Comparative potential nutritive value of grasses, creeping legumes and multipurpose trees commonly in sub humid region in the Eastern parts of Tanzania

D J Mtui¹, F P Lekule², M N Shem², T Ichinohe²and T Fujihara^1,3

¹Laboratory of Animal Science, Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane 690-8504, Japan
dorahmtui@hotmail.com
²Department of Animal Science and Production, Sokoine University of Agriculture, P.O. Box 3004, Morogoro, Tanzania
³Faculty of Bioresource, Mie University, Tsu-shi, Mie 514-8507, Japan

Abstract

The nutritive values of three grasses (Cynodon plectostychus, Panicum maximum, Pennisetum purpureum), three creeping legumes (CL) (Calopogonia muconoides, Macroptilium atropurpureum, Neonotonia wightii) and three multipurpose trees (MPTs) (Leucaena leucocephala, Gliricidia sepium, Morus alba) native to Eastern Tanzania, collected during two seasons (i.e. wet and dry) were evaluated. Forages were analyzed for chemical composition including polyphenolics and in vitro gas production characteristics. Tannin bioassay studies were done on CL and MPTs after in vitro incubation with or without addition of polyethylene glycol (PEG) as a tannin binding agent.

The forages had variable crude protein contents which were influenced by seasonal variations. The CP content ranged from 120 (Cynodon plectostychus, wet season) to 69 g/kg DM (Pennisetum purpureum, dry season) in grasses; from 217 (Macroptilium atropurpureum, dry season) to 141 g/kg DM (Neonotonia wightii, wet season) in CL and from 317 (Leucaena leucocephala, dry season) to 212 g/kg DM (Morus alba, wet season) in MPTs. Forage type and seasonal interaction affected neutral detergent fiber (NDF) content but not acid detergent (ADF) and acid detergent lignin (ADL) levels. Grasses had high levels of NDF and ADF while MPTs had the lowest levels in each season. The ADL contents were highest in CL but lowest in grasses in both seasons. The contents of total extractable tannins (TET) in CL and MPTs were influenced by the type of season and species interaction and ranged from 67.9 (Neonotonia wightii, dry season) to 9.3 mg/g DM (Morus alba, wet season). The season variation had no effect (P>0.05) on the in vitro gas production volumes and fermentation characteristics. At 12h of incubation, grasses produced least gas compared to CL and MPTs. From 24h to 72h of incubation, Calopogonia muconoides produced highest volume of gas. At 96 h of incubation, Cynodon plectostychus produced the highest gas volume whilst Neonotonia wightii produced least gas volume throughout incubation period. The potential gas production was highest (P<0.05) in grasses compared to other forages and the high rate of gas production was observed in MPTs. Addition of PEG improved (P<0.05) 24h gas production, organic matter digestibility (OMD) and metabolisable energy (ME) in CL and MPTs and both in wet and dry seasons. In both seasons, high levels of 24 h gas production, OMD and ME were observed in Calopogonia muconoides. The lowest responses were in Gliricidia sepium.

Results indicate that seasonal variation affected protein content but not in vitro fermentation characteristics of the studies species. Creeping legumes (CL) and MPTs were observed to have high CP content (>100 g/kg DM) and moderate NDF levels (< 550 g/kg DM) suggesting their potential to be used as protein supplements. Polyethylene glycol (PEG) treatment improved the digestibility of Neonotonia wightii and Leucaena leucocephala (dry season) previously depressed by tannin’s anti nutritive activity, thus, improves their nutritive potential.

Key words: chemical composition, forages, in vitro gas production, season

Introduction

Natural pastures species are the main source of feed for ruminants, which form the major component of domesticated livestock in Tanzania. However, bimodal distribution of rainfall, uneven seasonal growth and availability of pasture has been considered as the major limitations to constant supply of forage for ruminants. When available even in limited quantity, grasses can not maintain the animal much of the year. The low quality of grasses is reflected in low production and reproductive performance, as well as slow growth in ruminants (Mafwere and Mtenga 1990; Ndemanisho et al 1998; Kakengi et al 2001).

