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

ANDRADA, ESTEFANÍA; MECHOUD, MÓNICA ; SUÁREZ, NADIA ELINA; ABEIJÓN MUKDSI, MARÍA CLAUDIA; MÁRQUEZ, ANTONELA; RUSSO, MATÍAS; LEBLANC, JEAN GUY; MEDINA, ROXANA BEATRIZ

Chapadmalal

Congreso; XVIII Congreso de la Sociedad Argentina de Microbiología General; 2023

Sociedad Argentina de Microbiología General

Bacterial inoculants are frequently used to improve the fermentation quality of silages, but their impact on the bioactive compounds’ content 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 it can also act as a growth promoter for livestock. Metagenomic analysis applied to silages is a recent approach that allows a better understanding of the ensiling process and the efficacy of its modulation through microbial additives. 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 CFU g fresh matter-1, using bacterial cell suspensions. The control group (UN, uninoculated) was prepared using a 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 in comparison to UN (ANOVA followed by Tukey’s test, p