ANSC 433 Lecture Notes - Lecture 3: Rumen, Anaerobic Organism, Syntrophy
23 May 2018
School
Department
Course
Professor
ANSC 433 – Animal Nutrition & Metabolism Chantal Coutu
1
Rumen Microbiology and Fermentation
The Rumen Environment
The Rumen as a fermentation vat
Inputs
Conditions
End Products
Carbon source
• Cellulose
• Hemicellulose
• Starch
N source
• NPN
• Protein
Lipids
Minerals
Vitamins
- Anaerobic
(anaerobiosis)
- Proper
microorganisms
(microbes)
- Warm (temp = 38-
42oC)
- pH = 5.5 – 7.5
- Fluid = water (saliva)
- Missing of rumen
contents
VFAs
• Acetate
• Propionate
• Butyrate
Microbes
• Protein
• Nucleic acids
By products
• Heat
• Methane (CH4)
• NH3
Rumen microorganisms
− General aspects
o One of the most complex natural microbial ecosystems
o Rumen microbes are interdependent: have a common feeding strategy (consortia) and exist
in syntrophy
o Dynamic population, influenced by diet and rumen environment
− Main type of microorganisms in the rumen:
o Bacteria
o Protozoa
o Fungi
o Methanogenic archea
o Bacteriophages
Rumen Bacteria
− 109 - 1010 rumen bacteria per mL of rumen contents
− Over 200 species have been identified (estimated > 3,000)
o Diversity of species is tremendous
o Diversity within niches too
− Rumen bacteria are generally found in one of three populations:
o Loosely or firmly attached to feed particles (60-80%)
o Rumen liquor (20-40%)
▪ Saliva and liquid getting into stomach + particles too dense to float
o Attached to rumen epithelium (</= 1%)
− Classified on the basis of the type of substrate utilized as the primary energy source
find more resources at oneclass.com
find more resources at oneclass.com
ANSC 433 – Animal Nutrition & Metabolism Chantal Coutu
2
Classification of Rumen bacteria by energy source
• Cellulolytic
• Hemicellulolytic
• Amylolytic
• Proteolytic
o Degrade proteins as energy source
• Sugar utilizing
• Acid utilizing
o Consume lactic acid + other acids from fermentation
• Methane producers (methanogenic archaea)
Cellulolytic
Amylolytic
Bacterial Species
(DON'T NEED TO
KNOW)
• Ruminococcus flavefacians
• Ruminococcus albus
• Bacteriodes succinogenes
• Butyrivibrio fibrisolvens
• Bacteriodes ruminocola
• Bacteriodes amylophilus
• Selenomonas ruminantium
Growth Requirements
Cellulose - thrive in conditions with high
abundance of cellulose
Hemicellulose
Pectin
Sugar, Starch - concentrates (ground
corn)
Peptides
Amino acids
Many also require
Ammonia
Isoacids - branched-chain amino acids
Starch
B-vitamins
Ammonia B-vitamins
Fermentation Products
Acetate
Butyrate
H2
CO2
Propionate - made within
to use glucose
Butyrate
Acetate
Lactate
H2
CO2
Rumen pH
Requirement
High (> 6.0) - below isn't good
Tolerate a more acidic pH (5.7)
Fat Tolerance
Low - don't like fat but add it to feed
cause it's good
Higher than fiber digesters
Susceptibility to
ionophores
Some are susceptible
Most aren't susceptible
Reproduction speed
Slow - slow growers
Faster than fiber digesters - grow
faster
Rumen Protozoa
• 105 - 106 protozoal cells/mL
• Equal to bacteria in total mass
• > 100 species have been identified
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Missing of rumen contents: acetate, propionate, butyrate. Rumen microorganisms: one of the most complex natural microbial ecosystems, rumen microbes are interdependent: have a common feeding strategy (consortia) and exist in syntrophy, dynamic population, influenced by diet and rumen environment. Main type of microorganisms in the rumen: bacteria, protozoa, fungi, methanogenic archea, bacteriophages. 109 - 1010 rumen bacteria per ml of rumen contents. Over 200 species have been identified (estimated > 3,000: diversity of species is tremendous, diversity within niches too. Rumen bacteria are generally found in one of three populations: loosely or firmly attached to feed particles (60-80%, rumen liquor (20-40%) Saliva and liquid getting into stomach + particles too dense to float: attached to rumen epithelium (= 1%) Classified on the basis of the type of substrate utilized as the primary energy source. Classification of rumen bacteria by energy source: cellulolytic, hemicellulolytic, amylolytic, proteolytic, degrade proteins as energy source.
