Table 5.
Estimated change of antioxidant indices in plasma with the Se supplementation from Se yeast (n = 6)a.
| Variation | Equation of regression | Estimated Se supplementation from Se yeast (mg/kg) | Estimated maximum response | P-values | R2 |
|---|---|---|---|---|---|
| Quadratic regression equationb | |||||
| GSH-Px, mmol/ml | Y = 170.6 + 2581.7X – 8693.9X2 | 0.15 | 362 | <0.001 | 0.955 |
| CAT, U/ml | Y = 1.77 + 13.78X – 21.32X2 | 0.32 | 3.99 | <0.001 | 0.486 |
| TAC, U/ml | Y = 2.88 + 96.95X – 340.19X2 | 0.14 | 9.79 | <0.001 | 0.861 |
| MDA/TAC ratio | Y = 9.16 – 101.36X + 325.78X2 | 0.16 | 1.27 | <0.001 | 0.894 |
| Quadratic broken-line regression equationc | |||||
| GSH-Px, mmol/ml | Y = 318.4 – 11565.1 × (0.11 – X)2 | 0.11 | 318 | <0.001 | 0.732 |
| CAT, U/ml | Y = 3.99 – 21.32 × (0.32 – X)2 | 0.32 | 3.99 | <0.001 | 0.486 |
| TAC, U/ml | Y = 8.03 – 195.3 × (0.15 – X)2 | 0.15 | 8.03 | <0.001 | 0.512 |
Se yeast, selenium-enriched yeast; GSH-Px, glutathione peroxidase; CAT, catalase; TAC, total antioxidant capability; MDA, malondialdehyde.
Means were calculated using six replicates per treatment (one bird per replicate).
The quadratic model for regression is Y = A + BX + CX2. Y means the antioxidant indices in plasma, and the Se supplementation from Se yeast was estimated when the concentration of the antioxidant indices reached the maximum response.
The quadratic broken-line model for regression is Y = L + U × (R – X)2, where L is the plateau at values of X > R, R is the abscissa of the breakpoint, and the value of (R – X) is zero at values of X > R. Y means the antioxidant indices in plasma, L means the concentration of antioxidant indices at the plateau, and R means the Se supplementation from Se yeast.