Fermentation profile, chemical composition and microbial population in silages of Stylosanthes Campo Grande with microbial inoculant and pelletized citrus pulp
We evaluated the chemical composition, fermentation profile and microbial population of silages of Stylosanthes cv. Campo Grande with and without microbial inoculant and different levels of pelletized citrus pulp (0, 3, 6, 9 and 12% fresh forage basis), in different fermentation periods. The plant was harvested at 120 days after sowing, in the flowering stage. Subsequently, this material was chopped in a stationary forage machine and the combinations between the treatments were applied. Treated forages were packed in bag silos that were vacuumed to remove air, heat-sealed, and stored for 1, 3, 7, 14, 28 and 56 d. The microbial inoculant utilized was Sil All C4 (Alltech, Brazil), containing <i>Lactobacillus plantarum</i>, <i>Pediococcus acidilactici<i>, <i>L. salivarius</i> and <i>Enterococcus faecium</i>, at a rate of 1 × 10 <sup>5 </sup> cfu/g fresh forage basis. Data were analyzed by analysis of variance as a 5 × 2 × 6 factorial arrangement of treatments with main effects of pelletized citrus pulp (PCP), the presence or absence of inoculant (I), time of ensiling (T) and their interaction, using the procedure MIXED of SAS software, version 9.1. The DM content increased linearly (P < 0.05) as the PCP levels were increased. The PCP × I interaction had an effect (P < 0.05) on the CP content, with highest values observed in the inoculated silages. Interactions PCP × I and PCP × T affected (P < 0.05) the NH<sub>3</sub>-N content of silages. The pH and the concentrations of lactic, acetic, propionic and butyric acids were affected (P < 0.05) by the PC × I × T interaction. Maximum population of lactic acid bacteria (9.59 cfu/g) was recorded on the first day of fermentation in the non-inoculated silage, whose population decreased linearly over the fermentation period (P < 0.05). The population of enterobacteria was greater on the first day after ensiling, but from the fourth day its presence was not detected in all treatments. Interactions PCP × I and PCP × T affected the CP content of the silages, whereas the NDF and ADF levels of the silages were only affected (P < 0.05) by the PCP levels. Addition of inoculant and pelletized citrus pulp to Stylosanthes at ensiling increases lactic fermentation and restrict the butyric fermentation, providing better quality silage.
Sponsored by FAPEMIG, CNPq and INCT-CA
acetic acid, lactic acid, lactic acid bacteria