ABSTRACT
Six combinations of the tree foliage leaves, Cassava (CL), Acacia Saligna (ASL) and Prosopis juliflora (PL) were tested, CL (100%), ASL (100%), PL (100%), CL plus ASL (50:50), CL plus PL (50:50) and CL plus ASL plus PL (50:25:25), respectively. Then these six combinations were mixed with ammoniated rice straw (ARS) (50: 50) on dry matter basis. Protein content in tested plants was higher in CL (22.22%) compared to ASL (16.67%) and PL (17.02%), while protein content in mixtures of tree foliage leaves have close protein contents. The content of NDF and ADF in CL was lower than the rest of plants tested and their mixtures. The lowest amounts of potential-GP and potential-CH4 were shown with diets containing CL (T1) and ASL (T2) with ammoniated rice straw, while mixing the leaves of CL with ASL and/or PL raised the quantities of GP and CH4 released. Combination of foliage leaves with ammoniated rice straw in T4, T5 and T6 diets significantly (P<0.05) improved DM, OM and NDF degradability compared to T1, T2 and T3 diets containing tested leaves separately with ARS. The mixture of PL with ARS in T3 and T6 significantly (P<0.05) increased benefit of metabolizable energy (ME) compared to the CL or ASL with ARS in T1, T2, T4 and T5 diets. There was a positive correlation (r = 0.66, P<0.05) and (r = 0.60, P<0.05) between in vitro neutral detergent fiber degradability (IVNDFD) and both microbial protein (MP) and CH4, respectively. Also, positive correlation (r = 0.76, P<0.05) and (r = 0.65 P<0.05) where shown between MP and both GP and CH4, respectively. The decrease of CT concentration increased NH3-N, SCFA's, MP, and bacteria count and vice versa. There was no effect of different treatments on pH, protozoa count, propionic, A/P and Butyric. Mixture of separate foliage leaves with ARS in tested diet significantly (P<0.05) increased the amount of refused feed, especially for T1 and T2 diets. In contrast, the amount of feed refusal declined when combining different species of foliage leaves together.
The presence of CL and PL separate in tested diets (T1 and T3) or combined into the tested diets (T5) improved digestion of DM, OM, NDF, and ADF% compared to ASL. No significant differences found in protein digestion among tested diets. The results of the N balance showed a significant (P<0.05) increase in T3, T4 and T5 compared to other tested diets (T1, T2 and T6).
In conclusion, using foliage leaves rich in tannins to form of feed mixtures could help overcoming the negative effect of CT and reduce CH4 emitted.