Compositional evaluation of some dry season shrub and tree foliages in a transitionally vegetated zone of Nigeria

I Ikhimioya, M A Bamikole^*, A U Omoregie^** and U J Ikhatua^*

Department of Animal Science, Ambrose Alli University, Ekpoma, Nigeria
^*Department of Animal Science, University of Benin, Benin City, Nigeria
^**Department of Crop Science, Ambrose Alli University, Ekpoma, Nigeria
imounu_ikhimioya@yahoo.com

Abstract

The proximate composition, cell wall and mineral contents, and the levels of some anti-nutrients were assessed in the foliages of Afzelia africana, Bambusa vulgaris, Chromolaena odorata, Mangifera indica and Newbouldia laevis.

DM content ranged from 26.80% in Chromolaena odorata to 50.82% in Bambusa vulgaris. The leaves were generally high in CP which ranged from 15.13% in Mangifera indica to 29.85% in Afzelia africana. Gross energy in the foliages varied from 2.50 Kcal/g to 4.09 Kcal/g respectively in Mangifera indica and N. laevis. The highest value of NDF (54.38%) was recorded in Chromolaena odorata while Mangifera indica had the least value (42.40%). Mineral content analysis revealed that Afzelia africana contained the least content of Ca (0.31%) while Chromolaena odorata had the highest (1.52%). Chromolaena odorata also recorded the highest P content (0.39%) and the least was in Mangifera indica (0.20%). Sodium content varied from 0.39% in Chromolaena odorata to 0.14% in Afzelia africana. The lowest content of Cu (5.26ppm) was recorded in Newbouldia laevis while the highest value of 91.76ppm was from Chromolaena odorata. The concentration of Zn varied from 46.60ppm in Bambusa vulgaris to 277.88ppm in Chromolaena odorata. Among the anti-nutrient contents examined, the haemaglutinnin value was least in Chromolaena odorata(9.72mg/g) and highest in Newbouldia laevis(20.84mg/g). Phytic acid varied from 0.45% in Afzelia africana to 4.88% in Mangifera indica, while tannin content ranged between 0.17% in Afzelia africana and 3.51% in Mangifera indica.

The implication of the results is that, based on the observed nutritional compositions and ready availability of the foliages, especially in the dry season when the quality of available grasses drops, they showed promise of being adequate for the supplementation of ruminants' diets.

Keywords: Anti-nutrient, cell wall, foliages, mineral, Nigeria, proximate composition, transitional vegetation zone

Introduction

Ruminant livestock in most parts of the tropics graze extensively on naturally growing forages which are poor in quality. These tropical forages compared to those in the temperate, support lower levels of ruminant animal production mainly because they contain less nitrogen and are less digestible (Minson 1980). The quality and quantity of these grasses become more critical in the dry seasons and thereby imposing more serious constraint to the development and productivity of these animals (Topps 1992). A wide variety of plant species are found in the tropics with shrubs and trees being the most visible forms in many of these landscapes (McKell 1980), of which, the utilization of many is rather opportunistic (Kallah et al 2000).

In the past, research efforts on alternative feed resources for ruminants have concentrated more on a limited number of the available plant foliages with little information on the nutrient status of the various other foliages in relation to their being utilized as feed for ruminants. Broadly therefore, the objective of this study was to evaluate the nutritive value of the foliages from some common tree and shrub observed to be available and green all the year round in the study area for the possibility of integrating them into ruminant feeding systems in Nigeria. Thus, in this first phase of the study, broad examination of the proximate, cell wall and mineral compositions as well as the assessment of the levels of some anti-nutritional factors in some shrub and tree foliages in the derived savannah zone of Nigeria was carried out.

