Macronutrient selection by sharp snout seabream ( Diplodus puntazzo)

Abstract

This study is concerned with the investigation of feed preference in juvenile sharp snout seabream ( Diplodus puntazzo). Three isoenergetic diets, high protein–low fat (HPLF), medium protein and fat (MPMF) and high fat–low protein (LPHF) were tested using six feeding regimes. Three groups of fish were used as controls to test the diets independently, while to the other three, a different diet combination was provided (HPLF–MPMF, MPMF–LPHF and HPLF–LPHF). Diets were provided by means of one or two self-feeders and fish had continuous access to one or two diets. Fish had an initial weight of 11.1±3.8 g (mean±S.D.) and after 45 days of feeding, no significant differences ( P<0.05) was observed in specific growth rate (SGR), feed conversion ratio (FCR) and protein efficiency ratio (PER) among different groups. Fish on HPLF–MPMF and HPLF–LPHF feeding regimes showed the highest growth rate of 1.96% per day and the lowest feed conversion ratio of 1.09, respectively. The result obtained showed that although there was different availability of diets among groups, macronutrient consumption appears to converge suggesting a target intake (47% protein and 10% fat content). The protein content of the diet influenced feed consumption, growth and feed conversion ratio.