The digestibility of nutrient sources for common carp, Cyprinus carpio Linnaeus

The apparent digestibility of protein, fats, carbohydrate and energy within three feed ingredients (wheat, barley and corn) for common carp, Cyprinus carpio Linnaeus, was studied, using chromic oxide as a dietary marker. Each experimental diet consisted of a mixture of the test ingredient and 50% basal diet (containing 50% soybean meal, 35% wheat meal, 10% soybean oil, plus 5% vitamins, egg yolk, guar and chromic oxide). It was found that in wheat meal the protein had an apparent digestibility of 92%, and the lipid an apparent digestibility of 80%. The apparent digestibility of corn was 81% for protein and 90% for lipid, while for barley the figures were 73% and 67%, respectively. For apparent digestible energy, the figures were 12.39 kJ g^?1 for wheat, 6.69 kJ g^?1 for barley and 9.32 kJ g^?1 for corn.