Populações microbianas e composição química de silagem de capim-mombaça (Panicum maximum) inoculado com Streptococcus bovis isolado de rúmen

Abstract

The objective of this work was to evaluate the effects of the inoculation of two strains of Streptococcus bovis (HC5 e JB1) and of the fermentation period of silos on pH, ammonia production and development of lactic bacteria (LAB) and enterobacter (ENT) in Panicum maximum cv. Mombaça silage. The experimental design was completely randomized, assigned in factorial outline 3 × 5 (control and two inoculants and five opening periods), with tree replicates. There was effect of inoculants, fermentation period and two effects interaction, for all analyzed parameters. The ammonia values increased during fermentation period, while pH decreased, both control and inoculated silage, and in the last opening period the ammonia concentration were 10,69, 9,54 and 8,93 mg/dl and pH values were 4,46, 4,27 and 4,28, to the control, inoculated with HC5 and inoculated with JB1 treatment, respectively. The maximum value of BAL to control treatment was observed at seventh fermentation day (8,85 log UFC/g). The inoculated treatments displayed maximum values at fourteenth day with values 9,11 and 9,41 log UFC/g, to HC5 and JB1, respectively. The inoculation increased dry matter and crude protein content of silages. The inoculation with Streptococcus bovis HC5 and JB1 reduces the pH values and decreased the ammonia concentration, beyond favoring development of lactic bacteria, in detriment of enterobacter, improving nutritional value of mombaça-grass silage.