Using barley cultivars differing widely in β-glucan content, we aimed to determine their effects on small intestinal macronutrient digestion in 24 ileorectostomised rats. The rats were fed 1 of 4 experimental diets, each containing a different barley variety, for 11 d. The diets had a content of 0, 2.1, 2.6 and 4.3 g of β-glucan/100 g. Feed intake and faecal excretion of fat, protein, starch, and non-starch polysaccharides were determined in the final 5 d of the study and apparent macronutrient digestibility calculated. Higher dietary levels of β-glucan (2.6% and 4.3%) lowered feed intake (by 15 and 19%, respectively) but final body weight was only lowered by the 4.3% β-glucan diet relative to rats fed the 0% β-glucan diet (all ps < 0.05). Protein, lipid and starch digestibility was unrelated to the dietary β-glucan content. Higher dietary levels of barley β-glucan lower feed intake of ileorectostomised rats, which is independent of intestinal fermentation and unrelated to macronutrient digestibility.
Keywords: Barley; beta-glucan; fat; fibre; ileorectostomy; macronutrient digestibility; protein; rat; satiety; starch; wholegrain.