Effect of different drying systems for the conservation of olive leaves on their nutritive value for ruminants
Abstract
Leaves obtained from olive trees (Olea europaea L.) were stored under various conditions for periods up to 42 months. Duration of storage had a marked effect on crude protein digestibility of leaves when fed to sheep. Protein appeared to be unavailable to animals fed leaves stored for 24 months or longer. The effect of storage on organic matter digestibility was less dramatic and due largely to the loss of soluble cell contents (r = 0.97). As a result, the proportion of water-insoluble dry matter and lignin present in leaves increased with duration of storage while the proportion of water or acetone-water (60:30 v/v) soluble material decreased. Despite being unavailable in vivo, cellulase digestion released protein from the water-insoluble residues of stored leaves in greater amounts than that released from freshly-dried leaves. It appears likely that protein released from stored leaves was in the form of a complex and remained unavailable to the animal. Hydrolysable and condensed tannins were not detected in fresh or dried leaves and could not have acted as complexing agents. The seco-iridoid glycoside oleuropein was found in fresh tissue (69.9 g kg(-1)) but concentrations decreased on storage in parallel with the observed decrease in crude protein digestibility (r = 0.80). ((C) Elsevier/Inra).
Full text
O iginal
a icle
E ec
o
di e en
d ying
sys ems
o
he
conse a ion
o
oli e
lea es
on
hei
nu i i e
alue
o
uminan s
Manuel
Delgado-Pe íñez
a
And ew
Chesson
Go don
J.
P o an
Ana
Ga ido
c
Augus o
Gómez-Cab e a
"Dp o.
Ciencias
Ag o o es ales,
Uni e sidad
de
Se illa,
C a.
U e a
Km.
1,
410 13 Se illa, Spain
b
Rowe
Resea ch
Ins i u e,
Bucksbu n,
Abe deen,
AB21
9SB,
UK
!Dp o.
P oduccion
Animal,
Uni e sidad
de
Có doba,
Apdo.
3048,
14080
Có doba,
Spain
(Recei ed
I Decembe
1997;
accep ed
6
Janua y
1998)
Abs ac -Lea es
ob ained
om
oli e
ees
(Olea
eu opaea
L.)
we e
s o ed
unde
a ious
con-
di ions
o
pe iods
up
o
42
mon hs.
Du a ion
o
s o age
had
a
ma ked
e ec
on
c ude
p o ein
diges ibili y
o
lea es
when
ed
o
sheep.
P o ein
appea ed
o
be
una ailable
o
animals
ed
lea es
s o ed
o
24
mon hs
o
longe .
The
e ec
o
s o age
on
o ganic
ma e
diges ibili y
was
less
d ama ic
and due
la gely
o
he
loss
o
soluble
cell
con en s
(
=
0.97).
As
a
esul ,
he
p o-
po ion
o
wa e -insoluble
d y
ma e
and
lignin
p esen
in
lea es
inc eased
wi h
du a ion
o
s o age
while
he
p opo ion
o
wa e
o
ace one-wa e
(60:40
/ )
soluble
ma e ial
dec eased.
Despi e
being
una ailable
in
i o,
cellulase
diges ion
eleased
p o ein
om
he
wa e -insoluble
esidues
o
s o ed
lea es
in
g ea e
amoun s
han
ha
eleased
om
eshly-d ied
lea es.
I
appea s
likely
ha
p o ein
eleased
om
s o ed
lea es
was
in
he
o m
o
a complex
and
emained
una ailable
o
he
animal.
Hyd olysable
and
condensed
annins
we e
no
de ec ed
in
esh
o
d ied
lea es
and
could
no
ha e
ac ed
as
complexing
agen s.
The
seco-i idoid
glycoside
oleu opein
was
ound
in
esh
issue
(69.9
g
kg-
1)
bu
concen a ions
dec eased
on
s o age
in
pa allel
wi h
he
obse ed
dec ease
in
c ude
p o ein
diges ibili y
(
=
0.80).
(©
Else ie
/
In a)
oli e
lea es
/
diges ibili y
/
sheep
/
p o ein
/
phenolic
compounds
Résumé -
E e s
de
di é en s
modes
de
conse a ion
des
euilles
d’oli ie
su
leu
aleu
nu i i e
pou
les
uminan s.
