Table 8 Multiple regression analysis to choose the most important protein spectral parameters to predict protein supply using the NRC model
Predicted variable, Y | Variable selection (variables left in the model with P < 0.05) | Equation prediction: Y = a + b1 × x1 + b2 × x2 + … … . | Model R2 | RSDa | P value |
|---|---|---|---|---|---|
Absorbable microbial protein synthesis in the rumen (AMCP)b | |||||
MCPRDP | Amide I height, β-sheet height | Y = 106.55–703.13 × Amide I height + 1008.90 × β-sheet height | 0.67 | 11.507 | < 0.01 |
MCPTDN | Amide I height, β-sheet height | Y = 87.07 + 287.78 × Amide I height – 272.73 × β-sheet height | 0.82 | 1.470 | < 0.01 |
AMCP | Amide I height, β-sheet height | Y = 55.72 + 184.17 × Amide I height – 174.54 × β-sheet height | 0.82 | 0.941 | < 0.01 |
Truly absorbable rumen-the undegraded protein in the small intestine (ARUP)c | |||||
RUP | Amide I, II ratio | Y = −132.49 – 142.47 × Amide I, II ratio | 0.34 | 28.926 | < 0.01 |
ARUP | Amide I, II ratio | Y = −165.71 – 138.71 × Amide I, II ratio | 0.38 | 26.039 | < 0.01 |
Total metabolizable protein (MP) and degraded protein balance (DPB)d | |||||
MP | Amide I, II ratio | Y = −110.83 – 142.07 × Amide I, II ratio | 0.37 | 27.278 | < 0.01 |
DPB | Amide I height, β-sheet height | Y = 22.61–1166.80 × Amide I height + 1508.67 × β-sheet height | 0.74 | 13.358 | < 0.01 |
Feed milk values based on metabolic characteristics of protein predicted by NRC systeme | |||||
FMV | Amide I, II ratio | Y = −1.62 + 2.45 × Amide I, II ratio | 0.20 | 0.710 | < 0.01 |