Digestive process evaluation of steam and pressure treated sugarcane bagasse

Abstract

Two experiments were carried out in order to characterize the digestion process of auto-hydrolyzed sugarcane bagasse (AHB) under 19 kgf/cm² of pressure during 6 minutes. For this purpose, crude sugarcane bagasse (CB) were used as comparative roughage. Using the in situ method in the first experiment there were determined the degradation rate and extension of degradation of Elephant grass, CB and AHB. These roughages were incubated in the following diets: 1. 100% of coast-cross hay; 2. 65% of AHB + 35% of concentrate and 3. 47% of CB + 53% of concentrate. The best degradabilities results were obtained in exclusive hay and CB diets, showing that the AH B diet depressed the extensive and the degradation rate of different roughages incubated in it. When the AHB was incubated in exclusive hay diet (maximum of degradation), its degradability was much superior than CB degradability (60.97% x 33.58%, respectively), but in real conditions of rumen degradation (AHB and CB diets, respectively), these data were almost similar (34.80 x 32.39%, respectively). The results showed that the rumen conditions in the AHB diet was unfavorable to fiber degradation. in the second experiment, the same CB and AHB diets as used in the first experiment were evaluated using the in vivo digestibility assays and ruminal parameters as: VFA, N-NH3, pH, liquid and solid rate of passage and diet retention time in the whole digestive tract. The rumen conditions in the AHB diet were considered unfavorable to the fiber digestion as showed in the first experiment. The fiber degradation was probably depressed in AHB diet because of the low rumina! pH(5.95), the high rate of passage of the roughage (0.024/h) and the indequate ruminal physical conditions observed in this diet.