Growth and economic profit of gilthead sea bream (Sparus aurata, L.) fed sunflower meal

The utilisation of sunflower meal as a substitute for fish meal was evaluated in juvenile (44 g ± 4.6 on average) gilthead sea bream fed diets containing four levels of sunflower meal (0, 12, 24 and 36%). The experiment was divided into two phases; in the first one (until day 90), fish reached a weight of 189, 198, 187 and 174 g, respectively, the diet containing 36% gave the lowest specific growth rate (SGR) and the diet containing 12% sunflower meal the highest. In the second phase (from day 91 to day 248), fish growth was not significantly affected by treatments. In relation to feed intake (FI) and feed conversion ratio (FCR), the diet containing 36% sunflower meal gave the worst results in both phases. There were no statistical differences in body composition, but energy and protein efficiency were lowest in fish fed the diet containing 36% sunflower meal. Sensory differences between sea bream fed diets containing 0% and 24% sunflower meal were not detected. Optimum dietary level of sunflower meal for growth and feed conversion obtained from quadratic regression was 10-12%, but when economic aspects were considered, the optimum dietary level was 14-15% sunflower meal.