Topics:
Animal Nutrition, Animal Refresher
Energy Density of Fats
The energy of fat is how many times that of carbohydrate & protein?
- 1.25
- 2.25 — Correct Answer
- 6.25
- None
Explanation:
Correct Answer: 2.25
Fat (lipid) contains 2.25 times more energy than carbohydrates and proteins on a gram-for-gram basis. This is used in the TDN calculation formula: TDN% = DCP% + DCF% + DNFE% + (DEE% × 2.25).
Gross Energy Values of Major Nutrients
| Nutrient | Gross Energy (kcal/g) | Physiological Fuel Value (kcal/g) |
|---|---|---|
| Carbohydrate | 4.15 | 4.0 |
| Fat | 9.4 | 9.0 |
| Protein | 5.65 (−1.25 urinary loss) | 4.0 |
Why Fat Has Higher Energy
- Fats have a high H:O ratio — more hydrogen atoms available for oxidation compared to carbohydrates (which are already partially oxidized).
- Complete oxidation of fat yields more ATP per gram than carbohydrates or protein.
- Fat provides ~9 kcal/g vs carbohydrate's ~4 kcal/g → ratio of 9/4 ≈ 2.25×.
Why Other Options Are Wrong
- 1.25 → the energy loss correction for protein (5.65 − 1.25 = 4.4 kcal/g for protein); not the fat:carbohydrate ratio.
- 6.25 → the nitrogen-to-protein conversion factor (100/16 = 6.25); used in CP calculation.
- None → 2.25 is the correct multiplier.
📚 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.
