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Part I - Extended Abstracts Presentations


Characterization of the genotypic variation in the chemical composition and digestibility of Trichanthera gigantea (H. & B.) Nees.

M. Rosales[163], S. Ospina[164], E. Ararat[165]

Key words: chemical composition, forage potential, in vitro fermentability, provenances quality characterization, selection

Introduction

In the past few years, the development and implementation of economical alternatives of animal feeding has advanced toward the study and valuation of the local forage. This is the case of Nacedero Trichanthera gigantea, fodder trees specie that has contributed to enlarge the nutritional offer of different animal species, mainly monogastric, where it was noticed a variability in the evaluation with animals.

To establish if the phenotypic variation observed was fundamentally of genetic origin (by effect of provenance), to give a environment or product of interaction genotype - environment, CIPAV established a bank of provenances of the specie with representative species obtained in Colombia and Venezuela (Rosales, 1998).

Preliminary studies and characterization utilizing enzymatic patterns confirmed the high genetic variability within the specie. This variation can reveal through some organic characters; as its capacity of sprout after cut, expressed in its formation of biomass in the aerial part or in terms of its nutritional value, expressed through describers of its chemical composition, digestibility and fermentability.

In this study we advance toward the selection of “elite” provenances, with respect to parameters of the nutritional value.

Materials and methods

Twenty - two provenances of Trichanthera gigantea were characterized based on yield, forage quality and morphological, and physiological features. The vegetable material was sowed in tree nursery in Cali city, province of Cauca Valley, Colombia. A cut of uniformity was fulfilled and two experimental cuts at intervals of ninety days.

In the forage laboratory of Centro Internacional de Agricultura Tropical (CIAT), the samples were ground in a Willey - mill to pass a 1 - mm screen. The yield of Dry Matter (DM), was determined by standard methods, Crude Protein (CP), was determined by the Kjeldhal method (AOAC, 1980), Acid Fibre Detergent (ADF), Neuter Fibre Detergent (NDF), were analyzed according to Van Soest (1967), Extractable Condensed Tannins (ECT), were analyzed by the method of Terrill et al, (1992), In vitro Dry Matter Digestibility (IVDMD), was determined by the procedures of Tilley and Terry (1963), in vitro Fermentability by the method of gas production according to the procedures of Theodorou et al, (1994) The presence of anti-nutritional compounds such as flavonoides, coumarinas, glycosides, steroids, alkaloids, saponins and tannins were analyzed by methodology of Palomino and Mier (1992).

The data of forage yield, chemical composition, digestibility and fermentability were combined for to elaborate three indexes of forage potential and this way facilitate the comparison between provenances (Stewart, 1999). The data base about quality characterization together with the results of anti-nutritional compounds was subjected to hierarchical of classification analysis (cluster analysis), for similar groups of provenances to identify. The averages matrix for quantity characters associated with yield and quality forage was subjected to principal components analysis for the dimension the originals variables to reduce from three to four new synthetic variables, that explain the major percentage of the total variance of the original matrix and facilitate the subsequent hierarchical classification analysis.

Results

The most outstanding provenances according to the qualification obtained in the forage potential indexes were: Boconó, Tres Esquinas, Las Cruces, Rubio (Venezuelan) and El Cerrito, Sevilla and Ansermanuevo (Colombian). The morphological and chemical characters used in the quality characterization permitted to identify important differences between provenances; which according to the hierarchical classification analysis the collection of Trichanthera gigantea were separated in four contrast groups.

The characters associated with forage yield presented major variability of genetic type, in comparison with the characters of forage quality (chemical composition and digestibility)

The evident genetic variability available in Trichanthera gigantea is a manifestation of the speciation by geographical isolation and somatic variation accumulated by mutation. (Vega, 1988). The in vitro fermentability and the parameters associated to this test, were the characters with major contribution to the variability between provenances. According to the results of principal component analysis and the posterior classification analysis, the provenances could be group in five categories.

The in vitro fermentability and the production of crude protein of the provenances were associated to the geographical origin. Particularly the provenances from Cauca Valley (Colombia): El Cerrito, Buenaventura, Dagua, Sevilla, Ansermanuevo, presented high fermentability and low crude protein (CP), while those of Venezuelan provenances: Campo Elías, Biscucuy, Tres Esquinas, Turén, were little fermentable but with biggest production of crude protein (CP). The less promising provenances when were considered features of yield and forage quality and the indexes of forage potential were: Soatá, Chíscas, Caldono, Rionegro, Cali, Puerto Gaitán, Barbosa Campo Elías, Portuguesa.

