Do regrowth age and microbial inoculant usage affect the microbial diversity and fermentation characteristics of forage peanut silage?

Abstract

This study evaluated the fermentation characteristics, microbial diversity, chemical composition, and in vitro digestibility of forage peanut silage harvested at two regrowth ages and treated with microbial inoculants at different fermentation periods. A randomized block design was used, with two regrowth ages (R; 40 and 80 days), three microbial inoculants (I; control without inoculant [CTRL], strain AV14.17—Lactiplantibacillus pentosus strain AV14.17 [ISO], and commercial inoculant [CI] Sil-All 4 × 4 (Lallemand Animal Nutrition®, Patos de Minas-MG, Brazil), and four storage time (ST; 3, 14, 30, and 60 days after ensiling) arranged in a 2 × 3 × 4 factorial scheme, with four replications. The R × I × ST interaction had a significant effect (p ≤ .05) on the ammoniacal nitrogen content in relation to total nitrogen (NH₃-N/ total N) and on the yeast population. The I × ST interaction also had a significant effect (p ≤ .05) on pH, soluble carbohydrate, NH₃-N/total N, lactic acid bacteria, yeast, and filamentous fungi. Inoculated silages with ISO and CI showed lower pH and NH₃-N/total N values, as well as lower abundance of enterobacteria, yeast, and filamentous fungi. In silages inoculated with ISO, the relative abundance of genus Lactiplantibacillus was high and that of genus Enterobacter was low. Silages inoculated with ISO and CI showed predominance of the family Lactobacillaceae. The data support the recommendation to ensile forage peanut at both regrowth ages (40 and 80 days) associated with microbial inoculant application to promote improvements in the fermentation characteristics of the silage and a greater abundance of genus Lactiplantibacillus.