Effect of L-carnitine supplementation of sows on L-carnitine status, body composition and concentrations of lipids in liver and plasma of their piglets at birth and during the suckling period


Birkenfeld, C.; Doberenz, J.; Kluge, H.; Eder, K.

Animal Feed Science and Technology 129(1/2): 23-38

2006


Previous studies have shown that supplementation of sow diets with L-carnitine increases body weights of their piglets at birth. It has not yet been investigated whether piglets of sows supplemented with L-carnitine differ in their body composition or metabolic parameters from those of control sows at birth and during the suckling period. This study was performed to investigate whether supplementation of sows with L-carnitine during pregnancy and lactation influences body composition and lipid metabolism of their piglets. An experiment was conducted with 40 primiparous sows which were assigned to two groups of 20 sows each and had free access to a nutritionally adequate diet. One group was supplemented with 125 mg L-carnitine/day during pregnancy and 250 mg L-carnitine/day during lactation; the other group (control group) did not receive L-carnitine. L-Carnitine treated sows had a higher feed intake during pregnancy (P<0.05) and higher plasma concentrations of insulin-like growth factor-1 (IGF-1) on day 80 of pregnancy than control sows (P<0.05). The number of piglets born was not different between the two groups of sows, but L-carnitine treated sows had fewer stillborn piglets (P<0.05). Piglets of L-carnitine treated sows had higher concentrations of L-carnitine in plasma and carcass at birth and on days 10 and 20 of age than control piglets (P<0.05). Chemical composition (concentrations of total lipids, protein and ash) of the carcass and plasma concentrations of IGF-1 and insulin, which are important modulators of growth, did not show any difference between the two groups of piglets at birth and on days 10 and 20. Concentrations of lipids (triacylglycerols, cholesterol) in liver and plasma and concentration free fatty acids in plasma were also broadly similar between the two groups of piglets at birth and on days 10 and 20. In conclusion, this study shows that supplementation of sows with L-carnitine improves the L-carnitine status of their piglets at birth and during the suckling period but does not influence their body composition or lipid metabolism.

Available
online
at
www.sciencedirect.com
SCIENCE
ODIRECT.
Animal
Feed
Science
and
Technology
ELSEVIER
129
(2006)
23-38
ANIMAL
FEED
SCIENCE
AND
TECHNOLOGY
www.elsevier.com/locate/anifeedsci
Effect
of
L-carnitine
supplementation
of
sows
on
L-carnitine
status,
body
composition
and
concentrations
of
lipids
in
liver
and
plasma
of
their
piglets
at
birth
and
during
the
suckling
period
C.
Birkenfeld,
J.
Doberenz,
H.
Kluge,
K.
Eder*
Institut
fir
Ennihrungswissenschaften,
Martin-Luther-Uniyersitiit
Halle-Wittenberg,
Emil-A
bderhaldenstrasse
26,
D-06108
Halle/Saale,
Germany
Received
22
June
2005;
received
in
revised
form
25
November
2005;
accepted
2
December
2005
Abstract
Previous
studies
have
shown
that
supplementation
of
sow
diets
with
t-carnitine
increases
body
weights
of
their
piglets
at
birth.
It
has
not
yet
been
investigated
whether
piglets
of
sows
supplemented
with
t-carnitine
differ
in
their
body
composition
or
metabolic
parameters
from
those
of
control
sows
at
birth
and
during
the
suckling
period.
This
study
was
performed
to
investigate
whether
supplemen-
tation
of
sows
with
t-carnitine
during
pregnancy
and
lactation
influences
body
composition
and
lipid
metabolism
of
their
piglets.
An
experiment
was
conducted
with
40
primiparous
sows
which
were
assigned
to
two
groups
of
20
sows
each
and
had
free
access
to
a
nutritionally
adequate
diet.
One
group
was
supplemented
with
125
mg
t-carnitineiday
during
pregnancy
and
250
mg
t-carnitineiday
during
lactation;
the
other
group
(control
group)
did
not
receive
t-carnitine.
L-Carnitine
treated
sows
had
a
higher
feed
intake
during
pregnancy
(P<0.05)
and
higher
plasma
concentrations
of
insulin-like
growth
factor-1
(IGF-1)
on
day
80
of
pregnancy
than
control
sows
(P<0.05).
The
number
of
piglets
born
was
not
different
between
the
two
groups
of
sows,
but
t-carnitine
treated
sows
had
fewer
still-
born
piglets
(P<0.05).
Piglets
of
t-carnitine
treated
sows
had
higher
concentrations
of
t-carnitine
in
plasma
and
carcass
at
birth
and
on
days
10
and
20
of
age
than
control
piglets
(P<0.05).
Chemical
composition
(concentrations
of
total
lipids,
protein
and
ash)
of
the
carcass
and
plasma
concentrations
of
IGF-1
and
insulin,
which
are
important
modulators
of
growth,
did
not
show
any
difference
between
the
two
groups
of
piglets
at
birth
and
on
days
10
and
20.
Concentrations
of
lipids
(triacylglycerols,
*
Corresponding
author.
Tel.:
+49
345
5522702;
fax:
+49
345
5527124.
E-mail
address:
Klaus.eder@landw.uni-halle.de
(K.
Eder).
0377-8401/$
see
front
matter
©
2005
Elsevier
B.V.
All
rights
reserved.
doi:10.1016/j.anifeedsci.2005.12.007
24
C.
Birkenfeld
et
al.
/Animal
Feed
Science
and
Technology
129
(2006)
23-38
cholesterol)
in
liver
and
plasma
and
concentration
free
fatty
acids
in
plasma
were
also
broadly
similar
between
the
two
groups
of
piglets
at
birth
and
on
days
10
and
20.
In
conclusion,
this
study
shows
that
supplementation
of
sows
with
L-carnitine
improves
the
L-carnitine
status
of
their
piglets
at
birth
and
during
the
suckling
period
but
does
not
influence
their
body
composition
or
lipid
metabolism.
©
2005
Elsevier
B.V.
All
rights
reserved.
Keywords:
L-Camitine;
Sow;
Piglet;
Body
composition;
Lipids;
IGF-1;
Insulin
1.
Introduction
Recent
studies
have
demonstrated
that
supplementation
of
sows
with
L-carnitine
dur-
ing
pregnancy
increases
body
weights
of
piglets
and
litters
at
birth
(Musser
et
al.,
1999;
Eder
et
al.,
2001a;
Ramanau
et
al.,
2002).
The
biochemical
mechanisms
underlying
this
effect
are
largely
unknown.
Musser
et
al.
(1999)
observed
increased
plasma
concentrations
of
insulin-like
growth
factor-1
(IGF-1)
in
sows
supplemented
with
L-carnitine
and
sug-
gested
that
this
is
responsible
for
higher
birth
weights
of
their
progeny.
