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Microbial ecology of the rumen: impact on nutrition and the environment
John Wallace
© R.J. Wallace 2004
Rowett picture“We bring together extensive capabilities and expertise in nutritional research to pursue cutting edge science aimed at
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and health policies.
• Introduction to the rumen and its microorganisms
• Impact of the rumen on nutrition• Ruminants and the environment• Ruminant products and human health
Microbial ecology of the rumen: impact on nutrition and the environment
Cow picture
The rumen
CATTLE AND SHEEP
Stomach(Abomasum)
Rumen
Reticulum
Omasum
Jejunum
Ileum
Colon
Caecum
PIG
Stomach
Jejunum
Ileum
Caecum
Colon
Gut anatomy
Rumen ciliate protozoa
100 m
Fungal picture
Rumen anaerobic fungi
50 m
Fungal picture
© R.J. Wallace 2004
Rowett picture
1 m
Rumen bacteria
ProteobacteriaM ethanomicrobium mobile (M59142)
0.1
82 .7
88 .3
Proteobacter ia (OTUs 1-3)
Cytophaga-Flexibacter-Bactero ides Group (OTUs 6-78)
Low G+C Gram Positive Bacteria (OTUs 80-174)
Fibrobacter Group (OTU 175)High G+C Gram Positive Bacteria (OTUs 176 &177)Chlamydiales-Verrucimicrobia Group (OTUs 1 78 & 179)Spirochaetes (180)
Phylum? (OT U 4)
Phylum? (OTU 5)
Phylum? (OTU 79)
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
High bacterial diversity
Cytophaga-Flexibacter-Bacteroides [CFB]
Proteobacteria
Low G+C Gram positive
High G+C Gram positive, Fibrobacter,Spirochaetes, etc
Rumen methanogenic archaea
1 m
109 - 1010 BACTERIA
Up to 106 PROTOZOA
?? ANAEROBIC FUNGI
108 ARCHAEA
per g digesta
FOOD
UNDIGESTED FOOD +
MICROORGANISMS
ACETATE
VFA PROPIONATE
BUTYRATEMETHANE
Metabolism in the rumen
• Introduction to the rumen and its microorganisms
• Impact of the rumen on nutrition• Ruminants and the environment• Ruminant products and human health
Microbial ecology of the rumen: impact on nutrition and the environment
Fibre breakdownRuminococcus flavefaciens
Fibrobacter succinogenes
Protein metabolism
Protein
Peptides
Amino acids
Ammonia
Ammonia
Undegraded food protein +
Microbial protein
Food protein
Microbial protein
B
A
Urea
INEFFICIENCES
Loss of N Microbial protein breakdown
Amino acid imbalance
B
C
A
C
Breakdown of microbial protein
Sample R038
0
2
4
6
8
10
12
14
16
0 1 2 3
Incubation time (h)
Rat
e of
deg
rada
tion
(%)
Control
5000
3000
1500
1000
500
Concentration (ppm)
Lonicera japonica (Japanese
honeysuckle)
Rumen-up: influence on protozoal activity in vitro
Methane, ruminants and the environment
Methane, ruminants and the environment
•
How much is methane a problem as a greenhouse gas?
•
Is methane from ruminants really a major part of the problem ?
•
How does methane formation occur?•
How can we inhibit methane formation?
•
Encapsulated fumaric acid, efficacy and commercial considerations
Greenhouse gases: CO2
Methane as a greenhouse gas
CH4 has a global warming potential (“radiative forcing”) 21 times that of CO2
Methane contributes approximately 18% to the overall global warming effectUS Environmental Protection Agency, 2000
Methane as a greenhouse gas
Dlugokencky et al., 2003
t½
of CH4
in atmosphere is 12 years
70% of global methane formation is due to man's activities
Sources of atmospheric methane
US Environmental Protection Agency, 2001
Therefore, 20% of global methane formation is due to ruminants
Sources of atmospheric methane
US Environmental Protection Agency, 2001
And so 20% of the 18% = 3.6% of the total radiative forcing is caused by ruminants
Sources of atmospheric methane
US Environmental Protection Agency, 2001
Ruminants, cars and methane
164 g CO2
/km at 19,000 km/year= 164
19000 g CO2
/year= 3
106 g CO2
/year
=
500 L CH4
/day = 365
500 L/year
= 2
105
L/year= 2
16/22
105
g/year= 1.5
105 g/year
21
1.5
105 g CO2
/year
3
106 g CO2
/year
Ruminants, cars and methane
=
Ruminants, cars and methane
=
The New Zealand response
Carbon tax As part of the Climate Change Policy Package, released in 2002, the government will be introducing a carbon tax in New Zealand from April 1, 2007. Hon. Pete Hodgson, Convener of the Ministerial Group on Climate Change, has announced that the carbon tax will be set at $15 per tonne of CO2
and has released a consultation paper on the implementation of the tax.
