Comparison of the cholesterol-lowering properties of whole barley, oat bran, and wheat red dog in chicks and rats

Cereal Chem. 69(3):240-244 Ground meal of two barley cultivars, Waxbar (WXB) and controls, the WRD diet increased serum cholesterol in chicks and had Prowashonupana (PWSNP), was compared with oat bran (OB) and wheat no effect on rats. PWSNP did not lower cholesterol levels in the rat red dog (WRD) for their cholesterol-lowering effects in chicks and rats. experiment but did in the chick experiment (P < 0.05). In rats, a high Total 83-glucan, total dietary fiber (TDF), and soluble dietary fiber were fiber level of WXB and OB (10% TDF) was more effective than a lower 16.9, 33.4, and 18.1% for PWSNP; 7.9, 15.0, and 8.3% for WXB; 6.6, level in reducing total and LDL cholesterol. Soluble 18-glucan appeared 16.6, and 6.9 for OB; and 2.6, 35.0, and 4.1 for WRD. In both chicks to be the strongest predictor of the serum cholesterol response in both and rats, OB and WXB demonstrated a significant (P < 0.05) lowering species. Barley grain can offer a high-fiber, cholesterol-lowering alternative effect on total and low-density lipoprotein (LDL) cholesterol levels, but to OB. Further research is required to clarify inconsistencies in lipid high-density lipoprotein cholesterol was not decreased. Compared with responses among animals fed different barley cultivars. Cereal grains, noted for their dietary fiber content, have an important place in the well-balanced diet. Differentiation of watersoluble and insoluble fiber components has helped elucidate the physiological effects of fiber (Schneeman 1989). The soluble fractions appear to exert a hypocholesterolemic effect in humans and animals (Anderson et al 1990), whereas the insoluble fiber fractions generally do not exhibit this effect (Anderson and TietyenClark 1986). Among the cereal grains, oats (Chen et al 1981) and barley (Newman et al 1989) appear to be the most effective in lowering serum cholesterol. Both grains have a high proportion of soluble dietary fiber (SDF), particularly 8-glucans. Klopfenstein (1988) reviewed the role of /3-glucans in nutrition and health. Individual barley cultivars vary widely in contents of total and soluble ,/-glucans (Anderson et al 1978, Aman and Graham 1987), and differences have been reported in their physiological effects. For example, when Fadel et al (1987) fed two barley cultivars with similar /3-glucan content to chicks, one was highly effective in lowering serum cholesterol, whereas the other had no effect. When ,/-glucanase was added to the diets, no hypocholesterolemic effect was found. This experiment was designed to test the hypocholesterolemic property of four cereal products: oat bran (OB), wheat red dog (WRD), and ground meal of two barley cultivars, Waxbar (WXB) and Prowashonupana (PWSNP). Both of the barley cultivars previously had demonstrated serum cholesterol lowering properties when fed to chicks (R. K. Newman and C. W. Newman, unpublished data). This study was undertaken as a cooperative venture at Montana State University, where the chick model was used, and at Kansas State University, where identical raw materials were fed to rats. MATERIALS AND METHODS Source Preparation of Grains Two barley cultivars were obtained from Rocky Mountain Grains, Inc., Bozeman, MT. PWSNP, a high-protein, waxy, shortawned, hull-less barley, was developed by the late R. F. Eslick at Montana State University. WXB, a commercially released waxy barley cultivar, was developed by Western Plant Breeders, Bozeman, MT. WRD (a mixture of wheat bran, germ, and flour) and OB (SCM 350) were obtained from ConAgra Milling Co., Omaha, NE. The barleys also were ground at that facility. 'Montana.Agricultural Experiment Station, Montana State University, Bozeman 59717. Contribution J-2652 from the Montana Agricultural Experiment Station. 2 Department of Grain Science and Industry, Kansas State University, Manhattan 66506. Contribution 91-434-5 from the Kansas Agricultural Experiment Station. @1992 American Association of Cereal Chemists, Inc. 240 CEREAL CHEMISTRY Before incorporation into the test diets, all cereal products were ground through a 0.159-cm hammermill screen (Fitz Mill, The FitzPatrick Co., Elmhurst, IL) to produce similar particle size in the products. Chemical and Physical Analysis Analyses for moisture, protein (N X 6.25) and fat (ether extract) were performed using AACC (1983) methods 44-15A, 46-16, and 30-20, respectively. Total dietary fiber (TDF) was measured using a TDF assay kit (Sigma Chemical Co., St. Louis, MO) based on a modification of the method of Prosky et al (1988). Insoluble dietary fiber was determined using AACC (1983) methods 3220 and 32-21, and SDF was calculated by difference. The method of Aman and Graham (1987) was used for total and soluble /3glucans at Montana State University. Relative viscosity was measured using an acid extract according to Aastrup (1979). Results of the chemical and physical analyses are shown in Table I. Chick-Feeding Experiment Day-old chicks were obtained from H & N Hatchery, Redmond, WA, and fed an 18% protein corn and soybean meal diet for seven days to allow for growth and adjustment. For an additional six days, chicks were fed the same diet with 0.5% added cholesterol to increase serum cholesterol levels. Four randomly chosen chicks were fasted for 12 hr, and blood was drawn to determine initial serum cholesterol levels. Experimental chick diet formulations are shown in Table II. All diets were calculated to contain approximately 20% protein, TABLE I Chemical Compositiona and Physical Measurements of Barley, Oat Bran, and Wheat Red Dog