Ž . Aquaculture 179 1999 25–33 ž Growth of mediterranean yellowtail Seriola / dumerilii fed extruded diets containing different levels of protein and lipid M. Jover a, ) , A. Garcıa-Gomez b,1 , A. Tomas a,2 , ´ ´ ´ F. De la Gandara b,1 , L. Perez a,2 ´ ´ a Departamento de Ciencia Animal, Laboratorio de Acuicultura, UniÕersidad Politecnica de Valencia, Camino ´ de Vera, 14, 46071, Valencia, Spain b Instituto Espanol de Oceanografıa, Centro Oceanografico de Murcia, Planta Experimental de CultiÕos ˜ ´ ´ Marinos, Carretera de la Azohıa s r n, 30860-Puerto de Mazarron, Murcia, Spain ´ ´ Abstract Young Mediterranean yellowtail were maintained for 10 months in three different weight Ž . groups 114, 141 and 192 g initial mean liveweight and fed four extruded diets containing two Ž . Ž . protein levels 45 and 50% CP and two lipid levels 14 and 17% according to a factorial design. Survival at the end of trial was around 70% and was unaffected by treatment. Final mean liveweights were 1044, 1098, 1336 and 1163 g for groups fed 45r14, 45r17, 50r14 and 50r17 proteinrlipid diets, respectively. The effect of lipid level was not significant, but the growth of fish fed diets containing 50% CP was higher than those fed the 45% CP diets. Nutritive parameters such as, feed intake, feed conversion ratio and PER were not affected by diets. Body composition and nutrient retention values were similar for fish fed various diets. Viscerosomatic index was higher for fish fed diets containing 17% lipid and hepatosomatic index was higher for those fed 50% CP or 12% lipid. Dressout percentage was higher for fish fed diets containing 50% CP. q 1999 Elsevier Science B.V. All rights reserved. Keywords: Seriola dumerilii; Yellowtail; Nutrition; Growth; Protein; Cooking-extruded diets ) Corresponding author. Tel.: q34-6-3877434; fax: q34-6-3877439; E-mail: mjover@dca.upv.es 1 Tel.: q34-68-153339; fax: q34-68-153934. 2 Tel.: q34-6-3877434; fax: q34-6-3877439. 0044-8486r99r$ - see front matter q 1999 Elsevier Science B.V. All rights reserved. Ž . PII: S0044-8486 99 00149-0