Topics:
Animal Nutrition, Animal Refresher
Controller of Rumen Microbial Population
Microbial population in rumen is controlled by:
- Bacteria
- Fungi
- Protozoa — Correct Answer
- None
Explanation:
Correct Answer: Protozoa
Protozoa control the rumen microbial population because they actively prey on bacteria — engulfing and digesting bacterial cells. This predator-prey relationship determines the equilibrium of bacterial numbers in the rumen.
Protozoa as Population Controllers
- Protozoa (population: 10⁶/ml) prey on bacteria (population: 10¹⁰⁻¹¹/ml)
- By eating bacteria, protozoa prevent excessive bacterial overgrowth
- Defaunation (removal of protozoa) → bacterial numbers increase significantly
- Majority of rumen protozoa are ciliate protozoa
- Also described as "mini-ruminant" by Von Soest
Functions of Each Rumen Microorganism
| Organism | Primary Function |
|---|---|
| Protozoa | Controls bacterial population; starch engulfment; rumen buffering |
| Bacteria | VFA production; fibre/starch fermentation |
| Fungi | Substrate penetration by breaking lignocellulosic bonds |
| Bacteriophage | Lyses bacteria → releases bacterial protein for host |
Why Other Options Are Wrong
- Bacteria → the prey in this relationship; do not control the population of other microbes
- Fungi → break down lignocellulosic material; do not control total microbial population
- None → incorrect; protozoa are established as the population controllers through predation
📚 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.
