Orden et al., 2000. Asian-Aust. J. Anim. Sci., 13 (7): 906-912

The effect of ammonia treatment and rice bran supplementation on the in situ rumen degradation of rice straw was determined using three Japanese Corriedale wethers fitted with a permanent rumen cannula. About 4-g samples of diets containing 100% untreated rice straw (URS); 100% ammonia treated rice straw (ARS); 65% URS+30% rice bran (RB)+5% soyabean meal (SBM) (T1); and 85% ARS+15% RB (T2) were incubated at 0, 4, 8, 16, 24, 48, 72 and 96 h in the rumen of sheep to measure DM, CP and NDF degradability. The DM disappearance of ARS based diets was about 20% higher than that of URS based diets. Rice bran supplementation improved DM disappearance of URS but not of ARS. Degradation parameters showed that ammoniation increased rate (c) of straw degradation resulting in higher DM and fibre degradability but RB supplementation did not. ARS gave similar DM and CP solubility and effective rumen degradability (ED) with that of the supplemented groups indicating that ammoniation alone can give the same effect on rumen degradability of sheep receiving low quality roughage. All degradation parameters for NDF were consistently higher in ARS based-diets indicating improved fibre solubility. Rice bran supplementation did not affect degradation characteristics of the diets except of soluble DM and CP fraction (A) of URS but not of ARS.