Novel lactic acid bacteria strains enhance the conservation of elephant grass silage cv. BRS Capiaçu

Abstract

Elephant grass ensilage might result in high dry matter (DM) loss and a reduction in feed quality. Knowledge of microbiota and the use of specific microbial inoculants can reduce DM losses and result in better fermentations and final products. The aim of the study was to characterise lactic acid bacteria (LAB) from elephant grass silages and subsequently select the promising strains to be used as microbial inoculants. Eighty-six LAB strains isolated from silages (7 from corn, 14 from sugarcane and 65 from elephant grass silages) were characterised and evaluated. Thirteen strains that showed the highest growth, pH reduction, production of interest metabolites and the ability to inhibit undesirable microorganisms and the strain L. hilgardii CCMA 0170 were evaluated in experimental silos. The aerobic stability, fermentative profile and microbial population of elephant grass silages of BRS Capiaçu cultivar were evaluated after 60 days of storage. No LAB was found in elephant grass before ensiling. The elephant grass silage fermentation was characterised by the succession of Lactobacillus sakei, L. plantarum group, Pediococcus pentosaceus and L. brevis. The silages inoculated with CCMA 0170 (L. hilgardii) CCMA 1394 and CCMA 1402 (L. plantarum), CCMA 1409 (L. brevis), CCMA 1363 and CCMA 1364 (L. farraginis) showed the smallest DM loss (mean of 38 g/kg of ensiled vs. 123 g/kg in control silage) and high aerobic stability (mean of 33.1 h vs. 21.2 h in control silage). Among the tested strains, the CCMA 1364 strain stands out as resulting in silages with low yeast populations, undetectable levels of butyric acid and high aerobic stability. Our results highlight the importance of the research and evaluation of new strains adapted to the fermentative process of each forage.