IGF-1
plays
an
important
role
in
the
development
of
the
placenta
and
the
transport
of
nutrients
across
the
placental
barrier
(Kelley
et
al.,
1995;
Sterle
et
al.,
1995;
Gluckman,
1997).
An
increased
transplacental
supply
of
the
fetus
with
glucose
leads
to
increased
fetal
insulin
secretion,
which
might
enhance
the
formation
of
lipids,
i.e.
triacylglycerols
and
cholesterol,
through
activation
of
sterol
regulatory
element
binding
proteins
(SREBP)-1
and
-2
in
liver
and
adipose
tissue
(Shimano,
2001;
Cagen
et
al.,
2005;
Yellaturu
et
al.,
2005).
Indeed,
an
increased
plasma
IGF-1
concentration
in
sows
during
the
last
3
weeks
of
gestation
induced
by
porcine
growth-hormone
(pGH)
treatment
led
to
an
increased
percentage
of
total
lipids
in
neonates
(Kveragas
et
al.,
1986).
An
increased
transplacental
supply
of
nutrients
also
leads
to
increased
secretion
of
IGF-1
in
the
fetus
(Gluckman,
1997).
IGF-1,
the
main
fetal
growth
promoting
factor,
enhances
accretion
of
protein
in
particular.
In
contrast,
insulin
has
a
negligible
effect
on
lean
body
mass
but
strongly
enhances
lipid
synthesis
(Gluckman,
1997).
It
has
not
yet
been
investigated
whether
L-carnitine
supplementation
of
sows
influ-
ences
body
composition,
i.e.
lipid
accumulation,
of
their
piglets
relative
to
piglets
of
control
sows.
Newborn
piglets
have
a
low
capacity
for
endogenous
formation
of
L-carnitine
in
their
liver
(Borum,
1983;
Baltzell
et
al.,
1987;
Coffey
et
al.,
1991).
L-Carnitine
concentrations
in
blood
and
tissues
of
suckling
piglets
might
therefore
be
influenced
by
the
supply
with
L-
carnitine
through
the
milk.
Due
to
its
biological
function
(Bremer,
1963),
a
raised
L-carnitine
status
could
be
associated
with
a
higher
rate
of
13-oxidation
of
long
chain
fatty
acids.
In
piglets
and
growing
pigs
L-carnitine
supplementation
has
already
been
shown
to
increase
the
rate
of
I3-oxidation
by
increased
activity
of
carnitine
palmitoyltransferase
I
(CPT-1)
and
to
reduce
the
content
of
total
lipids
in
the
whole
body
(Owen
et
al., 1996,
2001a,b;
Heo
et
al.,
2000).
It
has
not
yet
been
investigated
whether
raising
the
L-carnitine
status
of
suckling
piglets
by
supplementing
their
lactating
mothers
with
L-carnitine
influences
their
body
composition
(i.e.
whole
body
lipid
content).
The
aim
of
this
study
was
to
find
out
whether
changes
in
maternal
IGF-1
concentra-
tions
through
L-carnitine
supplementation
could
lead
to
alterations
of
body
composition
C.
Birkenfeld
et
al.
/Animal
Feed
Science
and
Technology
129
(2006)
23-38
25
and
lipid
metabolism
in
their
piglets
at
birth
and
during
the
suckling
period
via
altered
con-
centrations
of
insulin
and
IGF-1.
We
therefore
determined
plasma
IGF-1
in
the
sows
in
late
pregnancy
(days
80
and
100
of
pregnancy).
As
the
availability
of
IGF-1
to
target
cells
can
be
modified
by
IGF-binding
proteins
(IGFBP)
(Thissen
et
al.,
1994),
we
also
determined
plasma
concentrations
of
IGFBP-3,
the
most
important
IGFBP
in
plasma
of
pigs
(Owens
et
al.,
1991).
To
show
a
possible
relationship
between
the
maternal
L-carnitine
status
and
that
of
newborn
and
suckling
piglets,
we
also
determined
concentrations
of
L-carnitine
in
plasma
and
milk
of
sows
and
in
plasma
and
carcass
of
piglets
at
birth
and
at
10
and
20
days
of
age.
To
study
body
composition
and
lipid
metabolism
of
piglets,
we
determined
the
concentrations
of
major
nutrients
(fat,
protein,
ash)
in
the
carcass
and
the
concentrations
of
lipids
(triacylglycerols,
cholesterol)
in
liver
and
plasma
as
well
as
plasma
concentra-
tions
of
insulin
and
IGF-1,
which
are
important
modulators
of
lipid
metabolism
and
body
composition.
2.
Materials
and
methods
2.1.
Animals
and
housing
Fourty
crossbred
gilts
(German
Landrace
x
Large
White)
with
an
average
body
weight
of
136
kg
(±9,
S.D.)
acquired
from
a
local
breeder
were
assigned
to
two
groups
of
20
animals
each.
Their
sexual
cycle
was
synchronized
by
oral
administration
of
20
mg
Altrenogest
per
day
(Regumate
®
,
Hoechst
Roussel
Vet.
N.V.,
Frankfurt,
Germany).
The
sows
were
artificially
inseminated
with
sperm
from
Pietrain
boars.
In
the
L-carnitine
treated
group,
19
of
the
20
sows
conceived;
in
the
control
group,
16
of
the
20
sows
conceived.
As
only
30
single
farrowing
pens
were
available,
only
15
of
the
19
pregnant
sows
in
the
L-carnitine
treated
group,
randomly
selected,
were
considered
for
their
reproductive
performance.
Two
sows
in
the
control
group
were
removed
before
littering
from
the
experiment
because
they
had
osteochondrosis
in
their
knee
joints.
The
sows
were
kept
in
single
crates
until
day
30
of
pregnancy.
From
day
30
to
110
of
pregnancy
the
sows
were
kept
in
groups
of
six
to
eight
in
pens
measuring
45
m
2
which
had
fully
slatted
floors,
nipple
drinkers
and
electronic
feeding
stations.
On
day
110
of
pregnancy,
they
were
moved
to
the
farrowing
accommodation
where
they
were
housed
in
single
farrowing
pens.
Prior
to
farrowing
rubber
mats
were
put
down
as
lying
surface
for
the
piglets.
An
infrared
heater
was
suspended
above
each
rubber
mat
to
keep
the
temperature
for
the
newborn
piglets
at
a
constant
35
°C.
The
climate
in
the
dry
sow
accommodation
and
the
farrowing
unit
was
maintained
at
a
temperature
of
19
±
2
°C
and
60-80%
relative
humidity
by
means
of
an
air
conditioning
system.
A
light—dark
cycle
(12-h
light:12-h
dark)
was
applied.
All
animal
procedures
described
followed
established
guidelines
for
the
care
and
handling
of
laboratory
animals
and
were
approved
by
the
regional
council
of
Saxony-Anhalt.
2.2.
