Características da silagem de resíduo úmido de fécula de mandioca adicionada de níveis de ureia

Abstract

This study aimed to evaluate the nutritive and microbiological composition and fermentation changes in the residue of wet cassava starch (RWCS) ensiled with different levels of urea. The experimental design was a randomized split plot 4x2, with four levels of urea added in the residue of wet cassava starch (0, 5, 10, 15 and 20 g/kg as fed) allocated to plots, and the sampling positions in the silo (superficial and intermediate) allocated to the subplots. The RWCS was ensiled in air circular concrete silos with approximately 1000 kg of capacity. Urea was added to RWCS between layers at the time of ensiling and the material was kept ensiled for a period of 45 days. After the fermentation period, the silos were opened and samples were collected for the determination of temperature, pH, total nitrogen, ammonia, dry matter, mineral matter, organic matter, crude protein, neutral detergent fiber (NDF), acid detergent fiber (ADF), cellulose, hemicellulose and lignin, and the population of fungi and yeasts, lactic acid bacteria and Clostridium. The urea addition to the level of 20 g/kg as fed silage for the residue of wet cassava starch with approximately 18 % of DM increases the pH, total N, NH3-N, crude protein, NDF and ADF of silage. However, this addition reduce the populations of lactic acid bacteria, fungi, yeasts and the total population of microorganisms without altering the content of dry matter, hemicellulose, cellulose and lignin.