Topics:
Animal Nutrition, Animal Refresher
Components Excluded from ADF
In detergent method of forage analysis, Acid detergent fiber (ADF) does NOT include:
- Cellulose
- Hemicelluloses — Correct Answer
- Lignin
- Silica
Explanation:
Correct Answer: Hemicellulose
In the Van Soest detergent method, Acid Detergent Fibre (ADF) contains cellulose, lignin, and silica — but NOT hemicellulose. Hemicellulose is the component that distinguishes NDF from ADF (ADS = NDF − ADF = Hemicellulose).
Van Soest Method — Fibre Fractions
| Fraction | Components |
|---|---|
| NDF (Neutral Detergent Fibre) | Hemicellulose + Cellulose + Lignin + Silica (entire plant cell wall) |
| ADF (Acid Detergent Fibre) | Cellulose + Lignin + Silica (NOT hemicellulose) |
| ADS (Acid Detergent Soluble) | Hemicellulose (= NDF − ADF) |
| NDS (Neutral Detergent Solubles) | Soluble carbohydrates, starch, proteins, pectins (cell contents) |
Key Relationship
- NDF − ADF = Hemicellulose (the ADF-soluble = ADS fraction)
- ADF is boiled with Acid Detergent Solution: CTAB in 1N H₂SO₄
- NDF is boiled with Neutral Detergent (Sodium Lauryl Sulphate) at pH 7
Why Other Options Are Wrong
- Cellulose → IS included in ADF
- Lignin → IS included in ADF (most indigestible component)
- Silica → IS included in ADF (Acid Insoluble Ash portion)
📚 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.
