Question

In energy partitioning, the gross energy content per unit of feed minus the gross energy content per unit of faeces resulting from consumption of that feed represents what among the followings?

• A. Metabolizable energy
• B. Digestible energy
• C. Net energy
• D. Urinary energy

Hint:

Remember the sequential order of energy losses:
1. Faeces: GE \( \rightarrow \) DE
2. Urine & Gas: DE \( \rightarrow \) ME
3. Heat: ME \( \rightarrow \) NE

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Energy partitioning describes how the gross energy of feed is processed and lost as it passes through the animal's digestive tract and metabolism.
As feed is consumed, energy is lost at several consecutive stages: faeces, urine, gases, and metabolic heat.

Step 2: Detailed Explanation:
Let us review the energy flow pathways:
1. Gross Energy (GE):
The total chemical energy in the feed, measured by complete combustion in a bomb calorimeter.
2. Digestible Energy (DE):
The energy remaining after subtracting the energy lost in undigested faeces:
\[ \text{DE} = \text{GE} - \text{Faecal Energy (FE)} \]
3. Metabolizable Energy (ME):
The energy remaining after subtracting energy lost in urine (UE) and combustible gases (such as methane) from DE:
\[ \text{ME} = \text{DE} - \text{Urinary Energy} - \text{Gaseous Energy} \]
4. Net Energy (NE):
The energy remaining after subtracting the heat increment of feeding (heat lost during digestion and metabolism) from ME.
Based on this pathway, Gross Energy minus Faecal Energy represents Digestible Energy.

Step 3: Final Answer:
The value represents Digestible energy, corresponding to option 2.