Dietary fibers extracted from Saccharina japonica can improve metabolic syndrome and ameliorate gut microbiota dysbiosis induced by high fat diet

Abstract

Fig. 1. Characterization of dietary fiber extracted from Saccharina japonica . Fig. 2. The overall regulatory activity of dietary fiber extracted from Saccharina japonica in metabolic syndrome mice. • The dietary fiber sample (DFSJ) extracted from Saccharina japonica shows good water holding capacity (11.34 ± 1.63 g/g) and swelling property (32.9 ± 2.52 mL/g). • DFSJ can effectively reduce fasting blood glucose (FBG), improve insulin resistance (IR) in HFD mice. • DFSJ can reduce inflammatory factors, improve the hepatic oxidative stress and protect visceral organs from the injury of high fat diet. • DFSJ can ameliorate the gut microbiota dysbiosis, increase the relative abundance of some beneficial bacteria ( Bifidobacterium, Turicibacter, Akkermansia ) in gut and improve the production of short-chain fatty acid (SCFA). Metabolic syndrome (MetS) is a pathological state of multiple metabolic abnormalities. Dietary fibers (DFs) has been widely concerned about its positive role in MetS. Different from the DFs of terrestrial plants, the DFs of seaweeds has unique composition and structural characteristics. The aim of this study is to investigate the composition and microstructures of DF derived from Saccharina japonica , and its positive effects on MetS mice induced by high fat diet (HFD). We extracted DF from S. japonica (DFSJ). DFSJ has a high proportion of soluble dietary fiber (SDF) and it shows good water holding capacity (11.34 ± 1.63 g/g) and swelling property (32.9 ± 2.52 mL/g). Supplementing DFSJ can significantly improve insulin resistance (IR), dyslipidemia in HFD mice. Besides, DFSJ can reduce inflammatory factors (TNF-α, MCP-1 and IL-6), improve the hepatic oxidative stress and protect visceral organs from the injury of HFD. Finally, 16S rDNA high-throughput sequencing was used to further analyze the profile changes of gut microbiota. The results indicated that supplementing DFSJ can effectively ameliorate gut microbiota dysbiosis. In particular, DFSJ can increase the relative abundance of some beneficial bacteria, such as Bifidobacterium, Turicibacter and Akkermansia . Our results indicated that DFSJ has a comprehensive regulatory effect on MetS, and it is involved in various regulatory pathways, such as antioxidant, anti-inflammatory, hypoglycemic and hypolipidemic pathways in HFD-induced MetS mice. Our results reveal the great potential of DFSJ as an effective regulator on various metabolic abnormalities of MetS.