This present study was carried out at the facilities of the Alto Amazonas Agrarian Agency between November 2022 - April 2023, with the purpose of evaluating the growth of “paco”, Piaractus brachypomus, fed with a diet based on predigested soybean cake (TSP) and grown under a closed recirculation system. The recirculation system was made up of 9 experimental units such as 160 l plastic trays, applying 3 treatments (T1=30% TSP; T2=40% TSP and T3=50% TSP), each treatment with 3 repetitions, with 9 experimental units; Likewise, the diet digestibility study was carried out. The results show greater use in the fish fed with the T3 treatment, achieving greater growth in weight and length, finding a significant difference (p<0.05) between the treatments evaluated; Likewise, a significant difference (p<0.05) was found in the specific growth rate (SGR), feed conversion factor (FCA) and surviva...