Forage legumes are utilized in tropical and sub-tropical to ruminants grazing poor quality roughages especially during dry season and their importance in ruminant production has been recognized in Tanzania. They are well known to improve the efficiency of protein digestion in rumen and have been incorporated into feeding regime to improve the nutrition status of the animals (Mero and Uden 1998; Kakengi et al 2001; Rubanza et al 2007). Tropical leguminous forages have been reported to contain tannins in varying concentrations. The presence of tannins in these legumes may reduce the availability of nitrogen and amino acids required for rumen microbial growth due to formation of strong tannin-protein complexes. When in high concentration in the leguminous forages, tannins reduce ruminal and postruminal digestion of protein (Barry et al 1986). However, when the tannins concentrations are low, they have been shown to prevent extensive proteolysis in the rumen and increase intestinal absorption of amino acids (Barry et al 1986).

There is scant information on the nutritive value of local forages found in Tanzania, especially sub humid areas in Morogoro Region (Mtui et al 2008). In addition, effect of seasons on the chemical composition and nutritional value of leguminous forages is largely unknown. The use of chemical composition in combination with in vitro digestibility and degradability can be a useful tool for preliminary evaluation of nutritive value of feed resources.

Therefore, the current study was conducted to establish the effect of season on the chemical composition and in vitro fermentation characteristics of the grasses, creeping legumes and multipurpose trees found in the sub-humid areas of Tanzania, and to examine the effect of addition of polyethylene glycol on the in vitro digestibility of the leguminous forages.  

Material and methods 

Study area and collection of forages

Forages comprised of grasses; Cynodon plectostychus, Panicum maximum, Pennisetum purpureum, creeping legumes (CL): Calopogonia muconoides, Macroptilium atropurpureum, Neonotonia wightii and multipurpose trees (MPTs): Leucaena leucocephala, Gliricidia sepium, Morus alba, collected from four administrative wards in Turiani division (37⁰ 36’- 38⁰ E; 5⁰-7⁰ S), Mvomero district, Morogoro, Tanzania  during wet (March-May) and dry (July-September) seasons, were used for this study. The area lies approximately 380-500 m above sea level and is sub-humid, receives bimodal rainfall which range between 1000-1200 mm per annum, with most of rains falling between February and May. Average temperatures range from 15⁰ C to 29 ⁰C per annum. The area is composed mainly of lowland and small hills covered with grass intermingled with shrubs and leguminous plants.

Each season, sampling was done early in the morning when farmers went out to harvest/ cut forages to feed their animals under “cut and carry” system. Grasses and CL were collected from 10 subplots randomly selected using a quadrant technique. In each plot a metal quadrant (0.5m²) was thrown at the interval of 5 m in 16 linear transects of about 35 m each. Samples were harvested about 5 cm above the ground using a hand sickle until the adequate amounts were obtained. A total of 10 samples were collected from each sub locations.

Multipurpose trees samples were harvested from 20 randomly selected farms in each ward where these trees were planted along the edges as farm boundaries, alley cropping and or inter-cropped trees in crop farms. On each farm, with a random start, leaves and twigs were plucked from 10-12 trees.

Samples of individual species were dried at 50°C using an airforced oven for 48 h to constant weight. Then, all samples of each species type were pooled and ground to pass through 2.0 mm sieve. Thereafter, the sample was sub-sampled into 27 samples, which represented three (3) samples per species per season.

Chemical analyses

Crude protein (N x 6.25, Kjeldahl technique) were measured according to standard methods (AOAC, 1984). Neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) were determined according to the methods of Van Soest et al (1991). The extraction of phenolics was done using 70% aqueous acetone. The concentration of total extractable phenolics (TEPH) was assayed using Folin Ciocalteu and tannic acid standard (Makkar 2000). Total extractable tannin (TET) was estimated indirectly after being absorbed to insoluble polyvinyl polypyrrolidone (PVPP). The concentration of TET was calculated by subtracting the TEPH remaining after PVPP treatment from TEPH. For both the TEPH and TET, the absorbance was measured using a spectrophotometer (Quatification-2 program pack, Shimadzu Corporation, Kyoto, Japan).

