Apparent digestibility of feedstuffs by Nile tilapia (Oreochromis niloticus)

Apparent digestibility of corn, corn-starch, extruded corn, corn-germ, sorghum, wheat middlings, rice meal, corn gluten meal. gluten 60, soybean meal, canola meal, cottonseed meal, fish meal, meat and bone meal, poultry by-product meal, blood meal and poultry feathers hydrolyzed meal were determined for Nile tilapia juveniles (100 +/- 10 g) fed purified diet and 0.10% chromic oxide. Fish were maintained in 5 aquaria (250 L) at a density of 20 fish/aquarium for feeding, from 8 a.m. to 5:30 p.m. After this period, they were transferred for aquaria (300 L) appropriate for fecal collection. The apparent digestibility of nutrient was determined by assessing the difference between the feed and fecal concentrations of the marker. Results of this study indicate that among energy ingredients, corn, extruded corn, wheat middlings and rice meal had the highest apparent digestibility coefficient and gluten 60, corn gluten meal, canola meal for protein ingredients. Among animal sources, poultry by-product and fish meal showed high apparent coefficients and poultry feathers hydrolyzed and blood meal low apparent coefficients for Nile tilapia.