4! Fr++- . * REPUBLIQUE DU SENEGAL ...
4!
Fr++-
.
*
REPUBLIQUE DU SENEGAL
MINISTERE DU DEVELOPPEMENT
RURAL ET DE L’HYDRAULIQUE
INSTITUT SENEGALAIS DE RECHERCHES
AGRICOLES (I.S.R.A.)
DEPARTEMENT DE RECHERCHES SUR LES
PRODUCTIONS ET LA SANTE ANIMALES
LABORATOIRE NATIONAL DE L’ELEVAGE
ET DE RECHERCHES VETERINAIRES
B.P. 2057
DAKAR - HANN
C O M P A R A T I V E R U M I N A I - NI-I-ROGEN
D E G R A D A B I L I T Y O F TROPICAI- BROWSE
A N D T E M P E R A T E
F O R A G E S ,
TOURE-FALL S. and MICHALET-DOREAU B.’
ISRA LNERV BP 2057 DAKAR, SENEGAL
‘INRA CRZV-THEIX 63122 CEYRAT, FRANCE
Paper reference: SS*1
Number of text pages: 4
Number of tables: 2
Number of figure: 1
Paper presented at the XVII International
Grassland Congress : 8-23 february, New-Zeland
Australia, 1993.
REF. No021 /RES.AL.
JUIN 1992.
COMPARATIVE RUMINAL NITROGEN DEGRADABILITY OF TROPICAL BROWSE AND
TEMPERATE FORAGES.
TOURE-FALL S. and MICHALET-DOREAU B.’
ISRA LNERV BP 2057 DAKAR, SENEGAL
‘INRA CRZV-THEIX 63122 CEYRAT, FRANCE
ABSTRACT
T h e nitrogen ( N ) d i s t r i b u t i o n o f 2 t r o p i c a l b r o w s e l e a v e s (Balanites
aegyptiaca a n d G u i e r a s e n e g a l e n s i s ) a n d o f 2 t e m p e r a t e l e g u m e f o r a g e s
(Alfalfa hays) was determined and the rumina1 degradation of total N and
fiber N fractions (NDSN, AFN, ADFN) was measured with nylon bag method.
The average N degradability of temperate forages was not different,
77.1, but that of the browse forages varied from 27.5% (Guiera) to 85.1%
(Balmites). The neutral-detergent-soluble N degraded rapidly in the rumen,
whereas the acid-detergent-fiber N remained undegraded for all samples.
The available fiber N was not high, except for
the 3rd growth alfalfa (28%
total N) in which 63.3 was degraded. The lowest N degradability of Guiera
leaves cari be explained by N content in cell wall and lignocellulose.
.
KEYWORDS: alfalfa hays, rumina1 N degradation, tropical browse forages.
INTRODUCTION
Trees and shrubs represent an important food resource for ruminants
i n d r y African t r o p i c a l r e g i o n s . T h e i r h i g h nitrogen (N) c o n t e n t e x p r e s s e d
i n t e r m s o f crude protein i s w e l l k n o w n . A l t h o u g h crude protein i s a f i r s t
r
and common indicator of N content of forages, it does not give their real N
status,
r e p r e s e n t e d b y t h e i r t r u e a v a i l a b i l i t y r e l a t e d t o N cell wall
components and antiquality factors like tanins (Mc Leod, 1974)
T h e N d i s t r i b u t i o n i n t h e p l a n t cell provides a n u s e f u l l c r i t e r i a o f
feedstuffs nitrogen quality evaluation. Total N cari be divided into neutral,
acid-detergent soluble and insoluble parts which roughly estimate the rapid,
slow degradable and undigestible N (Krishnamoorthy et al., 1982). TO explain
the variations in forages N quality, we intended to describe the N location
i n p l a n t cell. T h e rumina1 d e g r a d a t i o n p r o f i l e o f t h e d i f f e r e n t N portions
w a s i n v e s t i g a t e d w i t h n y l o n b a g m e t h o d . W e compared n a t i v e west African
fodder tree leaves, Guiera senegalensis and Balanites aegyptiaca with two
temperate Alfalfa hays, Medicago sativa
MATERIAL AND METHODS
Tree leaves, sampled in the sudanian and sahelian area of Sénégal and
d r i e d a t 60°C, a n d A l f a l f a h a y s , h a r v e s t e d a t t h e I N R A s t a t i o n o f T h e i x
( F r a n c e ) , w e r e g r o u n d t h r o u g h 0 . 8 m m s c r e e n . I n situ m e a s u r e m e n t s o f
degradation (10 incubation times between 1 and 96 h) were carried out by
u s i n g 3 n o n l a c t a t i n g cows r e c e i v i n g 7 k g D M /animal/day o f a h a y a n d
c o n c e n t r a t e d i e t (70/30). A f t e r i n c u b a t i o n , t h e b a g s w e r e w a s h e d , b e a t e n
during 7 m n i n a “ s t o m a c h e r ” and washed again, to minimize the bacterial
c o n t a m i n a t i o n o f t h e b a g r e s i d u e s (Michalet-Doreau a n d O u l d - B a h , 1 9 8 9 ) .
