RUMINAL FERMENTATION AND TANNINS BIOACTIVITY OF SOME BROWSES USING A SEMI-AUTOMATED GAS PRODUCTION TECHNIQUE

The nutritive value, tannins bioactivity and methane production of some tropical plants e.g. Acacia (Acacia saligna), Leucaena (Leucaena leucocephala), Atriplex (Atriplex caseneace), Eucalyptus (Eucalytus globules), and Alfalafa (Medicago sativa) hay were evaluated by chemical composition and gasp production (GP) technique in vitro. Chemical analysis indicated that crude protein content was ranged from 95.4 to 204.0 g kg-1DM for eucalyptus and leucaena, respectively. The leucaena and alfalfa had the highest neutral detergent fibre (NDF) content (543.1 and 546.7g kg-1DM), respectively. Atriplex had the lowest content (173.8 g kg-1DM) of acid detergent fibre (ADF) and acid detergent lignin (ADL, 85.89 g kg-1DM). Alfalfa, atriplex and eucalyptus had negligible condensed tannins (CT) content (0.2, 0.3, 4.9 eq-g leucocyanidin kg-1DM), while acacia and leucaena had the highest CT (61.4 and 32.5 eq-g leucocyanidin kg-1DM). The acacia and leucaena produced less GP in the absence of PEG. Inclusion of PEG in fermentation of tropical browses resulted in a significant increase of GP (28.1 and 87.4 1%) particularly the plants rich in condensed tannins. The methane production was decreased significantly (P alfalfa > acacia > eucalyptus > leucaena. Partitioning factor (PF) values were differed significantly (