (20SC), Mg-restricted (-Mg20SC), —Mg20SC plus purple laver ( —Mg20SCP), and 20SC plus purple 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 was designed to contain double amount of Mg. After a 3-week experimental period, rats were decapitated. Blood serum, right kidney, and right femur were collected and Mg, calcium (Ca), phosphorus (P) were determined. Serum Mg concentration of the �” Mg20SC was 1/3 of the 20SC, indicating apparent hypomagnesemia. Serum P also showed lowered concentration. On the other hand, the serum Ca indicated higher value than the other groups, indicating hypercalcemia. Addition of purple laver to — Mg20SC diet resulted in a normal serum Mg, Ca, and P level. The Mg-scarcity (—Mg20SC) rats accumulated much amount of kidney Ca. Whereas, there was 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 theash, Mg, and P. All of the results indicated that the purple laver Mg was used as a Mg source. © 1993, Center for Academic Publications Japan. All rights reserved.