The influence of energy level on the feed intake, growth, food conversion and body composition of Sparus aurata

Abstract Sparus aurata of mean weight 43.7 g were fed five diets differing in energy (soybean oil) for three months. Lowest energy diet contained 19,610 J/g and highest 21,140 J/g. Protein and fat contents for the species exceeded the minimum requirements of 40% and 8%, respectively. Feed intake and growth were significantly higher for fish on the lower energy (soybean oil) diets. Energy conversion factor was also significantly lower in the lower energy diets. No significant differences in feed or protein and ash conversion factors, protein efficiency ratio, protein productive value and feed conversion efficiency were found. Increases in body protein and fat and energy were significantly higher in the lower energy treatments; however, body composition was not affected by treatment. Significant correlation coefficients between different body components enabled calculation of regression equations by which biologically important parameters, such as protein, fat, ash and energy, can be estimated from a relatively simple moisture determination.