Obesity-induced alterations in the gut microbiome in female mice fed a high-fat diet are antagonized by dietary supplementation with a novel, wax ester–rich, marine oil

Pauke C Schots,Kirsten M Jansen,Jakub Mrazek,Alice M Pedersen,Ragnar L Olsen,Terje S Larsen

doi:10.1016/j.nutres.2020.09.002

Pauke C Schots, Kirsten M Jansen + Show 4 more

Open Access

https://doi.org/10.1016/j.nutres.2020.09.002

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Abstract

Dietary supplementation with calanus oil, a novel wax ester–rich marine oil, has been shown to reduce adiposity in high-fat diet (HFD)–induced obese mice. Current evidence suggests that obesity and its comorbidities are intrinsically linked with unfavorable changes in the intestinal microbiome. Thus, in line with its antiobesity effect, we hypothesized that dietary supplementation with calanus oil should counteract the obesity-related deleterious changes in the gut microbiota. Seven-week-old female C57bl/6J mice received an HFD for 12 weeks to induce obesity followed by 8-week supplementation with 2% calanus oil. For comparative reasons, another group of mice was treated with exenatide, an antiobesogenic glucagon-like peptide-1 receptor agonist. Mice fed normal chow diet or nonsupplemented HFD for 20 weeks served as lean and obese controls, respectively. 16S rRNA gene sequencing was performed on fecal samples from the colon. HFD increased the abundance of the Lactococcus and Leuconostoc genera relative to normal chow diet, whereas abundances of Allobaculum and Oscillospira were decreased. Supplementation with calanus oil led to an apparent overrepresentation of Lactobacillus and Streptococcus and underrepresentation of Bilophila. Exenatide prevented the HFD-induced increase in Lactococcus and caused a decrease in the abundance of Streptococcus compared to the HFD group. Thus, HFD altered the gut microbiota composition in an unhealthy direction by increasing the abundance of proinflammatory genera while reducing those considered health-promoting. These obesity-induced changes were antagonized by both calanus oil and exenatide.

Highlights

The role of gut microbiota in human health has received significant interest in recent years
We show that long-term feeding on a high-fat diet (HFD) led to an increase in the intestinal abundance of the bacterial genera Lactococcus and Leuconostoc, whereas the abundance of Allobaculum and Oscillospira was decreased
Administration of the glucagon-like peptide-1 (GLP-1) analog exenatide prevented the HFD-induced increase in Lactococcus, and in addition, it caused a decrease in the abundance of Streptococcus

Summary

Introduction

The role of gut microbiota in human health has received significant interest in recent years. Alterations in the composition of the gut microbiome have been associated with obesity and metabolic disorders, such as insulin resistance and type 2 diabetes mellitus, thereby increasing the risk for cardiometabolic disease [1,2,3,4,5]. Studies describing the impact of EPA and DHA on the gut microbiota in humans are relatively sparse. Rajkumar et al [10] were the first to study the impact of EPA and DHA on human gut microbiota but failed to detect any major effects on its composition. Later studies providing omega-3 PUFA supplements to both healthy and obese individuals revealed similar changes in both groups, such as a decrease in Faecalibacterium, often associated with an increase in the Bacteroidetes and butyrate-producing bacteria of the Lachnospiraceae family [11,12,13]. Animal studies have reported alterations in gut microbiota following dietary supplementation with marine oils, and interestingly, these alterations in the microbiome were associated with reductions in body weight gain and white adipose tissue (WAT) inflammation [14] as well as a reduced adiposity index [15]

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