• Asian-Australasian Journal of Animal Sciences
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• 제16권10호
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• pp.1429-1437
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• 2003

Browse tree legume leaves from Acacia spp (A. nilotica, A. tortilis, A. polyacantha), Dichrostachys sp, Flagea villosa, Piliostigma thonningii, Harrisonia sp were evaluated for nutritive potential (chemical compositions and degradability characteristics) compared to Gliricidia sepium. Effect of tannins anti-nutritive activity on digestibility was also assessed by polyethylene glycol (PEG) tannin bioassay. Crude protein (CP), ash, neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) differed (p<0.05) between legume foliages. Mean CP, ash, NDF, ADF and ADL for fodder species tested were 158, 92, 385, 145, and 100 g/kg DM, respectively. CP ranged from 115 (P. thonningii) to 205 g/kg DM (G. sepium). Acacia spp had moderate CP values (g/kg DM) of 144 (A. nilotica), to high CP in A. tortilis (188) and A. polyacantha (194) comparable to G. sepium. The forages had relatively lower fiber compositions. A. nilotica had (p<0.05) lowest NDF, ADF and ADL (182, 68 and 44) compared to P. thonningii (619, 196 and 130) g/kg DM, respectively. Except G. sepium, all fodder species had detectable high phenolic and tannin contents greater than 5% DM, an upper beneficial level in animal feeding and nutrition. Mean total phenolics (TP), total tannins (TT) and condensed tannins (CT) (or proanthocyanidins) for fodder species tested were 139, 113 and 43 mg/g DM, respectively. F. villosa had (p<0.05) lowest TP and TT of 65 and 56 mg/g DM, respectively, compared to A. nilotica (237 and 236 mg/g DM, respectively). The CT varied (p<0.05) from 6 (F. villosa) to 74 mg/g DM (Dichrostachys sp). In vitro organic matter (OM) degradability (OMD) differed (p<0.05) between fodder species. G. sepium had (p<0.05) high degradability potential compared to A. polyacantha that had (p<0.05) the lowest OMD values. Forage degradability ranked: G. sepium>A. nilotica>P. thonningi>F. villosa>Dichrostachys sp>A. tortilis>A. polyacantha. Addition of PEG resulted to (p<0.05) improvement in in vitro OM digestibility (IVD). Increase in IVD was mainly due to binding action of PEG on tannins; and represents potential nutritive values previously depressed by tannins anti-nutritive activity. Browse fodder has potential as sources of ruminal nitrogen especially for ruminants consuming low quality roughages due to high protein, lower fiber compositions and high potential digestibility. However, utilization of browse supplements in ruminants is hampered by high phenolic and tannin contents. Deactivation of tannin anti-nutritive activity, possibly by feeding tanniniferous browse with other readily available nitrogen sources to dilute tannin anti-nutritive activity could improve utilization of browse fodder supplements. Further studies are needed to assess browse fodder palatability and intake, and their effect on growth performance in ruminants.

• Asian-Australasian Journal of Animal Sciences
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• 제18권1호
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• pp.54-60
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• 2005

A study was conducted with the objective of evaluating the nutritive value of some browse species from Kenya. The species evaluated included: Bauhinia alba, Bauhinia variegata, Bridelia micrantha, Calliandra calothyrsus, Carisa edulis, Cratylia argentea, Gliricidia sepium, Lantana camara, Maerua angolensis, Sesbania micrantha and S. sesban. The browses were evaluated by their chemical composition including phenolics, in vitro gas production and tannin activity (tannin bioassay). All the species had high crude protein content (149-268 g/kg DM) and low NDF content (239-549 g/kg DM). The feeds had varying contents of total extractable tannins (TET) ranging from low (3-22 mg/g DM), moderate (42-58 mg/g DM) and high (77-152 mg/g DM). Calliandra calothyrsus had the highest tannin content. Significant (p<0.05) variation in gas production was recorded among the species. Sesbania micrantha had the highest (p<0.05) potential gas production while Gliricidia sepium had the highest (p<0.05) rate of gas production. Use of polyethylene glycol (PEG 6000), to assess the adverse affect of tannins, indicated that tannins in browse species with high tannin content had inhibitory effects on rumen microbial fermentation as indicated by the gas production. Estimated organic matter digestibility and metabolizable energy also increased with PEG addition. The results of this study indicate that such Kenyan browse species have the potential to be used as feed supplements for ruminant animals.