Table 2.
The effect of partial replacement of fish meal with whey protein concentrate on the growth performance and the whole body composition (g/kg) of Nile tilapia fingerlings.
| Parameters | WPC0 | WPC13.8 | WPC27.7 | WPC41.6 | WPC55.5 | Regression Analysis ** | |
|---|---|---|---|---|---|---|---|
| Linear | Quadratic | ||||||
| Growth performance parameters | |||||||
| Initial wt. (g/fish) | 18.62 ± 0.19 | 18.43 ± 0.04 | 18.71 ± 0.04 | 18.77 ± 0.07 | 18.73 ± 0.07 | 0.11 | 0.84 |
| Final BW (g/fish) | 30.08 ± 0.89 | 30.01 ± 0.79 | 28.62 ± 0.21 | 29.69 ± 1.16 | 28.61 ± 0.48 | 0.21 | 0.88 |
| Daily BWG (g/fish) | 0.16 ± 0.01 | 0.16 ± 0.01 | 0.14 ± 0.003 | 0.15 ± 0.01 | 0.14 ± 0.007 | 0.13 | 0.89 |
| Total BWG (g/fish) | 11.46 ± 0.74 | 11.57 ± 0.76 | 9.91 ± 0.25 | 10.92 ± 1.11 | 9.87 ± 0.55 | 0.13 | 0.89 |
| Total FI (g/fish) | 30.23 ± 1.64 | 27.40 ± 1.65 | 26.23 ± 1.01 | 30.62 ± 1.02 | 29.33 ± 0.60 | 0.72 | 0.09 |
| FCR | 2.67 ± 0.28 | 2.37 ± 0.06 | 2.65 ± 0.16 | 2.86 ± 0.32 | 2.98 ± 0.16 | 0.14 | 0.37 |
| PER | 1.14 ± 0.13 | 1.25 ± 0.03 | 1.13 ± 0.07 | 1.06 ± 0.11 | 1.001 ± 0.05 | 0.01 | 0.98 |
| SGR (%/day) | 0.68 ± 0.03 | 0.69 ± 0.03 | 0.60 ± 0.01 | 0.65 ± 0.05 | 0.60 ± 0.02 | 0.09 | 0.90 |
| Survival% after bacterial challenge | 66.66 ± 7.95 | 88.88 ± 2.63 | 91.11 ± 2.22 | 95.55 ± 2.47 | 97.77 ± 2.22 | 0.00 | 0.03 |
| Total wt. of the surviving fish after bacterial challenge (g) | 299.15 ± 27.89 | 409.81 ± 9.84 | 381.72 ± 10.17 | 425.74 ± 20.19 | 419.83 ± 15.02 | 0.001 | 0.03 |
| Whole body composition (g/kg) | |||||||
| Dry Matter # | 222.6 ± 0.8 | 222.6 ± 8.7 | 229.0 ± 3.1 | 226.3 ± 3.5 | 230.1 ± 3.8 | 0.29 | 0.70 |
| Crude protein * | 652.8 ± 5.83 | 683.3 ± 21.73 | 661.0 ± 21.10 | 660.1 ± 11.3 | 683.3 ± 15.9 | 0.481 | 0.912 |
| Fat * | 156.6 ± 8.8 | 156.6 ± 3.3 | 170.0 ± 5.7 | 133.3 ± 8.8 | 136.6 ± 8.8 | 0.02 | 0.15 |
| Ash * | 113.0 ± 3.8 | 113.3 ± 8.4 | 100.06 ± 1.3 | 139.1 ± 0. 9 | 121.8 ± 2.5 | 0.01 | 0.31 |
** The regressions were considered significant when p ≤ 0.05. BW: Body weight; BWG: Body weight gain; FI: Feed intake; FCR: Feed conversion ratio; PER: Protein efficiency ratio; SGR: Specific growth rate. # On a fresh basis. * On dry matter basis.