Diets
and
feeding
Two
commercial
sow
diets
were
used
whose
composition
and
nutrient
concentra-
tions
are
shown
in
Table
1.
The
first
diet
("gestation
diet",
SAL-SM-W4,
Sachsische
26
C.
Birkenfeld
et
al.
/Animal
Feed
Science
and
Technology
129
(2006)
23-38
Table
1
Composition
of
the
diets
used
during
pregnancy
and
lactation
Gestation
diet
Lactation
diet
Ingredient
(g/kg)
Dried
sugar
beet
pulp
300
Barley
225
263
Wheat
250
Wheat
bran
217
Wheat
meal
80
Wheat
bran
80
Peas
80
Oat
bran
70
Malt
sprouts
69
Extracted
sunflower
meal
50
Wheat
gluten
feed
28
57
Extracted
soybean
meal
20
106
Vegetable
oil
25
Alfalfa
meal
15
Molasses
8.7
Calcium
carbonate
4.4
11.3
Dried
yeast
10
Sodium
chloride
3.5
6
Monocalcium
phosphate
1
Vitamin
and
mineral
premix
2.5
11
L-Lysine
1.9
4.3
DL-methionine
0.4
Nutrients
Crude
protein
(g/kg)
138
173
Crude
fibre
(g/kg)
124
45
Crude
ash
(g/kg)
74
52
Crude
fat
(g/kg)
27
52
Lysine
(g/kg)
6.4
9.9
Methionine
(g/kg)
2.1
2.4
Threonine
(g/kg)
4.6
5.7
Tryptophan
(g/kg)
1.5
2.1
L-Carnitine
(mg/kg)
10
3
Metabolisable
energy
(MJ/kg)
a
9.0
13.0
a
Calculated
according
to
recommendations
by
Gesellschaft
fiir
Ernahningsphysiologie
(1987).
MUSKATOR-Werke
GmbH,
Riesa,
Germany)
was
fed
during
pregnancy.
Until
day
110
of
pregnancy,
this
diet
was
offered
for
ad
libitum
consumption.
The
daily
feed
intake
of
the
sows
was
recorded
by
means
of
an
electronic
sow
feeding
station
(Type
IVOG
2FR
VH,
HokoFarm,
Insentec
B.V.,
Marknesse,
The
Netherlands).
From
day
110
to
farrowing
each
sow
was
fed
2.5
kg
of
this
diet
per
day.
The
second
diet
("lactation
diet",
SL-INT
573,
Sachsische
MUSKATOR-Werke
GmbH,
Riesa,
Germany)
was
fed
during
the
lactation
period.
On
the
day
of
farrowing
the
sows
were
fed
1.5
kg
of
the
diet,
which
was
then
successively
increased
(3
kg/day
on
days
1
and
2
of
lactation;
4.5
kg/day
on
days
3
and
4
of
lactation;
ad
libitum
consumption
from
day
5
of
lactation
to
weaning).
Water
was
provided
from
nipple
drinker
systems
throughout
the
whole
feeding
period.
C.
Birkenfeld
et
al.
/Animal
Feed
Science
and
Technology
129
(2006)
23-38
27
2.3.
Supplementation
of
L-carnitine
Supplementation
of
L-carnitine
in
the
treatment
group
was
started
21
days
before
insem-
ination.
Until
insemination
and
throughout
the
entire
pregnancy
sows
in
the
treatment
group
were
supplemented
with
125
mg
L-carnitine/day.
During
lactation
they
were
given
250
mg
of
L-carnitine/day.
L-Carnitine
was
supplied
as
tablets
containing
L-carnitine
(62.5
mg/tablet),
lactose
and
dextrose,
supplied
by
Lohmann
Animal
Health
(Cuxhaven,
Germany).
Each
sow
was
given
two
tablets
once
daily
in
the
morning
(09:00
h)
by
hand
during
pregnancy
and
two
tablets
twice
daily
(09:00,
16:00
h)
during
lactation.
The
L-carnitine
dosage
was
based
on
our
recent
studies
(Ramanau
et
al.,
2002,
2004).
Control
animals
were
given
placebo
tablets
without
L-carnitine.
2.4.
Standardization
of litter
sizes
Five
to
six
hours
after
birth
one
piglet
with
a
body
weight
representing
the
mean
of
the
whole
group
was
selected,
killed
and
used
for
analysis
of
its
body
composition.
In
order
to
eliminate
the
effect
of
litter
size
on
body
composition
and
metabolism,
the
litter
size
of
all
sows
was
then
standardised
to
eight
piglets/litter
within
2
days
of
farrowing.
Sows
with
more
than
eight
piglets
had
the
surplus
piglets
taken
away
and
sows
with
less
than
eight
piglets
were
given
piglets
from
other
sows
of
the
same
group.
Piglets
removed
from
sows
and
piglets
given
to
sows
were
selected
on
the
basis
of
their
body
weights.
The
average
weight
of
piglets
from
each
individual
sow
after
litter
standardization
was
matched
to
that
before
litter
standardization.
Surplus
piglets
were
nursed
by
one
remaining
sow
in
each
group
who
was
no
longer
included
in
the
trial.
Between
days
3
and
10
of
the
suckling
period,
four
piglets
of
control
sows
and
three
piglets
of
sows
supplemented
with
L-carnitine
dropped
out.
These
piglets
were
immediately
replaced
by
equivalent
piglets
with
similar
body
weights
that
had
previously
been
nursed
by
the
remaining
control
or
L-carnitine
treated
sow.
After
10
days
another
piglet
from
each
litter
representing
the
mean
body
weight
of
its
litter
mates
was
selected
and
used
for
further
analysis.
This
left
seven
piglets
in
each
litter.
On
day
20,
a
third
piglet
from
each
litter
was
selected
and
used
for
further
analysis,
reducing
litter
size
to
six
piglets.
2.5.
Data
recording
Only
sows
whose
litters
were
standardized
were
evaluated
for
body
weights,
number
of
piglets
born,
piglet
and
litter
weights
at
birth
and
plasma
L-carnitine
concentrations.
Sows
were
weighed
(using
scales
with
an
accuracy
of
±100
g)
on
days
1
and
110
of
pregnancy.
The
number
of
piglets
born
(total,
number
born
alive
and
number
stillborn)
was
recorded.
Individual
piglets
were
weighed
at
birth
(not
later
than
6
h
after
birth)
and
on
days
10
and
20
of
lactation
using
scales
with
an
accuracy
of
±10
g.
2.6.
Determination
of
nutrients
and
L-carnitine
in
carcasses
and
diets
The
piglets
were
euthanized
by
bleeding.
Blood
of
the
piglets
was
collected
for
fur-
ther
analysis
of
plasma
variables.
Immediately
after
removal
of
the
gastrointestinal
tract
28
C.
Birkenfeld
et
al.
/Animal
Feed
Science
and
Technology
129
(2006)
23-38
caudal
of
the
diaphragm
and
removal
of
liver,
gallbladder,
spleen
and
kidneys
the
carcass
was
frozen
at
—20
°C.