Des
euilles
d’oli ie
(Olea
eu opaea
L)
on
é é
s ockeés
dans
di -
é en es
condi ions
du an
des
pé iodes
allan jusqu’à
42
mois.
La
du ée
du
s ockage
a
eu
d’impo -
an s
e e s
su
la
diges ibili é
chez
le
mou on
des
ma iè es
azo ées
des
euilles.
Les
ma iè es
*
Co espondence
and
ep in s.
Tel.:
34 423
3669;
ax:
34 423 2644;
e-mail:
[email p o ec ed]
azo ées
des
euilles
s ockées
pendan
24
mois
ou
plus
n’on
plus
é é
u ilisées
pa
les
animaux.
Les
e e s
du
s ockage
su
la
diges ibili é
de
la
ma iè e
o ganique
on
é é
moins
d ama iques
e
son
dus
su ou
à
la
pe e
du
con enu
cellulai e
soluble
(
=
0,97).
Il
en
a
ésul é
que
la
p opo ion
de
lignine
e
de
ma iè e
sèche
insoluble
dans
l’eau
p ésen e
dans
les
euilles
a
augmen é
a ec
la
du ée
du
s ockage,
andis
que
le
ma é iel
soluble
dans
l’eau
ou
en
mélange
(60:40
/ )
acé one-
eau
a
diminué.
Les
p o éines
des
euilles
s ockées,
quoique
non
u ilisables
in
i o,
on
é é
libé-
ées
des
ésidus
insolubles
dans
l’eau
pa
une
cellulase
en
quan i és
plus
g andes
que
celles
qui
on
é é
libé ées
des
euilles
aîches
séchées.
Il
es
p obable
que
les
p o éines
libé ées
pa
les
euilles
s ockées
on
pa ie
d’un
complexe
inu ilisable
pa
l’animal.
Les
anins
hyd olysables
e
condensés
n’on
pu
ê e
dé ec és
dans
les
euilles
aîches
ou
sèches
e
n’on
donc
pas
agi
comme
agen
complexan .
La
glycoside
seco-i idoïde
oléu opéine
a
é é
ou ée
dans
les
issus
ais
séchés
(69,9
g
kg-’)
mais
les
concen a ions
on
diminué
p opo ionellemen
a ec
le
diminu-
ion
de
la
diges ibili é
des
p o éines
(
=
0,80)
du an
le
s ockage.
(©
Else ie
/
In a)
euilles
d’oli ie
/
diges ibili é
/
mou on
/
p o éine/
composés
phénoliques
1.
INTRODUCTION
The
use
o
ee
oliage
as
eed
in
animal
p oduc ion
sys ems
is
a
common
p ac ice
in
d y
and
semi-d y
a eas.
In
he
Medi e -
anean
basin,
whe e
app oxima ely
98%
o
he
wo ld
p oduc ion
o
oli es
akes
place
[5],
he
mos
commonly
used
oliage
comes
om
oli e
ees.
T adi ional
mana-
gemen
sys ems
allowed
goa s
and
sheep
o
eely
oam
he
oli e
g o es
eeding
on
he
lea es
om
p uned
b anches.
How-
e e ,
cu en
p ac ice
a o s
ga he ing
and
bu ning
p unings
o
limi
he
sp ead
o
pa asi es
and
o
allow
ploughing
be ween
ees.
This
has
esul ed
in
a
sho age
o
uminan
eed
in
some
pa s
o
Spain
and
has
enewed
in e es in
de eloping
al e -
na i e
s a egies
o
he
u iliza ion
o oli e
by-p oduc s
in
animal
eeding
sys ems.
Any
mo e
o
collec
and
s o e
he
p un-
ings
om
oli e
ees
in ol es
d ying
he
lea es.
In
a
p elimina y
s udy,
G6mez-
Cab e a
e
al.
[8]
ound
ha
he
d y
ma e
diges ibili y
and
he
a ailabili y
o
p o-
ein
o
uminan s
ell
subs an ially
when
oli e
lea es
we e
ai -d ied
a
ambien
em-
pe a u es.
The
ex en
o
hese
losses
was
de e mined
by
he
se e i y
and
du a ion
o
he
d ying.