In vitro organic matter degradability study

Animals and rumen fluid extraction

Rumen liquor for the in vitro gas production and tannin bioassay was obtained from three mature healthy Japanese Corriedale sheep fitted with permanent rumen fistula (70 mm). The animals were fed on standard diet of 800 g DM timothy hay and 200 g DM concentrate (2-parts wheat bran and 1-part rolled barley) twice daily at 0900 and 1600 h in equal sized meals. The animals had free access to water and mineral lick throughout the experimental period. The rumen liquor was withdrawn prior morning feeding, mixed, strained through four layers of cheesecloth and kept at approximately 39^oC in water bath flushed with CO₂ before use and diluted with culture media as described by Menke and Steingass (1988).

In vitro gas production

Samples were incubated in vitro with rumen fluid in calibrated glass syringes. About 200 mg of feed sample (milled through 1.0 mm sieve) were weighed in duplicate into 100 ml calibrated glass syringes. Vaseline oil was applied to the piston to ease movement and to prevent escape of gas. The syringes were pre-warmed at 39^oC for 1 hr before addition of 30 ± 0.5 ml of rumen liquor buffer mixture (ratio 1:2) into each syringe. Blanks with buffer rumen fluid without feed sample were also included. All the syringes were incubated in a water bath maintained at 39 ± 0.1^oC.  The gas readings (ml) were recorded after 3, 6, 12, 24, 48, 72 and 96 h of incubation. 

The gas production characteristics were estimated by fitting the mean gas volumes to the exponential equation by Ørskov and McDonald (1979):

 p = a + b (1-e^-ct),

Where,

P is the gas production (mlg^-1 OM) at time t
a is the gas production (mlg^-1 OM) from immediate soluble OM fraction.
Constant b is the gas production (mlg^-1 OM) from the insoluble degradable fraction,
a + b is the potential gas production and
c is the gas production (ml/g OM) rate constant per hour (h) from b.

Effect of polyethylene glycol (PEG) addition on digestibility:

The adverse effects of tannins on in vitro OM digestibility were assessed by incubation of about 500 mg DM of the feed samples with or without 1.0 g Polyethylene glycol (PEG) (molecular weight 6000) (Makkar 2000). The feed samples were incubated in 100 ml glass syringes (Menke and Steingass 1988). The PEG tannin bioassay was conducted according to Makkar (2000). The syringes were pre-warmed at 39^oC for 1 h before addition of 40 ± 0.5 ml rumen-liquor buffer mixture (ratio 1:3) into the syringes and incubated in triplicate in a water bath maintained at 39 ± 0.1^oC. Blanks were also included in the incubation. The gas production readings (ml) were recorded after 2, 4, 6, 8, 12, 16 and 24 h of incubation for both PEG, non PEG treated and blank samples.

Feed organic matter digestibility (OMD) (%) and metabolizable energy (ME) (MJkg^-1 DM) were estimated from the following Menke and Steingass (1988) and Makkar and Becker (1996) equations based on 24 h gas production (Gv, ml) and crude protein content (CP, % DM):

OMD (%) = 14.88+0.889 Gv +0.45 CP

ME (MJkg^-1 DM) = 2.20 +0.136 Gv + 0.057 CP

Statistical analysis

Gas production data were fitted to the asymptote exponential model using Neway Excel computer program (Chen X.B., Rowett Research Institute, Aberdeen). Analysis of variance (ANOVA) was carried out on chemical composition, phenolics, in vitro gas production characteristics, degradability and digestibility estimates data using the General Linear Model (GLM) procedure (SAS/ Statview 1999). Means on the estimated parameters were compared using Fisher’s least significance difference.

Results and discussion

Chemical composition

Table 1 shows variation of chemical components analyzed in the forages.

The crude protein (CP) concentrations varied (P<0.05) among species and between seasons. Among grasses, the high CP levels were recorded in Cynodon plectostychus (120 g/kg DM, wet season) and the lowest levels in Pennisetum purpureum (69 g/kg DM, dry season). Creeping legumes and MPTs had high levels of CP in dry season (217 vs. 317 g/kg DM in Macroptilium atropurpureum and Leucaena leucocephala, respectively) and lowest levels in wet season (141 vs. 212 g/kg DM in Neonotonia wightii and Gliricidia sepium, respectively). The fiber components (NDF, ADF and ADL) varied significantly (P<0.05) between seasons but with exception of NDF, the concentration levels in ADF and ADL didn’t show any interaction between forage species and the type of season. Panicum maximum, Macroptilium atropurpureum and Leucaena leucocephala had highest NDF and ADF levels in wet season while Cynodon plectostychus, Calopogonia muconoides and Gliricidia sepium had the highest concentration in dry season. The ADL levels were lowest in grasses in both seasons and highest in CL.

