Abstract: The intervening effect of dietary supplementation of proanthocyanidin B2 on dysfunctional blood lipid metabolism was evaluated in a mouse model of hyperlipidemia induced by a high-fat diet, and the underlying mechanism was explored from the perspective of intestinal flora. C57BL/6 mice (5 weeks old) were randomly divided into three groups: control group (A), high-fat diet (HFD) group (B), and proanthocyanidin B2 treatment group (C). After feeding for 12 weeks, visceral organ indices, blood lipids, hepatic enzyme activities and antioxidant capacity in liver and colon tissues were determined, the intestinal flora was analyzed using Illumina high-throughput sequencing technology, and changes in short-chain fatty acid contents in the feces of the mice were detected by gas chromatography-mass spectrometry. The results showed that proanthocyanidin B2 significantly reduced the levels of serum total cholesterol, triglyceride and atherosclerosis index (P < 0.05), significantly increased lipoprotein lipase activity, hepatic lipase activity, total lipase activity, and antioxidant activity, and inhibited malondialdehyde accumulation as an indicator of oxidative damage (P < 0.05). Taxonomic classification of the mouse intestinal microbiome at the phylum and genus levels demonstrated that proanthocyanidin B2 could increase Bacteroidetes/Firmicutes ratio in the intestinal flora of the HFD-fed mice and result in significant differences in the abundance of 13 species of bacteria, including Escherichia-shigella, Bacteroidales_S24-7_group, Ruminococcaceae, Bifidobacterium and Parabacteroides. The dominant bacterial genera in the proanthocyanidin B2 group were Romboutsia, Lachnospiraceae and Parabacteroides. Proanthocyanidin B2 significantly increased the contents of butyric acid in the feces of the HFD-fed mice (P < 0.05). Therefore, proanthocyanidin B2 can regulate the intestinal flora structure, thus preventing high-fat?diet-induced?dyslipidemia.

Key words: proanthocyanidin B2, blood lipid metabolism, antioxidant, intestinal flora