This
was
con a y
o
obse -
a ions
made
wi h
he
annin- ich
oak
lea es
whe e
d ying
appea ed
o
ha e
no
o
e en
a
sligh ly
bene icial
e ec
on
nu i-
i e alue
[15, 16].
I
is
well
ecognized
ha
i
empe a-
u es
exceed
abou
50 °C
du ing
he
d ying
o
eed
samples
he
appa en
lignin
and
ibe
con en s
inc ease
[27],
addi ional
ni ogen
becomes
bound
o
he
ibe
ac-
ion
[6,
7,
24]
and
diges ibili y
may
be
educed
[13].
Howe e ,
he
p oxima e
analysis
o
o en-d ied
and
ai -d ied
oli e
lea es
by
G6mez-Cab e a
e
al.
[8]
p o-
ided
li le
e idence
o such
changes
and
an
al e na i e
mechanism
esponsible
o
he
obse ed
subs an ial
all
in
c ude
p o-
ein
diges ibili y
was
equi ed.
This
led
G6mez-Cab e a
and
his
colleagues
o
sug-
ges
ha
phenolic
compounds
in
slowly
d ied lea es
may
a ec
pala abili y
and
inhibi
he
diges ion
p ocess.
The
aim
o
he
p esen
pape
was
o
examine
he
e ec
o
a
ange
o
d ying
p ocesses,
di e ing
in
du a ion,
empe a u e
and
exposu e
o
mois u e,
on
nu i i e
alue
and
o
es ab-
lish
whe he
he
many
phenolic
com-
pounds
p esen
in
oli e
lea es
(see
able
I;
[ 12])
a e
implica ed
in
he
educed
o ganic
ma e
and
p o ein
diges ibili y
o
he
d ied
lea es
when
ed
o
sheep.
2.
MATERIALS
AND
METHODS
2.1.
Collec ion
and
s o age
o
oli e
lea es
Collec ions
o
ma u e
b anches
we e
made
du ing
ou ine
p uning
o Picual
and
Hojiblanca
cul i a s
o
oli e
ees
(Olea
eu opaea
L.)
in
Feb ua y
in
1987
and
again
in
1990 and
1991.
F esh
lea es
we e
collec ed
om
he
same
ees
in
Sep embe
1992.
B anches
acqui ed
in
1987
we e
ei he
immedia ely
d ied
in
a
o ced-ai
o en
a
60-65 °C
o
16
h
and
he
lea es
hen
sepa a ed
om
b anches
by
hand
(OD
sample)
o
hey
we e
le
o
ai
d y
in
a
shed
a
ambien
empe a u e
as
p e iously
desc ibed
by
G6mez-
Cab e a
e
al.
[8].
A e
3
mon hs
he
lea es
we e
emo ed
om
ai -d ied
b anches
by
c ushing
and
manual
sepa a ion.
Samples
o
he
lea es
we e
hen
s o ed
in
sealed con ain-
e s
un il
equi ed
(sample
AD3)
o
le
unde
ambien
condi ions
o
a
u he
21
(sample
AD24)
o
39
mon hs
(sample
AD42).
B anches
cu
om
ees
in
1990
we e
ei he
baled
(0.6
x
0.4
x
0.3
m)
and
le
o
d y
in
a
shed
a
ambi-
en
empe a u e
o
9
mon hs
a e
which
ime
he
lea es
we e
manually
emo ed
(BB
sam-
ple),
o
he
lea es
and
wigs,
emo ed
mechan-
ically
om
he
b anches
immedia ely
a e
p uning,
we e
le
unbaled
o
ai -d y
and
a e
24
mon hs
(BP24)
and
42
mon hs
(MP42)
he
lea es
mechanically
sepa a ed
om
he
wigs.
Finally,
a
sample
o b anches
ha es ed
in
1991
1
was
allowed
o
become
sa u a ed
wi h
ain
wa e
be o e
s o ing
unde
d y
condi ions
in
a
shed
o
a
pe iod
o
12
mon hs
ollowed
by
he
mechanical
emo al
o
he
lea es.
Occu -
ence
o
e men a ion
was
e iden
in
his
sam-
ple
(BF).
Sepa a ed
lea
ma e ial
om
all
sam-
ples
was
s o ed
wi hou
u he
ea men
o
diges ibili y
de e mina ions
o
g ound
o
pass
a
1
mm
sc een
in
p epa a ion
o
analysis.