The TEPH and TET concentrations varied (P<0.05) among species and between seasons. The TEPH and TET concentrations in wet season, ranged from 8.8 to 30. 8 mg/g DM and 9.3 to 32.7 mg/g DM, in Morus alba and Neonotonia wightii, respectively.  During dry season, the TEPH and TET concentrations ranged from 10 to 62.5 mg/g DM and 11 to 67.9 mg/g DM in Morus alba and Neonotonia wightii, respectively.

Dry season is the most difficult period in ruminant production in the tropics as grasses, which form basal diet tend to have low protein contents. Protein is the most limiting nutrient for ruminant productivity, a deficiency being manifested in overall low performance of the animal. Therefore, any feed offered to animal should provide enough nitrogen for the microbes in the rumen for optimal animal performance.

The protein content of CL (140-216 g CP/kg DM) is consistent with values reported by Mero and Uden (1998) for Tanzanian herbaceous legumes; and those reported elsewhere (Matizha et al 1997) in the tropical region. The observed high CP content of the MPTs (211-317 g/kg DM) justifies the use of the MPTs to supplement poor quality natural pastures (Kakengi et al 2001; Rubanza et al 2007). Low CP contents in CL and MPTs in wet season compared to the ones in dry season is partly explained by the proportion of leaves/herbage harvested for the purpose of the study. During dry season, only the greenest parts of the forages were harvested. Therefore, leguminous forages represent potential feed resources that could be utilized as protein supplement to correct deficient nitrogen to ruminant animals fed on poor quality basal roughages especially during dry seasons.

With the exception of grasses, CL and MPTs were observed to be of good nutritional quality due to high CP content (>100 g/kg DM) and moderate NDF content (< 550 g/kg DM) (Leng 1990). High fiber content of grasses was not uncommon as grasses are known to have high fiber content even in wet season compared to other feeds (Pamo et al 2007). The NDF content of more than 65 % NDF was reported to limit DM intake (Van Soest 1991) thus they are of low quality. Therefore, moderate fiber compositions (NDF, ADF and ADL) of the CL and MPTs indicate a highly promising nutritive potential.

 The tannin levels (with exception of Neonotonia wightii and Leucaena leucocephala in dry season) in CL and MPTs were less than 30 mg/g DM. This is the range that has been reported to have nutritional benefits to ruminants by protecting dietary proteins from excessive ruminal degradation without affecting feed intake or fiber digestion. Levels higher than 40 mg/g DM depress intake and animal growth (Barry et al 1986; Jackson et al 1996). High tannin levels in tropical leguminous forages had previously reported (Jackson et al 1996; Mupangwa et al 2000). Therefore, with the exception of Neonotonia wightii and Leucaena leucocephala, it is unlikely that tannin in the remaining forages would have detrimental effects on feed intake and growth of ruminants.

In vitro gas production and fermentation characteristics

The in vitro cumulative gas production levels and their fermentation characteristics did not vary (P>0.05) between wet and dry season therefore the reported data are the average values and are shown without seasonal variations (Table 2).

However, significant (P<0.05) variations in gas production and fermentation parameters were observed among species. After 12 h of incubation grasses produced least gas compared to CL and MPTs. From 24 h to 72 h of incubation, Calopogonia muconoides followed by grasses produced highest gas volume. At 96 h of incubation Cynodon plectostychusproduced highest gas volume. Throughout incubation period, Neonotonia wightii produced the lowest gas volume. The potential gas production was highest in Pennisetum purpureum and lowest in Morus alba. The rate of gas production was highest in Leucaena leucocephala and Gliricidia sepium and lowest in Neonotonia wightii and Macroptilium atropurpureum. 

Gas production is a result of feed fermentation in vitro that simulates the rumen degradability phenomenon. Gas is produced from feed fermentation and indirectly from CO₂ released from buffer mixture by volatile fatty acids (acetates, butyrates and propionates). Differences of feed degradability are largely dependent on the content of fiber and crude protein (Rubanza et al 2003).

