Hypocholesterolemic effects of microbial protease-resistant fraction of Katsuobushi in ovariectomized rats depend on the both oil and undigested protein.
The purpose of this study was to examine which component in the microbial protease-resistant fraction of Katsuobushi (KBR), smoke-dried bonito, is hypocholesterolemic in ovariectomized rats (OVX-rats). KBR contains two major components: oil and protease-resistant protein. Oil extracted from KBR (EX) was rich in palmitic, oleic and docosahexaenoic acids. OVX-rats were fed one of the following diets for 28 d: diets containing casein as the protein source (C or C+EX diet), a diet containing KBR as the protein source (KBR diet) or diets containing degreased KBR as the protein source (DF/KBR or DF/KBR+EX diet). The C and DF/KBR diets contained soybean oil as the oil source. In the C+EX, KBR and DF/KBR+EX diets, soybean oil was replaced by oil extracted from KBR (EX). Plasma total- and low density lipoprotein-cholesterol concentrations in the C+EX, KBR and DF/KBR+EX groups, but not in the DF/KBR group, were significantly lower than that in the C group. Fecal bile acid excretion was significantly greater in the C+EX, KBR, DF/KBR and DF/KBR+EX groups in comparison to the C group, whereas excretion in the KBR and DF/KBR+EX groups was significantly greater than in the C+EX and DF/KBR groups. Cholesterol 7alpha-hydroxylase activity was higher in the C+EX, KBR, DF/KBR and DF/KBR+EX groups than the C group. In OVX-rats fed C, C+EX or KBR for 28 d, bile acid flux into the small intestine increased in KBR and C+EX groups in comparison to the C group. The hypocholesterolemic effect of KBR in OVX-rats reflected in increased fecal bile acid excretion may be mediated by increased bile acid flux caused by EX and the binding of bile acids by protease-resistant proteins.
Matsumoto
Junichi
J
Marutomo Co. Ltd, Ehime, Japan.
Erami
Kazuo
K
Ogawa
Hiroshi
H
Doi
Mikiharu
M
Kishida
Taro
T
Ebihara
Kiyoshi
K
D000821:Animal Feed; D000818:Animals; D000924:Anticholesteremic Agents / Q000494:pharmacology*; D001835:Body Weight; D002784:Cholesterol / Q000097:blood*; D000072474:Cytochrome P450 Family 7; D004042:Dietary Fats, Unsaturated / Q000494:pharmacology*; D004044:Dietary Proteins / Q000378:metabolism / Q000494:pharmacology*; D004435:Eating; D005243:Feces; D005260:Female; D005395:Fish Oils / Q000494:pharmacology*; D005396:Fish Products; D010052:Ovariectomy; D051381:Rats; D017208:Rats, Wistar; D013250:Steroid Hydroxylases / Q000378:metabolism; D013256:Steroids / Q000378:metabolism
D000924:Anticholesteremic Agents; D004042:Dietary Fats, Unsaturated; D004044:Dietary Proteins; D005395:Fish Oils; D013256:Steroids; D002784:Cholesterol; D013250:Steroid Hydroxylases; D000072474:Cytochrome P450 Family 7; C490784:Cyp7b1 protein, rat; C050128:steroid (23R)-hydroxylase