Two
samples,
su icien
o
analysis
only,
we e
p epa ed
om
he
esh
lea es
collec ed
in
Sep embe
1992:
one
eeze-d ied
o
p o-
duce
minimum
change
on
d ying
(sample
FD)
and
he
second,
compa able
o
he
OD
sample
p epa ed
o
diges ibili y
expe imen s,
d ied
in
a
acuum
o en
a
he
lowe
empe a u e
o
40 °C
o
144
h
o
minimize
oxida i e
dam-
age
(sample
VO).
2.2.
Diges ibili y
de e mina ions
The
diges ibili y
o
he
eigh
samples
o
oli e
lea es
p epa ed
a e
a ious
condi ions
o
s o age
we e
measu ed
using
ou
adul
Segu ena
sheep
as
desc ibed
by
G6mez-Cab -
e a
e
al.
[8].
The
amoun
o
oli e
lea o e ed
o
he
sheep
was
70
g
DM/kg
O.
75
and
150
g
o
dehulled
sun lowe
seed
meal
was
mixed
wi h
he
lea as
a
p o ein
supplemen .
The
adap a ion
pe iod
was
14
days
ollowed
by
10
days
o
collec ion
o eces.
D y
ma e ,
ash
and
c ude
p o ein
con en
o
lea es,
die s
and
collec ed
eces
we e
de e mined
ollowing
he
ecom-
mended
AOAC
me hods.
Acid
de e gen
ibe
(ADF)
and
acid
de e gen
lignin
(ADL)
we e
quan i ied
by
he
me hod
o
Robe son
and
Van
Soes
[22].
O ganic
d y
ma e
and
c ude
p o ein
diges ibili y
o
he
oli e
lea es
we e
calcula ed
by
di e ence,
aking
in o
accoun
he
measu ed
diges ibili y
o
he
sun lowe
componen
o
he
die .
2.3.
Ex ac ion
and
analysis
o
lea
samples
Samples
o
lea
ma e ial
(10
g)
we e
ex ac ed
wi h
pe oleum
e he
o
emo e
chlo ophyll
and
lipids,
ollowed
by
ex ac ion
ei he
wi h
wa e
o
1
h
a
40 °C
o
cold
ace-
one-wa e
(60:40
/ )
o e nigh .
Pe oleum-
e he
ex ac s
we e
disca ded
bu
he
ace one-
wa e
and
aqueous
ex ac s
we e
e ained,
eeze-d ied
(a e
emo al
o
any
ace one),
and
weighed.
F eeze-d ied
ex ac s
and
ex ac ed
esidues
we e
eeze -milled
unde
liquid
ni ogen
o
3
min
(Spex
6700
eeze -
mill,
Spex
Indus ies
Inc.,
Edison,
NJ,
USA)
p io
o
analysis.
To al
phenolics
we e
measu ed
using
he
ace yl
b omide
me hod
[ 17,
18]
and
exp essed
as
e ulic
acid
equi alen s
by
e e ence
o
a
s anda d
calib a ion
cu e.
Ex ac s
we e
exam-
ined
o
he
p esence
o
hyd olysable
annins
(gallo annins)
by
he
me hod
o
Inonue
and
Hage man
[ 10]
and
condensed
annins
using
he
me hod
desc ibed
o
p oan hocyanidins
by
Po e
e
al.
[21
]. Oleu opein
was
ex ac ed
om
oli e
lea es
(20
mg)
by
sonica ion
wi h
80%
e hanol
(I
mL)
con aining
0.01
mg
anisic
acid
as
in e nal
s anda d.
The
sample
was
cen-
i uged,
he
esidue
emo ed
and
wa e
(1
mL)
added
o
he
supe na an
p io
o
emo al
o
he
e hanol
unde
a
s eam
o
ni ogen.
The
sample
was
hen
applied
o
a
C18
solid
phase
ex ac ion
ca idge
(Accubond,
J.W.
Scien-
i ic,
Folsom,
USA),
which
had
been
p e-equi-
lib a ed
wi h
me hanol
(3
x
1
mL)
and
wa e
(3
x
I mL),
washed
wi h
wa e
(I
mL)
and
elu ed
wi h
50%
e hanol
(2
x
400
pL).
