In this paper, a mathematical model was used to evaluate a dynamical hybrid system for optimizing and controlling the efficacy of plant-based protein in aquafeeds. Fishmeal, raw rapeseed meal, and a fermented meal with yeast and fungi were used as test ingredients for the determination of apparent digestibility coefficients of dry matter, crude protein, crude lipid, energy, and essential amino acids for olive flounder using diets containing 0.5% Cr2O3 as an inert indicator. Among all ingredients tested, FM had the maximum (...) ADC of dry matter, and energy. Fermented meals showed higher ADC. Amino acid digestibility reflects protein digestibility in most cases. Interestingly, protease, lipase, and amylase activities were better expressed in RM-Koji, RM-Yeast, and FM over RM, respectively. The current results deliver important information on nutrients and energy bioavailability in raw and fermented RM, which can be implemented to accurately formulate applied feeds for olive flounder. Compared with other applicable systems, the complexity of the approach implemented has been considerably reduced. (shrink)