Changes in Gut Microbiota in Rats Fed a High Fat Diet Correlate with Obesity-Associated Metabolic Parameters

Abstract

The gut microbiota is emerging as a new factor in the development of obesity. Many studies have described changes in microbiota composition in response to obesity and high fat diet (HFD) at the phylum level. In this study we used 16s RNA high throughput sequencing on faecal samples from rats chronically fed HFD or control chow (n = 10 per group, 16 weeks) to investigate changes in gut microbiota composition at the species level. 53.17% dissimilarity between groups was observed at the species level. Lactobacillus intestinalis dominated the microbiota in rats under the chow diet. However this species was considerably less abundant in rats fed HFD (P<0.0001), this being compensated by an increase in abundance of propionate/acetate producing species. To further understand the influence of these species on the development of the obese phenotype, we correlated their abundance with metabolic parameters associated with obesity. Of the taxa contributing the most to dissimilarity between groups, 10 presented significant correlations with at least one of the tested parameters, three of them correlated positively with all metabolic parameters: Phascolarctobacterium, Proteus mirabilis and Veillonellaceae, all propionate/acetate producers. Lactobacillus intestinalis was the only species whose abundance was negatively correlated with change in body weight and fat mass. This species decreased drastically in response to HFD, favouring propionate/acetate producing bacterial species whose abundance was strongly correlated with adiposity and deterioration of metabolic factors. Our observations suggest that these species may play a key role in the development of obesity in response to a HFD.

Gut microbiota are linked to increased susceptibility to hepatic steatosis in low-aerobic-capacity rats fed an acute high-fat diet

“…Typically, chronic HFD-induced obesity in both humans and rodents is marked by an increase in Firmicutes and a decrease in Bacteroidetes (21,30). However, two studies of diet-induced obesity in humans and mice revealed decreases in Firmicutes, which is consistent with our results (27,48). More recently it was observed that mice fed a lard-based diet had an enrichment in Bacteroidetes compared with a fish oil-based diet (6).…”

Physiological regulation of the heat shock response by glutamine: implications for chronic low-grade inflammatory diseases in age-related conditions

“…Accordingly, bacterial lipopolysaccharide (LPS) was identified as a triggering factor for such diseases, whereas mice feeding on a high-fat diet (HFD) were found to increase the proportion of LPS-containing microbiota in their intestines. These observations were further confirmed in many other subsequent studies [331][332][333]. In fact, a huge body of evidence indicates that gut microbiota participates in wholebody metabolism by affecting energy balance, glucose metabolism, and low-grade inflammation associated with obesity and related metabolic disorders, particularly because gut microbiota controls gut barrier function and the onset of metabolic endotoxemia [331].…”

Phascolarctobacterium faecium abundant colonization in human gastrointestinal tract

“…specialise in the utilisation of succinate produced by other bacteria (8). In parallel, the abundance of Bacteroides and Parabacteroides, both major producers of succinate, increased by high fat diet and was positively correlated with body weight (19). The elderly and individuals aged less than 1 year consumed relative less fat and have a relative low body weight, this may resulted in Bacteroides and Parabacteroides decreased, and the availa ble succinate for P. faecium was decreased.…”

“…This phenomenon may be attributed to the diet habit. A previous study demonstrated that rats fed with high-fat diet appeared to have a higher amount of the short chain fatty acid producers, including P. faecium (18). Besides, Phascolarctobacterium spp.…”