ANTIOXIDANT PROFILE AND BACTERIAL COMMUNITY COMPOSITION OF CORN STOVER SILAGES INOCULATED WITH FERULIC ACID ESTERASE-PRODUCING LACTOBACILLI

ANDRADA, E; MECHOUD, MA; SUAREZ, N.; ABEIJÓN MUKDSI, M.C.; MARQUEZ, A.; RUSSO, M.; LEBLANC, J.G.; MEDINA, R.

Congreso; XVIII CONGRESO DE LA SOCIEDAD ARGENTINA DE MICROBIOLOGIA GENERAL; 2023

Bacterial inoculants are frequently used to improve the fermentation quality of silages, but their impact on the bioactive compounds is still unknown. Ferulic acid esterase-producing (FAE+) lactobacilli can potentially increase the release of ferulic acid (FA) from its esterified forms in forages. FA is a well-known antioxidant compound, and evidence suggests that it can also act as a growth promoter for livestock. Metagenomic analysis applied to silages are a recent approach that allows for a better understanding of the influence of inoculants. In this work, we evaluated the effects of FAE+ lactobacilli on functional characteristics and the bacterial community composition of corn stover silages. Laboratory-scale silages were inoculated with FAE+ strains: Lactiplantibacillus (L.) plantarum CRL2241 (LP1), Lactiplantibacillus (L.) plantarum CRL046 (LP2), Lactobacillus johnsonii CRL2240 (LJ) or Levilactobacillus brevis CRL2239 (LB). The inoculation rate was 1×106 UFC g fresh matter-1, using bacterial cell suspensions. Control group (UN, uninoculated) was prepared using sterile suspension buffer. At 60 days of ensiling, total phenolic content (TPC, using Folin-Ciocalteu reagent), DPPH-scavenging activity, and free FA content (using HPLC) was determined in methanolic extracts. Total DNA was extracted from ground lyophilized samples of all groups except LP2. Amplification of the V3-V4 hypervariable region of the 16S rRNA was performed using 2x KAPA HiFi HotStart ReadyMix (Roche, USA) and standard primers (341F and 805R). Sequencing was performed in a NextSeq 550 system (Illumina, UK). TPC was reduced in LP1, LP2 and LJ silages when compared to UN (ANOVA followed by Tukey’s test, p