References

ASSOCIATION OF OFFICIAL ANALYTICAL CHEMIST (AOAC). Official methods of analysis. Washington: Association of Official Analytical Chemist, 1980. 13th ed.

PALOMINO, M. E. and MIER, C. E. Detección de algunos metabolitos secundarios. Impreso; Universidad Nacional de Colombia. Sede Palmira. 1993. 7 p.

ROSALES, M. Mauricio. Avances de la investigación en la variación del valor nutricional de procedencias de Trichanthera gigantea (H. & B.) Nees. En: Conferencia Electrónica de la FAO sobre Agroforestería para la producción animal en Latinoamérica. 1998.

STEWART, J. L. Variación genética en árboles forrajeros. En: Congreso Latinoamericano de agroforestería para la producción animal sostenible. (1º: 1999: Cali). Memoria electrónica. CIPAV. 1999. ISBN 958-9386-22

TERRILL, T. H; ROWAN, A. M; DOUGLAS, G. B y BARRY, T. N. Determination of extractable and bound condensed tannin concentration in forage plants; protein concentrate meals and cereal grains. J. Sci. Food Agric. 58: 321- 329. 1992.

THEODOROU, M. K; WILLIAMS, B. A; DHANOA, M. S; MCALLAN, A. B y FRANCE, J. A simple gas production method using a pressure transducer to determine the fermentation kinetics of ruminant feeds. En: Animal Feed Science and Technology. Vol. 48. 1994, p. 185 - 197.

TILLEY, J. M Y TERRY, R. A. A two - stage technique for the in vitro digestion of forage crops. En: Journal British Grass. Socc. Vol. 18. 1963, p. 104 - 111

VAN SOEST, P. J. y WINE, R. H. Use of detergents in the analysis of fibrous feeds. IV determination of plant cell wall constituents. En: Journal Assoc Official A Chem. Vol. 50:50. 1967.

VEGA, O. Urbano. Mejoramiento genético de plantas. Editorial América. Maracay Venezuela. 1988. p. 173 - 176.

Microbial detoxification of anti-nutritional factors in Acacia angustissima

Agnes Odenyo[166], Paschal Osuji[167], Jess Reed[168], Alexandra Smith[169],
Roderick Mackie[170] Christopher McSweeney[171], and Jean Hanson[172]

Key words: Acacia angustissima, anti-nutrients, detoxification, rumen microbes, tannins.

Introduction

The major limitation to ruminant production in many tropical regions of Africa, Asia and Latin America is poor nutrition. The low nitrogen (6.2-10.6 g/kg DM) and high fibre 676-742 g/kg DM) of native grasses and crop residues (Seyoum and Zinash, 1989), which form the basis of the diets in these regions, is a primary constraint. Supplementation of tropical roughages with leguminous fodder trees is a promising method to alleviate nutrient deficiencies. Fodder trees provide valuable supplementary nutrients for livestock in addition to their other uses as medicine, fuel wood, building materials, wind breakers, nitrogen fixation, for erosion control and other agro-forestry applications.

Acacia angustissima is a fodder tree with a potential as a leguminous supplement. It is fast growing, well adapted to free draining acid infertile soils, shows excellent drought tolerance, retains green leaf during long dry seasons (Gutteridge, 1994) and has high nitrogen (33.2 to 40.8 g/kg DM) (Dzowela et al., 1997; Odenyo et al., 1997). Leaf yields up to 5 t per ha per year have been reported (Dzowela et al., 1997). Branching habits enables the plant to withstand frequent cutting or defoliation. However, the best accession of A. angustissima (ILRI accession 15132) contains anti-nutrients that limit its use as a feedstuff. Reduction or elimination of the effects of the ant-nutrients in A. angustissima (accession 15132) would make this plant an important protein supplements for ruminants owned by resource poor farmers who are the majority of farmers in the tropics.

