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

Abstract

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 poultry by-product meals produced for the Greek industry were tested at various 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 system 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 fed the control diet containing white fish meal but was not statistically significant ( P<0.05). Similar results were obtained for the fish fed the poultry 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 seabream ( P<0.05). At the level of 75% of the protein, however, the material caused a severe decrease in growth performance, feed efficiency, protein efficiency ratio and apparent net protein utilisation. Inferior quality was also demonstrated by the other poultry meal available on the Greek market. Protein digestibility coefficients were measured for all diets and essential amino acid indices and chemical score values were calculated.