Question

Which one of the following cereal grains contains a considerable amount of tannins?

• A. Oat
• B. Maize
• C. Barley
• D. Sorghum

Hint:

Feed Grain Antinutritional Factors:
Sorghum = CONDENSED TANNINS (Binds proteins; astringent).
Rye = Ergot alkaloids.
Raw Barley = $\beta$-Glucans.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Polyphenolic antinutritional factors in feed grains: bird-resistant brown sorghum varieties contain high levels of condensed tannins (proanthocyanidins) in the testa layer.
Key Formula or Approach:
\[ \text{Condensed Tannins (Sorghum)} + \text{Dietary/Digestive Proteins} \longrightarrow \text{Insoluble Tannin-Protein Complexes (Reduces Digestibility)} \]

Step 2: Detailed Explanation:
In grain chemistry and animal nutrition:
- Sorghum (Jowar, Sorghum bicolor): Brown and bird-resistant varieties possess a pigmented testa layer containing high concentrations ($1.0 - 5.0\%$) of Condensed Tannins (Proanthocyanidins).
- Tannins bind dietary proteins, digestive proteases, and starches, forming insoluble enzyme-resistant complexes that reduce palatability, feed intake, and protein/energy digestibility in poultry and pigs (mitigated by reconstituting, alkali treatment, or methionine supplementation).
- (Maize, barley, and oats contain negligible tannins).

Step 3: Final Answer:
Thus, Sorghum contains a considerable amount of tannins, corresponding to option (D).