Toxicity of Acacia angustissima

In two studies (El Hassan et al., 1995; Odenyo et al., 1997a) it was shown that extracts of A. angustissima were toxic to rumen bacteria particularly cellulolytic species. Acacia angustissima has also been shown to have low palatability, low digestibility (48% after 24 h) and has caused death to sheep when fed without gradual adaptation (Odenyo et al., 1997a). Rats fed a diet containing 20% A. angustissima ad libitum died within 2-5 d. while those fed A. angustissima at levels of 15 and 10% had severe weight loss and early death (2 and 7-10 d respectively) (Smith et al., in press). Rabbits fed A. angustissima leaves (20% of the diet) showed progressive low intake and average body weight reduction (-5.3 g/d) as compared to rabbits on control diet (5.9 g/d). All the rabbits on A. angustissima leaves showed central nervous system disturbances such as falling, trembling, hind leg paralysis, and constant urination. It was concluded that A. angustissima leaves were toxic to small ruminants and laboratory animals. However, the toxic compound was not known.

Identification of the toxic compound in A. angustissima

Tannins

A study (Odenyo et al., 1999) showed that addition of PEG significantly improved gas and ammonia production from tannin-rich fodder leaves, however, the greatest improvements were from A. angustissima leaves (Table 1). Effects of PEG have been shown (Barry, 1985) to be specific to tannins and that in the absence of tannins PEG has no effect on fermentation. Analysis of tannin contents in A. angustissima showed high levels of soluble tannin (Odenyo et al., 1997).

Table 1. Effect of PEG-4000 on gas released in vitro (ml/100mg DM) when various tannin-containing fodder tree leaves were incubated for 120 h with rumen fluid from Ethiopian ruminants.

Plant species

Borana cows

Free ranging goats

Free ranging sheep

-PEG

+ PEG

-PEG

+ PEG

-PEG

+ PEG

A. angustissima (SD)

5.1

12.1

6.9

17.3

3.9

13.4

C. calothyrsus (FD)

14.5

18.5

16.8

22.7

13.3

17.9

C. calothyrsus (OD)

12.7

16.1

16.5

20.3

12.0

16.5

L. diversifolia (OD)

20.7

19.8

23.8

26.4

18.3

20.7

L. leucocephala (OD)

21.7

19.5

25.1

24.6

22.3

20.2

L. pallida (OD)

22.0

20.6

24.4

25.7

19.3

21.6

T. bracteolata (OD)

19.8

16.6

20.5

21.8

17.1

16.3

s.e

2.4

1.1

2.4

1.2

2.3

1.1

- PEG, without polyethylene glycol; + PEG, with polyethylene glycol. SD, sun dried; FD, freeze dried; OD, oven dried; s.e, standard error of the mean, n = 9 (Odenyo et al., 1999a).

Thirty rabbits with average body weight of 1.27 kg were fed A. angutissima accessions 460, 16581, 15132, 16261, 16501, 18575, 18577, and 18578 at 30% of the diet with or without PEG. The control rabbits were fed concentrate alone. Dry matter intake and weight gains were significantly different (P<0.01) between rabbits supplemented with PEG- treated A. angustissima and those fed A. angustissima without PEG (Table 2). No significant differences (P>0.05) were observed between the rabbits supplemented with PEG- treated A. angustissima and those fed concentrate. The results suggested that PEG improved utilization of A. angustissima accessions suggesting that tannin was a major anti-nutritional factor in all the accessions tested.

Non-protein amino acids

Odenyo et al. (1997a,b) showed that the toxicity symptoms observed in sheep fed A. angustissima were similar to those seen in Lathyrus toxicity. A non-protein amino acid, 2, 4-diaminobutanoic acid (DABA) in Lathyrus sylvestris has been shown to cause similar symptoms in sheep (Rowe et al., 1993). Because of the similarity of these symptoms, it was hypothesized that non-protein amino acid(s) may also contribute to the toxic effects of A. angustissima. A second amino acid, 4-N-acetyl-2, 4-diaminobutanoic acid (ADAB) has also been found in seeds of A. angustissima (Evans et al., 1993). Analysis of leaf and seed extracts from A. angustissima showed that ADAB was the major non-protein amino acid in A. angustissima leaf (15 mg/g) and seed (20 mg/g) extracts (Reed, 2000). A recent study by McSweeney et al. (2000) showed that three additional non-protein amino acids beta acetyl diaminopropionic acid (ADAP) was present (1.0 - 4.4 g/kg DM) in leaf extracts of A. angustissima accession (38/88). Oxalyl diaminobutyric (ODAB) and oxalyl diaminopropionic (ODAP) were present at low concentration.

