| Two Japanese quail strains, respectively atherosclerosis-susceptible (SUS) and-resistant (RES), have been shown to be good models to study cholesterol metabolism and transportation associated with atherosclerosis. Our objective was to examine possible difference in intestinal microbiota between these strains when fed a control diet and a cholesterol enriched diet, to determine how host genotype and diet could affect the intestinal microbiome that may play a part in cholesterol metabolism. A factorial study with both strains and two diets (control, cholesterol) was carried out. Cecal, duodenal and ileal content were collected respectively from 12 week old quail that have been on their respective diets for 6 weeks. DNA was extracted from the samples and the variable region 3 to 5 of the bacterial 16S rRNA gene was amplified. The amplicon libraries were subjected to pyrosequencing.The results showed (1) PCA of β-diversity showed four distinct cecal microbiota communities that can be assigned to the 4 treatment groups (RES/control, RC; RES/cholesterol, RE; SUS/control, SC; SUS/cholesterol, SE). At the Phylum level, the 4 treatment groups had distinct Firmicutes community characteristics but no significant difference in Bacteroidetes. Eubacterium dolichum was rare in RC but became overabundant in RE. An unclassified species of Lactobacillaceae was found in abundance in SC but the same species was rare in RE. On the other hand, two Lactobacillus species were only found in RC and an unclassified Lachnospiraceae species was abundant in RE but rare in SC. The abundance of species of Lachnospiraceae, Ruminococcaceae and Coprobacillaceae was positively correlated with plasma Total Cholesterol, plasma LDL, and LDL/HDL ratio. (2) PLS-DA of β-diversity showed four distinct duodenal microbiota communities that can be assigned to the 4 treatment groups (RC, SC, RE, SE). The diet and genotype factors had effects on microbial phylum, family and genus levels. RC was characterized by species belong to Ruminococcus, Alicyclobacillus and unclassified Streptococcaceae; SC was characterized by species belong to Lactobacillaceae, including Lactobacillus reuteri; RE had seven characteristic species, six of them belong to Proteobacteria; SE had 24 characteristic species including salivarius Lactobacillus and dolichum Eubacterium. The abundance of species of Lactobacillu and Ruminococcaceae in duodenum was positively correlated with TC, LDL, TGs and LDL/HDL ratio. (3) The composition and structure of ileal bacterial communities was no different among four treatment groups (RC, SC, RE, SE). The relative abundance of microbiota on different level was no different except genus Lactobacillus was highly abundant in RES. SC was characterized by species belong to Pseudomonas, Lactobacillus, Arthrobacter, and Bifidobacterium saeculare and Eubacterium coprostanoligenes; RC was characterized by Pseudomonas koreensis and unclassified Lactobacillus. RC and SC was common species were Lactobacillus mucosae and other three unclassified Lactobacillus. RE was characterized by Actinobacteria, while SE was characterized species belong to Proteobacteria. (4) In this study, samples taken from the GI tracts of four treatments examined the characteristic bacterial communities along the Japanese quail GI tract, including those present in the duodenum, ileum and cecum. Further analyses revealed that duodenal had smaller phylogenetic diversity than ileum and ceca samples did. In addition, inter-subjects variations of microbiota were smaller in ceca samples then in small intestinal samples. We found that intestinal microbiota in three segments changed as similar in four treatment groups.Our study of intestinal microbiota in the Japanese quail has demonstrated that selection for susceptibility/resistance to diet induced atherosclerosis has also affected the quail’s GI tracts environment to host distinctly different intestinal microbiome. |
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