Effect of Lactobacillus buchneri and sodium benzoate on the fermentative profile, bacterial taxonomic diversity, and aerobic stability of sorghum silages at different fermentation times

The combined use of a microbial additive and a chemical additive in sorghum (Sorghum bicolor (L.) Moench) silages would reduce fermentation losses, favoring aerobic stability by modulating a favorable microbiome to control those losses. The purpose of this study was to evaluate the action of Lactobacillus buchneri and sodium benzoate on the fermentative profile, bacterial taxonomic diversity and aerobic stability of sorghum silages at different fermentation times. A completely randomized experimental design was adopted in a 4 × 4 factorial scheme, in order to evaluate four additives in sorghum silage (Control treatment, L. buchneri, sodium benzoate and L. buchneri combined with sodium benzoate) and four opening times (30, 60, 90 and 120 d fermentation), in five replicates. Silages inoculated with sodium benzoate showed higher pH values (3.70) at 90 d of fermentation, not differing (P > 0.05) from control (CTR) silage and the other silages. The largest lactic acid bacteria populations were observed at 120 d of fermentation in the silages inoculated with L. buchneri (9.06) followed by the silages inoculated with sodium benzoate and with the combination L. buchneri + sodium benzoate (8.37 and 8.85 log CFU, respectively) at 90 d of fermentation. For gas losses, in which silage treated with sodium benzoate showed lower values, with an average of 0.72% DM. The silages presenting a high DMR standard, ranging from 94.6% to 98.0%, with the exception of the CTR silages. Silages treated with L. buchneri showed higher values (98%) for the occurrence of the genus Lactobacillus in both fermentation times. The combined action of L. buchneri and sodium benzoate kept the Lactobacillus population stable at 30 and 120 d of fermentation. The combination of L. buchneri and sodium benzoate improved the fermentative profile and chemical composition of sorghum silages, reducing losses and increasing aerobic stability after 120 d of fermentation.