A study of partial replacement of fish meal with sunflower meal on growth, amino acid retention, and body composition of sharpsnout seabream, Diplodus puntazzo (Actinopterygii: Perciformes: Sparidae)

Abstract

Background. Our previous study demonstrated that sharpsnout seabream, Diplodus puntazzo (Walbaum, 1792), can be fed with up to 34.8% sunflower meal (SFM), with excellent results in growth parameters and feed efficiency. The aim of the current study was to test the replacement of fish meal with SFM in the diet formulation for sharpsnout seabream and to evaluate growth, nutritive parameters, amino acid retention, and body composition of the fish during the fattening period.

Materials and methods. Sixteen baskets (300-L capacity), each with thirteen fish, were distributed in a recirculated saltwater system to allow four experimental diets containing 40% crude protein (CP) and 20% crude lipid (CL) with 0%, 11.7%, 23.5%, and 34.8% SFM partially replacing fish meal to be used in quadruplicate for this experiment. The fish were fed these diets ad libitum during the experiment, which lasted for 162 days. Growth, nutrition efficiency, biometrics, carcass composition, amino acid composition, and amino acid retention of the experimental fish were evaluated.

Results. There were no statistical differences in the growth parameters among the treatments. However, fish fed a diet containing 34.8% SFM had the lowest feed intake (FI), lowest feed conversion ratio (FCR), and the highest protein efficiency ratio (PER). There were also no statistical differences in the biometric parameters although fish fed the diet containing 10% SFM had the lowest CP levels. Leucine was the only difference in the essential amino acid (EEA) profile with fish fed a diet containing 11.7% SFM having the lowest levels of leucine. Although there were fluctuations among the amino acid retentions, they were not statistically significant.

Conclusion. SFM (up to 34.8%) can be included in the diets of sharpsnout seabream, thereby, replacing 27% of the fish meal without altering the fish growth.