The
organs
cranial
of
the
diaphragm
remained
in
the
carcass
and
were
included
in
the
analysis
of
the
piglets'
body
composition.
The
carcasses
were
first
cut
with
a
saw
(MADO
Perekta
Plus,
MKB
649,
Maschinenfabrik
Dornhan,
Germany),
then
finely
chopped
to
a
mushy
consistency
using
a
chopper
(MADO
Adjutant,
MTK
661,
Maschinenfabrik
Dornhan,
Germany)
and
finally
homogenized
for
3
min
with
a
homoge-
nizer
(FOSS
TECATOR,
2094
Homogenizer,
Hogands,
Sweden).
A
representative
sample
of
500
g
was
drawn
from
the
resulting
carcass
pulp,
freeze-dried
(CHRIST
Beta
100800,
MARTIN
CHRIST,
Osterode,
Germany)
and
then
finely
ground
in
a
water-cooled
grinder
(IKA-Universalmilhle,
M20,
IKA
Labortechnik
Staufen,
Germany)
to
a
particle
size
of
1
mm.
The
analysis
of
crude
nutrient
concentrations
in
the
carcass
(dry
matter,
crude
pro-
tein,
crude
fat,
crude
ash)
was
performed
in
triplicate
using
an
official
German
standard
method
(Bassler
and
Buchholz,
1993).
Concentrations
of
crude
nutrients
and
amino
acids
in
diets
were
analysed
according
to
the
same
official
German
standard
methods
(Bassler
and
Buchholz,
1993).
For
the
anal-
ysis
of
amino
acids,
samples
were
oxidized
and
then
hydrolysed
with
6
M
hydrochloric
acid.
Separation
and
quantification
of
amino
acids
was
performed
by
ion
exchange
chro-
matography
following
post-column
derivatisation
in
an
amino
acid
analyser
(Biotronic
LC
3000,
Eppendorf,
Hamburg,
Germany).
For
the
determination
of
tryptophan
the
diet
was
digested
with barium
hydroxide
(Fontaine
et
al.,
1998).
The
tryptophan
content
was
deter-
mined
by
reversed-phase
high
performance
liquid
chromatography
(Eder
et
al.,
2001b).
The
concentration
of
total
carnitine
in
plasma,
carcass
and
diet
was
determined
by
a
radio-
chemical
method,
which
is
based
on
the
conversion
of
carnitine
into
[
3
1I]acetylcarnitine
by
carnitine-O-acetyltransferase
(McGarry
and
Foster,
1976).
2.7.
Collection
of
plasma
and
milk
samples
On
days
80
and
100
of
pregnancy
sows
were
bled
6
h
after
feeding
by
puncture
of
the
fossa
jugularis.
Plasma
was
obtained
by
centrifugation
of
the
blood
(1900
x
g,
10
min,
4
°C).
Plasma
lipoproteins
were
separated
by
step-wise
ultracentrifugation
(Mikro-
Ultrazentrifuge,
Sorvall
Products,
Bad
Homburg,
Germany)
at
712,000
x
g
at
4
°C
for
1.5
h
(Tiedink
and
Katan,
1989).
Plasma
densities
were
adjusted
with
sodium
chloride
and
sodium
bromide.
The
lipoprotein
fractions
[very
low
density
lipoproteins
(VLDL,
8
<
1.006
g/mL);
low
density
lipoproteins
(LDL,
1.006
g/mL
<
8
<
1.063
g/mL)
and
high
density
lipoproteins
(HDL,
8>
1.063
g/mL)]
were
removed
by
suction.
Five
to
eight
hours
after
farrowing
and
on
days
10
and
20
of
lactation
the
sows
were
given
15
IU
oxytocin
(Atarost
Tierarzneimit-
telfabrik,
Twistringen,
Germany)
by
intramuscular
injection.
Fifty
milliliters
of
milk
was
expressed
manually
from
all
active
teats
of
each
sow.
2.8.
Analysis
of
hormones
and
lipids
Concentrations
of
insulin,
IGF-1
and
IGFBP-3
in
plasma
were
determined
with
commercial
ELISA
kits.
Insulin
was
determined
with
a
MEDGENIX
INS-EASIA
kit
(Biosource
Europe
S.
A.,
Nivelles,
Belgium);
intra-
and
interassay
coefficients
of
varia-
tion
(n=
6)
were
2.4
and
5.8%,
respectively;
the
detection
limit
of
the
assay
according
to
C.
Birkenfeld
et
al.
/Animal
Feed
Science
and
Technology
129
(2006)
23-38
29
manufacturer
instruction
was
1.1
pmol/L.
IGF-1
was
determined
with
a
OCTEIA
®
IGF-1-kit
(Immunodiagnostic
Systems,
Boldon,
United
ICingdom).
IGFBP-3
was
determined
with
a
ACTIVE
®
IGFBP-3
kit
[Diagnostic
Systems
Laboratories
(DSL)
Inc.,
Webster,
TX,
USA].
Lipids
of
the
liver
were
extracted
using
a
mixture
of
n-hexane
and
isopropanol
(3:2,
v/v)
(Ham
and
Radin,
1978).
Lipids
of
the
extracts
were
dissolved
in
the
aqueous
phase
of
the
test
reagent
with
Triton
X-100
(De
Hoff
et
al.,
1978).
Concentrations
of
cholesterol
and
triacylglycerols
were
determined
in
plasma, LDL,
HDL
and
liver
lipid
extracts
using
enzymatic
reagent
kits
(Ecoline
®
DiaSys
Diagnostics
Sytems
GmbH,
Holzheim,
Germany).
2.9.
Statistical
analysis
All
statistics
were
carried
out
using
SAS
(2004).
All
dependent
variables
were
analysed
for
normal
distribution
using
the
Shapiro—Wilk
test.
The
effect
of
the
treatment on
body
weights
of
piglets
at
birth
was
analysed
with
a
mixed
linear
model
(procedure
mixed)
which
included
the
treatment
(control
versus
+L-carnitine)
as
a
fixed
effect
and
sows
as
random
effects.
All
other
normal
distributed
variables
were
analysed
for
significant
differences
by
Student's
t-test.
Non-parametric
variables
were
evaluated
for
significant
differences
by
Wilcoxon
test.
Means
were
considered
significantly
different
for
P<0.05.
3.
Results
3.1.
Feed
intake,
body
weights
of
sows,
number
and
birth
weights
of
piglets
Sows
supplemented
with
L-carnitine
had
a
higher
feed
intake
during
pregnancy
and
a
higher
body
weight
on
day
110
of
pregnancy
than
control
sows
(Table
2).
The
total
number
of
piglets
born
and
piglets
born
alive
did
not
differ
between
control
sows
and
sows
supplemented
with
L-carnitine.