Table 2. Average DM intake and body weight gain for rabbits fed various accessions of Acacia angustissima with or without polyethylene glycol (PEG) as a protein supplement.

Accessions

DM Intake (g/d)

Weight gain (g/d)

Tannins

-PEG

+PEG

-PEG

+PEG

Soluble (%)

Condensed (Abs/g)

460

22.35

105.42

-0.3802

20.9557

23.5

26.8

15132

38.35

121.24

-5.0466

21.9490

17.7

25.3

16261

25.11

114.98

3.3460

25.9751

17.7

25.2

16501

26.35

119.36

-0.2430

21.1855

20.27

27.1

18575

25.00

123.94

-0.7559

23.2514

ND

ND

18577

24.33

112.75

-2.8945

21.7659

26.7

26.2

18578

24.43

110.06

-4.7222

16.5854

21.9

23.1

Alfalfa

95.11

ND

13.72

ND

9.39

4.6

Concentrate

100.64

107.10

10.0700

18.5151

ND

ND

ND, Not determined; (n=3). (Odenyo et al., unpublished data).

Alleviation of the effect of Anti-nutrients in A. angustissima

Several approaches to alleviate the problems associated with anti-nutrients in feeds plant have been reviewed by Kumar (1992). However, most of these methods focus on the plants and are not appropriate particularly to the resource poor farmers. A better alternative to the removal of anti-nutrients would be in the rumen at the microbial level. This study focused on rumen microbial adaptation and detoxification. This method does not modify the plant and thus preserves its natural products, which have evolved in the plant to allow it to survive in its environment. The microbial strategy (Jones and Megarrity, 1986) involves the isolation and identification of naturally occurring rumen microbes (or consortia) with the capability to tolerate or detoxify the anti-nutrients. The isolates are then transferred to the rumen of non-adapted animals to alleviate the toxicity caused by the specific anti-nutrient.

Isolation of bacteria tolerant to tannins and non-protein amino acids in A. angustissima

Targeting the rumen microbes as a method to ameliorate the effects of tannin, several tannin tolerant bacteria were isolated from enrichment cultures of rumen microflora of bush duiker, sheep (adapted to A. angustissima) and free-ranging goat, established in medium containing crude tannin extracts (70% acetone) from A. angustissima or tannic acid. The nucleotide sequences of polymerase chain reaction (PCR) products derived from the 16S rRNA genes of the isolates were determined and compared with accessions in ribosomal RNA databases. The results suggested that one isolate clustered with of Streptococcus species (Streptococcus gallolyticus/S. caprinus and S. bovis), four isolates clustered with Selenomonas ruminantium, one clustered with Klebsiella spp. and one with Butyrivibrio fibrisolvens lineage type 3 (Willems et al., 1996). Isolation of bacteria capable of modifying non-protein amino acids is underway.

Potential environmental and economic benefits on Africa, Asia and Latin America

The principal requirement in the target countries is for greater meat and milk production to satisfy the increasing demand due to population growth. Identification of rumen microbes with ability to detoxify anti-nutrients in A. angustissima and successful transfer will promote its use as feedstuffs and afford the farmers the opportunity to plant more trees. The increased use of these trees will add cover to the now bare grazing field thus contributing to environmental protection and natural resource management. Additionally, establishment of fodder tree technology could provide increased nutrition for livestock and subsequently improved animal health, reproductive performance and faster growth rates. Improved animal health could in turn result in increased income and food security for farm families.

References

Barry TN (1985) The role of condensed tannins in the nutritional value of Lotus pendunculatus for sheep * 3. Rates of body and wool growth. Brit J Nut 54: 211-217.

Benjamin AK (1988) Productivity of five shrub legume species in the sub-tropics. Diploma of Tropical Agriculture, Report, pp.37.The University of Queensland.

Seyum B and Zenash S (1989) The composition of Ethiopian feedstuffs. Research report NO. 6. Institute of Agricultural Research, Addis Ababa, Ethiopia.

Dzowela BH, Hove L, Maasdorp BV and Mafongoya (1997) Recent work on the establishment, production and utilization of multipurpose trees as a feed resource in Zimbabwe. Anim Feed Sci Technol 69:1-15.