The
e hanol
was
pa ially
emo ed
unde
a
s eam
o
ni o-
gen
and
20
pL
o
he
p edomina ely
aqueous
sample
analyzed
by
HPLC
using
a
100
x
4.6
mm
5
p
Sphe iso b
ODS2
(Hich om
L d.,
UK)
column.
The
eluen
was
35%
me hanol
in
0.5%
ace ic
acid
a
a
low
a e
o
I mL
min-
I
and
de ec ion
was
by
UV
a
280
nm.
The
p o ein
con en
o
he
ex ac s
was
de e mined
by
he
p o ein-dye
binding
me hod
[11
using
bo ine
se um
albumin
as
s anda d,
o
as
c ude
p o ein
(N
x
6.25)
calcula ed
om
he
ni ogen
con en
de e mined
by
Kjeldahl
diges ion.
C ude
p o ein
in
he
insoluble
esidues
was
calcula ed
om
Kjeldahl
ni o-
gen
de e mina ions.
Wa e
o
wa e -ace one-
insoluble
esidues
we e
incuba ed
wi h
a
com-
me cial
cellulase
p epa a ion
(Fluka
ex
T ichode
l7
11£l
eseii)
o
24
h
a
40 °C
in
20
mM
ace a e
bu e
(pH
4.5),
and
he
d y
ma e
and
ni ogen
con en
o
non-diges ed
ma e ial
mea-
su ed
and
he
alues
ob ained
used
o
calcu-
la e
he
ex en
o cell
wall
b eakdown
and
p o-
ein
(ni ogen)
elease.
The
esul s
we e
subjec ed
o
s a is ical
ana-
lysis
using
he
PROC
MEANS
and
PROC
CORR
p ocedu es
o
he
SAS
so wa e
pack-
age
[23].
3. RESULTS
3.1.
In
i o
deg adabili y
o
s o ed
lea es
Inc easing
he
se e i y
o
du a ion
o
he
d ying
condi ions
had
a
ma ked
e ec
on
bo h
o ganic
ma e
(OMD)
and
c ude
p o ein
diges ibili y
(CPD)
in
sheep
( able
0.
Compa ison
o
he
OD
and
AD3
samples,
which
had
simila
OMD
alues
bu
di e en
CPD,
sugges ed
p o ein
diges ibili y
was
mo e
sensi i e
o
hea
han
o
du a ion
o
s o age
bu
compa i-
son
o
AD3,
AD24
and
AD42
showed
ha
bo h
ac ions
we e
a ec ed
by
s o age.
Since
he
p opo ion
o
ADF
and
ADL
p esen
in
he
lea
samples
inc eased
wi h
s o age
i
is
p obable
ha
any
dec ease
in
OMD
was
la gely
a
e lec ion
o
a
loss
ini ially
o
highly
deg adable
cell
con en s
and
la e ly
o
he
b eakdown
o
he
mo e
diges ible
cell
wall
ma e ial.
The
solubil-
i y
o
DM
in
ace one-wa e ,
shown
in
able
II,
was
consis en
wi h
his
iew
and
a
di ec
ela ionship
(
=
0.95)
was
ound
be ween
soluble
d y
ma e
and
he
OMD
de e mined
in
i o
igu e
I
Wa e
alone
was
uni e sally
less
e ec i e
han
ace-
one-wa e
in
solubilising
bo h
d y
ma -
e
and
p o ein
(da a
no
p esen ed)
al hough
he e
was
s ill
a
di ec
ela ion-
ship
be ween
OMD
and
soluble
d y
ma -
e
(
=
0.97).
The
amoun
o
p o ein
ex ac ed
by
wa e
alone
was
hal
o
less
han
he
amoun
ex ac ed
by
ace one-wa e
om
he
co esponding
sample
shown
in
able
11,
al hough
he
magni ude
o
he
di e -
ence
did
no
ob iously
ela e
o
ea men .
Di ec
measu emen
o
soluble
p o ein
by
a
dye-binding
me hod
and
es ima es
made
om
he
ni ogen
con en
(c ude
p o ein)
we e
in
good
ag eemen
o he
eeze-
d ied
and
acuum
o en
d ied
samples
bu
di e ed
in
hose
samples
exposed
o
head
o
p olonged
s o age.
