Evaluation of Brewer's spent grain as a plasma lipid lowering agent in rats fed cholesterol enriched diets

Brewer's spent grain (BSG), a byproduct of the beer industry, is predominantly fibrous components of barley. As the effects of cereal grain fiber and their oil on blood lipids is controversial, the purpose of this study was to evaluate the impact of BSG and oil cold extracted from BSG on plasma lipids in the rat. Seventy female Fischer rats were housed in individual wire cages on a 12 hour light/dark cycle at 20-24°C and were fed water and one of the following diets ad libitum; I. Control - 10% corn oil, 4% cellufil; II BSG - 10% corn oil, 4% BSG fiber; III. BSG oil - 8% corn oil, 2% BSG oil, 4% cellufil. Diets IV through VII had 1% cholesterol and 0.5% cholic acid added and were as follows: IV Control - 10% corn oil, 4% cellufil; V. BSG - 8% corn oil, 2% BSG oil, 4% BSG fiber; VI. BSG Fiber - 10% corn oil, 4% BSG fiber; VII. BSG oil - 8% corn oil, 2% BSG oil, 4% cellufil. After nine weeks the animals were anesthetized with ether and blood was withdrawn by brachial bleeding. Plasma samples were analyzed for total and HDL cholesterol. Plasma lipids were evaluated by lipoprotein electrophoresis. Mean total and HDL cholesterol levels (mg/dL) were as follows: I. Control - 99,94; II. BSG Fiber - 94,98; III. BSG Oil - 103,98; IV. Control - 441,128; V. BSG - 475, 152; VI. BSG Fiber - 437,153; VII. BSG Oil - 448,134. In non-cholesterol fed rats the BSG fiber decreased plasma total cholesterol values by 5% as compared to controls and the BSG oil increased total cholesterol values 4% as compared to control with most of the increase being HDL cholesterol. Some alterations were noted in the plasma lipids of rats fed the diets containing cholesterol and cholic acid. Total cholesterols in rats fed BSG were 8% higher than in cholesterol fed controls with BSG oil and fiber causing less than a 1.5% difference in total cholesterol. Rats on diets with BSG, BSG oil and fiber had an increase of 5-19% in HDL. Brewer's spent grain and its fiber and oil fractions at the levels used in the current study appeared to cause slight variations in plasma lipids of rats but were not statistically significantly different between dietary treatment.