El Hassan SM, Lahlou-Kassi A, Newbold CJ and Wallace RJ (1995) Antimicrobial factors in African multipurpose trees. In: Wallace RJ and Lahlou-Kassi A (eds), Rumen ecology research planning Proc Workshop, pp.43-54. ILRI Addis Ababa, Ethiopia.

Evans C S, Shah AJ, Adlard MW and Arce MLR (1993) Non-protein amino acids in seeds of neotropical species of Acacia. Phytochemistry. 32: 123-126.

Gutteridge RC (1994) Other species of multipurpose forage tree legume. In: Gutteridge RC and Shelton HM (eds), Forage tree legumes in tropical agriculture pp 98-99. CAB International Wallingford, UK.

Jones R J and Megarrity RG (1986) Successful transfer of DHP-degrading bacteria from Hawaiian goats to Australian ruminants to overcome the toxicity of leucaena. Aust Vet J 63:259-262.

Kumar R (1992) Anti-nutritional factors, the potential risk of toxicity and method to alleviate them. In Speedy A and Pugliese PL (eds) Legume Trees and Other Fodder Trees as Protein sources for Livestock pp 145-160. FAO Anim Prod Health Paper 102.

McSweeney CS, Conlan LL, Hegarty M, Krause DO, Lowry JB and Orr P (2000) HPLC identification of toxic non-protein amino acids in the tropical leguminous tree acacia angustissima. (Manuscript in preparation)

Norton BW (1994) Nutritive value of tree legumes. In: Gutteridge RC and Shelton HM (eds), Forage tree legumes in tropical agriculture, pp 177-191. CAB International, Wallingford UK.

Odenyo A.A, Osuji PO, Karanfil O and Adinew K (1997a) Microbiological evaluation of Acacia angustissima as a protein supplement for sheep. Anim Feed Sci Technol 69: 99-112.

Odenyo AA, McSweeney CS, Palmer B, Negassa D and Osuji PO (1999a) In vitro screening of rumen fluid samples from indigenous African ruminants provide evidence for rumen fluid with superior capabilities to digest tannin-containing fodders. Aust J Agric Res 50:1147-1157.

Rowe LD, Ivie GW, DeLoach JR and Foster JG (1993) The toxic effects of mature flatpea (Lathyrus Sylvestris L CV Lathco) on sheep. Vet Hum Toxicol 35(2): 127-133.

Alternative utilization of the legume trees Leucaena leucocephala, Albizia lebbeck, and Bauhinia purpurea in silvopastoral systems

I. Hernández[173], J. E. Benavides[174] and L. Simón[175]

Introduction

Three alternative uses of trees for livestock production were studied: grazing/browsing systems under Leucaena leucocephala, Albizia lebbeck and Bauhinia purpurea; pruning and addition to the soil of foliage from L. Leucocephala; and, finally, pruning of L. leucocephala trees at the beginning of the dry season, to increase edible biomass production for the animals in this season. In the first alternative, four productive systems were evaluated: pasture only; A. lebbeck associated with pasture; B. purpurea associated with pasture and L. leucocephala associated with pasture. The work was carried out on a 7.92 ha field with six paddocks per system. The trees were homogenized leaving between 1200-1600 trees/system (600-800 trees/ha), with an average height of 1.8 m; the area covered by pasture was 65%. Two grazing cycles were evaluated: dry season 1995/1996, and dry season 1996/1997, with commercial Zebu animals of 220-230 kg initial live weight in the first cycle and 260-270 kg initial live weight in the second cycle. No supplementation was used, and water and salts were supplied ad libitum. Neither irrigation nor fertilization was used.

Analyzing the four systems during two cycles of grazing/browsing, it was evident that the systems including trees were different from the system with only pasture (Figure 1). After separating the different sub-systems involved in the grazing/browsing alternative, the highest amounts of edible biomass from the trees to which the animals had access, were achieved in the systems with L. leucocephala (around 660 kg DM/ha at the beginning of the experiment, and 320 kg DM/ha at the end), and with B. purpurea (about 520 kg DM/ha at the beginning, and 410 kg DM/ha at the end).

Regarding the pasture sub-system, the more stable yields were reached in the system with L. leucocephala; in the other two systems with trees, grass productions were higher than those of the pasture alone (at the end of the cycles evaluated, their yields were 3-4 t DM/ha). Nevertheless, in both cases there was a decrease in grass quantity. The production results obtained in the animal component show that the potential of the systems with trees is higher than that of the pasture grounds with only one grass stratum.

