0649 The effect of a microbial inoculant at two application rates on the aerobic stability of high-moisture corn

The purpose of this study was to evaluate the effect of a microbial inoculant at two application rates on the fermentation and aerobic stability of high-moisture corn (HMC). High-moisture corn (74% DM) was 1) untreated (control), 2) treated with Lactobacillus buchneri (NCIMB 30139) at an application rate of 400,000 cfu/g of fresh material (LB400), or 3) treated with L. buchneri (NCIMB 30139) at a rate of 600,000 cfu/g of fresh material (LB600). The inoculant was supplied by Volac Intl., Ltd., United Kingdom. Five replicated lab silos (7.5 L) for each treatment were packed (density of 658 kg DM/m3) and ensiled for 30 and 92 d between 21 and 23°C. Data were analyzed as a 3 × 2 factorial arrangement of treatments with the main effects of treatment, day, and their interaction. High-moisture corn was analyzed for fermentation end products, number of yeasts, and aerobic stability. At 92 d, the pH of LB400 and LB600 (4.48 and 4.47) was higher (P < 0.01) than that of control (4.33). All treatments had similar concentrations of lactic acid at 30 d, but by 92 d, lactic acid concentrations decreased (P < 0.01) in LB400 and LB600 (0.36 and 0.41%) compared with untreated HMC (0.58%). At 30 d, treatment with LB400 and LB600 (0.36 and 0.30%) had higher (P < 0.01) concentrations of acetic acid compared with control (0.05%). At 92 d, untreated HMC (0.15%) had lower (P < 0.01) concentrations of acetic acid than LB400 and LB600 (0.79 and 0.86%). Treatment with LB400 and LB600 (0.32 to 0.55%) increased (P < 0.01) 1,2-propanediol concentrations compared with untreated HMC (0.00 to 0.09%) at both 30 and 92 d. At both ensiling times, HMC treated with LB400 and LB600 (<2.00 to 2.97 log cfu/g) had fewer (P < 0.01) yeasts than control HMC (4.04 to 5.93 log cfu/g). At 30 and 92 d, treatment with LB400 and LB600 (>217 h) greatly increased (P < 0.01) aerobic stability compared with untreated HMC (16 to 56 h). This experiment showed that inoculation with L. buchneri (NCIMB 30139) can improve the fermentation characteristics and the aerobic stability of HMC.