<p> Supplementary Data Supplementary Table 1. Ash and elemental composition of juvenile Atlantic salmon body cross-sections</p><p>Mineral Composition (× kg-1) SPC35 SPC50 SPC65 SPC80 *Model Day 63(prior to vaccination) Selected with P < 0.05 Ash (g) 2.12±0.06 2.00±0.03 1.90±0.06 1.83±0.08 Linear Phosphorus (P) (mg) 4887±208 4875±472 4220±102 4336±314 Linear Calcium (Ca) (mg) 4265±286 4269±511 3602±95 3069±704 Linear Ca: P ratio 0.87±0.03 0.87±0.03 0.85±0.01 0.70±0.01 Linear Magnesium (Mg) (mg) 369±11 351±12 320±4 345±22 Quadratic Manganese (Mn) (mg) 0.96±0.05 1.09±0.21 0.85±0.11 0.82±0.05 Linear Zinc (Zn) (mg) 22.02±0.67 22.29±2.78 19.41±0.88 20.88±1.64 Linear Day 97(34 days post vaccination) Ash (g) 1.77±0.02 1.85±0.05 1.74±0.05 1.71±0.09 Linear Phosphorus (P) (mg) 3480±25 3602±53 3439±114 3261±62 Linear Calcium (Ca) (mg) 2127±171 2328±190 2002±101 1816±89 Linear Ca: P ratio 0.61±0.04 0.65±0.05 0.58±0.02 0.56±0.04 Linear Magnesium (Mg) (mg) 305±5 315±5 308±12 298±4 Quadratic Manganese (Mn) (mg) 0.56±0.05 0.70±0.08 0.58±0.06 0.54±0.02 Linear Zinc (Zn) (mg) 13.29±1.28 14.60±1.11 13.19±0.67 12.06±0.58 Linear</p><p>Data for ash and elemental composition are referred as means ± SD of 4 pooled samples (1 pool of 6 body cross-section homogenates per tank) (Raw data). Abbreviations: SPC 35 - diet with 35 % of dietary protein from soy protein concentrate (SPC); SPC 50 - diet with 50 % of dietary protein from SPC; SPC 65 - diet with 65 % of dietary protein from SPC; SPC 80 - diet with 80% of dietary protein from SPC. *Raw data were fitted in models with increasing complexity where tank was included as a random effect, sampling time as a categorical variable and the percentage of protein from SPC as a continuous factor possibly having non-linear (quadratic) effects. The Linear model included sampling time and the % of dietary protein from SPC with their interaction whereas the Quadratic model was more complex including an additional quadratic effect of the % of dietary protein from SPC with interactions to reveal any non-linearity in the studied response. The models were compared with a likelihood ratio test (LRT) to assess if the improvement in the likelihood required a more complex model or whether the simpler model was sufficient for the description of the data. Models demonstrating possibilities (P values) < 0.05 were selected as the best for the description of these data. Supplementary Data</p><p>Supplementary Table 2. Haematological and immunological responses of Atlantic salmon juveniles</p><p>PRE *Model VACCINATIO SPC35 SPC50 SPC65 SPC80 Selected with P N < 0.05 Haematocrit (%) 53.0±4.5 51.9±4.7 51.8±4.7 51.3±4.4 Linear Leucocytes (× 107× 6.7±2.3 7.5± 1.7 7.1± 0.9 6.4 ±2.0 Linear ml-1) Lymphocytes (×107× 4.2±1.6 4.3±1.1 4.1±0.6 3.6±1.4 Linear ml-1) Thrombocytes 2.2±0.9 3.0±1.0 2.6±0.7 2.7±1.2 Quadratic (×107× ml-1) Granulocytes (×107× 0.1±0.1 0.1±0.1 0.1±0.1 0.1±0.04 - ml-1) Monocytes (×107× 0.02±0.02 0.02±0.02 0.02±0.02 0.02±0.03 - ml-1) Lysozyme act. (units × min-1× ml-1 of 369.8±80.4 480.2±90.9 442.1±78.2 389.7±118.5 Quadratic plasma) Haemolytic act. -1 (units H50 × ml of 444.3±87.9 497.4±130.4 528.4±105.2 416.4±64.8 Quadratic plasma) HKMs resp. burst (NBT) (OD for 105 0.2±0.2 0.2±0.1 0.2±0.1 0.3±0.1 - nuclei) Stimulated HKMs resp. burst (OD for 0.4±0.3 0.4±0.2 0.4±0.3 0.5±0.2 - 105 nuclei) Total plasma protein (mg × ml-1 of 48.3±5.2 49.5±3.6 47.7±2.8 47.4±4.9 - plasma) Antiprotease activity -1 845.6±96.6 908±39.8 855.7±60.2 891.6±67.4 - (Units