In
hese
samples
he
dye-binding
me hod
ga e
lowe
alues
han
he
c ude
p o ein
de e mina ion,
pos-
sibly
implying
some
complexing
o
he
p o ein.
While
he
o al
c ude
p o ein
con-
en
a ied
depending
on
d y
ma e
con-
en
( able
0,
he
p opo ion
o
o al
p o ein
ep esen ed
by
he
ace one-wa e
insoluble
ac ion
emained
essen ially
cons an
(0.80-0.84)
in
all
bu
one
sample.
The
excep ion
was
sample
MF
which
had
been
delibe a ely
encou aged
o
e men
on
s o -
age.
In
his
sample,
he
amoun
o
solu-
ble
p o ein
was
subs an ially
highe
and
he
insoluble
p o ein
ac ion
was
(0.70)
co espondingly
educed.
The
obse ed
solubili y
o
p o ein
in
ace one-wa e
o
wa e
alone
sugges ed
ha ,
e en
i
none
o
he
insoluble
p o ein
was
po en ially
deg adable,
15-20%
o
he
o al
c ude
p o ein
should
be
a ailable
o
he
animal
and
ha
in
he
MF
ac ion
his
alue
would
be
close
o
30%.
How-
e e ,
his
was
no
suppo ed
by
he
ani-
mal
expe imen s
in
which
ew
o
he
in
i o
CPD
alues
app oached
his
igu e
and
in
he
case
o
he
MP24,
MP42
and
MF
samples,
none
o
he
p o ein
appa -
en ly
was
a ailable
( able
0,
In
appa en
con adic ion
o
he
in
i o
esul s,
in
i o
diges ion
o
he
wa e -
o
ace one-wa e -
insoluble
esidues
o
he
lea es
wi h
a
comme cial
cellulase
esul ed
in
subs an-
ial
solubilisa ion
o
bo h
d y
ma e
and
c ude
p o ein
( able
III,
esul s
o
wa e -
soluble
ex ac s
only
shown).
The
c ude
p o ein
eleased
om
s o ed
lea es
was
compa able
wi h
o
g ea e
in
amoun
han
ha
eleased
om
he
o en
(OD)
and
eeze-d ied
(FD)
samples
p epa ed
soon
a e
ha es
in
he
labo a o y.
Ex ended
s o age
(24
and
42
mon hs)
and
e men-
a ion
(MF
sample)
appea ed
o
bo h
con-
se e
and
p omo e
he
d y
ma e
and
c ude
p o ein
in
i o
deg ada ion
o
he
samples
in
ma ked
con as
o
he
esul s
obse ed
in
i o.
3.2.
An i-nu i ional
ac o s
in
oli e
lea es
Since
cell
wall
deg ading
enzymes
we e
able
o
diges
a
subs an ial
p opo ion
o
all
lea
samples
in
i o,
he
poo
diges ibili y
o
d y
ma e
and
p o ein
obse ed
o
some
samples
when
ed
o
animals
ela ed
ei he
o
he
biological
una ailabili y
o
he
eleased
ma e ial
o
o
he
di ec
inhi-
bi ion
o
he
umen
mic o lo a.
Hyd olysable
o
condensed
annins
we e
no
de ec ed
in
any
wa e
o
ace one-wa e
ex ac s
o
oli e
lea es
and
we e
dis-
coun ed
as
a
possible
an i-nu i ional
ac-
o .
The
seco-i idoid
glycoside
oleu opein
was
ound
in
subs an ial
amoun s
( able
li!
in
eeze-d ied
samples
bu
in
lowe
concen a ions
in
lea es
which
had
been
s o ed.
The
ex en
o
oleu opein
disap-
pea ance
was
ela ed
o
he
all
in
OMD
(
=
0.83)
and
o
he
educ ion
in
CPD
( = 0.80).
The
ace yl-b omide
me hod
p o ided
an
al e na i e
and
mo e
speci ic
measu e
o
lignin
con en
o
he
wa e
and
ace one-
wa e
insoluble
esidues
han
did
ADL
al hough
he e
was
a
clea
ela ionship
(
=
0.79)
be ween
he
wo
measu es.
