Hepatic LDL receptor mRNA in rats is increased by dietary mushroom (Agaricus bisporus) fiber and sugar beet fiber

Plasma cholesterol concentration is reduced by feeding some dietary fibers and mushroom fruit body, but the mechanism is not fully understood. We exam ined the effects of mushroom (Agaricus bisporus) fiber and sugar beet fiber on serum cholesterol and hepatic LDL receptor mRNA in rats. Rats were fed a cholesterol-free diet with 50 g/kg cellulose powder (CP), 50 g/kg mushroo m (Agaricus bisporus) fiber (MSF) or 50 g/kg sugar beet fiber (BF) for 4 wk . There were no significant differences in the body weight, food intake and cecum weight among the groups. The relative liver weight in the CP group w as significantly greater than that in the MSF and BF groups. The cecal pH i n the CP and MSF groups was significantly higher than that in the BF group. Cecal acetic acid, butyric acid and total short-chain fatty acid (SCFA) co ncentrations in the BF group were significantly higher than those in the ot her groups. The serum total cholesterol, VLDL + intermediate density lipopr otein (IDL) + IDL cholesterol concentrations in the CP group were significa ntly greater than those in the MSF and BF groups. The HDL cholesterol conce ntration in the MSF group was significantly lower than that in the CP group . The hepatic LDL receptor mRNA level in the MSF and BF groups was signific antly higher than that in the CP group. The results of this study demonstra te that mushroom fiber and sugar beet fiber lowered the serum total cholest erol level by enhancement of the hepatic LDL receptor mRNA.