Available Carbohydrate in Rapeseed Meal and Soybean Meal as Determined by a Chemical Method and a Chick Bioassay

Abstract

Available carbohydrate was determined using a chemical method and a chick bioassay. Results of the chemical assay showed that the total soluble sugars and starch in two samples of rapeseed meal and one sample of soybean meal were 15.0% and 23.6%, respectively. Results of the bioassay showed that the available carbohydrate in the same samples of rapeseed meal and soybean meal was 6.9% and 14.1%, respectively. The values obtained by bioassay are lower than those obtained by chemical analysis, which may be due to the fact that the bioassay reflects not only the amount of available carbohydrate but also its absorbability. Calculations indicate that the difference in amount of available carbohydrate in rapeseed meal and soybean meal accounts for 19% of the difference in metabolizable energy of these two feedstuffs.