High inclusion levels of poultry meals and related byproducts in diets forgilthead seabream Sparus aurata L.

The feasibility of replacing fish meal protein at high levels of 75 and 100 % with a high quality poultry meat meal was assessed in diets for gilthead seabream. A combined mixture of poultry meat meal and feather meal was also tested at high inclusion levels of 75 and 100%. Finally, two lower grade p oultry by-product meals produced for the Greek industry were tested at vari ous levels for comparison. The diets were isocaloric containing 18 MJ/kg of gross energy, isonitrogenous (CP:45%) and had a lipid content of 13% on an as fed basis. The experiment was carried out in a semiclosed rearing syste m and its duration was 84 days. The groups of fish fed 75 and 100% poultry meat meal showed a slight reduction in growth parameters compared to fish f ed the control diet containing white fish meal but was not statistically si gnificant (P < 0.05). Similar results were obtained for the fish fed the po ultry and feather mixture. Feed efficiency, protein and energy utilisation followed the same trends. One of the locally produced meals at substitution levels of up to 50% produced no significant reduction in growth of seabrea m (P < 0.05). At the level of 75% of the protein, however, the material cau sed a severe decrease in growth performance, feed efficiency, protein effic iency ratio and apparent net protein utilisation. Inferior quality was also demonstrated by the other poultry meal available on the Greek market. Prot ein digestibility coefficients were measured for all diets and essential am ino acid indices and chemical score values were calculated. (C) 1999 Elsevi er Science B.V. All rights reserved.