But
the
number
of
stillborn
piglets
was
lower
in
sows
Table
2
Body
weights,
feed
intake,
number
of
piglets
and
weights
of
piglets
and
litters
in
control
sows
and
sows
supple-
mented
with
L-carnitine
Control
+L-Carnitine
S.E.M.
Body
weights
of
sows
(kg)
Day
1
135
137
1.65
Day
110
210a
219b
2.21
Feed
intake,
days
1-110
(kg/day)
3.3
3
.
713
0.08
Feed
intake,
lactation
(kg/day)
5.2
5.3
0.10
Piglets
born
(n)
11.4
10.6
0.41
Piglets
born
alive
(n)
10.5
10.4
0.39
Piglets
stillborn
(n)
0.8a
0.13
Weights
of
piglets
at
birth
(kg)
1.28
1.40
0.05
Weights
of
litters
at
birth
(kg)
13.2
14.4
0.43
Means
(n
=13
for
control,
n
=14
for
+L-carnitine).
Means
with
different
superscript
letters
(a
andb)
are
significantly
different
(P<0.05).
30
C.
Birkenfeld
et
al.
/Animal
Feed
Science
and
Technology
129
(2006)
23-38
Table
3
Concentrations
of
IGF-1
and
IGF-binding
protein
3
in
plasma
of
control
sows
and
sows
supplemented
with
L-carnitine
Control
+L-Carnitine
S.E.M.
IGF-1
(nmol/L)
Day
80
3
.
9a
5.6
b
0.40
IGF-binding
protein
3
(nmol/L)
Day
80
0.60a
0.52
b
0.020
Day
100
0.55
0.47
0.026
Means
(n
=13
for
control,
n
=14
for
+L-carnitine).
Means
with
different
superscript
letters
(a
andb)
are
significantly
different
(P<0.05).
supplemented
with
L-carnitine
than
in
control
sows.
Piglets
and
litters
of
sows
supplemented
with
L-carnitine
were
9
and
9%,
respectively,
heavier
at
birth
than
those
of
control
sows.
Differences
in
weights
of
piglets
and
litters
were
not
statistically
significant,
however.
The
feed
intake
of
the
sows
during
lactation
did
not
differ
between
the
two
groups.
3.2.
Concentrations
of
IGF-1
and
IGFBP-3
in
sow
plasma
on
days
80
and
100
of
pregnancy
On
day
80
of
pregnancy
sows
supplemented
with
L-carnitine
had
higher
concentrations
of
IGF-1
and
lower
concentrations
of
IGFBP-3 in
plasma
than
control
sows
(Table
3).
On
day
100
of
pregnancy,
a
reliable
determination
of
plasma
concentrations
of
IGF-1
was
not
possible
because
in
7
of
the
13
control
sows
and
7
of
the
14
L-carnitine
treated
sows
plasma
IGF-1
concentration
was
below
the
detection
limit
of
1
nmol/L.
Plasma
concentration
of
IGFBP-3
on
day
100
did
not
differ
between
sows
treated
with
L-carnitine
and
control
sows.
3.3.
Concentrations
of
total
L-carnitine
in
plasma
and
milk
of
sows
On
day
80
of
pregnancy,
the
concentration
of
total
L-carnitine
in
plasma
did
not
differ
between
both
groups
of
sows
(Table
4).
In
contrast,
the
plasma
concentration
of
total
L-
carnitine
on
day
100
was
significantly
higher
in
sows
supplemented
with
L-carnitine
than
in
control
sows.
At
birth,
sows
supplemented
with
L-carnitine
moreover
tended
to
have
a
Table
4
Concentrations
of
total
L-carnitine
in
plasma
and
milk
of
control
sows
and
sows
supplemented
with
L-carnitine
Control
+L-Carnitine
S.E.M.
Plasma
(µmol/L)
Day
80
8.0
11.0
1.16
Day
100
8.8a
14.9b
1.35
Milk
(µmol/L)
Day
1
(colostrum)
183
221
11.4
Day
10
137a
212b
11.8
Day
20
126a
179
b
8.4
Means
(n
=13
for
control,
n
=14
for
+L-carnitine).
Means
with
different
superscript
letters
(a
andb)
are
significantly
different
(P<0.05).
C.
Birkenfeld
et
al.
/Animal
Feed
Science
and
Technology
129
(2006)
23-38
31
Table
5
Concentrations
of
total
L-camitine,
IGF-1
and
insulin
in
plasma
of
piglets
of
control
sows
and
piglets
of
sows
supplemented
with
L-camitine
at
birth
(day
1)
and
at
days
10
and
20
of
age
Control
+L-camitine
S.E.M.
L-Camitine
(µmol/L)
Day
1
(birth)
15.1a
20.0
b
1.30
Day
10
15.6a
22.9b
1.73
Day
20
12.8a
17.5
b
1.18
IGF-1
(nmol/L)
*
Day
10
5.4
6.4
0.57
Day
20
6.7
7.9
0.67
Insulin
(pmol/L)
Day
1
(birth)
203
201
43.9
Day
10
89
78
12.7
Day
20
92
64
12.9
Means
(n
=13
for
control,
n
=14
for
+L-camitine).
Means
with
different
superscript
letters
(a
andb)
are
significantly
different
(P<0.05).
*
IGF-1
concentrations
at
day
1
(birth)
in
8
of
the
13
piglets
of
control
sows
and
in
7
of
the
14
piglets
of
L-camitine
treated
sows
were
below
the
detection
limit
of
1
nmol/L.
higher
concentration
of
total
L-carnitine
in
milk
than
control
sows
(P<0.10).
On
days
10
and
20
of
lactation,
the
concentration
of
L-carnitine
in
milk
was
significantly
higher
in
sows
supplemented
with
L-carnitine
than
in
control
sows.
3.4.
Concentrations
of
total
L-carnitine,
IGF-1
and
insulin
in
of
piglets
at
birth
and
at
10
and
20
days
of
age
Piglets
of
sows
supplemented
with
L-carnitine
had
higher
concentrations
of
total
L-
carnitine
in
plasma
and
carcass
at
birth
and
on
days
10
and
20
than
piglets
of
control
sows
(Table
5).
Plasma
concentration
of
IGF-1
at
birth
could
not
be
determined
in
a
reliable
way
because
in
8
of
the
13
piglets
of
control
sows
and
in
7
of
the
14
piglets
of
L-carnitine
treated
sows
it
was
below
the
detection
limit
of
1
nmol/L.
Plasma
concentrations
of
IGF-1
on
days
10
and
20
as
well
as
plasma
concentrations
of
insulin,
either
at
birth
or
on
days
10
and
20
did
not
differ
between
both
groups
of
piglets.
3.5.
Body
weights,
chemical
carcass
composition
and
L-carnitine
concentrations
of
piglets
at
birth
and
at
10
and
20
days
of
age
After
litter
standardization
piglets
of
sows
supplemented
with
L-carnitine
did
not
differ
in
weight
from
those
of
control
sows
at
birth
or
on
days
10
and
20
of
lactation
(Table
6).