Materials and methods

This study was conducted using leaves harvested between December 2003 and January 2004, from five naturally growing common trees and shrubs namely: Mangifera indica (L.), Afzelia africana (Sm.), Bambusa vulgaris (L.), Chromolaena odorata (L.) and Newbouldia laevis (P. Beauv.), found within and around Ambrose Alli University, Ekpoma, Nigeria. The study area is located between Latitude 3^o8` and 7<sup>o</sup>8`N, and Longitude 3^o2` and 9<sup>o</sup>8`E and at an altitude of 335m above sea level. The climate is humid tropical, characterized by a dry period (November to March) and a wet period (April to October). Annual rainfall in this location ranges between 1200mm and 1500mm. Mean temperature and humidity during the study ranged from 20 to 31^oC and 71 to 83% respectively. The area is vegetated transitionally between the dense rainforest to the south and the sparse derived savannah to the north.

Foliages from each of the five sampled plants were collected fresh and almost immediately dried in a forced-air oven at 60^oC until constant weight was attained to determine their DM contents and then milled to pass through a 1mm mesh sieve for subsequent analyses. Crude protein was determined by the micro-kjeldahl procedure (Nx6.25), ash by incineration at 500^oC for 2h in a closed furnace. Gross energy values for the foliages were determined using a bomb calorimeter. All analyses in this study were done following standard procedures as outlined by AOAC (1990).

The cell wall constituents comprising neutral detergent fibre (NDF), acid detergent fibre (ADF) and lignin, were determined according to the methods described by Van Soest et al (1991). The NDF was assayed with sodium sulphite, devoid of alpha amylase and expressed with residual ash. The difference between the values for NDF and ADF, and that between ADF and lignin provided the values for hemicellulose and cellulose respectively.

Analysis of the mineral concentrations in the sampled foliages was by wet digestion using nitric-perchloric acid mixture. The mineral elements Ca, Mg, Fe, Cu, Zn and Mn were determined by the atomic absorption spectrophotometer using the Bulk Scientific model 200a (East Norwalk, USA) while the flame photometer (FP 410 Corning) was used to estimate the Na and K contents. Phosphorus concentrations were determined colorimetrically (Parkinson and Allen 1975).

Haemagglutinnin was estimated using the method of Huprikar and Sohonie (1975), oxalate by the precipitation method of AOAC (1980), phytic acid by the method of Wheeler and Ferrell (1971), saponin by the procedure of Walls et al (1952), tannin by the Folin-Denis reagent method of Hoff and Singleton (1977) and trypsin inhibitor by the method of Kakade et al (1974).

Results

The proximate composition of the shrub and tree foliages determined in this study is presented in Table 1.

Dry matter content ranged from 26.80% in Chromolaena odorata to 50.82% in Bambusa vulgaris. The foliages from all the plants studied showed relatively high crude protein values ranging from 15.13% in Mangifera indica to 29.85% in Afzelia africana. Ash value ranged from 2.49% in Newbouldia laevis to 10.61% in Bambusa vulgaris. The highest ether extract content was recorded for Newbouldia laevis (13.59%) while Bambusa vulgaris recorded the least value (7.20%). The gross energy content averaged 3.16 Kcal/g in all the foliages ranging from 2.50 Kcal/g to 4.09 Kcal/g respectively in Mangifera indica and Newbouldia laevis.

Table 2 represents the results of the cell wall content analysis of the shrub and tree foliages in this experiment.

The highest neutral detergent fibre (NDF) content of 53.97% was recorded in Afzelia africana and the least of 42.40% in Mangifera indica. Acid detergent fibre (ADF) level ranged from 32.27% in Bambusa vulgaris to 42.69% in Afzelia africana. Lignin content range was from 9.93% in Bambusa vulgaris, to 15.93% in Newbouldia laevis. Cellulose content was relatively close in range and varied from 22.34% in Bambusa vulgaris to 30.75% in Afzelia africana. The highest recorded value for hemicellulose was 17.25% in Chromolaena odorata and the lowest of 6.20% was in Mangifera indica.

The concentration of mineral elements in the investigated foliages is presented in Table 3.

