Effect of ensiling of acacia saligna and leucaena leucocephalia leaves wiht different levels f urea on the chemical composition, in vitro gas production, energy values and organic matter digestibility

The effects of ensiling of acacia (Acacia saligna, AC) and leucaena (Leucaena leucocephala LE) leaves with different levels of urea (U, 0, 1, 3 or 5%) on gas production, energy value and organic matter digestibility (OMD%) of AC LE were assessed. The acacia and leucaena were ensiled for 35 days. Ground samples (200 mg DM) of the ensiled from the eight treatments were incubated in glass syringes with rumen fluid obtained from fistulated sheep fed berseem hay and commercial concentrate mixture twice a day Cumulative gas production was recorded at 3, 6, 9, 12, 24, 72 and 96 h of incubation and the kinetics of gas production was described by using the equation: Gas (Y) = a + b (1-exp . ct), Ensiling of AC and LE leaves with U increased crude protein and ash, while the contents of tested samples of total (TP), total tannins (TT) and condensed tannins (CT) were decreased Also, ensiling of AC and LE leaves with U significantly (P 0.05) decreased gas production. The gas production volume was significantly (P 0.05) higher for ensiled and LE leaves without U than ensiled AC with 5%U or ensiled LE with 3%U. The maximum rate of gas production increased after ensiling AC and LE leaves with 5% and 3% U, respectively. The calculated values of metabolizable energy(ME) and net energy (NE) were significantly (P0.05) increased for ensiled AC with 3 and 5%U while ensiled LE with U was not significantly affected The organic matter digestibility (OMD %) and microbial protein production were significantly(P0. 05) higher for ensiled AC and LE with U, while short chain fatty acids (SCFA) were significantly (P0.05) decreased.The concentrations of TP, TT and CT were strongly correlated (p0.01). The TP, TT and CT were negatively related(P0. 01) with neutral detergent fiber (NDF) and acid detergent fiber (ADF), but not with hemicelluloses (HEMI). The crude protein was strongly correlated (p0.01) with NDF, ADF and CT and negatively related (p0.01) with TF and TT, but not with HEMI.. In conclusion, there were negative effects on the in vitro gas production occurring more consistently when AC and LE were ensiled with different levels of U, while OMD% and microbial proteins were significantly (P0.05) increased. The in vitro digestibility and gas production parameters were significantly correlated with chemical composition of shrubs. Finally, urea treatment improved the degradation of AC and LE.