In the current study, the observed high extent of cumulative gas production volume in grasses than in leguminous forages had been previously reported for the tropical forages (Melaku et al 2003; Osuga et al 2006). The high extent of gas production in grasses might be due to high OM availability in grasses than in CL and MPTs, with the OM fermented to form VFAs and therefore high gas volumes being produced. The high CP and relatively higher non-structural carbohydrate contents of CL and MPTs may have resulted into the substrate yielding more microbial biomass production and polysaccharides storage in the cell than those of the grasses and hence, causing less gas production (Osuga et al 2006).

The observed low gas production in Neonotonia wightii compared to other forages might be due to its high tannin content. Tannins depress forage digestibility by binding feed nutrients rendering them unavailable for digestion. High tannin content in the feed reduces the population of fiber degrading bacteria in the rumen and hence low activity (Makkar and Becker 1996; Getachew et al 2000). The high gas production observed in Leucaena leucocephala despite presence of tannins has been previously reported (Norton 1994). According to Norton (1994), sometimes tannins do not reduce digestibility, which is probably due to the nature and chemical properties of tannins in those forages, indicating that not all tannins decrease protein degradability in the rumen.

Based on gas production potential in forages, Morus alba ranked the lowest while grasses were the highest. This trend could be due to amount of lignin and extent of lignifications and possibly due level of tannins and other anti nutritive factors and their related biological activities. The rate at which different feed sample are fermented is a reflection of microbial growth and accessibility of feed to microbial enzymes (Getachew et al 2000). High rates of feed OM degradability observed in MPTs in this study had been previously reported. Makkar and Becker (1996) and Keir  et al (1997) reported values of 0.026 – 0.059 for MPTs which are similar to those obtained in the present study. This is probably due to presence of high fermentable carbohydrate, especially at initial incubation hours. Thus the higher values obtained for the rate of feed degradability in the forages may indicate a better nutrient availability for rumen microorganisms in animals fed with these forages (Getachew et al 2000).

Effect of polyethylene glycol (PEG) on in vitro digestibility

The effect of addition of PEG on 24h gas production, OMD and ME are presented in Table 3.

Although the type of season did not influence the rate of cumulative gas production, it affected (P<0.05) the 24h gas production, OMD and ME when treated with PEG. The highly seasonal variation was noted in Neonotonia wightii (1.06 vs. 7.15 %, 0.43 vs. 2.77 %, and 0.49 vs. 3.02 %, for wet and dry season on 24 h gas production, OMD and ME, respectively). Among MPTs, M. alba had the highest and lowest increase in 24 h gas production, OMD and ME (6.03 vs. 0.56%, 2.18 vs. 0.2%, and 2.47 vs. 0.24%, for wet and dry season on 24 h gas production, OMD and ME, respectively).

Overall, CL and MPTs in the current study had moderate to low increase in gas production (<10%) on addition of PEG indicating that PEG’s effect and/or tannin content is low. The lower effect supports the concept that the nature and magnitude of the effect of PEG depend on factors such as tannin structure and level of tannin in the foliage. PEG increases the availability of nutrients to rumen micro-organisms, especially carbohydrates and nitrogen (Silanikove et al 1999).

In the present study, the highest increased of in vitro gas production, OMD and ME upon the PEG treatment was observed in Calopogonia muconoides in both seasons. This may partly be explained by the presence of other anti-nutritive factors apart from tannin, which were neutralized by PEG (Silanikove et al 1999). The high increase of responses upon PEG treatment in Neonotonia wightii emphasizes the negative effect of tannins on digestibility. PEG, a non-nutritive synthetic polymer, has a high affinity to tannins and makes tannins inert by forming tannin PEG complexes (Makkar et al 1995). PEG also can also liberate protein from the preformed tannin-protein complexes (Barry et al 1986).

Some studies clearly showed that PEG supplementation increased the gas production and volatile fatty acid production (Getachew et al 2001; Getachew et al 2002). Current findings of the effect of PEG on improved digestibility and ME of MPTs are considerably lower than those obtained by Rubanza et al (2007), Kamalak et al (2006) and Mtui et al (2008) for tropical browses. Leaves of leguminous trees did not give the same response with PEG treatment, possibly due to differences in chemical composition of tannins (Kamalak et al 2006), variation in tannin anti nutritive activity between foliage species (Rubanza et al 2003), the nature, chemical structure  and degree of polymerization of tannin (Schofield et al 2001).

