Elimination of Rumen Ciliate Protozoa (Defaunation) | Animal Husbandry & Veterinary Science Optional for UPSC PDF Download

Elimination of Rumen Ciliate Protozoa (Defaunation)

Impact on Rumen Microbial Population:

• Protozoa make up a significant portion of rumen microorganism biomass, and their removal leads to changes in bacterial populations and organic matter digestion.
• Defaunation boosts the total number of bacteria present in the rumen because protozoa consume bacteria and compete with them for nutrients.
• The microflora composition shifts towards smaller Gram-negative and selenomonas-like bacteria in defaunated animals.

Role of Protozoa in Methane Production:

• Protozoa host methanogenic bacteria that work closely with them. These bacteria utilize hydrogen from protozoa to produce methane by reacting with CO₂.

Effects on Fungi and Cell-Wall Carbohydrate Digestion:

• Fungal populations in the rumen increase after defaunation.
• Defaunation notably impacts the digestion of cell-wall carbohydrates, particularly affecting cell-wall carbohydrate breakdown.

Enhanced Microbial Nitrogen Yield and its Implications:

• Defaunation significantly boosts microbial nitrogen yield, promoting net microbial growth and reducing the fermentation of organic matter in the rumen of treated animals.
• This effect is especially beneficial for animals on low-protein diets, where bacterial nitrogen is a primary source of intestinal proteins.

Advantages and Considerations:

• Defaunation can help conserve dietary proteins in low-protein diets but may hinder cell-wall degradation in roughage-poor diets.
• Under defaunation conditions, exploring new cellulolytic bacterial strains or genetically modifying rumen bacteria could enhance cell-wall carbohydrate digestion.