The gross energy (GE) of feces, urine, diets and rice bran samples were measured by an automatic adiabatic oxygen bomb calorimeter (Parr 6300 Calorimeter, Moline, IL, USA) with benzoic acid as a standard. Before the GE of urine was measured, a 4 mL sample of urine was injected onto 2 filter papers in a special crucible, and dried for 8 h in a 65°C drying oven. The starch content was determined after converting starch to glucose using an enzyme assay kit (Megazym International Ireland, Wicklow, Ireland).