Abstract
Abstract: Ensiling has been known as a method to preserve the moist in crops by controlling anaerobic fermentation. If management requirements are not met, to improve silage quality, additives are often used. Inoculation of Lactobacillus in the ensiling process has been recommended in order to make good quality silage. The objective of this study was to investigate the effects of different additives of homo- and hetero-fermentative bacteria on the fermentation characteristics, microorganism content, and aerobic stability of corn (Zea mays L. cv. Xinsiyu 10) silage during aerobic conditions for silage production practice. The corn was ensiled at 4 different treatments: Control (CK) had no added inoculants; the T group (homo-fermentative bacteria) contained Lactobacillus plantarum and Pediococcus acidilactici with a ratio of 1:1, 1×105 cfu/g; the Y group (hetero-fermentative bacteria) contained Lactobacillus buchneri at 1×105 cfu/g; and the T+Y group (all of these homo- and hetero-fermentative bacteria) contained Lactobacillus plantarum, Pediococcus acidilactici and Lactobacillus buchneri with a ratio of 1:1:1, 1×105 cfu/g, and then they were fermented for 60 days. Silage samples were collected when the silos were opened for 0, 48, 96, 144, 192, and 240 h and then analyzed to determine pH value, dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), water soluble carbohydrates (WSC), lactic acid, acetic acid, and NH3-N, and the aerobic stability was evaluated by using an online multi-channel data logger temperature recorder. Microbial populations (Lactobacillus, moulds, yeast and aerobic bacteria) in the silage were also determined. The comprehensive assessment was performed for the 4 treatments through the calculation of 12 indices by a membership function analysis. The results showed that aerobic stability time in the Y and TY treatments reached 195.58 and 196.21 h, respectively, 63.87-64.67 h longer than that in the CK and T treatments in air respectively (P<0.05), and acetic acid concentrations were significantly higher than that in the CK and T treatments (P<0.05). T treatment showed the lowest pH value among the treatments, 0.5%-15.2% lower than other treatments (P<0.05), and lactic acid concentrations were significantly higher than that in the CK and Y treatments (2.4%-46.5%, P<0.05). Y treatment had the highest water soluble carbohydrates concentrations and the lowest population of moulds among the treatments (3.5%-24.5%, 4.6%-45.2% respectively; P<0.05). The NH3-N concentrations and populations of aerobic bacteria in the CK were 11.1%-43.7% and 1.2%-15.1% respectively greater than that in the T, Y, and TY treatments (P<0.05), and CO2 concentrations in CK treatment also were the highest among the treatments (P<0.05). Significant linear relationship existed between moulds, aerobic bacteria populations, and silos opening time; the relationships between CO2 concentrations, lactic acid bacteria, yeast populations and silos opening time were best described by Allometric I, ExpDec I, and Logistic equation respectively. Comprehensive evaluation was as follows: Y > TY>T>CK. Therefore, corn silage with silage addition of hetero-fermentative bacteria was better than adding silage homo-fermentative bacteria or mixed biological inoculant containing homo- and hetero-fermentative bacteria in enhancing silage fermentation quality, reducing the number of harmful microbes, and prolonging aerobic stability during the silos opening time.
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