S u b s t r a t e a n d b a g r e s i d u e s w e r e a n a l y s e d o n N , n e u t r a l - d e t e r g e n t - f i b e r
( N D F ) a n d a c i d - d e t e r g e n t - f i b e r ( A D F ) . R e s i d u e s o f N D F a n d A D F w e r e
a n a l y s e d o n N i n o r d e r t o d e t e r m i n e n e u t r a l - a n d a c i d - d e t e r g e n t f i b e r N
(NDFN and ADFN). Available fiber N (AFN) was calculated as NDFN minus
ADFN for both substrates and residues. Neutral-detergent-soluble N (NDSN)
was calculated as total N minus NDFN.
The degradation kinetics of total N, NDFN and AFN were fitted to an
exponential
mode1
with
and
w i t h o u t l a g t i m e .
T O c o m p a r e f o r a g e s
degradability, a turnover rate in rumen of .04 per hour was used. The data
w e r e a n a l y s e d u s i n g a G L M procedure ( S A S I n s t i t u t e ) w i t h 2 m a i n effects,
f e e d s t u f f a n d a n i m a l .
T h e f e e d s t u f f effect means w e r e s e p a r a t e d b y
Duncan’s test.
RESULTS AND DISCUSSION
N content in the forages varied from 1.48 to 5.19% DM, whereas the N
d i s t r i b u t i o n i n cell wall w a s d i f f e r e n t .
The average N in NDFN as a
7
Proportion of total N represented 30% in the temperate forages (Table 1).
Sanderson and Wedin (1989) and Krishnamoorthy et al. (1982) reported 18%
and 36% respectivly. Most (>50%) of Guiera N was NDFN while it r e p r e s e n t e d
only 20% for Balanites. Differences b e t w e e n t h e 2 t r e e l e a v e s w e r e e v e v
larger in ADFN, 37% Guiera N and 5% Balanites N. ADFN was high in fodder
t r e e s (Koné e t ai., 1989), but the variations were less pronounced than in
our results.
A s a consequence o f t h e i r c h e m i c a l c o m p o s i t i o n , t h e r e w e r e l a r g e
differences i n d e g r a d a t i o n p r o f i l e s o f t h e b r o w s e f o r a g e s . G u i e r a N
d e g r a d a b i l i t y w a s
l o w e r t h a n t h a t o f B a l a n i t e s ( T a b l e 2 ) . T h i s l o w
degradability
i s d u e t o a n i m p o r t a n t undegradable N f r a c t i o n , t h e
d e g r a d a t i o n i s s l o w a n d b e g i n s a f t e r a l a g t i m e . H o A h n e t al. ( 1 9 8 9 )
reported a large variation in ruminai N degradation of 12 browse legumes.
