Abstract
Two experiments were conducted to determine the effects of Leucaena leucocephala (leucaena) and Gliricidia sepium (gliricidia) supplementation on intake, digestion, outflow rates, microbial protein yield and live-weight changes in sheep fed with ammoniated rice straw (ARS). In experiment 1, three rumen cannulated Japanese Corriedale wether (mean body weight of 35.6 kg) in $3{\times}3$ Latin Square Design were used. Animals were fed ad libitum ARS alone, or supplemented with 200 g of either leucaena or gliricidia. In experiment 2, twenty-four growing native Philippine sheep with average body weight of $13.5{\pm}0.25kg$ were used in a completely randomized design (CRD) and offered similar diets to those of experiment 1. Supplementation increased total dry matter intake and nutrient digestibility except for fiber (p<0.05) without affecting ARS consumption. Nitrogen balance revealed that absorbed and retained N was significantly higher in leucaena and gliricidia. The significant improvement in N utilization and more digestible OM intake brought about by the inclusion of leucaena and gliricidia to ARS resulted in increased (p<0.05) microbial N yield. Efficiency of microbial N supply in supplemented group was not significantly different, but higher (p<0.05) than the 24.92 g N/kg DOMR for ARS group. Liquid outflow rate was 7.8 and 6.8 %/h, while the solid phase of rumen digesta was 4.4 and 3.8 %/h for the leucaena and gliricidia group respectively, which were significantly higher than 5.30 and 2.50 %/h in the control diet. The increase in total DMI resulted to higher (p<0.01) growth performance and efficient feed utilization. Average daily gain (ADG) was 19.3, 34.6 and 33.9 g/d for the ARS, leucaena and gliricidia respectively. It is therefore concluded that addition of leucaena and gliricidia to ARS in could increase nutrient intake and digestibility, subsequently improving N utilization and livestock performance.