Evaluation of Nitrogen-Corrected Metabolizable Energy of Feedstuffs Commonly Used for Dry Canine Diets

Abstract

Four mature Beagles weighing 15 kg on average were used to determine digestible energy (DE) and digestible crude protein (DCP) contents of 20 samples of 17 feedstuffs, and nitrogencorrected metabolizable energy (MEn) was individually estimated with an equation [MEn = -DE1.25DCP], which was proposed by our previous work. Digestibility of crude protein, acid ether extract, and nitrogen-free extract varied in a wide range among feedstuffs, even among three samples of feather meal. The digestibility of crude protein, acid ether extract, and nitrogen-free extract as well as the DE content showed a significant negative correlation with crude fiber contents among 13 samples of 12 feedstuffs other than animal by-product feedstuffs and cornstarch. The system proposed by NRC to evaluate dietary metabolizable energy (ME) in dogs tended to underestimate the energy value of some feedstuffs, especially low-fiber starchy feedstuffs such as cereals and cornstarch, but tended to overestimate other feedstuffs, especially high-fiber feedstuffs such as wheat bran and rice bran. This was due to the fixed digestibility of proximate components adopted by NRC. Present results suggest that the MEn obtained by applying actually determined DE and DCP to the above equation would be more reliable than the ME values estimated according to the NRC system.