The effectof a chemical treatment (ammoniation with urea) or a biological treatment (innoculationwith the fungus Pleurotus ostreatus) on the nutritive value of Brachiariadecumbens hay was evaluated by means of chemical analyses and a digestibilitytrial with sheep. Both treatments lasted 42 days, and thereafter the hay wasdried and ground for animal feeding. The experimental diets were the following:untreated Brachiaria hay (FNT); untreated hay plus urea added in the trough(FNT+U); fungus-treated hay plus urea (FTB+U); and ammoniated hay plus untreatedhay (FTQ+FNT). The FNT+U, FTB+U and FTQ+FNT diets were isonitrogenous. Boththe chemical and biological treatments caused changes in hay chemical composition.Ammoniation raised crude protein (CP) and acid detergent fiber (ADF) contentsand reduced both hemicellulose(HEM) content and the proportion of hemicelullosein cell walls (HEM-NDF). The biological treatment tended to raise CP; it increasedADF, lignin (LIG), cellulose proportion in cell walls (CEL-FDN) and lignin proportionin cell walls (LIG-FDN); it reduced neutral detergent fiber (NDF), HEM and HEM-NDF.However, it reduced dry matter (DM), NDF, cellulose (CEL) and FDA digestibility;however, it increased intake, probably due to smaller NDF content and smallerparticle size, causing a higher rate of passage. Both the biological and chemicaltreatments are important alternatives in increasing the nutritive value of lignocellulosicmaterials. Nevertheless, the results obtained in this experiment were not satisfactory.
