Topics:
Animal Nutrition, Animal Refresher
Definition of Net Protein Utilization
Net protein utilization (NPU) is defined as:
- $\frac{Retained N}{Intake N} \times 100$
- $Biological value \times Digestibility coefficient$
- Both correct — Correct Answer
- None
Explanation:
Correct Answer: Both correct
Net Protein Utilization (NPU) can be validly defined by both formulas: (1) Retained N / Intake N × 100 (direct measurement), and (2) Biological Value (BV) × Digestibility Coefficient (calculated from component measures). Both yield the same result and are used in different experimental contexts.
Protein Quality Evaluation Parameters
| Parameter | Formula | Measures |
|---|---|---|
| Biological Value (BV) | Retained N / Absorbed N × 100 | Efficiency of absorbed protein retention |
| Digestibility Coefficient (DC) | Absorbed N / Intake N × 100 | Proportion of N absorbed from diet |
| NPU | Retained N / Intake N × 100 = BV × DC | Overall protein utilization efficiency |
| PER | Weight gain / Protein consumed | Growth per unit protein (for non-ruminants) |
Key Relationships
- NPU = BV × Digestibility — this is a mathematical identity, not an approximation.
- NPU considers BOTH absorption (digestibility) and retention (biological value) losses.
- NPU is applicable to both ruminants and non-ruminants.
- Ideal protein: NPU approaches 100% (complete retention of all dietary N).
Why Other Options Are Wrong
- Each individual formula alone is incomplete — Both correct is the right answer since the two expressions are mathematically equivalent.
📚 About this Topic — Animal Nutrition
This multiple choice question is from Animal Nutrition, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Nutrition to strengthen your preparation.