The second alternative is related to the effect of adding the foliage of L. leucocephala to the soil on the forage production of Panicum maximum cv. Likoni (Hernández et al. 2000c).. The basis of the analysis consisted of the biomass inputs and outputs produced in the system. A design of divided plots with four replications was used, in which the main plots corresponded to the years, and the sub-plots to the treatments. There were four treatments: control (P. maximum as a monocrop); L. leucocephala and P. maximum sown in association without pruning the trees; L. leucocephala and P. maximum sown in association with pruning and no (0%) addition of foliage to the soil; L. leucocephala and P. maximum sown in association with pruning and 50 % of the tree foliage added to the soil, as well as L. leucocephala and P. maximum sown in association with pruning and 100 % of the tree foliage added to the soil.

Fig. 1. Final live weight (kg/animal) of the animals evaluated in the systems.

Results suggest that biomass volumes contributed by L. leucocephala to the system in both years were higher than 15 t DM/ha. This represents contributions of 554, 26, 152 and 241 kg/ha of N, P, K and Ca respectively.

The quality of P. maximum forage showed a tendency to increase in the systems with trees (pruned or non-pruned). Regarding grass biomass production, in the treatments in which trees were pruned (0.50 and 100 %) and their foliage was added to the soil, similar positive results were reached, which differed (P<0.001) from the treatment where the trees were not pruned (Table 1). Regarding the balance between deposited and exported nutrients (Table 2), in the treatment where 100 % of the foliage was added to the soil, most of the nutrients were added in high amounts with the pruned biomass (+ 216, + 2 and + 22 kg/ha of N, P and Ca, respectively), except in the case of K (- 46 kg/ha).

The third alternative concerns the management of pruning of L. leucocephala at the beginning of the dry season, in order to stimulate the production of edible biomass for animal feed in the dry season. Two trials were carried out. In the first trial, a randomized block design was used with a 2x4 factorial arrangement with four replications. The performance of L. leucocephala was studied, after being initially pruned in November and December, on biomass production in February, March, April and May (Hernández et al., 1999)

Table 1. Content of crude protein (%) of P. maximum forage related to treatments and time.

Content of crude protein (%)


Years


SD ±

1995

1996


10.76

10.01

1.82

Levels of deposited foliage (%)

Sig SD ±

Control

With trees

0

50

100


7.36b

11.64a

10.77a

11.24a

11.27a

1.21*

a,b Values with the same letter do not differ significantly p <0,05 (Duncan, 1955) * p<0,05

Table 2. Minerals (kg DM/ha) contributed, and exported, and their balance in the association of L. leucocephala and P. maximum.

Variables

 

Treatments

Control

With trees

0

50

100

N

Deposited1

0

0

0

164

389

Exported2

77

102

467

317

173

Balance3

-77

-102

-467

-153

+216

P

Deposited

0

0

0

7

18

Exported

13

8

30

24

16

Balance

-13

-8

-30

-17

+2

K

Deposited

0

0

0

44

108

Exported

93

88

218

186

154

Balance

-93

-88

-218

-142

-46

Ca

Deposited

0

0

0

76

165

Exported

73

59

569

366

143

Balance

-73

-59

-569

-290

+22

1 Nutrients deposited in the soil with the biomass of L. leucocephala. 2. Nutrients exported from the association of L. leucocephala and P. maximum. 3. Nutrient deficit in the soil.

The production of edible biomass was 1.19 t DM/ha in March that did not differ (p<0.05) from April through May. Biomass production rates of leaves and non-ligneous stems was higher with the initial pruning of December and showed a tendency to stabilize itself from April to May; while the growth of ligneous stems increased slightly with time. When increasing the interval between defoliations in L. leucocephala, more ligneous tissue was formed, which was shown by an increase in height (Trial 1;).

In the other trial, a randomized block design was used with a 2x2 factorial arrangement, and four replications (Hernández et al., 2000a). The factors studied were two pruning frequency at the beginning of the dry season (November and December) and combined pruning frequency during the dry season (February-April vs. March-May). These results showed that L. leucocephala is able to supply high amounts of biomass during the dry season. It reached a total production of 2.78 t DM/ha, from which 1.92 t DM were edible, in the March-May combined treatment, statistically differing (p<0.001) from the February-March combined pruning (Trial 2;).