Conclusions 

• Grasses which constitute the basic diet for ruminant in Tanzania (i.e C. plectostychus, Panicum maximumand Pennisetum purpureum) are low in CP and this account for at least the low productivity of animals, especially during the dry season. Therefore, lowest nutritive value observed in grasses especially during dry season appears to be due to high fiber content and low CP levels.

  
  

• This study support the notion that CL and MPTs are excellent sources of CP irrespective of season, suitable for supplementing feed rations in all seasons. However, the effect of fiber, extent of lignifications and phenolics compound in some leguminous plants on the availability of protein for efficient fermentation of fibrous low quality feedstuffs should always be considered. 

  
  

• Treatment with PEG improved significantly (P<0.05) the digestibility of forages by reversing effect of tannins on digestibility.

Acknowledgment  

Financial aid to the first author provided by Bishop Williams Memorial Funds (Japan) is deeply acknowledged.

References  

AOAC (Association of Official Analytical Chemists) 1984 Official Methods of Analysis. 14^th edition. Washington DC, USA.

Barry T N, Manley T R, Duncan S J 1986 The role of condensed tannins in the nutritional value of Lotus pedunculatus for sheep. 4. Sites of carbohydrate and protein digestion as influenced by dietary reactive tannin concentration.  British Journal of Nutrition 55: 123–137.

Getachew G, Makkar H P S and Becker K 2000 Effect of Polyethylene glycol on in vitro degradability of nitrogen and microbial protein synthesis from tannin-rich browse and herbaceous legumes.  British Journal of Nutrition 84: 73-83

Getachew G, Makkar H P S and Becker K 2001 Method of polyethylene glycol application to tannin-containing browses to improve microbial fermentation and efficiency of microbial protein synthesis from tannin-containing browses. Animal Feed Science and Technology 92: 51-57

Getachew G, Makkar H P S and Becker K 2002 Tropical browses: contents of phenolic compounds, in vitro gas production and stoichiometric relationship between short chain fatty acid and in vitro gas production. Journal of Agricultural Science 139: 341-352

Jackson F S, Barry T N, Lascano C and Palmer B 1996 The extractable and bound condensed tannin content of leaves from tropical tree. Journal of the Science of Food and Agriculture 71: 103-110

Kakengi A M V, Shem M N, Mtengeti E P and Otsyina R 2001 Leucaena leucocephala leaf meal as a supplement to diet of cattle grazing dairy cattle in semi-arid western Tanzania. Agroforestry Systems 52: 73-82

Kamalak A 2006 Determination of the nutritive value of leaves of a native grown shrub, Glycyrrhiza glabra L. using in vitro and in situ measurements. Small Ruminant Research 64: (3) 268-278

Keir B, Nguyen V L, Preston T R and Ørskov E R 1997 Nutritive value of leaves from tropical trees and shrubs: 1. In vitro gas production and in sacco rumen degradability. Livestock Research for Rural Development. (9) 4:  http://www.lrrd.org/lrrd9/4/bren941.htm

Leng R A 1990 Factors affecting the utilization of ‘poor quality’ forages by ruminants particularly under tropical condition. Nutrition Research Reviews 3: 277–303

Mafwere W D and Mtenga L A 1990 Lablab (Dolichos lablab) as protein supplement for weaned fattening lambs. In: Rey B, Lebbie S H B and Reynolds L (Editors). Small Ruminant Research and Development in Africa. Proceedings of the First Biennial Conference of the African Small Ruminant Research Network, ILRAD, Nairobi, Kenya, 10-14, December 1990. http://www.ilri.org/infoserv/webpub/fulldocs/x5520b/x5520b12.htm

Makkar H P S 2000 Quantification of Tannins in Tree Foliage. A Laboratory Manual for the FAO/IAEA Co-ordinated Research Project on ‘Use of Nuclear and Related Techniques to Develop Simple Tannin Assays for Predicting and Improving the Safety and Efficiency of Feeding Ruminants on Tanniniferous Tree foliage’. Joint FAO/IAEA of Nuclear Techniques in Food and Agriculture. Animal Production and Health Sub-programme, FAO/IAEA Working Document, IAEA, Vienna, Austria, pp 40. http://www-naweb.iaea.org/nafa/aph/public/pubd31022manual-tannin.pdf

Makkar H P S and Becker K 1996 A bioassay for polyphenols(tannins). Polyphenols Communications 96, July 15-18, Bordeaux, France.