Whatever the forage, ADFN fraction is not degraded and NDSN degradability
is high. 50% of AFN was degraded, except Guiera in which that fraction was
completely undegraded. However the AFN content is low, thus its influence .
on total N degradability is low, except for the 3rd growth alfalfa (Figure 1).
SO N degradability is nearly equal to NDSN fraction, expressed in total N.
The N distribution is more homogenous in the temperate forages than in the
studied browse forages. Consequently, the variations in N degradability are
m o r e i m p o r t a n t f o r t h e s e f o r a g e s t h a n f o r t h e t e m p e r a t e f o r a g e s . I n o u r
study, the lowest N degradability of Guiera leaves cari be explained by the
.
N distribution in plant cell.
ACKNOWLEDGEMENTS
This work is supported in part by the International Fundation of Science
(grant B/1107-02) a n d b y t h e European
Economie c o m m u n i t y (STD2/215
Prog ram).
REFERENCES
AHN, J.H.; ROBERTSON, B.M.; ELLIOTT, R.; GUTTERIDGE, R.C.; FORD, C.W. 1989:
Quality assessment of tropical browse legumes: T a n i n c o n t e n t a n d protein
degradation. Animal Feed Science and Technology 27: 147-156.
KONE, A.R.; RICHARD, D.; GUERIN, H. 1989: Teneur en constituants pariétaux
e t e n m a t i é r e s
a z o t é e s d e s l i g n e u x f o u r r a g e r s d ’ A f r i q u e O c c i d e n t a l e .
Proceedings of the XVI International Grassland Congress: 947-948.
KRISHNAMOORTHY,U.; MUSCAT0,T.V.; SNIFFEN, C.J.; VAN SOEST, P.J. 1982:
Nitrogen fractions in selected feedstuffs. Journal of Dairy Science 65: 217-
225.
MC LEOD, M.N. 1974: Plant tannins- Their role in forage quality. Nutrition
abstracts and review 44: 804-834.
MICHALET-DOREAU, B.; OULD-BAH, M.Y. 1989: Estimation of the extend of
b a c t e r i a l c o n t a m i n a t i o n i n b a g r e s i d u e s a n d i t ’ s i n f l u e n c e o n i n s a c c o
measurments of forage nitrogen degradation in the rumen. Proceedings of
the XVI International Grassland Congress: 909-910.
S A N D E R S O N , M . A . ; W E D I N , W . F . 1 9 8 9 : Nitrogen i n t h e d e t e r g e n t f i b r e
fractions of temperate legumes and grasses. Grass and Forage Science 44:
159-I 68.
Table 1 : Chemical composition of forages % DM) (% total N)
Composition
Forages
Total N
NDFN
ADFN
AFN
NDSN
Guiera
1 . 4 8
-83
.55
.28
.65
5 6 . 0
37.1
1 8 . 9
4 4 . 0
Balanites
5.19
.89
.28
.61
4 . 3 0
1 7 . 1
5 . 4
1 1 . 7
82.I
Alfalfa (2)
2 . 2 0
.51
-18
.33
1.69
23.1
8.1
1 5 . 0
76.1
Alfalfa (3)
2 . 8 5
1.04
.23
.81
1.81
3 6 . 5
8.1
2 8 . 4
6 3 . 5
,/-
b
Table 2 : N degradation profiles of forages
Kinetic degradation Parameters
Forages
Degradability (%)
a 6)
b W4
c (h-l)
lag time (h)
Undegradable
Guiera
15.7b
26.0”
.024b
4.3b
58.3b
27.5b
B alanites
69.2”
22.7”
.096”
.o”
8 . 0 ”
85.1”
Alfalfa (2) 37.4”
51.6b
-115”
.o”
1 0 . 9 ”
75.1”
Alfalfa (3) 42.8”
50.4b
.121”
.P
6.8”
79.1”
Different letters in a same column correspond to a significative difference between means.
Figure 1 : Degradable N of forages (%) and its partitioning into degradable NDSN, AFN and ADFN
60
NDSN
40
El AFN
n ADFN
20
0 Guiera Balanites Alfalfa (2) Alfalfa (3)
Fr++-
.