Weights
of
carcasses
of
piglets
of
control
sows
and
those
of
sows
supplemented
with
L-
carnitine
did
also
not
differ
at
birth
or
on
days
10
and
20.
Concentrations
of
protein
and
ash
in
carcass
dry
matter
decreased
continuously
from
birth
to
day
20
while
the
concentration
of
fat
increased
continuously.
But
the
concentrations
of
these
nutrients
in
the
carcasses
did
not
differ
between
piglets
of
control
sows
and
those
of
L-carnitine
supplemented
sows
at
any
time.
Piglets
of
sows
supplemented
with
L-carnitine
had
higher
concentrations
of
32
C.
Birkenfeld
et
al.
/Animal
Feed
Science
and
Technology
129
(2006)
23-38
Table
6
Chemical
composition
and
L-carnitine
concentration
of
carcass
of
piglets
of
control
sows
and
piglets
of
sows
supplemented
with
L-carnitine
at
birth
(day
1)
and
at
days
10
and
20
of
age
Control
+L-Camitine
S.E.M.
Day
1
(birth)
Body
weight
(kg)
1.32
1.38
0.050
Carcass
weight
(kg)
1.09
1.11
0.040
Dry
matter
(DM)
(g/kg)
189
187
2.1
Crude
protein
(g/kg
DM)
565
576
4.7
Crude
fat
(g/kg
DM)
57
52
1.8
Crude
ash
(g/kg
DM)
220
221
2.6
L-Camitine
(µmol/g
DM)
0.94a
1.05
b
0.030
Day
10
Body
weight
(kg)
3.35
3.41
0.091
Carcass
weight
(kg)
2.78
2.86
0.077
Dry
matter
(DM)
(g/kg)
301
291
3.3
Crude
protein
(g/kg
DM)
469
471
5.6
Crude
fat
(g/kg
DM)
409
391
7.2
Crude
ash
(g/kg
DM)
104
111
2.3
L-Camitine
(µmol/g
DM)
1.32a
1.73
b
0.055
Day
20
Body
weight
(kg)
6.58
6.55
0.141
Carcass
weight
(kg)
5.60
5.58
0.126
Dry
matter
(DM)
(g/kg)
345
345
3.0
Crude
protein
(g/kg
DM)
415
420
4.0
Crude
fat
(g/kg
DM)
438
442
5.2
Crude
ash
(g/kg
DM)
90
85
1.7
L-Camitine
(µmol/g
DM)
1.39a
1.80
0.062
Means
(n
=13
for
control,
n
=14
for
+L-camitine).
Means
with
different
superscript
letters
(a
andb)
are
significantly
different
(P<0.05).
total
L-carnitine
in
carcass
at
birth
and
on
days
10
and
20
than
piglets
of
control
sows
(Table
6).
3.6.
Concentrations
of
lipids
in
plasma
and
liver
of
piglets
at
birth
and
at
10
and
20
days
of
age
Piglets
of
sows
supplemented
with
L-carnitine
had
lower
plasma
concentrations
of
total
cholesterol
at
birth
than
piglets
of
control
sows
(Table
7).
On
days
10
and
20,
plasma
con-
centrations
of
total
cholesterol
were
not
different
between
the
two
groups
of
piglets.
Plasma
triacylglycerols
did
not
differ
between
the
two
groups
of
piglets
at
birth
and
on
day
10.
On
day
20,
plasma
triacylglycerol
concentration
was
higher
in
piglets
of
sows
supplemented
with
L-carnitine
than
in
piglets
of
control
sows.
Concentrations
of
triacylglycerols
and
total
cholesterol
in
various
lipoprotein
fractions
(VLDL,
LDL,
HDL)
did
not
differ
between
both
groups
of
piglets
(data
not
shown)
with
the
only
exception
of
a
reduced
concentration
of
cholesterol
in
HDL
in
piglets
of
sows
supplemented
with
L-carnitine
compared
to
piglets
of
control
sows
(0.35
versus
0.44
mmol/L,
S.E.M.
=
0.020
mmol/L,
P<0.05).
Plasma
free
C.
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et
al.
/Animal
Feed
Science
and
Technology
129
(2006)
23-38
33
Table
7
Concentrations
of
lipids
in
plasma
and
liver
of
piglets
of
control
sows
and
piglets
of
sows
supplemented
with
L-carnitine
at
birth
(day
1)
and
at
days
10
and
20
of
age
Control
+L-Camitine
S.E.M.
Total
cholesterol,
plasma
(mmol/L)
Day
1
(birth)
1.25a
1.01b
0.053
Day
10
3.06
3.11
0.112
Day
20
4.58
5.04
0.157
Triacylglycerols,
plasma
(mmol/L)
Day
1
(birth)
0.42
0.46
0.050
Day
10
0.82
0.95
0.057
Day
20
0.67a
0.88
b
0.055
Free
fatty
acids,
plasma
(mmol/L)
Day
1
(birth)
0.22
0.23
0.021
Day
10
0.36
0.43
0.043
Day
20
0.27
0.32
0.026
Total
cholesterol,
liver
(µmol/g)
Day
1
(birth)
6.51
5.92
0.433
Day
10
6.14
5.01
0.351
Day
20
7.59
8.17
0.288
Triacylglycerols,
liver
(µmol/g)
Day
1
(birth)
17.8
16.9
1.39
Day
10
8.3
9.7
0.63
Day
20
12.3
12.5
0.33
Means
(n
=13
for
control,
n
=14
for
+L-camitine).
Means
with
different
superscript
letters
(a
andb)
are
significantly
different
(P<0.05).
fatty
acids
and
hepatic
concentrations
of
total
cholesterol
and
triacylglycerols
did
not
differ
between
the
two
groups
of
piglets
at
any
time
(Table
7).
4.
Discussion
In
this
study,
sows
were
treated
with
L-carnitine
during
pregnancy
and
lactation.
The
finding
that
piglet
and
litter
weights
at
birth
did
not
differ
between
sows
supplemented
with
L-carnitine
and
control
sows
disagrees
with
recent
studies
conducted
with
a
large
number
of
sows
which
showed
that
L-carnitine
supplementation
increases
weights
of
litters
and
individual
piglets
significantly
(Musser
et
al.,
1999;
Eder
et
al.,
2001a;
Ramanau
et
al.,
2002).
However,
we
are
aware
that
the
experiment
presented
due
to
the
small
number
of
sows
is
not
suitable
to
study
effects
of
L-carnitine
on
litter
parameters
at
birth.
The
finding
that
L-carnitine
supplemented
sows
had
higher
plasma
IGF-1
concentrations
on
day
80
of
pregnancy
agrees
with
the
recent
observation
of
Musser
et
al.
(1999).
