Tuna liver meal (TLM) was tested to replace fish meal (FM) in diets for carp fry, Cyprinus carpio Linneus, 1758. Triplicate groups of fish with average weight of 0.32 ± 0.65g were fed each of six isonitogenous (42%), isolipidic (16%) and isoenergetic (18 KJ DE g^-1) diets prepared to include 0, 10, 20, 30, 40 and 50% (diets 1- 6, respectively) of FM protein being substituted by TLM. The control diet contained fish meal (17.14%) and soybean meal (46.9%) as the main sources of dietary protein. After 13 weeks of feeding, fish fed diet 2 and diet 3 exhibited the highest (P<0.05) values for live weight gain, specific growth rate, condition factor, better feed conversion ratio and protein efficiency ratio compared to the others. Survival range was from 70 to 87.5%. However, fish fed diet 6 exhibited lower growth and survival than those fed other diets. Apparent protein and lipid digestibility values for fish fed diet 2 or diet 3 were higher than the others. There were no significant (P>0.05) differences in the crude protein and ash content in the whole-body. However, moisture and lipid contents were significantly (P<0.05) affected by dietary treatments. These results indicate that up to 20% of FM protein in fish diet can be replaced by TLM without adverse effects on fish growth, feed utilization and body composition.

Key words: Cyprinus carpio, fish meal, tuna liver meal, growth, digestibility.