PSXIII-26 Effects of Lentilactobacillus lactis and Lentilactobacillus buchneri on fermentation and aerobic stability in corn grain silages

Abstract

Abstract The inclusion of corn grain silages (early-harvest and reconstitute grain) in the diets has gained wide acceptance in the last decade among Brazilian farms. Thus, reducing losses in these silages is one of the main goals. The objective of this study was to evaluate the effects of an inoculant containing Lentilactobacillus lactis O224 and Lentilactobacillus buchneri LB1819 on fermentation, microbial counts, and aerobic stability in reconstituted corn grain (RCG) and high-moisture corn (HMC). Two experiments were carried out, which tested the inclusion of no additive (CON) and the addition of L. lactis and L. buchneri. For both trials, the inoculant was added at a theoretical rate of 1.5 x 105 CFU/g of feed. For HMC, corn kernels (30.1% of moisture) were processed and ensiled in 5-L jars for 44 or 64 d. For RCG, corn kernels were purchased at 14% moisture, ground, and water was added to reach 35% moisture. Afterwards, ground kernels were ensiled in 5-L jars for 21 or 42 d. Measurements included fermentation end-products (acids, alcohols, and NH3-N), microbial counts (LAB, yeasts, and molds), and aerobic stability. Both trials were set up as a completely randomized design using a 2 x 2 factorial arrangement. Data were analyzed using MIXED procedure of SAS, followed by a Tukey test at P ≤ 0.05. In both experiments, inoculated silages had reduced concentrations of lactic acid and greater concentrations of acetic acid and 1,2-propanediol. These three fermentation end products increased over time for both treatments. In HMC, there was an interaction between inoculation and time of conservation for propionic acid concentrations. Also, the concentration of NH3-N was greater in treated silages. In both experiments, the population of LAB was greater in inoculated silages. For RCG, yeast population was greater in CON treatment. During aerobic exposure, treated silages remained more stable in both trials. In HMC, the aerobic stability was > 240 h for treated silages, whereas CON silages had 94 h of stability. Still in HMC, the peaks of temperature were 39.5 and 28.2 oC and the pH values (after 10 d of aerobic exposure) were 6.81 and 4.38 for CON and inoculated silages, respectively. In RCG, the aerobic stability was more pronounced at 42 d of conservation (35 vs 66 h for CON and inoculated silages, respectively). Overall, the combination of L. lactis and L. buchneri modulates corn grain silages fermentation and improves aerobic stability.