LAUSR

Abstract The aim of study was to characterize the value of crude glycerin as an energy source and to compare chemical composition, pH, density, in vitro dry matter (DM) digestibility (IVDMD), kinetics of thermal decomposition of mass loss and heat flow and in vitro gas production of crude glycerin to those of purified glycerin. Crude glycerin contained 108 g/kg DM of lipids with a proportion of 707.4 g of unsaturated fatty acids per kg of total fatty acids. The IVDMD was higher for pure than crude glycerin (918 versus 766 g/kg DM). Total gas production of crude glycerin was lower than that of pure glycerin (8.5 versus 14.3 ml gas/100 mg DM). Total energy release was greater for crude than purified glycerin (4996 versus 3713 kJ/kg DM). The quality of crude glycerin suggests that crude glycerin could be incorporated in ruminant diets as an energy source.