*
REPUBLIQUE DU SENEGAL
MINISTERE DU DEVELOPPEMENT
RURAL ET DE L’HYDRAULIQUE
INSTITUT SENEGALAIS DE RECHERCHES
AGRICOLES (I.S.R.A.)
DEPARTEMENT DE RECHERCHES SUR LES
PRODUCTIONS ET LA SANTE ANIMALES
LABORATOIRE NATIONAL DE L’ELEVAGE
ET DE RECHERCHES VETERINAIRES
B.P. 2057
DAKAR - HANN
C O M P A R A T I V E R U M I N A I - NI-I-ROGEN
D E G R A D A B I L I T Y O F TROPICAI- BROWSE
A N D T E M P E R A T E
F O R A G E S ,
TOURE-FALL S. and MICHALET-DOREAU B.’
ISRA LNERV BP 2057 DAKAR, SENEGAL
‘INRA CRZV-THEIX 63122 CEYRAT, FRANCE
Paper reference: SS*1
Number of text pages: 4
Number of tables: 2
Number of figure: 1
Paper presented at the XVII International
Grassland Congress : 8-23 february, New-Zeland
Australia, 1993.
REF. No021 /RES.AL.
JUIN 1992.
COMPARATIVE RUMINAL NITROGEN DEGRADABILITY OF TROPICAL BROWSE AND
TEMPERATE FORAGES.
TOURE-FALL S. and MICHALET-DOREAU B.’
ISRA LNERV BP 2057 DAKAR, SENEGAL
‘INRA CRZV-THEIX 63122 CEYRAT, FRANCE
ABSTRACT
T h e nitrogen ( N ) d i s t r i b u t i o n o f 2 t r o p i c a l b r o w s e l e a v e s (Balanites
aegyptiaca a n d G u i e r a s e n e g a l e n s i s ) a n d o f 2 t e m p e r a t e l e g u m e f o r a g e s
(Alfalfa hays) was determined and the rumina1 degradation of total N and
fiber N fractions (NDSN, AFN, ADFN) was measured with nylon bag method.
The average N degradability of temperate forages was not different,
77.1, but that of the browse forages varied from 27.5% (Guiera) to 85.1%
(Balmites). The neutral-detergent-soluble N degraded rapidly in the rumen,
whereas the acid-detergent-fiber N remained undegraded for all samples.
The available fiber N was not high, except for
the 3rd growth alfalfa (28%
total N) in which 63.3 was degraded. The lowest N degradability of Guiera
leaves cari be explained by N content in cell wall and lignocellulose.
.
KEYWORDS: alfalfa hays, rumina1 N degradation, tropical browse forages.
INTRODUCTION
Trees and shrubs represent an important food resource for ruminants
i n d r y African t r o p i c a l r e g i o n s . T h e i r h i g h nitrogen (N) c o n t e n t e x p r e s s e d
i n t e r m s o f crude protein i s w e l l k n o w n . A l t h o u g h crude protein i s a f i r s t
r
and common indicator of N content of forages, it does not give their real N
status,
r e p r e s e n t e d b y t h e i r t r u e a v a i l a b i l i t y r e l a t e d t o N cell wall
components and antiquality factors like tanins (Mc Leod, 1974)
T h e N d i s t r i b u t i o n i n t h e p l a n t cell provides a n u s e f u l l c r i t e r i a o f
feedstuffs nitrogen quality evaluation. Total N cari be divided into neutral,
acid-detergent soluble and insoluble parts which roughly estimate the rapid,
slow degradable and undigestible N (Krishnamoorthy et al., 1982). TO explain
the variations in forages N quality, we intended to describe the N location
i n p l a n t cell. T h e rumina1 d e g r a d a t i o n p r o f i l e o f t h e d i f f e r e n t N portions
w a s i n v e s t i g a t e d w i t h n y l o n b a g m e t h o d . W e compared n a t i v e west African
fodder tree leaves, Guiera senegalensis and Balanites aegyptiaca with two
temperate Alfalfa hays, Medicago sativa
MATERIAL AND METHODS
Tree leaves, sampled in the sudanian and sahelian area of Sénégal and
d r i e d a t 60°C, a n d A l f a l f a h a y s , h a r v e s t e d a t t h e I N R A s t a t i o n o f T h e i x
( F r a n c e ) , w e r e g r o u n d t h r o u g h 0 . 8 m m s c r e e n . I n situ m e a s u r e m e n t s o f
degradation (10 incubation times between 1 and 96 h) were carried out by
u s i n g 3 n o n l a c t a t i n g cows r e c e i v i n g 7 k g D M /animal/day o f a h a y a n d
c o n c e n t r a t e d i e t (70/30). A f t e r i n c u b a t i o n , t h e b a g s w e r e w a s h e d , b e a t e n
during 7 m n i n a “ s t o m a c h e r ” and washed again, to minimize the bacterial
c o n t a m i n a t i o n o f t h e b a g r e s i d u e s (Michalet-Doreau a n d O u l d - B a h , 1 9 8 9 ) .
S u b s t r a t e a n d b a g r e s i d u e s w e r e a n a l y s e d o n N , n e u t r a l - d e t e r g e n t - f i b e r
( N D F ) a n d a c i d - d e t e r g e n t - f i b e r ( A D F ) . R e s i d u e s o f N D F a n d A D F w e r e
a n a l y s e d o n N i n o r d e r t o d e t e r m i n e n e u t r a l - a n d a c i d - d e t e r g e n t f i b e r N
(NDFN and ADFN). Available fiber N (AFN) was calculated as NDFN minus
ADFN for both substrates and residues. Neutral-detergent-soluble N (NDSN)
was calculated as total N minus NDFN.
The degradation kinetics of total N, NDFN and AFN were fitted to an
exponential
mode1
with
and
w i t h o u t l a g t i m e .
T O c o m p a r e f o r a g e s
degradability, a turnover rate in rumen of .04 per hour was used. The data
w e r e a n a l y s e d u s i n g a G L M procedure ( S A S I n s t i t u t e ) w i t h 2 m a i n effects,
f e e d s t u f f a n d a n i m a l .
T h e f e e d s t u f f effect means w e r e s e p a r a t e d b y
Duncan’s test.
RESULTS AND DISCUSSION
N content in the forages varied from 1.48 to 5.19% DM, whereas the N
d i s t r i b u t i o n i n cell wall w a s d i f f e r e n t .
The average N in NDFN as a
7
Proportion of total N represented 30% in the temperate forages (Table 1).
Sanderson and Wedin (1989) and Krishnamoorthy et al. (1982) reported 18%
and 36% respectivly. Most (>50%) of Guiera N was NDFN while it r e p r e s e n t e d
only 20% for Balanites. Differences b e t w e e n t h e 2 t r e e l e a v e s w e r e e v e v
larger in ADFN, 37% Guiera N and 5% Balanites N. ADFN was high in fodder
t r e e s (Koné e t ai., 1989), but the variations were less pronounced than in
our results.
A s a consequence o f t h e i r c h e m i c a l c o m p o s i t i o n , t h e r e w e r e l a r g e
differences i n d e g r a d a t i o n p r o f i l e s o f t h e b r o w s e f o r a g e s . G u i e r a N
d e g r a d a b i l i t y w a s
l o w e r t h a n t h a t o f B a l a n i t e s ( T a b l e 2 ) . T h i s l o w
degradability
i s d u e t o a n i m p o r t a n t undegradable N f r a c t i o n , t h e
d e g r a d a t i o n i s s l o w a n d b e g i n s a f t e r a l a g t i m e . H o A h n e t al. ( 1 9 8 9 )
reported a large variation in ruminai N degradation of 12 browse legumes.
Whatever the forage, ADFN fraction is not degraded and NDSN degradability
is high. 50% of AFN was degraded, except Guiera in which that fraction was
completely undegraded. However the AFN content is low, thus its influence .
on total N degradability is low, except for the 3rd growth alfalfa (Figure 1).
