Fecal Microbial Enterotypes Differentially Respond to a High-fat Diet Based on Sex in Fischer-344 Rats

Abstract

The gut microbiota interacts with the host gut environment, which is influenced by such factors as sex, age, and host diet. These factors induce changes in the microbial composition. The aim of this study was to identify differences in the gut microbiome of Fisher-344 (F344) rats fed a high-fat diet (HFD), depending on their age and sex. Fecal microbiomes from 6-, 31-, and 74-week-old, and 2-year-old both male and female rats (corresponding to 5-, 30-, 60-, and 80-year-old humans) were analyzed using 16S rRNA gene sequencing, phylogenetic investigation of communities by reconstruction of unobserved states, and enterotype (E) assessment. Moreover, the effect of an HFD on colonic epithelial cells was measured using real-time quantitative PCR. Alpha diversity decreased in the HFD group regardless of age and sex. Based on the enterotype clustering of the whole fecal microbiome, clusters from male rats were divided into E1 and E2 enterotypes, while clusters from female rats were divided into E1, E2, and E3 enterotypes. The female E3 group showed a significantly high abundance in the Ruminococcus genus and expression of Tlr2 mRNA, which may reflect compensation to the HFD. Moreover, the female E3 group showed a lower ratio of opportunistic pathogenic strains to commensal strains compared to the female E2 group. Administration of an HFD influenced the rat fecal microbiota in all assessed age groups, which could be further differentiated by sex. In particular, female rats showed a compensatory enterotype response to an HFD compared to male rats.

Enterotype-Dependent Probiotic-Mediated Changes in the Male Rat Intestinal Microbiome In Vivo and In Vitro

“…The majority of microbiomes in our set belonged to the enterotype with a low abundance of Verrucomicrobia, characteristic of Enterotype 1 (E1) in [60]. Therefore, we retained the same name for the main cluster, although we did not observe a clear dominance of Firmicutes over Bacteroidetes (Figure 3a, Supplementary Table S1), as previously reported [60].…”

“…The Jensen-Shannon distances between samples were then calculated based on different in size and composition sets of potential marker taxa. The Calinski-Harabasz indices computed at this stage revealed variability in the optimal number of potential clusters, but using 208 genera with an abundance of ≥0.1% in at least one dataset provided the optimum with the two enterotypes (Figure 2), consistent with the two enterotypes identified in the gut microbiomes of male rats [60]. When the feeding experiment was finished, metagenomic DNA was isolated from control samples and used for 16S rRNA taxonomic analysis.…”

“…Of direct relevance to our study are the data obtained by Choi and co-authors [60], who identified two enterotypes in the intestinal microbiota of 24 male rats, whereas a similar number (25) of female animals were clustered into three groups. Fan and co-authors [61] identified three enterotypes in the intestine of Ochotona curzoniae and showed that the transition of animals to laboratory nutrition altered the composition of dominant bacteria, resulting in a "single enterotype".…”

“…The majority of microbiomes in our set belonged to the enterotype with a low abundance of Verrucomicrobia, characteristic of Enterotype 1 (E1) in [60]. Therefore, we retained the same name for the main cluster, although we did not observe a clear dominance of Firmicutes over Bacteroidetes (Figure 3a, Supplementary Table S1), as previously reported [60]. Twelve rats with E1 microbiomes received three doses of the probiotic (Figure 3b-d), and samples from rats 4s and 5s were available to trace their recovery from a single probiotic administration.…”

The Effect of Clostridium butyricum on Gut Microbial Changes and Functional Profiles of Metabolism in High-fat Diet–fed Rats Depending on Age and Sex

“…[56][57][58] However, in our study, we consistently confirmed an increase in A. muciniphila after long-term administration of a HFD. 28,59 Furthermore, we found a negative correlation between the relative fecal abundance of A. muciniphila and fecal concentrations of acetic acid and butyric acid (Supplementary Fig. 3).…”