These
authors
reported
increased
IGF-1
plasma
concentrations
in
sows
supplemented
with
L-carnitine
on
days
60
and
90
of
pregnancy.
A
recent
study
(Waylan
et
al.,
2005)
did
not
find
an
effect
of
L-carnitine
on
plasma
IGF-I
concentrations
in
sows
at
days
28
and
57
of
pregnancy.
The
comparison
of
that
study
with
our
study
and
that
of
Musser
et
al.
(1999)
suggests
that
an
34
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et
al.
/Animal
Feed
Science
and
Technology
129
(2006)
23-38
effect
of
L-carnitine
on
plasma
IGF-1
concentration
might
occur
predominately
after
mid
gestation.
The
biological action
of
IGFs
can
be
modified
by
IGFBPs,
which
regulate
their
clearance
from
the
circulation
and
modulate
their
bioavailability
to
target
tissues
(Thissen
et
al.,
1994).
The
main
circulating
IGFBP
in
postnatal
pigs
is
IGFBP-3
(Owens
et
al.,
1991),
which
binds
the
IGFs
and
increases
their
half-life.
Changes
in
the
circulating
concentration
of
IGFBP-3
may
lead
to
changes
in
the
concentration
of
free
IGF-1
(Rehfeldt
et
al.,
2004).
The
finding
of
a
reduced
plasma
concentration
of
IGFBP-3
suggests
that
plasma
IGF-1
in
sows
supplemented
with
L-carnitine
might
have
been
more
available
to
target
tissues
than
in
control
sows.
In
this
study
diets
were
fed
ad
libitum
and
sows
supplemented
with
L-carnitine
had
higher
feed
intakes
than
control
sows.
As
an
increased
energy
intake
can
raise
plasma
IGF-1
concentrations
in
sows
(Rehfeldt
et
al.,
2004)
the
possibility
that
the
higher
plasma
concentrations
of
IGF-1
were
caused
by
an
increased
feed
intake
cannot
be
ruled
out.
The
finding
that
IGF-1
concentrations
at
day
100
are
very
low
agrees
with
some
other
investigations
which
showed
a
clear
decrease
of
plasma
IGF-1
in
sows
at
the
late
pregnancy
(Armstrong
et
al.,
1994;
Musser
et
al.,
1999).
This
is
probably
the
result
of
a
decreased
stimulation
of
IGF-1
secretion
by
growth-hormone
releasing
factor
and
somatotropin
(Armstrong
et
al.,
1994).
In
the
study
of
Waylan
et
al.
(2005)
plasma
IGF-1
concentrations
of
control
sows
decreased
from
15
nmol/L
at
day
0
of
gestation
to
7
nmol/L
at
day
28
and
2
nmol/L
at
day
57.
In
the
study
of
Musser
et
al.
(1999),
plasma
IGF-1
concentrations
of
control
sows
declined
from
9
nmol/L
at
day
10
of
gestation
to
5
and
3
nmol/L
at
days
60
and
90,
respectively.
An
IGF-1
concentration
of
3.90
nmol/L
in
plasma
of
control
sows
at
day
80
of
pregnancy
agrees
well
with
the
concentrations
reported
by
Musser
et
al.
(1999).
The
finding
that
plasma
IGF-1
concentrations
on
day
100
were
below
1
nmol/L
in
more
than
half
of
the
sows
shows
that
IGF-1
concentrations
in
pregnant
sows
are
continuously
declining
until
parturition.
Because
the
detection
limit
of
the
assay
used
in
our
study
was
1
nmol/L,
we
were
not
able
to
determine
whether
differences
in
plasma
IGF-1
concentration
between
both
groups
of
sows
may
also
exist
at
day
100
of
pregnancy.
The
determination
of
L-carnitine
concentrations
in
carcass
and
plasma
of
piglets
shows
that
L-carnitine
supplementation
of
sows
improves
the
L-carnitine
status
of
their
newborn
piglets.
This
effect
might
be
due
to
an
increased
transfer
of
L-carnitine
from
the
maternal
blood
to
the
fetuses
as
a
result
of
the
higher
plasma
L-carnitine
concentrations
in
mothers
supplemented
with
L-carnitine.
The
finding
that
the
content
of
total
lipids
in
carcass,
con-
centrations
of
triacylglycerols
and
cholesterol
in
liver,
plasma
and
lipoproteins
and
plasma
concentrations
of
free
fatty
acids
were
not
different
between
neonatal
piglets
of
sows
supple-
mented
with
L-carnitine
and
those
of
control
sows
suggests
that
L-carnitine
supplementation
of
sows
influences
neither
lipid
biosynthesis
nor
lipolysis
in
the
fetus
close
to
term.
This
finding
accords
with
the
observation
that
the
concentration
of
insulin
which
stimulates
lipogenesis
and
inhibits
lipolysis
was
not
different
between
the
two
groups
of
piglets.
The
only
change
in
lipid
parameters
observed
in
neonatal
piglets
of
sows
supplemented
with
L-
carnitine
compared
with
piglets
of
control
sows
was
a
reduced
concentration
of
cholesterol
in
plasma
and
lipoproteins.
This
could
be
due
to
impaired
secretion
of
cholesterol
from
the
liver
into
the
blood.
But
synthesis
of
cholesterol
was
probably
not
altered
because
the
concentration
of
cholesterol
in
the
liver
did
not
differ
between
the
two
groups
of
piglets.
The
finding
of
very
low
plasma
concentrations
of
IGF-1
in
neonatal
piglets
agrees
with
obser-
vations
of
several
other
studies
which
have
shown
that
plasma
IGF-1
at
birth
are
low
and
C.
Birkenfeld
et
al.
/Animal
Feed
Science
and
Technology
129
(2006)
23-38
35
thereafter
increase
rapidly
during
the
first
2
weeks
of
postnatal
life
as
a
result
of
the
onset
of
growth-hormone
stimulated
IGF-1
production
by
the
liver
(Lee
et
al.,
1991;
Gluckman,
1995).
Because
plasma
IGF-1
concentrations
of
more
of
the
half
of
the
piglets
was
below
the
detection
limit
of
the
IGF-1
assay
used
in
this
study,
we
were
not
able
to
detect
potential
differences
in
plasma
IGF-1
concentration
between
both
groups
of
piglets
at
birth.
To
eliminate
the
effects
of
litter
size
on
the
parameters
investigated
in
the
piglets,
litters
were
standardized
to
an
equal
amount
of
piglets/litter.
Because
after
birth
and
on
days
10
and
20
of
lactation,
one
piglet
was
removed
from
each
litter
for
analysis
of
carcass
composition,
litter
sizes
being
8,
7
and
6
after
birth
and
at
days
10
and
20,
respectively,
were
much
lower
than
under
practical
condition.
The
litter
size
influences
the
milk
production
of
the
sow
and
its
energy
requirement
(Etienne
et
al.,
1998;
Noblet
et
al.,
1998).
