Cutting management and inoculants alter the fermentative profile and quality of elephant grass silage cultivar BRS Capiaçu

Abstract

BRS Capiaçu elephant grass stands out for its high yield and forage quality, being a great option to produce silages, but undesirable fermentations are common in this forage that can be avoided by adjusting the DM concentration or the use of inoculants. The aim of this study was to evaluate the effect of new inoculants on silages of elephant grass cultivar BRS Capiaçu with different DM concentrations and different storage times. Elephant grass was ensiled with two different DM concentrations called: low DM (90 days of regrowth) and high DM (110 days of regrowth) and inoculated with the strains CCMA 1394 – Lactiplantibacillus plantarum (LP), CCMA 0170 – Lentilactobacillus hilgardii (LH), and their combination (LP + LH). These strains were selected for reducing DM losses and increasing the aerobic stability of elephant grass silage. Fermentative profile, lactic acid bacteria (LAB) count, yeast, filamentous fungi, enterobacteria, aerobic spore-forming bacteria (EASFB) and mesophilic microorganisms, particle distribution, aerobic stability and metataxonomic analysis of silages with 62 and 104 days of storage were evaluated. The forage harvested with low DM had a DM concentration of 167.7 g.kg -1 of fresh matter (FM) and the forage harvested with high DM had

a DM concentration of 242.6 g.kg -1 of FM. The forage with high DM showed higher

concentrations of acetic acid and neutral detergent fiber (NDF), lower concentrations of water- soluble carbohydrates (WAC) and higher population of microorganisms evaluated. All

inoculants reduced the population of undesirable microorganisms in the silages, although they didn’t reduce the pH of the silage in relation to the control. The LH and LP + LH inoculants stood out for reducing the DM losses of silages with low DM (32.3 and 21.7 g kg-1 DM, respectively), reducing the ethanol concentration after 104 days of ensiling (6 .01 and 3.36 g kg-1 DM, respectively), reduce the yeast population with 62 days of storage (2.44 and 2.12 log CFU.g-1 , respectively) and increase the aerobic stability in the silage with high DM after 62 days of ensiling (45.75 and 45.50 h, respectively). Silages with low DM had the lowest DM losses (mean of 53.0 g.kg-1

vs 70.9 g kg-1 DM of silage with high DM), higher production of lactic acid (mean of 64.06 g.kg-1 DM vs 28.76 g.kg-1 DM of silage with high DM) and lower pH values (4.55 vs 4.73 of silage with high DM). Storage time affected the fermentative profile, microbial population and particle distribution of silages. The prokaryotic community profile differed in silages with different DM concentrations. The CCMA 0170 strain is promising for use as an inoculant in silages of elephant grass BRS Capiaçu. Due to the better fermentative profile presented, it is recommended to ensile forage with low DM.