Fish meal replacement with solvent-extracted soybean meal or soy protein isolate in a practical diet formulation for Florida pompano (Trachinotus carolinus, L.) reared in low salinity

Abstract

Two 8-week growth trials were conducted with juvenile Florida pompano, Trachinotus carolinus fed 0–1000 g kg)1 replacement of fish meal (FM) protein with soybean meal (SBM) or soy protein isolate (SPI). Practical-type diets were formulated with at least 360 g kg)1 digestible protein and 24 mg kJ)1 digestible protein/digestible energy. Weight gain and efficiency were not different between 0 and 800 g kg)1 FM protein replacement with SBM. Regression of weight gain and protein productive value suggested a conservative level of SBM substitution was 380 g kg)1 FM protein. It appeared that lysine could be limiting beyond 400 g kg)1 FM replacement. No significant differences were detected in fish fed 0 and 200 g kg)1 FM protein replacement with SPI. A decrease in weight gain and efficiency parameters occurred at 400 g kg)1 protein replacement, and fish fed a replacement of 600 g kg)1 or greater with SPI exhibited signs of starvation. A third trial indicated intake and growth were significantly reduced (P < 0.0001) in fish fed 600 g kg)1 relative to 0 g kg)1 FM protein replacement with SPI. Poor palatability of diets containing 400 g kg)1 or more FM protein replacement with SPI appeared to be the causative factor for poor performance.