The
objective
of
this
study
was
to
evaluate
the
effects
of
2-methylbutyrate
supplemen
tation
on
rumen
microflora,
enzyme
activities
and
methane
production
in
Simmental
steers
consuming
a
diet
consisting
of
600
g/kg
corn
stover
and
400
g/kg
concentrate
(dry
mat
ter
[DM]
basis).
Eight
ruminally
cannulated
Simmental
steers
were
used
in
a
replicated
4
×
4
Latin
square
design.
The
treatments
were:
control
(without
2-methylbutyrate),
low
2-methylbutyrate
(LMB),
medium
2-methylbutyrate
(MMB)
and
high
2-methylbutyrate
(HMB)
with
0,
8.4,
16.8
and
25.2
g
2-methylbutyrate
per
steer
and
per
day,
respectively.
Dry
matter
intake
(averaged
9
kg/day)
was
restricted
to
a
maximum
of
0.9
of
ad
libitum
intake.
Whether
direct
counts,
roll-tube
technique
or
real-time
PCR
quantification
were
used,
populations
of
total
bacteria,
cellulolytic
bacteria
and
anaerobic
fungi
linearly
increased
(P<0.04)
and
were
higher
(P<0.05)
for
MMB
and
HMB
than
for
control
and
LMB,
whereas
those
of
protozoa
and
total
methanogens
linearly
reduced
and
were
lower
for
MMB
and
HMB
than
for
control
and
LMB.
With
increasing
2-methylbutyrate
supplementation,
real
time
PCR
quantification
of
populations
of
Ruminococcus
albus,
Ruminococcus
flavefaciens,
Bufyrivibrio
fibrisolvens
and
Fibrobacter
succinogenes
linearly
increased
(P<0.05)
and
was
higher
for
MMB
and
HMB
than
for
control
(P<0.05).
Activities
of
CMCase,
xylanase
and
?
glucosidase
linearly
increased
(P<0.05)
and
were
higher
(P<0.05)
for
MMB
and
HMB
than
for
control
and
LMB,
whereas
that
of
protease
linearly
reduced
(P<0.05)
and
was
lower
for
MMB
and
HMB
than
for
control
and
LMB
(P<0.05).
Activities
of
?-amylase
and
?-glucosidase
tended
to
be
higher
(P<0.08)
for
MMB
and
HMB
than
for
control
and
LMB,
but
activity
of
urease
tended
to
be
lower
for
MMB
and
HMB
than
for
control
and
LMB.
Methane
pro
duction
linearly
decreased
(P<0.01)
and
was
lower
for
MMB
and
HMB
than
for
control
(P<0.05)
with
increasing
2-methylbutyrate
supplementation.
Effective
degradabilities
of
cellulose
and
hemicellulose
of
corn
stover
linearly
increased
(P<0.01)
and
were
higher
Abbreviations:
ADF,
acid
detergent
fiber;
BCVFA,
branched
chain
volatile
fatty
acids;
BW,
body
weight;
CMCase,
carboxymethyl-cellulase;
CP,
crude
protein;
DM,
dry
matter;
ED,
effective
degradability;
HMB,
high
2-methylbutyrate;
LMB,
low
2-methylbutyrate;
MMB,
medium
2-methylbutyrate;
N,
nitrogen;
aNDF,
neutral
detergent
fiber;
OM,
organic
matter;
VFA,
volatile
fatty
acid.
∗
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