Table 3. Dry season production of leaves, non-ligneous stems, and edible biomass of L. leucocephala pruned at the beginning of the dry season.

Component

Initial pruning

SD ±

Final pruning

SE ±

Nov.

Dec.

Feb.

March

April

May

Leaves

0.87

0.96

0.09

0.31b

1.03a

1.04a

1.31a

0.12*

Non-ligneous stems

0.10

0.11

0.014

0.09bc

0.16a

0.11b

0.07c

0.02*

Edible biomass

0.97

1.08

0.09

0.40b

1.19a

1.15a

1.38a

0.13*

a,b Values with the same letter across do not differ significantly, p <0.05 (Duncan, 1955). * p<0.05

Table 4. Dry season production of leaves, non-ligneous stems and edible biomass of L. leucocephala pruned at the beginning of the dry season (Trial 2)

Component

Initial pruning

SD ±

Final pruning

SE ±

November

December

Feb-March

April-May

Leaves

1.28

1.23

0.1003

0.84

1.67

0.1003***

Non-ligneous Stem

0.19

0.21

0.0118

0.15

0.26

0.0118***

Edible Biomass

1.46

1.44

0.1109

0.99

1.92

0.1109***

a,b Values with the same letter across differ significantly, p<0.05 (Duncan, 1955). *** p<0.001.

Cuban livestock is undergoing a transformation period, and the systems with trees are visualized as an important strategy for the recovery of this sector. With this work, the first to be carried out on this subject in the country, a group of methodological and conceptual fundamentals, as well as productive results, are offered. This could be the basis for future research that could expand on the alternatives proposed here, while defining new options for the use of trees in animal production systems.

References

HERNáNDEZ, I.; BENAVIDES, J.E.; PÉREZ, E.; SIMóN, L. 2000a. Efecto de podas combinadas en la producción de biomasa de Leucaena leucocephala el período seco en Cuba. Pastos y forrajes, Cuba, 22:39

HERNáNDEZ, I.; BENAVIDES, J.E.; SIMóN, L. 1999. Manejo de las defoliaciones de Leucaena leucocephala para la producción de forraje en el período seco en Cuba. 2. Efecto de podas únicas en el valor nutritivo. Pastos y forrajes, Cuba, 22:135

HERNÁNDEZ, I.; BENAVIDES, J.E.; SIMóN, L. 2000b. Efecto de la adición del follaje de Leucaena leucocephala en el balance de nutrientes y en el suelo. Pastos y forrajes, Cuba, 22:309

HERNÁNDEZ, I.; BENAVIDES, J.E.; SIMóN, L;. PÉREZ, E.; 2000c. Efecto de la adición en el suelo del follaje de Leucaena leucocephala en la producción de biomasa de Panicum maximum. Pastos y forrajes, Cuba, 22:225


[163] Organización de las Naciones Unidas Para la Agricultura y la Alimentación - FAO. Roma, Italia.
[164] Centro para la Investigación en Sistemas Sostenibles de producción Agropecuaria, CIPAV, Cali, Colombia.
[165] Universidad Nacional de Colombia, Sede Palmira, Valle del Cauca, Colombia
[166] International Livestock Research Institute, P. O. Box 5689, Addis Ababa, Ethiopia.
[167] International Livestock Research Institute, P. O. Box 5689, Addis Ababa, Ethiopia
[168] University of Wisconsin- Madison WI 53706-1284, USA.
[169] University of Illinois, Urbana, IL 61801, USA.; Agricultural Research Council, Animal Nutrition and Animal Products Institute, Irene, South Africa.
[170] University of Illinois, Urbana, IL 61801, USA.
[171] CSIRO Tropical Agriculture, Long Pocket Laboratory, Private Bag No 3, Indooroopilly, Qld 4068, Australia
[172] International Livestock Research Institute, P. O. Box 5689, Addis Ababa, Ethiopia.
[173] Experimental Station of Grasses and Forages “Indio Hatuey”. Matanzas, Cuba.
[174] Universidad de Costa Rica, San José, Costa Rica
[175] Experimental Station of Grasses and Forages “Indio Hatuey”. Matanzas, Cuba.

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