High wholegrain barley β-glucan lowers food intake but does not alter small intestinal macronutrient digestibility in ileorectostomised rats

Abstract

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

Acknowledgements

We thank Bruce May and Paul Orchard for conducting the dietary fibre analyses and Dr Shin Taketa of Okayama University for use of the bgl barley grain and Dr Zhongyi Li, CSIRO Agriculture for the HH29 and Himalaya 292 barley grains used in this study.

Disclosure statement

The authors have no conflict of interest. The study was financially supported by the CSIRO Food Futures Flagship.