TI75 × ml )** Total plasma IgM (mg × ml-1 of 1.9±3.0 1.3±2.3 2.3±2.0 0.9±1.1 Quadratic plasma) 7 DAYS POST VACCINATIO N Haematocrit (%) 52.2±5.1 49.4±4.3 51.6±6.7 47.8±4.3 Linear Leucocytes (× 107 × 8.4±1.7 8.5±1.9 8.2±3.0 6.4±2.5 Linear ml-1) Lymphocytes (×107× 4.5±1.3 4.7±1.5 4.8±1.9 3.5±1.5 Linear ml-1) Thrombocytes 3.4±1.0 3.3±0.9 3.1±1.3 2.6±1.2 Quadratic (×107× ml-1) Granulocytes (×107× 0.4±0.3 0.4±0.3 0.4±0.3 0.3±0.2 - ml-1) Monocytes (×107× 0.02±0.03 0.04±0.04 0.03±0.04 0.02±0.02 - ml-1) Lysozyme act. (units × min-1× ml-1 of 639.4±216.0 719.4±75.1 662.0±184.1 698.63±97.0 Quadratic plasma) Haemolytic act. -1 (units H50 × ml of 446.0±96.1 447.2±108.1 529.0±133.7 507.6±209.1 Quadratic plasma) HKMs resp. burst (NBT) (OD for 105 0.6±0.5 0.8±0.4 0.9±0.3 0.8±0.2 - nuclei) Stimulated HKMs resp. burst (OD for 0.9±0.8 1.0±0.6 1.1±0.4 1.1±0.3 - 105 nuclei) Total plasma protein (mg × ml-1 of 42.1±5.7 39.5±2.6 40.3±3.1 37.3±3.5 - plasma) Antiprotease activity -1 653.3±98.6 677.9±138.2 647.1±98.0 667.8±97.6 - (Units TI75 × ml )** Total plasma IgM 3.6±2.3 4.9±3.6 6.5±4.1 3.8±2.9 Quadratic (mg × ml-1 of plasma) 34 DAYS POST VACCINATIO N Haematocrit (%) 55.3±4.1 54.5±2.8 54.4±3.3 53.0±4.9 Linear Leucocytes (× 107× 8.7±1.5 8.6±1.5 9.4±2.9 9.3±2.9 Linear ml-1) Lymphocytes (×107× 4.1±0.9 3.9±1.2 4.8±1.7 5.5±2.7 Linear ml-1) Thrombocytes 4.2±1.1 4.5±1.2 4.8±2.2 3.8±1.2 Quadratic (×107× ml-1) Granulocytes (×107× 0.4±0.2 0.2±0.1 0.3±0.2 0.2±0.1 - ml-1) Monocytes (×107× 0.05±0.05 0.03±0.03 0.05±0.05 0.04±0.05 - ml-1) Lysozyme act. (units × min-1× ml-1 of 438.4±68.4 373.3±96.3 450.4±62.7 390.0±78.9 Quadratic plasma) Haemolytic act. -1 (units H50 × ml of 1183.7±126.7 1344.6±242.2 1424.9±208.2 1072.4±126.9 Quadratic plasma) HKMs resp. burst (NBT) (OD for 105 0.2±0.1 0.3±0.2 0.2±0.1 0.3±0.2 - nuclei) Stimulated HKMs resp. burst (OD for 0.3±0.1 0.3±0.2 0.2±0.1 0.3±0.2 - 105 nuclei) Total plasma protein (mg × ml-1 of 46.4±7.7 8.6±1.5 9.4±2.9 9.3±2.9 - plasma) Antiprotease activity -1 596.6±15.9 604.0±16.8 600.6±30.2 598.9±11.6 - (Units TI75 × ml )** Total plasma IgM (mg × ml-1 of 3.6±3.8 6.4±2.6 5.6±2.8 2.9±2.2 Quadratic plasma) Specific IgM 0.02±0.01 0.02±0.01 0.02±0.01 0.02±0.01 - (plasma titers)</p><p>Values for immune responses are means ±SD of 8 pools of 2 fish per diet ±SD; haematocrit values are means ±SD of 24 fish; leukocyte and differential leucocyte counts are means ± SD of 12 fish per diet. (Raw data) Abbreviations: SPC 35 - diet with 35 % soy protein concentrate (SPC); SPC 50 - diet with 50 % SPC; SPC 65 - diet with 65 % SPC; SPC 80 - diet with 80% SPC. -1 -1 **Units TI75 × min × ml of plasma. *Raw data were fitted in models with increasing complexity where tank was included as a random effect, sampling time as a categorical variable and the percentage of protein from SPC as a continuous factor possibly having non-linear (quadratic) effects. The Linear model included sampling time and the % of dietary protein from SPC with their interaction whereas the Quadratic model was more complex including an additional quadratic effect of the % of dietary protein from SPC with interactions to reveal any non-linearity in the studied response. The models were compared with a likelihood ratio test (LRT) to assess if the improvement in the likelihood required a more complex model or whether the simpler model was sufficient for the description of the data. Models demonstrating possibilities (P values) < 0.05 were selected as the best for the description of these data. </p>