Evaluation of Bioprocessed Soy Products As Fish Meal Replacements in Yellow Perch Diets

A 14-week feeding trial was conducted to evaluate juvenile Yellow Perch Perca flavescens (Mitchill) response to diets containing bioprocessed soy white flake (BWF), pretreated BWF (EBWF), or commercial soy protein concentrate (SPC) as complete fish meal (FM) replacements. A FM control and six test diets were formulated in a factorial design using the three basal soy products, with and without lysine and methionine supplementation. Relative growth of fish fed the supplemented EBWF diet (338%) was not significantly different from the FM control (402%). The commercial SPC diet resulted in depressed survival, consumption and growth performance, but improved feed efficiency and apparent protein digestibility. Amino acid supplementation consistently improved growth performance and fillet yield across soy-based diets. Intestinal histology scores showed no significant difference between diets. Organosomatic measurements revealed significantly lower visceral fat and hepatosomatic indices in fish fed the SPC diet. Overall, results indicate that progressive pretreatment and processing can improve growth performance over commercial SPC. Given the increasing cost and reduced availability of FM, further research is needed to optimize soy bioprocessing conditions to successfully minimize or eliminate the use of FM in Yellow Perch diets.