Influence of graded dietary protein levels on gilthead seabream performances (Sparus aurata, L.)

Gilthead sea bream (Sparus aurata) of 70-72 g initial body weight were fed seven extruded iso-energetic diets (22,1 MJ Kg-1) with different protein levels: 35 (diet 35), 38 (diet 38), 41 (diet 41), 44 (diet 44), 47 (diet 47), 50 (diet 50), 53 % (diet 53). Fish were fed to satiation twice a day for six days and once on Sunday during the week. The trial lasted 77 days. Protein dietary level had no effect on feed consumption. SGR was similar in fish fed diets 47, 50 and 53, where the highest values were scored. The lowest value of FCR was registered in fish fed diet 47, even though there was no statistical differences in fish fed diets containing protein from 38 to 53%. From practical considerations, the most profitable combination between SGR and FCR was found in fish fed diet 47