Extract of the Microalga Nitzschia laevis Prevents High-Fat-Diet-Induced Obesity in Mice by Modulating the Composition of Gut Microbiota

Scope The aim of the present study is to investigate the efficacy of Nitzschia laevis extract (NLE) in preventing obesity in mice fed with a high-fat diet (HFD), and the potential underlying mechanisms focusing on modulation of the gut microbiota profile. Methods and results Physiological, histological, and biochemical parameters and gut microbiota compositions are compared among four experimental groups fed respectively with the following diets for 8 weeks: Normal chow diet, HFD, HFD + low concentration of NLE, and HFD + high concentration of NLE. The results demonstrate that NLE supplementation significantly reduces body weight gain and effectively prevents lipid accumulation in the white adipose tissue and liver of the mice. Mechanistic analysis reveals that NLE promotes the expression of uncoupling protein 1 and peroxisome proliferators-activated receptor-gamma coactivator-1 mRNA in brown adipose tissue. Furthermore, NLE protects the gut epithelium and positively reshapes the gut microbiota composition against the damaging effect of HFD. Conclusions NLE supplementation demonstrates a protective effect against HFD-induced obesity in mice, which is associated with reshaping the profile of gut microbiota. To the best of our knowledge, this has been the first report on the potential of microalgal extract to prevent obesity by modulating gut microbiota.