Topics:
Animal Nutrition, Animal Refresher
Estimation of Protein Quality
Method used for estimation of protein quality in ruminants as well as non-ruminants is:
- Nitrogen balance — Correct Answer
- Biological value
- DCP estimation by digestion trial
- Protein equivalent
Explanation:
Correct Answer: Nitrogen balance
Nitrogen balance is the only protein quality method applicable to BOTH ruminants and non-ruminants. It measures the difference between nitrogen (protein) intake and nitrogen excreted (in faeces + urine), reflecting net protein retention or loss in the body.
Protein Quality Evaluation Methods by Species
| Method | Applicable to | Notes |
|---|---|---|
| Nitrogen balance | Both ruminants & non-ruminants | Universal method |
| Biological Value (BV) | Non-ruminants primarily | Based on absorbed N retained |
| PER (Protein Efficiency Ratio) | Non-ruminants | Weight gain per g protein consumed |
| DCP (digestibility trial) | Ruminants | Measures digestible crude protein |
| Protein equivalent | Ruminants | NPN contribution included |
N Balance Formula
- N Balance = N intake − (Faecal N + Urinary N)
- Positive balance = anabolism (growth, pregnancy, lactation)
- Negative balance = catabolism (starvation, disease)
- Zero balance = maintenance
Why Other Options Are Wrong
- Biological value → primarily for non-ruminants; not routinely used in ruminants.
- DCP estimation → ruminant-specific method only.
- Protein equivalent → ruminant-specific (includes NPN sources like urea).
📚 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.
