Topics:
Animal Nutrition, Animal Refresher
Characteristics of Ruminal Bacteria
Which of the following is true about ruminal bacteria?
- The majority of rumen bacteria are gram (-)ve & obligate anaerobes
- Population of rumen bacteria per ml of rumen liquor is $10^{9}-10^{11}$
- They grow well at $39^{\circ}C$ temperature
- All the above — Correct Answer
Explanation:
Correct Answer: All the above
All three statements about ruminal bacteria are correct: the majority are Gram-negative obligate anaerobes, the bacterial population is 10⁹–10¹¹ per ml (textbook notes 10¹⁰⁻¹¹ per ml), and they grow optimally at 39°C.
Ruminal Bacteria — Key Facts
| Feature | Details |
|---|---|
| Gram staining | Majority are Gram (−)ve |
| Oxygen requirement | Mostly obligate anaerobes |
| Exception | Lactic acid-producing bacteria are facultative anaerobes; attached to ruminal wall |
| Population (per ml rumen liquor) | 10¹⁰⁻¹¹ (bacteria); 10⁶ (protozoa); 10³ (fungi); 10⁹ (bacteriophage) |
| Optimal temperature | 39°C |
| Normal rumen pH | 6.5–6.8 |
Key Ruminal Bacteria by Function
- Cellulose digesting: Fibrobacter succinogenes, Ruminococcus albus
- Starch digesting: Streptococcus bovis
- Methanogenic: Methanobacterium ruminantium
- Hemicellulose digesting: Butyrivibrio fibrisolvens
Why Other Options Are Wrong
- Each individual statement is correct on its own — making "All the above" the complete and accurate answer
📚 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.