Foliage from Afzelia africana had the least calcium concentration of 0.31% with 1.52% in Chromolaena odorata being the highest. Phosphorus ranged from 0.20% in Mangifera indica to 0.39% in Chromolaena odorata. The potassium content in the foliages was between 1.02% in Newbouldia laevis and 3.04% in Chromolaena odorata. Sodium values were from 0.14% in Afzelia africana to 0.39% in Chromolaena odorata. The content of magnesium was from 0.11% in Afzelia africana to 0.27% in both Chromolaena odorata and Newbouldia laevis.

The level of copper varied from 5.26ppm in Newbouldia laevis to 91.76ppm in Chromolaena odorata. Iron content in the foliages was between 72.20ppm in Mangifera indica to 81.90ppm in Afzelia africana. The composition of manganese which did not differ much between the foliages, ranged from 86.27ppm in Mangifera indica to 143.80ppm in Chromolaena odorata. Zinc varied from a low value of 46.60ppm in Bambusa vulgaris to a high value of 277.88ppm recorded for Chromolaena odorata.

Table 4 presents the result for components of some anti-nutritional factors in the shrub and tree foliages.

Haemagglutinnin content varied from 9.72mg/g in Chromolaena odorata to 20.84mg/g in Newbouldia laevis. The level of oxalate ranged from 0.77% in Mangifera indica to 1.89% in Chromolaena odorata. Phytic acid estimate was from 0.46% in Afzelia africana to 4.88% in Mangifera indica. The least value recorded for saponin was 0.50% in Chromolaena odorata and the highest was 4.40% in Afzelia africana. Tannin concentration ranged from 0.17% in Afzelia africana to 3.51% in Mangifera indica. Observed estimates for trypsin inhibitor was between 9.87mg/g in Bambusa vulgaris to 22.37mg/g in Chromolaena odorata.

Discussion

Crude protein contents in the investigated leaves were higher than the average of 12.50% obtained for other native browse plants by Le Houèrou (1980). The CP content for Bambusa vulgaris was quite high for a tropical grass species. Afzelia Africana, a legume, had the highest CP content which agrees with Ivory (1990) that leguminous browse plants contain higher protein content than the non-leguminous species. Although virtually unknown as animal fodder, with a CP content of 15.57%, Newbouldia laevis showed promise of being a useful ruminant diet especially being a common boundary or living fence plant. The relatively high CP values in the foliages studied appeared satisfactory for animal production since they exceeded the minimum protein requirement of 10-12% (ARC 1985) for ruminants. The value of feeds to goats depends on the amount of energy they supply (Sauvant and Morand-Fehr 1991). Thus, compared to the recommendations of NRC (1981), only Afzelia africana (3.25 Kcal/g), Chromolaena odorata (3.19 Kcal/g) and Newbouldia laevis (4.09 Kcal/g) met the minimum gross energy requirement level of 3.26Kcal/g for goats in this study. The lower energy values recorded for Bambusa vulgaris and Mangifera indica (2.76 Kcal/g and 2.50 Kcal/g respectively) may probably be due to their low ether extract contents. Newbouldia laevis potentially appeared to be a good energy source for goats.

NDF content in these foliages, though relatively high, was generally lower than the safe upper level of 60% thought to guarantee appreciable intake of forages (Meissner et al 1991). The study by Nyamangara and Ndlovu (1995) with goats on natural vegetation with NDF contents of between 59% and 79%, indicates that this cell wall component in the foliages should be adequately degraded.

