Department of Applied Biological Science, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu-shi, Tokyo, Japan.
AMED-CREST, Japan Agency for Medical Research and Development, Chiyoda-ku, Tokyo, Japan.
PLoS One. 2018 Apr 26;13(4):e0196579. doi: 10.1371/journal.pone.0196579. eCollection 2018.
Dietary intake of barley β-glucan (BG) is known to affect energy metabolism. However, its underlying mechanism remains poorly understood because studies have presented inconsistent results, with both positive and negative effects reported in terms of satiety, energy intake, weight loss, and glycemic control. The objective of this study was to clarify the physiological role underlying the metabolic benefits of barley BG using a mouse model of high fat diet (HFD)-induced obesity. Male 4-wk-old C57BL/6J mice were fed an HFD with 20% barley flour containing either high BG (HBG; 2% BG) or low BG (LBG; 0.6% BG) levels under conventional and germ-free (GF) conditions for 12 wks. In addition, mice were fed either an HFD with 5% cellulose (HFC; high fiber cellulose) or 5% barley BG (HFB; high fiber β-glucan) for 12 wks. Then, metabolic parameters, gut microbial compositions, and the production of fecal short-chain fatty acids (SCFAs) were analyzed. The weight gain and fat mass of HBG-fed mice were lower than those of control mice at 16-wk-old. Moreover, the secretion of the gut hormones PYY and GLP-1 increased in HBG-fed mice, thereby reducing food intake and improving insulin sensitivity by changing the gut microbiota and increasing SCFAs (especially, butyrate) under conventional condition. These effects in HBG-fed mice were abolished under GF conditions. Moreover, the HFB diets also increased PYY and GLP-1 secretion, and decreased food intake compared with that in HFC-fed mice. These results suggest that the beneficial metabolic effects of barley BG are primary due to the suppression of appetite and improvement of insulin sensitivity, which are induced by gut hormone secretion promoted via gut microbiota-produced SCFAs.
大麦β-葡聚糖（BG）的饮食摄入量已知会影响能量代谢。然而，其潜在机制仍知之甚少，因为研究结果不一致，饱腹感、能量摄入、体重减轻和血糖控制方面既有积极影响，也有消极影响。本研究旨在使用高脂肪饮食（HFD）诱导肥胖的小鼠模型阐明大麦 BG 代谢益处的生理作用。雄性 4 周龄 C57BL/6J 小鼠在常规和无菌（GF）条件下分别用含有高 BG（HBG；2% BG）或低 BG（LBG；0.6% BG）水平的 20%大麦粉的 HFD 喂养 12 周。此外，小鼠用 HFD 分别用 5%纤维素（HFC；高纤维纤维素）或 5%大麦 BG（HFB；高纤维β-葡聚糖）喂养 12 周。然后，分析代谢参数、肠道微生物组成和粪便短链脂肪酸（SCFA）的产生。16 周龄时，HBG 喂养的小鼠体重增加和脂肪量低于对照小鼠。此外，HBG 喂养的小鼠肠道激素 PYY 和 GLP-1 的分泌增加，从而通过改变肠道微生物群和增加 SCFA（特别是丁酸盐）来减少食物摄入并改善胰岛素敏感性。在 GF 条件下，HBG 喂养小鼠的这些作用被消除。此外，与 HFC 喂养的小鼠相比，HFB 饮食也增加了 PYY 和 GLP-1 的分泌，并减少了食物摄入。这些结果表明，大麦 BG 的有益代谢作用主要是由于通过肠道微生物群产生的 SCFA 促进肠激素分泌而抑制食欲和改善胰岛素敏感性。
