報　文

マンニトールの生体利用における腸内柵菌存在の意義

本郷　涼子1,2，中村　禎子1，奥恒行1*

1長崎県立大学シーボルト校大学院人間健康科学研究科
2長崎国際大学健康管理学部健康栄養学科

　Wistar male rats (50g) were divided into groups (6 per group) and raised with mild restricted feeding to give equalquantities of each test diet: 5% mannitol (MAN), sorbitol (SOR) or control (CON) for 26 days. We then investigated body weight gain, osmotic diarrhea and blood parameters. Rats receiving the MAN and SOR diets experienced osmotic diarrhea immediately after feeding, but recovered within 1 week. Cecal tissue and content weights were heavier in both MAN and SOR groups compared with the CON group (p <0.05), but final body weight, diet efficiency and blood parameters were not significantly different among the 3 groups.
To investigate the effect of intestinal microbes on mannitol metabolism, the intestinal microbes in rats were depleted by drinking sterilized water containing antibiotics. Twenty-four Wistar rats (120g) were divided into 4 groups: MAN-fed・conventional, [MAN(+micro)]; MAN-fed・microbes-depleted, [MAN(-micro)]; CON-fed・conventional,[CON(+micro)]; CON-fed・microbes-depleted, [CON(-micro)], and fed with mild restricted feeding for 20 days. Both MAN(+micro) and MAN(-micro) diets caused osmotic diarrhea. Rats in the MAN(+micro) group recovered from their diarrhea, but rats in the MAN(-micro) group did not recover throughout the experimental period. Cecal content weight was the heaviest in rats fed the CON(-micro) diet and the lightest in rats fed the MAN(+micro) diet. The subtracted final body weight (final body weight - cecal content weight) was greater in rats fed the MAN(+micro) diet than the MAN(-micro) diet.
Diet efficiency, using the subtracted final body weight, was the lowest in rats fed the MAN(-micro) diet. Total organic acid concentration in the cecum was increased in rats fed the MAN(+micro) diet compared with the CON(+micro) diet, and remarkably decreased in rats fed the MAN(-micro) diet. Our results demonstrate that the existence of intestinal microbes in
the gastrointestinal tract is essential for the utilization of MAN in the host.


Key words: mannitol, sorbitol, bioavailability, antibiotics-treated, microbes.

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