Calcium contents in the shrub and tree foliages were lower than values reported by Le Houèrou 1980 for browse plants. Relative to the suggested range of 0.19-0.77% (McDowell 1997) as requirement for small ruminants, the observed calcium content in the studied plant species seemed adequate for goats. Phosphorus in the plant foliages was low compared to the minimum requirements reported by Akinsoyinu (1986) for adult females (1.2%), growing (2.7%) and castrated (1.92%) WAD goats but however comparable to values reported by Topps (1992) for several browse plants. Potassium composition in the plants studied was well above the range of 0.01-1.0% recommended by McDowell (1992) for ruminants. Apart from Chromolaena odorata with 0.39%, the content of sodium in the plant leaves investigated were found to be mostly within suggested requirement range of 0.01-0.25% (Fettman et al 1984) for ruminants. Compared to the recommended range of 0.17-0.21% magnesium requirement for small ruminants (Suttle 1983), the studied shrub and tree leaves appeared suitable as source of magnesium as well as being comparable to 0.10-0.28% by Kallah et al (2000) for some native forbs of Nigeria. Copper in the investigated leaves was high compared to 8.8-17.6ppm (McDonald et al 1988) given as the normal range of copper in pastures except in Newbouldia laevis (5.26ppm). Iron content in all the shrub and tree leaves were observed to be adequate in meeting the requirement of goats going by the suggested 66ppm minimum iron levels for goats (ARC 1985). The observed values for manganese showed some level of sufficiency in meeting its requirement of 88ppm for goats (Kessler 1991). Zinc in the leaves appeared mostly adequate for goats when compared to ARC (1985) suggested requirements of 110ppm for ruminants.

Haemaglutinnin concentrations of up to 8.5g/Kg have been shown to induce a decline in feed intake. Thus, the range of 9.72-20.84mg/g in the examined leaves could induce low growth rate and feed intake in ruminants. Although the concentrations of oxalate in the tested leaves were comparatively high, they however were within reported range by Oke (1969). Phytic acid levels in the plants were generally lower than the threshold level of <5% prescribed by Laurena et al (1994). Feeding of plants with low to moderate levels of tannin usually results in little or no nutritional problems with ruminants although concentrations above 10% could be problematic (Chang and Fuller 1964). The less than 4% tannin level in all the shrubs and tree leaves studied were within the tolerable range for ruminants put at between 2-5% (Diagayétté and Huss 1981). These investigated leaves may thus be regarded safe for feeding ruminants especially when fed as supplements.
 

Conclusion

• The results general showed that the shrub and tree foliages under study have a high potential compared to the commonly available grass Panicum maximum, for ruminants in terms of their chemical compositions especially the high crude protein and low cell wall contents and generally tolerable anti-nutritional factor levels.

• This is of particular importance from the point of view of helping to check weight loss problems of ruminant livestock common in the dry season when the quality of available grasses would have dropped drastically in the tropics. Besides, the abundance of these shrub and tree foliages and their ability to remain green all-year-round in the study environment, guarantees a reduction in the feeding costs for ruminants.

 
References   

Akinsoyinu A O 1986 Minimum phosphorus requirement of dwarf goats for maintenance. Tropical Agriculture (Trinidad) 3:333-335.

AOAC 1980 Official Methods of Analysis, 13^th edition. Association of Official Analytical Chemists. Washington, DC.

AOAC 1990 Official Methods of Analysis, 15^th edition. Association of Official Analytical Chemists. Washington, DC.

ARC 1985 The nutrient requirement of farm animals. Technical Review and Summaries, Agricultural Research Council, London UK.

Chang S I and Fuller S I 1964 Effect of tannin content of grain sorghum on their feeding value for growing chicks. Poultry Science, 43: 30-37.

Diagayétté M and Huss W 1981 Tannin content of African pasture plants: Their effects on analytical data and in vitro digestibility. Animal Research and Development, 15: 79-90.

Fettman M J, Chase L E, Bentinck-Smith J, Coppock C E and Zinn S A 1984 Nutritional chloride deficiencies in early lactating Holstein cows. Journal of Dairy Science, 67: 2321.

Hoff J E and Singleton K E 1977 A method for the determination of Tannins. Journal of Food Science, 42:6-16.

Huprikar S V and Sohonie K 1975 Haemagglutinnins in Indian pulses II: Purification and properties of haemagglutinnin from white pea Pisum sativum. Ezymologia28:333-345.

Ivory D A 1990 Major characteristics, agronomic features and nutritional values of shrubs and tree fodders. In: Devendra C (editor), Shrubs and tree fodders for animals. Proceedings of a workshop held in Denpasar, Indonesia, 24-29 July 1989. International Development Research Centre, Ottawa, Canada. Pp 22-38.

Kakade M L, Rachis J J, McGhee J E and Puski G 1974 Determination of trypsin inhibitor activity of soy products. A collaborative analysis of an improved procedure. Cereal Chemistry, 51: 576-582.