Methane production in ruminants
95%5%
Fermentation
H2 + CO2
CH4
Protozoa, fungi, eubacteria
Archaea
Methane production in ruminants
Inhibition of methane formation
•
Halogenated hydrocarbons•
Other chemicals
•
Ionophores•
Acetogenesis
•
Immunisation•
Defaunation
•
Natural plant extracts•
Organic acids
Fermentation
H2 + CO2
CH4
[Organic acid + ]
Propionic acid
Decreasing methane emission using “organic acids”
COOH
C=O
CH2
COOH
Organic acids
COOH
CHOH
CH2
COOH
COOH
CH
CH
COOH
COOH
CH2
CH2
COOH
2H 2H
H2 O
Oxaloacetate Malate Fumarate Succinate
Propionate
COOH
COOHH
H
Bakeshure 451
Bakeshure 451 –
Consists of 85% fumaric acid and 15% partially
hydrogenated soybean oil
05
10152025
Feed Additive
Met
hane
Pr
oduc
tion
(L/d
)
Control Fumaric AcidBakeshure 451
Large scale feeding trial in Aberystwyth
LALNA
Saturated fatty acids
BIOHYDROGENATION
unsaturated saturated
LALNA
C18:2 c9 c12
C18:3 c9 c12 c15
Health implications of biohydrogenation in the rumen
LNA – linolenic acidLA – linoleic acid
CLA Stimulates Immune Response
Helps Prevent Heart Disease
Helps Prevent Cancer
Health implications of biohydrogenation in the rumen
0 2 4 6 8
Beef
Veal
Lamb
Milk
Cheese
Butter
Cream
Beef tallow
Fish
Chicken
Pork
Egg yolk
Olive oil
Corn oil
Sunflower oil
CLA content of fat (mg/g)
CLA in foods
To provide 10 g of CLA/day requires 3.6 kg cheese
CLA in foods
Rumen Animal tissues
C C C C C
C C C C C
2H conjugatedlinoleic acid
vaccenicacid
C C C C C
9 12C C C CC
C C C C C
2H
C C C C C
2H
linoleic acid
conjugatedlinoleic acid
vaccenicacid
stearic acid
Effects on biohydrogenation of unsaturated fatty acids
C C C C C
9 12C C C CC
C C C C C
2H
C C C C C
2H
linoleic acid
conjugatedlinoleic acid
vaccenicacid
stearic acid
cis
cis cis
trans
trans
19 samples with activity against B. proteoclasticus but not B. fibrisolvens
Butyrivibrio fibrisolvens
Butyrivibrio proteoclasticus
EC FP6Promotion of Safe, Healthy Food
Replacing antibiotics in animal feed
0
50
100
150
200
0 6 12 18 24Time (h)
Fatty
aci
d co
ncen
tratio
n (µ
g/m
L)
Vaccenic acid accumulates in the rumen
+ C. coronarium
- C. coronarium
Chrysanthemum coronarium
• C. coronarium inhibits last step in biohydrogenation process
• C. coronarium increases PUFA and CLA content of milk
Tracy’s Vision of the Future
Inhibition of methane formation
•
Defaunation–
Decreases methane formation by 20%
H2 CH4
Acetate
Glucose
Pyruvate Methanogens
Hydrogenosomes
Intracellular Hydrogen Transfer inCiliate Protozoa
H2CH4
H2
Defaunation
technically difficultAdaptation will always be a problem