Abstract:

In order to compare the effects of oat beta-glucan and Artemisia sphaerocephala Krasch. polysaccharide (ASP)
on the physiological parameters and the structure of the gut microbiota, human flora-associated (HFA) mouse model was
established by inoculating 30 germ-free mice with fecal suspension derived from a healthy volunteer. The HFA mice were
randomly divided into three groups: the first group was fed with normal diet (CT group), the second group was fed with
normal diet containing 5% oat beta-glucan (CT + OG group), and the third group was fed with normal diet with 5% ASP
(CT + ASP group). After 8 weeks of feeding, serum biochemical indexes were determined, pathological sections of liver
were stained with HE and fat levels were evaluated, and the change in the gut microbiota was analyzed by PCR-DGGE
(denaturing gradient gel electrophoresis). The results showed that the two kinds of polysaccharides reduced fasting serum
glucose level in HFA mice (P > 0.05) when compared with CT group, CT + OG group significantly reduced the content
of total triglyceride (P < 0.05), and total cholesterol content and high density lipoprotein cholesterol content in CT+ASP
group were significantly higher than those of CT and CT + OG group (P < 0.05). CT + OG group significantly decreased
the volume of fat cells obviously and displayed more dense arrangement of fat cells when compared CT + ASP group and
CT group. Moreover, the structure of the gut microbiota in polysaccharide-diet-fed HFA mice changed; their gut bacterial
diversity index increased, and the effect of ASP was superior to that of oat beta-glucan (P > 0.05). Polysaccharide diet
obviously altered physiological parameters and structure of gut microbiota in HFA mice. The composition and bacteria
abundance of intestinal flora in different polysaccharide-diet-fed HFA mice exhibited different changes which were
associated with the molecular weight of polysaccharides. In term of reducing the levels of fasting serum glucose, serum total
cholesterol and triglyceride, and the size of fat cells, the effect of low molecular weight oat beta-glucan was obviously better
than that of high molecular weight ASP in HFA mice. When it comes to increasing intestinal microbial diversity, the effect
of ASP was superior to oat beta-glucan distinctly.

Key words: human flora-associated mice, oat beta-glucan, Artemisia sphaerocephala Krasch. polysaccharide, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE)