Revista Computadorizada de Producción Porcina Volumen 12 (número 1) 2005
Título corto: Physico-chemical properties of tropical tree leaves may influence its nutritive value for monogastric animal species /Propiedades físico-químicas y valor nutritivo de especies arbóreas
PHYSICO-CHEMICAL PROPERTIES OF TROPICAL TREE LEAVES MAY INFLUENCE ITS NUTRITIVE VALUE FOR
MONOGASTRIC ANIMAL SPECIES
Pok Samkol 1 , Bun Y 1 and J. Ly 2
1
Centre for Livestock and Agriculture Development, University of Tropical Agriculture Foundation, Kandal Village, Kandal, Cambodia
email: samkolpok@yahoo.com
2 Swine Research Institute, PO Box 1, Punta Brava, Havana, Cuba
email: julioly@utafoundation.org
SUMMARY
Four representative samples of new and old leaves from six species of wild, uncultivated tropical trees were investigated for chemical composition, in vitro (pepsin/pancreatin) digestibility and physico-chemical characteristics as affected by leaf senescence (new, recently open at the top of branches and old, near to yellow color at the bottom of branches). The tree species investigated were mulberry (Morus alba), moringa (Moringa oleifera), hibiscus (Hibiscus rosa-sinensis), flemingia (Flemingia macrophylla), gliricidia (Gliricidia sepium) and trichanthera (Trichanthera gigantea).
All N characteristics studied showed a significant (P<0.05) interdependence amongst them, including the linear, inverse relationship, although rather low (r = - 0.580), found between in vitro N digestibility and N linked to cell wall. Overall, cell wall-linked N could explain
58.0% of in vitro N digestibility variability (P<0.003) whereas water-soluble N could explain 70.8% of this same index (P<0.001). In the tree leaves population examined, cell wall-linked N could explain 40.5% (P<0.022) of N insolubility in water (not shown).
It is suggested that simple, ready and easy to conduct physical methods may describe the nutritive value of tropical tree leaves to be used in monogastric farm animals feeding, such as pigs, horses and rabbits. It is considered that a high nutritive value in young tropical tree leaves strongly suggests that periodically cut foliage from tree plantations is in favor to its digestion in precaecal areas of the aforementioned animals. On the other hand, the probability that tree fertilization can improve the nutritive value of those foliages merits to be examined.
Key words: chemical composition, physico-chemical indices, nutritive value, leaves, tropical trees
Short title: Physico-chemical properties and nutritive value of tree leaves
LAS PROPIEDADES FISICO-QUIMICAS DE HOJAS DE ARBOLES TROPICALES PUEDEN INFLUIR EN SU VALOR
NUTRITIVO PARA ESPECIES ANIMALES MONOGASTRICAS
RESUMEN
Se investigaron cuat ro muestras representativas de hojas jóvenes y viejas de cada una de seis especies de árboles tropicales no cultivados. Se determinó la composición química, la digestibiilidad in vitro (pepsina-pancreatina) y características físico-químicas de las hojas jóvenes nuevas, recientemente abiertas en el ápice de las ramas y viejas, cerca del color amarillo, en el extreme inferior de las ramas. Las especies arbóreas investigadas fueron la morera (Morus alba), moringa (Moringa oleifera), marpacífico (Hibiscus rosasinensis), flemingia (Flemingia macrophylla), gliricidia (Gliricidia sepium) y tricantera (Trichanthera gigantea).
Todas las características que se estudiaron del N mostraron una interdependencia significativa (P<0.05) entre sí, incluyendo una relación inversa, lineal, aunque más bien baja (r = - 0.580), entre la digestibilidad in vitro N y el N ligado a la pared celular vegetal. En general, el N ligado a la pared celular vegetal pudiera explicar un 58.0% de la variabilidad en la digestibilidad in vitro del N (P<0.003) mientras que el N soluble en agua pudiera explicar un 70.8% de este mismo índice (P<0.001). En la población de hojas arbóreas que se investigaron, el N ligado a la pared celular vegetal explicó un 40.5% (P<0.022) de la insolubilidad del N en agua (no mostrado).
Se sugiere que métodos físicos simples, rápidos y fáciles de hacer pueden describir el valor nutritivo de hojas de árboles tropicales a ser uados en la alimentación de animales monogástricos de granja, tales como cerdos, caballos y conejos. Se considera que un valor nutritivo alto en hojas jóvenes de árboles tropicales puede sugerir en alto grado que el follaje cortado periódicamente en plantaciones arbóreas favorece la digestión en áreas prececales de las especies animales arriba mencionadas. Por otra parte, es probable que la fertilización de los árboles pueda mejorar el valor nutritivo de los follajes, lo que merece ser examinado.
Palabras claves: composición química, indices físicos-químicos, valor nutritivo, hojas, árboles tropicales
Título corto: Propiedades físico-químicas y valor nutritivo de hojas arbóreas
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Revista Computadorizada de Producción Porcina Volumen 12 (número 1) 2005
Título corto: Physico-chemical properties of tropical tree leaves may influence its nutritive value for monogastric animal species /Propiedades físico-químicas y valor nutritivo de especies arbóreas
INTRODUCTION
There are some indications that several tropical tree foliages are potential sources of protein for pigs
( Hutagalung 1981; Liganco Lopez 1990; Sánchez 1999; Ly
2004). These tree foliages, mainly composed of leaves, petioles and terminal stems from tree branches, offer the opportunity of using local available, perennial sources of physico-chemical characteristics. In this case, determination of DM, ash, crude fibre and N were conducted according to AOAC (1995) procedures, whereas NDF and NDF-N concentration was analyzed following Van Soest and Wine (1967) and Licitra et al
(1996) recommendations. DM and N solubility in samples was assayed according to Ly and Preston (2001) and water holding capacity analyses were conducted by the protein, which in turn can be added to tropical sources of energy, currently devoid of protein and fibre. However, protein sources from trees can adversely influence either the voluntary feed intake of pigs due to its bulkiness
(Tsaras et al 1998), or its digestibility, as a result of its high content of fibre (Bach-Knudsen and Jorgensen 2001). technique of Tsaras et al (1998).
In vitro (pepsin/pancreatin) incubation indices, simulating in vivo ileal digestibility, were determined in leaves plus petioles of the foliages as outlined by Dierick et al (1985).
Paired values were contrasted by the t-test within every
On the other hand, it has been found that there is a clear improvement in nutrient digestibility and N balance in pigs fed young leaves from some shrubs such as cassava, as compared to old foliage obtained from this same plant species. In this connection, leaf maturity or senescence may determine structural and biochemical changes in molecular architecture of plant tissues, therefore determining a deterioration of its nutritive value.
It has been suggested that N utilization from leaves by pigs could be associated to the nature of N linkage or blockage by cell wall (Bergner et al 1981, cited by Bergner
1995; Howard et al 1986). This hypothesis has been showed to be true in non conventional feedstuffs for pigs
(see for example, Jondreville et al 1995). In this connection, Ly and Preston (2001) have claimed that the N nutritive value of some tropical tree leaves depends upon of N solubility.
The objective of the herein reported investigation was to study some physico-chemical properties of several tropical tree foliages as related to its nutritive value.
MATERIALS AND METHODS
Four representative samples of new and old leaves from six species of wild, uncultivated tropical trees were investigated for chemical composition, in vitro
(pepsin/pancreatin) digestibility and physico-chemical characteristics as affected by leaf senescence (new, recently open at the top of branches and old, near to yellow color at the bottom of branches). The trees were located in the surroundings of the Experimental Farm of the Faculty of Animal Production, Royal University of
Agriculture (Phnom Penh). The tree species investigated were mulberry (Morus alba), moringa (Moringa oleifera), hibiscus (Hibiscus rosa-sinensis), flemingia (Flemingia macrophylla), gliricidia (Gliricidia sepium) and trichanthera
(Trichanthera gigantea).
The leaves plus petioles were separated from the branches and sun-dried, then milled by a hammer mill apparatus. The meal thus obtained were sampled four times and analysed for chemical composition and several tree species (Steel and Torrie 1980). Besides, the Pearson correlation matrix was assayed to screen possible interdependence amongst several physico-chemical and in vitro digestibility indices. The software package of minitab
13 for windows was used for processing all the information.
RESULTS AND DISCUSSION
Some aspects of tree leaves N characteristics are shown in table 1. According to the experimental evidence, new tree leaves had a higher N content and in vitro
(pepsin/pancreatin) N digestibility, and together with these findings, a lower content of N linked to cell wall and and a higher N solubility than old leaves. In fact, the N content of new leaves varied from 2.91 to 5.21% whereas in old leaves this index varied from 2.77 to 4.80% in dry basis respectively.
Table 1. Physico-chemical characteristics of tropical
tree foliages (in per cent)
Tree leaves N IVND NDF-N SOL-N
Gliricidia
New
Old
Moringa
New
Old
Hibiscus
New
Old
Flemingia
New
Old
Mulberry
New
Old
Trichanthera
New
Old
4.31
4.08
5.23
4.80
2.91
2.77
4.04
3.82
4.95
3.60
3.74
2.98
45.28
33.72
57.51
30.87
27.99
21.91
22.52
16.99
63.36
29.09
32.08
28.15
19.11
21.92
12.05
16.97
46.30
52.77
42.94
50.65
34.99
45.03
49.81
66.18
N, IVND, NDF-N and SOL-N expressed N content, in vitro
(pepsin/pancreatin) digestibility, N linked to cell wall and N solubility in water respectively
47.45
38.60
61.86
57.71
34.71
39.35
41.62
21.17
65.23
29.31
42.56
26.18
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Revista Computadorizada de Producción Porcina Volumen 12 (número 1) 2005
Título corto: Physico-chemical properties of tropical tree leaves may influence its nutritive value for monogastric animal species /Propiedades físico-químicas y valor nutritivo de especies arbóreas
According to the results of the analysis of variance, a trend
(P<0.10) was found of new tree leaves to contain a high total N and soluble N concentration than old leaves (table
2). However, this difference between new and old leaves was not significant (P<0.20) for N linked to cell wall, wall (Hogan and Lindsay 1980). In rabbits, Villamide and
Fraga (1998) has been suggested to be related to the acid detergent fibre presence, considering that ADF-N is related to heat-damaged protein and N associated with lignin (Villamide and Fraga 1998). although new leaves had a rather low NDF-N concentration (34.2%) as compared to old leaves (42.3%).
In vitro N digestibility was significantly higher (P<0.01) in new leaves as compared to old leaves.
Table 2. Physico-chemical characteristics of tropical
tree leaves. Effect of senescence
Tropical tree leaves
N, %
New
Old
EE ±
4.20
3.68
0.31+
+ P<0.10; ** P<0.01
IVND,
%
41.5
26.8
5.0**
NDF-N,
%
34.2
42.3
6.9
SOL-N,
%
48.9
40.5
5.5+
N, IVND, NDF-N and SOL-N expressed N content, in vitro
(pepsin/pancreatin) digestibility, N linked to cell wall and N solubility in water respectively
It is assumed that a higher sample population should
In contrast, very few investigations have revealed any in vitro N digestibility association with N solubility in water (Ly and Preston 2001). As illustration, the interdependence between N solubility and in vitro N digestibility as found in the present investigation is presented in figure 1.
70
60
50
40
30
20 y = 22.99 + 0.60 x
R
2
= 0.528
determine a more clear contrast amongst the maturity status in tropical tree leaves.
The interdependence amongst several tree leaves characteristics are listed in table 3.
Table 3. Pearson correlation matrix for N indices in tropical tree leaves
IVND
NDF-N
SOL-N
N
0.612
- 0.797
0.656
IVND
- 0.580
0.727
NDF-N
- 0.595
N, IVND, NDF-N and SOL-N expressed N content, in vitro (pepsin/pancreatin) digestibility, N linked to cell wall and N solubility in water respectively
P<0.05 for r<0.403
All N indices examined in the current study showed a significant (P<0.05) interdependence amongst them, including the linear, inverse relationship, although rather low (r = - 0.580), found between in vitro N digestibility and
N linked to cell wall.
Overall, cell wall-linked N could explain 33.6% of in vitro N digestibility variability (P<0.003) whereas water-soluble N could explain 52.8% of this same index (P<0.001). In the tree leaves population examined, cell wall-linked N could explain 40.5% (P<0.022) of N insolubility in water (not shown).
One possibility for explaining a relatively low correspondence amongst the aforementioned indices could be the relatively small population of trees examined, taking into account the great dispersion found for the examined data. In fact, digestion of N in ruminants has been shown to be affected by its association with plan cell
10
0
0 20 40
N solubility, %
Figure 1. N solubility and in vitro (pepsin/pancreatin) N digestibility of tropical tree leaves
It is suggested that simple, ready and easy to conduct physical methods may describe the nutritive value of tropical tree leaves to be used in monogastric-farm animals feeding, such as pigs, horses and rabbits.
However, more research should be conducted in order to lead to a higher accuracy in the relationships to be established between different N characteristics.
At a first approach, it is considered that a high nutritive value in young tropical tree leaves strongly suggests that periodically cut foliage from tree plantations is in favor to its digestion in precaecal areas of animals as it could be pigs or another simple-stomach species. On the other hand, the probability that tree fertilization can improve the nutritive value of those foliages would merit to be examined.
ACKNOWLEDGMENTS
The authors are indebted to the authorities of the Royal
University of Agriculture, Phnom Penh, for allowing the cultivation in its experimental farm of trees and shrubs used in the present investigation.
60 80
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Revista Computadorizada de Producción Porcina Volumen 12 (número 1) 2005
Título corto: Physico-chemical properties of tropical tree leaves may influence its nutritive value for monogastric animal species /Propiedades físico-químicas y valor nutritivo de especies arbóreas
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