As
would
be
expec ed,
he e
was
a
s ong
neg-
a i e
ela ionship
be ween
he
phenolic
con en
o
he
insoluble
esidues
and
amoun
o
d y
ma e
ex ac ed
by
wa e
(
=
-0.96)
o
ace one-wa e
(
=
-0.99),
mi o ing
he
ela ionship
wi h
ADL.
A
s ong
nega i e
ela ionship
( =-0.96)
was
ound
be ween
he
phenolic
con en
o
ex ac ed
lea
esidues
and
OMD
( igu e
2)
bu
he
ela ionship
wi h
CPD
was
con-
side ably
weake
and
no
signi ican
( = -0.75).
4.
DISCUSSION
T ee
lea es
used
as
an
addi ional
o
al e na i e
sou ce
o
nu ien s
in
many
opical
coun ies
o en
con ain
subs an-
ial
amoun s
o
condensed
annins.
These
ha e
been
shown
o
dep ess
pe o mance
when
ed
as
a
high
p opo ion
o
he
o al
die
o
uminan
animals.
D ying
o
such
lea es,
whe he
in
he
ield
o
in
he
labo-
a o y
does
no
appea
o
g ea ly
change
hei
annin
con en
o
nu i ional
alue
[4,
13,
14-16].
Whe e
he e
is
an
e ec
o conse a ion,
he
endency
is
o
imp o e
a he
han
dec ease
nu i i e
alue
o an-
nin- ich
lea es [ 16,
19].
The
oli e
lea es
used
in
his
s udy
we e
shown
o
be
ee
o
hyd olysable
and
con-
densed
annins.
Thei
esponse
o
d ying
mo e
closely
esembled
he
o age
sam-
ples
s udied
by
Mahyuddin
e
al.
[13].
In
pa icula ,
c ude
p o ein
diges ibili y
was
ound
o
be
ze o
in
h ee
o
he
conse ed
samples
and
much
educed
in
o he s,
implying
he
o ma ion
o
a
mo e
s able
complex
han
is
ypical
o
annin-p o ein
in e ac ions
[20]
wi h
no
pos - uminal
elease
o
p o ein.
Co ey
e
a]. 13]
wo k-
ing
wi h
escue,
Sceho ic
[24]
wi h
a
ange
o
o ages
and
G6mez-Cab e a
e
al.
[8]
wi h
oli e
lea es
ha e
all
epo ed
ha
o age
d ying
causes
a
g ea e
binding
o
ni ogen
o
he
ibe
ac ion.
Much
o
he
ni ogen
p esen
in
wa e -
and
sol en -ex ac ed
oli e
lea es
could
be
eleased
by
he
ac ion
o
a
comme cial
p epa a ion
o
cell
wall
deg ading
enzymes.
Since
a
simila elease
o
p o-
ein
would
be
expec ed
wi hin
he
umen,
he
esul ing
lack
o
a ailabili y
o
he
animal
indica es
ha
he
ni ogen,
al hough
pa ially
solubilised,
emains
complexed
in
a
o m
esis an
o
hos
o
mic obial
p o-
eoly ic
a ack.
In
he
absence
o
con-
densed
annins,
he
mos
likely
candida es
o
complex
o ma ion
wi h
p o ein
a e
o he
phenolic
compounds.
I
has
long
been
ecognized
ha
i ually
all
com-
pounds
wi h
a
phenolic
unc ionali y
can
co alen ly
link
o
sulphu -con aining
and
o he
amino
acids,
a
p ocess
aided
by
mois u e,
hea
and
ime
[25].
The
abili y
o
ace one-wa e
o
ex ac
mo e
ni ogen
om
s o ed
samples
han
wa e
alone
and
he
lowe
soluble
p o ein
es ima es
p o-
ided
by
he
dye-binding
also
a e
consis-
en
wi h
some
complexing
wi h
a
pheno-
lic
ac ion.
In
addi ion
o
lignin
in
he
cell
wall
ac ion,
oli e
lea es
and
ui
a e
cha -
ac e ized
by
a
high
concen a ion
o
oleu-
opein,
a
seco-i idoid
glycoside
which
impa s
he
bi e
as e o
he
ui
I I 11.
The
concen a ion
ound
in
he
FD
lea es
(70
g
kg-
I
d y
ma e )
ell
wi hin
he
ange
no mally
encoun e ed,
which
is
highly
a iable
and
can
each
90
g
kg-
I
d y
ma -
e
[26].
The e
was
a
conside able
all
in
oleu opein
con en
o
lea es
wi h
s o age,
he
ex en
o
which
could
be
co ela ed
wi h
he
loss
o
d y
ma e
and
CPD.
How-
e e ,
he
wo
may
no
be
causally
ela ed.
Loss
o
ex ac able
oleu opein
can
occu
because
o
hyd oly ic
b eakdown
[2,
28]
o
slow
oxida i e
polyme iza ion
[9]
wi h-
ou
any
in e ac ion
wi h
p o ein.
Poly-
me iza ion
o
oleu opein
o
i s
b eakdown
p oduc s
would
dec ease
solubili y
and
make
i
di icul
o
dis inguish
om
he
lignin
ac ion
in
any
g a ime ic
assays.
Fu he
wo k would
be
needed
o
es ablish
whe he
he
p o ein
which
appa en ly
becomes
complexed
wi h
phenolic
ma e-
ial
is
associa ed
p ima ily
wi h
lignin,
oleu opein,
o
bo h.
Howe e ,
any
sug-
ges ion
ha
oleu opein
migh
be
oxic
o
he
umen
mic o lo a
can
be
discoun ed.
The
highes
diges ibili ies
we e
eco ded
o
he
samples
wi h
he
g ea es
oleu-
opein
con en .
OMD
was
e iden ly
mo e
sensi i e
o
he
du a ion
o
s o age
han
o
hea .
Wa e
and
sol en -soluble
d y
ma e
dec eased
wi h
s o age
and
he
amoun
o
educ ion
was
s ongly
ela ed
o
he
dec ease
in
OMD.
The e
was
a
concomi an
ise
in
cell
wall
con en ,
pa icula ly
o
he
mo e
ligni ied
cell
ypes,
as
shown
by
he
inc ease
in
lignin,
whe he
measu ed
as
ADL
o
by
he
ace yl
b omide
me hod.
Howe e ,
as
indica ed
p e iously,
no
all
o
he
p opo ional
inc ease
in
lignin
may
be
due
o
he
loss
o
cell
con en s.
Com-
plexa ion
wi h
phenolics
may
also
ha e
con ibu ed
ma e ial
which
was
de ec ed
as
ADL.
O e all,
his
pa e n
o
e en s
is
consis en
wi h
he
dec ease
in
OMD
due
p incipally
o
loss
o cell
con en s
h ough
leaching
o
mic obial
ac ion
du ing
he
d ying
o
no mal
senescence
p ocesses
and
possible
wi h
he
loss
o
mo e
eadily
deg adable
cell
wall
ma e ial.
Thus
OMD
was
p incipally
de e mined
by
he
amoun
o
ma e ial
which
was
insoluble
in
wa e
o
sol en
and
i s
appa en
lignin
con en .
I
was
sugges ed
p e iously
ha
emo al
o
lea es
om
wigs
and
b anches
had
a
nega i e
e ec
on
bo h
OMD
and
CPD
[8].
Al hough
emo al
o
lea es
migh ,
in
he
sho
e m,
p omo e
au oly-
sis
and
loss
o cell
con en ,
he e
is
li le
o
sugges
ha
his
is
signi ican
in
he
longe
e m.
The
p ime
ac o
in
educing
nu i-
i e
alue
appea s
o
be
du a ion
o
s o -
age,
ollowed
by
hea ing
o
e men a ion
when
lea es
we e
exposed
o
ain all.
This
a gues
o
lea es
o
be
collec ed
d y,
s o ed
unde
co e
and
consumed
wi hin
a
3-4
mon h
pe iod.
ACKNOWLEDGMENTS
The
au ho s
acknowledge
he
awa d
o
an
EC
sho - e m
aining
and
mobili y
g an
o
M.
Delgado-Pe iez
and
he
p o ision
o
acil-
i ies
a
he
Rowe
Resea ch
Ins i u e
by
he
Sco ish
O ice
Depa men
o
Ag icul u e,
En i onmen
and
Fishe ies.
REFERENCES
[
I
]
B ad o d
M.M.,
A
apid
and
sensi i e
me hod
o
he
quan i a ion
o
mic og am
quan i ies
o