The effect of crude fibre on apparent digestibility and digestible energy content of extruded dog foods.

The apparent digestibility of nutrients and energy of 38 commercial dry extruded dog foods was measured using six adult (2 to 3 year-old) female Beagles. Diets contained [in g/kg dry matter (DM)]: 164-360 crude protein (CP); 79-261 ether extracts (EE); 8-33 crude fibre (CF) and 318-585 nitrogen free extracts (NFE). Apparent energy digestibility ranged from 77.3 to 91.6%, and was closely related to CF content (r=-0.85), yielding the resultant equation: GED (%)=94.00 - 4.04 x CF (% DM). The estimation of digestible energy content of foods from digestibility coefficients predicted from the above equation and gross energy measured or estimated from the Weende fractions, provides a more accurate prediction of experimental values than the Atwater approach followed by the National Research Council and the Association of American Feed Control Officials.