Samples of sugarcane bagasse, rice and cotton residues were irradiated with various doses (200, 400, 600, 800 and l000kGy) in an electron accelerator with or without anhydrous gaseous NH3 post-treatment, to evaluate the effects of irradiation on dry matter digestibility and on their chemical and physical properties. After irradiation, samples were dried and ground for chemical analysis. Dry matter digestibility was determined with the nylon bag technique. Structural analysis was performed using light and electron microscopy. Crude fiber and neutral detergent fiber significantly decreased (P<0.01) for irradiated samples. Phenolic contents increased with the applied dose indicating that lignin was decomposed. Dry matter digestibility increased with increasing dose. An increase of 24 digestibility units was observed for bagasse at highest dose. Based on microscopy, fragmentation of sugarcane bagasse was observed at 800-1000kGy and some celular alterations occurred at 200kGy for rice and cotton residues. lt was concluded that irradiation caused significant changes on chemical and physical properties and on digestibility of fibrous residues. Utilization of irradiated biomass for animal feed appears promising.
sugarcane bagasse; digestibility; ionizing radiation; residues
