The experiment was carried out to evaluate the fermentative and microbiological dynamics of the tropical grass silages using pelleted citrus pulp (PCP) as an additive. The Tanzania (Panicum maximum cv. Tanzania) and Marandu (Brachiaria brizantha (Hochst. ex. A. RICH) Stapf cv. Marandu) grasses were harvested at 64 and 49 days of regrowth, respectively. The following treatments were evaluated: control (0%), addition of 5% and 10% of pelleted citrus pulp (PCP) in a fresh matter basis, and seven fermentation periods (1, 4, 7, 14, 21, 28, and 56 days) after the ensilage. Experimental PVC silos with Bunsen valve to eliminate gas were used. The forage was compacted to obtain 550 kg/m³ of bulk density. It was used a split-plot arrangement in a complete randomized experimental design, with three replications per treatment. The addition of PCP increased the DM concentration and reduced the pH values of the silages. The concentration of NH3-N (total N) was affected by the PCP addition, and the absence of PCP resulted in silages with high N-ammonia concentration, which characterizes silages with questionable quality. The addition of PCP increased the molar concentration of the acetic and propionic acids. The enterobacteria population was detected only in the first day in the tanzaniagrass silage, and until the tenth eighth day of fermentation on the marandugrass silage. The homofermentative bacteria population was similar to the heterofermentative on the evaluated silages.
additives; bacteria; clostridium; organic acids; pH