Because
milk
production
does
not
increase
proportionally
to
litter size,
milk
intake
per
piglet
nursed
increases
when
the
litter
size
decreases.
Milk
intake
per
piglet
for
example
increased
from
0.7
to
1.0
kg/day
when
litter
size
decreased
from
12
to
4
(Elsey,
1971)
or
from
0.9
to
1.3
kg/day
when
litter
sizes
decreased
from
14
to
6
piglets/litter
(Auldist
et
al.,
1994).
This
means
that
piglets
of
the
small
litters
in
our
study
might
have
taken
in
more
milk
and
might
have
grown
faster
than
piglets
of
litters
with
normal
sizes.
Therefore,
we
cannot
exclude
the
possibility
that
some
effects
would
have
been
different
if
litter
sizes
would
have
been
larger
or
not
standardised.
In
recent
studies,
Eder
et
al.
(2001a),
Ramanau
et
al.
(2002,
2004)
and
Musser
et
al.
(1999)
observed
that
piglets
of
sows
supplemented
with
L-carnitine
grow
faster
during
the
suckling
period
than
piglets
of
control
sows.
It
has
been
shown
that
this
effect
is
due
to
a
higher
milk
production
of
sows
supplemented
with
L-carnitine
compared
to
control
sows
(Ramanau
et
al.,
2004).
The
observation
of
the
present
study
that
piglets
of
sows
supplemented
with
L-
carnitine
and
those
of
control
sows
did
not
differ
in
their
growth
during
the
suckling
period
indeed
could
be
due
to
the
small
litter
sizes
in
this
study.
The
determination
of
the
concentrations
of
L-carnitine
in
plasma
and
carcass
of
piglets
at
10
and
20
days
of
age
shows
that
suckling
piglets
of
sows
supplemented
with
L-carnitine
have
a
better
L-carnitine
status
than
piglets
of
control
sows.
This
might
be
due
to
the
higher
concentration
of
L-carnitine
in
the
milk
of
sows
supplemented
with
L-carnitine
compared
to
milk
of
control
sows.
In
a
previous
study
with
rats,
it
has
been
already
shown
that
carnitine
tissue
concentrations
during
the
early
suckling
period
are
strongly
related
to
the
carnitine
concentration
of
the
milk
(Flores
et
al.,
1996).
L-Carnitine
is
very
important
immediately
after
birth
because
it
is
required
for
generation
of
energy
by
I3-oxidation
as
the
glucose
supply
is
disrupted
and
glycogen
stores
are
rapidly
exhausted
(Warshaw
and
Curry,
1980).
Under
the
experimental
conditions
used
in
this
study,
piglets
of
L-carnitine
supplemented
did
not
differ
in
chemical
carcass
composition
(i.e.
content
of
total
lipids)
and
concentrations
of
lipids
in
liver,
plasma
and
lipoproteins
and
plasma
concentrations
of
free
fatty
acids
on
days
10
and
20
from
piglets
of
control
sows
although
they
had
a
better
L-carnitine
status.
The
observation
that
plasma
lipids
were
independent
of
the
L-carnitine
status
of
the
piglets
agrees
with
a
previous
study
with
piglets
in
which
feeding
of
a
formula
diet
with
a
low
concentration
of
L-carnitine
also
did
not
influence
the
concentration
of
triacylglycerols
in
plasma
(Coffey
et
al.,
1991).
The
only
change
in
lipid
parameters
observed
in
suckling
piglets
of
sows
supplemented
with
L-carnitine
compared
with
piglets
of
control
sows
was
an
increased
concentration
of
triacylglycerols
in
plasma
on
day
20
of
age.
This
could
be
due
to
an
increased
secretion
of
triacylglycerols
from
the
liver
into
the
blood
or
a
reduced
degradation
36
C.
Birkenfeld
et
al.
/Animal
Feed
Science
and
Technology
129
(2006)
23-38
of
triacylglycerol-rich
lipoproteins
by
lipoprotein
lipase.
But
synthesis
of
triacylglycerols
was
probably
not
altered
because
the
concentration
of
triacylglycerols
in
the
liver
did
not
differ
between
the
two
groups
of
piglets.
In
this
study,
we
did
not
perform
biochemical
analyses
of
enzyme
activities
involved
in
lipid
synthesis
or
I3-oxidation.
It
is,
however,
expected
that
biochemical
alterations
of
the
lipid
metabolism
should
be
associated
with
altered
concentrations
of
lipids
in
tissues
and
plasma.
Because
the
lipid
contents
in
the
carcasses
of
the
piglets
were
completely
unchanged
and
lipid
parameters
in
plasma
and
liver
were
only
negligibly
different
between
both
groups
of
piglets
we
suggest
that
the
improved
L-carnitine
status
of
piglets
of
sows
supplemented
with
L-carnitine
was
not
associated
with
serious
alterations
of
the
lipid
metabolism,
i.e.
13-
oxidation
of
fatty
acids
or
synthesis
of
lipids.
This
suggestion
disagrees
with
observations
in
weaned
piglets
and
growing
pigs
where
L-carnitine
supplementation
lowered
the
content
of
lipids
in
the
whole
body
as
a
result
of
enhanced
13-oxidation
of
fatty
acids
(Owen
et
al.,
1996;
Heo
et
al.,
2000;
Owen
et
al.,
2001b).
The
finding
that
body
composition
of
piglets
on
days
10
and
20
did
not
differ
between
the
two
groups
closely
accords
with
the
observation
of
unchanged
plasma
concentrations
of
insulin
and
IGF-1.
In
conclusion,
this
study
shows
that
L-carnitine
supplementation
of
sows
improves
the
L-carnitine
status
of
their
piglets
at
birth
and
during
the
suckling
period
but
does
not
influ-
ence
their
body
composition
or
concentrations
of
lipids
in
liver,
plasma
and
lipoproteins.
This
shows
that
piglets
of
sows
supplemented
with
L-carnitine
do
not
differ
in
their
lipid
metabolism
from
piglets
of
control
sows.
It
must
be
noted,
however,
that
in
this
study
piglets
of
sows
supplemented
with
L-carnitine
did
not
differ
in
their
body
weights
at
birth
and
dur-
ing
the
suckling
period
from
those
of
control
sows
which
is
in
clear
contradiction
to
recent
studies
(Musser
et
al.,
1999;
Eder
et
al.,
2001a;
Ramanau
et
al.,
2002,
2004).
Therefore,
the
possibility
that
piglets
of
sows
supplemented
with
L-carnitine
would
have
differed
in
their
body
composition
and
lipid
metabolism
from
piglets
of
control
sows
if
they
would
have
grown
faster
during
suckling
period
than
piglets
of
control
sows
as
recently
reported
(Musser
et
al., 1999;
Eder
et
al.,
2001a;
Ramanau
et
al.,
2002,
2004)
cannot
be
excluded.
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