som2011 ft-clermont popova feb2011

8/6/2019 SOM2011 FT-Clermont Popova Feb2011

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A L I M E N T A T I O N

A G R I C U L T U R E

E N V I R O N N E M E N T

Rumen environment andRumen environment and

methanogenesismethanogenesis

M. Popova,C. Martin, M. Eugne, M. Doreau, D. P. Morgavi

INRA-Theix Research Centre, Herbivore Research Unit, France


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Where CHWhere CH44comes from?comes from?

Feed

(carbohydrate polymer)

Monomer

Microbial biomass Volatile Fatty Acids

CO2

CH4

H2


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Many CH4 mitigation strategies are being

developedFocus on dietary factors

Type of pasture (Pinares-Patio et al., 2007)

Type of concentrate (Eugne et al.,2011)

Lipids supply (Martin et al.,2009)

Manipulate Rumen Microbiote (Morgavi et al., 2010)

How to reduce CHHow to reduce CH44emissions byemissions by

ruminants?ruminants?

But the microbial mechanisms of CH4production are still unclear


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CHCH44& Methanogens& Methanogens

CH4Methanogens

ReferenceNumbers Diversity

Linseed lipids no change no dataMosoni et al,

2008

Defaunation no change

Mosoni et al,

2010

Defaunation No dataLong term

change

Morgavi et al,

2006

no link between CHno link between CH44production andproduction and

numbers or diversity of methanogensnumbers or diversity of methanogens

How about Activity?How about Activity?


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2 x 10 feedlot bulls fed 2 finishing diets

CHCH44, starch and linseed, starch and linseed

-26%

(P


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o difference in methanogenico difference in methanogenicArchaea abundance betweenArchaea abundance between

diets, but methanogens werediets, but methanogens were

less metabolically active withless metabolically active withthe SL dietthe SL diet

log10 (copies mcrA g-1 DM rumen

content)

P=0.83

FFFFSLSLSLSL

8.3

8.7

9.1

9.5

umbersumbers

CH4,starchandlipids

How methanogens respond to diet

change?

2x10-7

Gene expression via 2-Ct

1x10

-7

0

FFFFFFFF

SLSLSLSLSLSLSLSL

P


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88.6%88.6%

75%75%

Lower methanogens diversityLower methanogens diversitywith SL dietwith SL diet

CH4,starchandlipids

How methanogens respond to diet

change?


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Lipid supply low: no toxic effect on rumen microbesLipid supply low: no toxic effect on rumen microbes

High starch content : bacterial andHigh starch content : bacterial and protozoalprotozoaldevelopmentdevelopment

log10 (copies rrs g-1 DM rumen contents)

FFFF

SLSLSLSL

9.0

9.3

9.6

9.9

Protozoa (cells ml-1 rumen fluid)

FFFF

SLSLSLSL

0

2x106

1x106

6x105

How about other microbes?

C

H4,starchandlipids

Bacteria Protozoa


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9999

CH4, starch and lipids

To summarize:

SL fed animals had lower DMI

Daily CH4 emissions lower with SL diet,

but

o difference in CH4 emissions g kg-1

DMILess diverse & less active methanogenic

population with SL diet

but- More abundant protozoal population : similar

CH4 g/kg DMIproduction may be due to a higherH

2/ DMI

(Popova et al., 2011)


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CH4and protozoa

Protozoa produce H2

Hosts for methanogens

Extracellular

Intracellular

methanogens

H2

CH4

Defaunation

(protozoa removal)

decreases CH4 production

by 10.5 % on average

(Morgavi et al, 2010)


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8.0

8.5

9.0

9.5

10.0

1

How do methanogens respond to

defaunation?

Log10(copiesmcrA/gDM

rumen

content)

P


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A L I M E N T A T I O N

A G R I C U L T U R E

E N V I R O N N E M E N T

Hydrogen availability : key factor to understand

methanogenesis mechanisms ?Hydrogen producers & methanogens : explore

interactions

Monitor the whole rumen ecosystem :Strategies to mitigate CH4 emissions

Rumen environment andRumen environment and

methanogenesismethanogenesis

som2011 ft-clermont popova feb2011

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