title: FLX pyrosequencing analysis of the effects of the brown-algal fermentable polysaccharides alginate and laminaran on rat cecal microbiotas.
abstract: Edible brown algae are used as major food material in Far East Asian countries, particularly in South Korea and Japan. They contain fermentable dietary fibers, alginic acid (uronic acid polymer) and laminaran (β-1,3-glucan), that are fermented into organic acids by intestinal bacteria. To clarify the effect of edible algae on the intestinal environment, the cecal microbiotas of rats fed diets containing no dietary fiber (control) or 2% (wt/wt) sodium alginate or laminaran for 2 weeks were analyzed using FLX amplicon pyrosequencing with bar-coded primers targeting the bacterial 16S rRNA gene. The most abundant phylum in all groups was Firmicutes. Specifically, Allobaculum was dominant in all diet groups. In addition, Bacteroides capillosus (37.1%) was abundant in the alginate group, while Clostridium ramosum (3.14%) and Parabacteroides distasonis (1.36%) were only detected in the laminaran group. Furthermore, rats fed alginate showed simplified microbiota phylotypes compared with others. With respect to cecal chemical compounds, laminaran increased cecal organic acid levels, particularly propionic acid. Alginate increased total cecal organic acids. Cecal putrefactive compounds, such as indole, H(2)S, and phenol, were decreased by both alginate and laminaran. These results indicate that edible brown algae can alter the intestinal environment, with fermentation by intestinal microbiota.
authors.affiliation: Department of Food Science and Technology, Faculty of Marine Science, Tokyo University of Marine Science and Technology, Tokyo, Japan.
authors.forename: Choa
authors.initials: C
authors.lastname: An
authors.forename: Takashi
authors.initials: T
authors.lastname: Kuda
authors.forename: Takahiro
authors.initials: T
authors.lastname: Yazaki
authors.forename: Hajime
authors.initials: H
authors.lastname: Takahashi
authors.forename: Bon
authors.initials: B
authors.lastname: Kimura
mesh_terms: D000464:Alginates / Q000378:metabolism*; D000818:Animals; D044822:Biodiversity; D002264:Carboxylic Acids / Q000032:analysis; D002432:Cecum / Q000382:microbiology*; D058893:DNA Barcoding, Taxonomic; D004032:Diet / Q000379:methods*; D005936:Glucans; D020723:Glucuronic Acid / Q000378:metabolism; D006603:Hexuronic Acids / Q000378:metabolism; D054892:Metagenome; D000459:Phaeophyceae / Q000737:chemistry*; D011134:Polysaccharides / Q000378:metabolism*; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D051381:Rats
chemical_list: D000464:Alginates; D002264:Carboxylic Acids; D005936:Glucans; D006603:Hexuronic Acids; D011134:Polysaccharides; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D020723:Glucuronic Acid; C008247:laminaran