Matizha W, Ngongoni N T and Topps J H 1997 Effect of supplementing veld hay with tropical legumes  Desmodium uncinatum, Stylosanthes guianensis and Macroptilium atropurpureum on intake, digestibility, outflow rates, nitrogen retention and live weight gain in lambs. Animal Feed Science and Technology 69: 187-193

Melaku S, Peters K J and Tegegne A 2003 In vitro and in sacco evaluation of selected multipurpose trees, wheat bran and Lablab purpureus as potential feed supplements to tef (Eragrostis tef) straw. Animal Feed Science and Technology 108:159-179

Menke K H and Steingass H 1988 Estimation of the energetic feed value obtained from chemical analysis and in vitro gas production using rumen fluid. Animal Research and Development 28:7-55.

Mero R N and Uden P 1998 Promising tropical grasses and legumes as feed resource in central Tanzania. Effects of feeding level on digestibility and voluntary intake of four grasses by sheep. Animal Feed Science and Technology 70 (1 -2): 79-95

Mtui D J, Shem M N, Lekule F P, Ichinohe T and Fujihara T 2008 Evaluation of chemical composition and in vitro gas production of browses collected from Tanzania.  Journal of Food, Agriculture and Environment  6 (3&4): 191-195

Mupangwa J F, Acamovic T, Topps N T and Hamudikuwanda H 2000 Content of soluble and bound condensed tannins of three tropical herbaceous forage legumes. Animal Feed Science and Technology 83: 139-144

Ndemanisho E E, Mtenga L A, Kimambo A E and Mtengeti E J 1998 Substitution of dry Leucaena leucocephala (DLL) leaves for cotton seed cake (CSC) as a protein supplement to urea treated maize stover fed to dairy weaner goats.  Animal Feed Science and Technology  73(3): 365-374

Norton B W 1994 Tree legumes as dietary supplements for ruminants. In: Gutteridge R C and Shelton H M (Editors). Forage tree legumes in tropical agriculture. CABI International, pp. 192-201

Ørskov E R and McDonald I 1979 The estimation of protein degradation in the rumen from incubation measurements weighted according to the rate of passage. Journal of Agriculture Science, Cambridge 92: 499-503

Osuga I M, Abdulrazak S A, Ichinohe T and Fujihara T 2006 Rumen degradation and in vitro gas production parameters in some browse forages, grasses and maize stover from Kenya.  Journal of Food, Agriculture and Environment 4: 60-64

Pamo E T, Boukila B, Fonteh F A, Tendonkeng F, Kana J R and Nanda A S 2007 Nutritive value of some grasses and leguminous tree leaves of the central region of Africa. Animal Feed Science and Technology 135: 273-282

Rubanza C D K, Shem M N, Otsyina R, Ichinohe T and Fujihara T 2003 Nutritive evaluation of some browse tree legume foliages native to semi-arid areas in western Tanzania.  Asian-Australasian Journal of Animal Science 16: 1429-1437

Rubanza C D K, Shem M N, Bakengesa S S, Ichinohe T and Fujihara T 2007 Effects of Acacia nilotica, Acacia polyacantha and Leucaena leucocephala leaf meal supplementation on performance of Small East African goats fed native pasture hay basal forages.  Small Ruminant Research 70 (2 & 3): 165 – 173

SAS/Statview 1999 Using Statview. Statistical Analysis System (SAS) Inc. 3rd Edition.

Schofield P, Mbugua D M and Pell A N 2001 Analysis of condensed tannins: a review.  Animal Feed Science and Technology 91: 21-41.

Silanikove N, Perevolotsky A and Provenza F D 1999 Use of tannin-binding chemicals to assay for their negative postingestive effects in ruminants. Satellite Symposium, International Symposium Ruminant Physiology: Polyphenolics in Tropical Ruminant Production. 11-14 October, Matopos, Zimbabwe.

Van Soest P J 1994 Nutritional ecology of the ruminants. Cornell University Press, Ithaca and London. pp 476.

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

Received 3 March 2009; Accepted 10 June 2009; Published 1 October 2009

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