Following the NRC (1985), the estimation of energy in pet foods is based on the chemical proximate analysis, assuming constant crude protein (CP), ether extract (EE) and nitrogen free extract (NFE) digestibilities. Recently, factorial equations based on the close relationship existing between the energy digestibility of foods and their crude fiber content have been proposed as good approaches for predicting energy content of food (Kienzle et al., 1998; Castrillo et al., 2001). The aim of this study was to develop a simple and reproducible in vitro method for predicting apparent energy digestibility of dry extruded dog foods