SO N degradability is nearly equal to NDSN fraction, expressed in total N.
The N distribution is more homogenous in the temperate forages than in the
studied browse forages. Consequently, the variations in N degradability are
m o r e i m p o r t a n t f o r t h e s e f o r a g e s t h a n f o r t h e t e m p e r a t e f o r a g e s . I n o u r
study, the lowest N degradability of Guiera leaves cari be explained by the
.
N distribution in plant cell.
ACKNOWLEDGEMENTS
This work is supported in part by the International Fundation of Science
(grant B/1107-02) a n d b y t h e European
Economie c o m m u n i t y (STD2/215
Prog ram).
REFERENCES
AHN, J.H.; ROBERTSON, B.M.; ELLIOTT, R.; GUTTERIDGE, R.C.; FORD, C.W. 1989:
Quality assessment of tropical browse legumes: T a n i n c o n t e n t a n d protein
degradation. Animal Feed Science and Technology 27: 147-156.
KONE, A.R.; RICHARD, D.; GUERIN, H. 1989: Teneur en constituants pariétaux
e t e n m a t i é r e s
a z o t é e s d e s l i g n e u x f o u r r a g e r s d ’ A f r i q u e O c c i d e n t a l e .
Proceedings of the XVI International Grassland Congress: 947-948.
KRISHNAMOORTHY,U.; MUSCAT0,T.V.; SNIFFEN, C.J.; VAN SOEST, P.J. 1982:
Nitrogen fractions in selected feedstuffs. Journal of Dairy Science 65: 217-
225.
MC LEOD, M.N. 1974: Plant tannins- Their role in forage quality. Nutrition
abstracts and review 44: 804-834.
MICHALET-DOREAU, B.; OULD-BAH, M.Y. 1989: Estimation of the extend of
b a c t e r i a l c o n t a m i n a t i o n i n b a g r e s i d u e s a n d i t ’ s i n f l u e n c e o n i n s a c c o
measurments of forage nitrogen degradation in the rumen. Proceedings of
the XVI International Grassland Congress: 909-910.
S A N D E R S O N , M . A . ; W E D I N , W . F . 1 9 8 9 : Nitrogen i n t h e d e t e r g e n t f i b r e
fractions of temperate legumes and grasses. Grass and Forage Science 44:
159-I 68.
Table 1 : Chemical composition of forages % DM) (% total N)
Composition
Forages
Total N
NDFN
ADFN
AFN
NDSN
Guiera
1 . 4 8
-83
.55
.28
.65
5 6 . 0
37.1
1 8 . 9
4 4 . 0
Balanites
5.19
.89
.28
.61
4 . 3 0
1 7 . 1
5 . 4
1 1 . 7
82.I
Alfalfa (2)
2 . 2 0
.51
-18
.33
1.69
23.1
8.1
1 5 . 0
76.1
Alfalfa (3)
2 . 8 5
1.04
.23
.81
1.81
3 6 . 5
8.1
2 8 . 4
6 3 . 5
,/-
b
Table 2 : N degradation profiles of forages
Kinetic degradation Parameters
Forages
Degradability (%)
a 6)
b W4
c (h-l)
lag time (h)
Undegradable
Guiera
15.7b
26.0”
.024b
4.3b
58.3b
27.5b
B alanites
69.2”
22.7”
.096”
.o”
8 . 0 ”
85.1”
Alfalfa (2) 37.4”
51.6b
-115”
.o”
1 0 . 9 ”
75.1”
Alfalfa (3) 42.8”
50.4b
.121”
.P
6.8”
79.1”
Different letters in a same column correspond to a significative difference between means.
Figure 1 : Degradable N of forages (%) and its partitioning into degradable NDSN, AFN and ADFN
60
NDSN
40
El AFN
n ADFN
20
0 Guiera Balanites Alfalfa (2) Alfalfa (3)