Dietary Fiber-Rich Barley Products Beneficially Affect the Intestinal Tract of Rats

Abstract

The objective of this study was to investigate the effects of barley-rich diets in the intestinal tract of rats. Four test groups (A-D) of 10 young male Wistar rats were fed diets containing 50 g/100 g barley extrudates (A, B and D) or mixtures (C) for 6 wk; the control diet contained no barley. The barley-containing supplements in the test diets were: A = cultivar "HiAmi"; B = "HiAmi" and "Prowashonupana" (50:50); C = "Prowashonupana" and Novelose (50:50); D = "Prowashonupana" and amylose from maize (60:40). These supplements contained 7-12 g/100 g beta-glucan and 7-24 g/100 g resistant starch. Additionally, 5 g microcrystalline cellulose/100 g was present in all diets. Carbohydrate utilization (indirect calorimetry) was lower (P < 0.05) in rats fed the barley-containing diets C or D than in the controls. In the test groups, the following differences from the controls were found: greater food intake in the last 2 wk (P < 0.05); increased weight gain in wk 6 (P < 0.05); greater mass of the ceca (groups B-D; P < 0.05) and colons (P < 0.001) as well as masses of cecal (groups C and D; P < 0.01) and colon contents (P < 0.001); greater concentrations of resistant starch in cecal and most of the colon contents (P < 0.05); and more beta-glucan in the small intestine, cecum and colon (P < 0.05). The numbers of coliforms and Bacteroides were lower than in the controls in groups B-D and those of Lactobacillus were greater in all test groups (P < 0.05). Short-chain fatty acids (SCFA) were higher in the cecal contents of the test groups (> or = 800 micro mol/g DM; P < 0.001) compared with the controls ( approximately 200 micro mol/g DM). Similarly, SCFA were higher in colon and feces of the test groups. The concentrations of excreted bile acids increased up to 30% during the feeding period. The proportions of secondary bile acids were lower and the amounts of neutral sterols (P < 0.001) were greater in feces of rats fed the barley-containing diets for 6 wk than in the controls. Diets containing more soluble macromolecular dietary fibers such as beta-glucans affected the excretion of bile acids and neutral sterols the most, whereas the fermentation of dietary fiber, including resistant starch, influenced the steroids in feces. These results suggest that dietary fiber-rich barley-containing diets have beneficial physiologic effects.

β-Glucans, History, and the Present: Immunomodulatory Aspects and Mechanisms of Action

“…It is known that cereals, mushrooms and yeast facilitate bowel motility and can be used in amelioration of intestinal problems, particularly obstipation (Battilana et al, 2001;Dongowski et al, 2002). Nondigestible β-glucans, forming a remarkable portion of these materials, are also able to modulate mucosal immunity of the intestinal tract (Tsukada et al, 2003).…”

Impact of dietary protein on microbiota composition and activity in the gastrointestinal tract of piglets in relation to gut health: a review

“…Accordingly, fermentable carbohydrates such as different types of resistant starch, non-starch polysaccharides (NSP) and nondigestible oligosaccharides have been shown to enhance proliferation of beneficial bacteria in the small intestine (Bikker et al, 2007). As a result, there was an increased production of straight-chain short-chain fatty acids (SCFA) that may be used as energy source by the host (Gaskins, 2001), but which are also known to exert selective antimicrobial effects against certain pathogens (Dongowski et al, 2002). On the other hand, excessive fermentation of dietary protein should be avoided because of the production of detrimental substances, including ammonia, amines and phenols (Jensen, 2001).…”

Nutrition Discussion Forum

“…In a complex study (Dongowski et al 2002), the physiological effects of DF-rich barley-containing diets (particularly extrudates) from the wholegrain type were evaluated in male Wistar rats. The diets that were fed differed in their concentrations of total DF and of individual DF (for example, b-glucan, RS).…”

“…The aim of that study was to investigate if barley-rich diets with an optimised DF composition would cause beneficial direct or indirect physiological effects in the intestinal tract. It was shown that feeding rats the diets containing 50 g barley products/100 g for 6 weeks resulted in increased masses of the caecum and colon as well as in higher weights of the intestinal contents, and in greater amounts of excreted steroids compared with those rats fed with the barley-free control diet (Dongowski et al 2002). There are only a few reports on the amount of steroids found in the intestinal tract during the feeding of barley-containing diets (Gallaher et al 1992;Lia et al 1995).…”