Kallah M S, Bale J O, Abdullahi U S, Muhammad I R and Lawal R 2000 Nutrient composition of native forbs semi arid and sub-humid savannas of Nigeria. Agroforestry systems, 84: 137-145.

Laurena A C, Jamela M A, Revilleza R and Mendoza E M T 1994 Polyphenols, phytate, cyanogenic glucosides and trypsin inhibitor activity of several Philippine indigenous food legumes. Journal of Food Composition and Analysis, 7: 194-202.

McDonald P, Edwards R A and Greenhalgh J F D 1988 Animal Nutrition. Longman Scientific and Technical, Essex, England. 543pp.

McDowell L R 1992 Minerals in animal and human nutrition. 1^st Edition, Academic Press, New York, USA.

McDowell L R 1997 Minerals for grazing ruminants in tropical regions. Bulletin, Institute for food and Agricultural Sciences, University of Florida, Gainesville, USA. 81pp.

McKell C M 1980 Multiple uses of fodder trees and shrubs-a worldwide perspective. In: Le Houèrou H N (editor), Browse in Africa: the current state of knowledge. ILCA, Addis Ababa, Ethiopia. Pp 141-150.

Meissner H H, Viljoen M O and van Niekerk W A 1991 Intake and digestibility by sheep of Anthephora, Panicum, Rhodes and Smooth finger grass. In: Proceedings of the IV^th International Rangeland Congress, September 1991. Montpellier, France. Pp648-649.

Minson D J 1980 Nutritional differences between tropical and temperate pastures. In: Morley, F.H.N. (Editor). Grazing animals. Elsevier, Amsterdam, Netherlands. Pg 103-157.

NRC 1981 Nutrient requirements of goats. N^o 15. National Research Council, National Academy of Science Press, Washington, DC, USA. 91pp.

Nyamangara M E and Ndlovu L R 1995 Feeding behaviour, feed intake, chemical and botanical composition of the diet of indigenous goats raised on natural vegetation in a semi-arid region of Zimbabwe. Journal of Agricultural Science (Cambridge), 124: 455-461.

Oke O L 1969 Oxalic acid in plants and in nutrition. World Review of Nutrition and Dietetics. 10: 263-303.

Palmer B and Ibrahim I M 1996 Calliandra calothyrsus forage for the tropics - A current assessment. Proceedings of an International Workshop on the genus Calliandra. January 1996, Bogor, Indonesia, Winrock International. Pp 183-194.

Parkinson J A and Allen S E 1975 A wet oxidation procedure suitable for the determination of nitrogen and mineral nutrients in biological material. Communications in Soil Science and Plant Analysis, 6: 1-11.

Sauvant D and Morand-Fehr P 1991 Energy requirements and allowances of adult goats. In: Morand-Fehr P (editor), Goat Nutrition. Pudoc, Wageningen, Netherlands. Pp 61-72.

Suttle N F 1983 Meeting the mineral requirement of sheep. In: Haresign W (editor), Sheep Production. Butterworth, London, UK. Pp 167-183.

Topps J H 1992 Potential, composition and use of legume shrubs and tree as fodder for livestock in the tropics. Journal of Agricultural Science (Cambridge). 118:1-18.

Van Soest P J, Robertson J D and Lewis B A 1991 Methods for dietary fibre, neutral detergent fibre and non-starch polysaccharides in relation to animal nutrition. Journal of Dairy Science, 74: 3583-3597. http://jds.fass.org/cgi/reprint/74/10/3583.pdf

Walls M E, Kratzer F W, Rothman E S and Eddy C R 1952 Steroidal Sapogenins. 1. Extraction, Isolation and Identification. Journal of Biological Chemistry 198:533-543.

Wheeler E L and Ferrell R E 1971 A method for phytic acid determination in wheat and wheat flour. Cereal Chemistry, 48:312-316.

Received 15 October 2006; Accepted 11 January 2007; Published 1 March 2007

Go to top