## 2 Materials and Methods
### Experimental Design and Diet Formulation  
A completely randomized experimental design was used, comprising five dietary treatments with four replicates per treatment. The diets were formulated to include different levels of HFM as a partial replacement for fishmeal, specifically at inclusion rates of 0% (control diet), 1.5%, 3.0%, 4.5%, and 6.0%. The HFM was obtained from BRF. S.A. (Toledo, Parana, Brazil) and its chemical composition are available in Table S1 of Supplementary Materials. To the best of the authors' knowledge, no research has investigated the recommended dietary inclusion level of HFM for _M. rosenbergii_. Thus, the dietary inclusion levels tested in the present trial were selected based on a precautionary approach, that is, we started with a low dosage aiming at minimizing the risk of eventual negative impact on animal health, welfare, and performance, and ensuring a safe evaluation of HFM potential. Diet formulation was carried out using SuperCrac(r) 6.1 software (Vicosa, Minas Gerais, Brazil), ensuring that all diets were iso-nitrogenous (44.2 \(\pm\) 0.4% crude protein) and iso-lipidic (14.8 \(\pm\) 0.1% crude lipids) to meet the nutritional requirements of _M. rosenbergii_ post-larvae [26]. The ingredients and proximate composition of the experimental diets are detailed in Table 1, as well as the diet amino acid (Table 2) and fatty acid profiles (Table 3). \begin{table}
\begin{tabular}{l c c c c c} \hline \hline  & \multicolumn{5}{c}{**Experimental Diets**} \\ \hline  & HFM 0\% & HFM 1.5\% & HFM 3.0\% & HFM 4.5\% & HFM 6.0\% \\ \hline \hline  & 0.00 & 1.50 & 3.00 & 4.50 & 6.00 \\ Fish meal & 12.16 & 10.62 & 9.05 & 7.49 & 5.92 \\ Soybean meal & 35.00 & 33.75 & 32.50 & 31.25 & 30.00 \\ Bone and meat meal & 12.00 & 12.00 & 12.00 & 12.00 & 12.00 \\ Poultry viscera meal & 10.00 & 10.00 & 10.00 & 10.00 & 10.00 \\ Wheat bran & 7.04 & 8.00 & 8.94 & 9.87 & 10.81 \\ Red blood cell meal & 4.00 & 4.00 & 4.00 & 4.00 & 4.00 \\ Ground cord & 5.00 & 5.00 & 5.00 & 5.00 & 5.00 \\ Soy lecithin & 2.00 & 2.00 & 2.0 & 2.00 & 2.00 \\ Fish oil & 8.31 & 8.36 & 8.39 & 8.41 & 8.44 \\ Binder & 0.50 & 0.50 & 0.50 & 0.50 & 0.50 \\ Limestone & 0.81 & 0.92 & 1.02 & 1.11 & 1.21 \\ Potassium chloride & 0.55 & 0.59 & 0.63 & 0.66 & 0.70 \\ Dicalcium phosphate & 0.40 & 0.62 & 0.83 & 1.05 & 1.26 \\ Vitamin and mineral premix 1 & 0.80 & 0.80 & 0.80 & 0.80 & 0.80 \\ Salt & 0.87 & 0.77 & 0.67 & 0.57 & 0.47 \\ DL—methionine & 0.35 & 0.37 & 0.38 & 0.40 & 0.41 \\ Lysine & 0.09 & 0.06 & 0.11 & 0.17 & 0.31 \\ Antifungal & 0.10 & 0.10 & 0.10 & 0.10 & 0.10 \\ Antioxidant & 0.02 & 0.02 & 0.02 & 0.02 & 0.02 \\ Magnesium sulphate & 0.00 & 0.01 & 0.02 & 0.02 & 0.03 \\ Total & 100\% & 100\% & 100\% & 100\% & 100\% \\ Proximate composition & & & & & \\ Dry matter (DM), \% & 93.5 \(\pm\) 0.04 & 93.9 \(\pm\) 0.04 & 94.2 \(\pm\) 0.01 & 93.5 \(\pm\) 0.04 & 93.4 \(\pm\) 0.02 \\ Crude protein, \% DM & 44.4 \(\pm\) 0.09 & 44.2 \(\pm\) 1.06 & 45.0 \(\pm\) 0.26 & 43.7 \(\pm\) 0.56 & 43.9 \(\pm\) 0.01 \\ Crude lipids, \% DM & 14.8 \(\pm\) 0.30 & 14.5 \(\pm\) 0.08 & 14.3 \(\pm\) 0.06 & 15.2 \(\pm\) 0.01 & 15.3 \(\pm\) 0.05 \\ Ash, \% DM & 16.4 \(\pm\) 0.65 & 15.8 \(\pm\) 0.03 & 15.9 \(\pm\) 0.35 & 15.5 \(\pm\) 0.06 & 15.3 \(\pm\) 0.04 \\ Crude fiber, \% DM & 2.90 \(\pm\) 0.21 & 3.21 \(\pm\) 0.15 & 2.65 \(\pm\) 0.69 & 3.49 \(\pm\) 0.15 & 3.21 \(\pm\) 0.14 \\ \hline \hline  & \multicolumn{5}{c}{HFM: Hydrolyzed feather meal: 1 Vitamin and mineral premix (levels per kg of product): vit: A.=1,000,000 IU; vit: D3—50,000 IU; vit: E–200,000 mg; vit: K3—50 mg; vit: B1—190 mg; vit: B2—200 mg; vit: B6—240 mg; vit: B12—3500 mg; folic acid—200 mg; calcium panthenate—400 mg; vit: C—25 g; biotin—40 mg; niacin—500 mg; Fe—12.5 g; Cu—2000 mg; Mn—7500 mg; Zn—25 g; I—200 mg; Fe—70 mg.} \\ \end{tabular}
\end{table} 
Table 2: Amino acid profile (mg/100 g: mean \(\pm\) SD) of the experimental diets containing different levels of hydrolyzed feather meal and fed _Macrobrachium rosenergii_ during the nursery phase.