Chemical composition and fermentation end-products of corn silage inoculated with Lactobacillus plantarum and Bacillus subtilis in farm silos

Homofermentative lactic acid bacteria (LAB) such as Lactobacillus plantarum and Bacillus are used to rapidly decrease the pH of forage during ensilage and inhibit the action of undesirable microorganisms after opening the silo, respectively, thereby avoiding undesired fermentation. Thus, objective was to compare the chemical composition and fermentation end-products of corn silages inoculated with LAB and Bacillus subtilis in farm silos. The maize studied was hybrid 2B710 Power Core (Dow AgroSciences), harvested with dry matter (DM) content between 33 to 35%, chopped 1 cm, and silage inoculated or not (control) with Lactobacillus plantarum (LP) associated with Bacillus subtilis (BS) (1x10⁵cfu / g forage) (remained closed for 120 days). The inoculants were diluted in distilled water and sprayed on the forage 20 tons during silo filling. Silage samples were collected during feedout and were oven dried (55?C for 72 h) and ground in a knife mill to pass through a 1-mm screen and analyzed for dry matter (DM), crude protein (CP), ash, ether extract (EE), neutral detergent fiber (aNDF), acid detergent fiber (ADF) and lignin contents. Cellulose and hemicellulose were determined by differences. A water extract was made from fresh silage samples (Kung et al., 1984) to determine pH of silages, volatile fatty acids (VFA) and ammoniacal nitrogen. The experiment was developed in a completely randomized design with 15 replicates. Data of corn silages were analyzed by ANOVA using MIXED procedure of SAS (v. 9.2 SAS Institute Inc., Cary, NC). Differences among means were tested using the F test, and significance was declared at P <= 0.05. Inoculated silage had lower pH than control silage (3.74 vs 3.86). The concentrations of acetic, butyric and ammoniacal nitrogen were not changed by inoculation. Control silage showed higher values of propionic acid (1.25) compared to inoculated silage (0.31). EE, CP, aNDF, ADF, Hemicellulose, cellulose and lignin contents were not changed by the inoculation. The use of inoculants composed by association between L. plantarum and B. subtilis applied on corn silage no promote changes on the chemical composition, but improves the fermentation procces.