The aim of this study was to reveal the reconstitution dynamics of alfalfa microbiota and their contribution to the fermentation quality of Napier grass silages. Napier grass was harvested at approximately 20% dry matter content, chopped to a theoretical length of cut of 2 to 3 cm, and ensiled in laboratory polyethylene plastic bags (400 × 250 mm) for 30 d. The Napier grass was treated with the following: natural fermentation and distilled water (NG), inoculum of alfalfa microbiota (AM), gamma-ray irradiation and distilled water (IR), and gamma-ray radiation and alfalfa microbiota (IR+AM). Three milliliters of inoculum (containing 8.93 log cfu/mL lactic acid bacteria, 9.76 log cfu/mL Enterobacteriaceae, 5.94 log cfu/mL yeast, and 6.53 log cfu/mL mold) eluted from equivalent fresh alfalfa (450 g) was added to each silo of AM and IR+AM treatments, and 3 mL of distilled water was added to the silo of the NG and IR treatments. Three triplicate silos per treatment were opened on d 1, 3, 5, 7, 14, and 30 for sampling and analysis of fermentation quality and bacterial community. Relative to the NG silages, IR+AM silages exhibited a higher lactic acid concentration. The higher acetic acid concentration in NG than in IR+AM silages after 7 d of ensiling was attributed to the dominant genus of Leuconostoc (64.29-49.04%). Adding alfalfa microbiota to sterile Napier grass could increase ammonia-N concentration compared with NG and IR silages after 3 d of ensiling. Leuconostoc was the most predominant genus in NG silages, followed by Lactobacillus. Pediococcus had a greater relative abundance than the indigenous microorganisms and was exclusively found in AM and IR+AM silages, whereas Lactobacillus exhibited a slight increase after 30 d of ensiling (relative abundance in each silage: 6.29 vs. 3.82%, respectively). Lactobacillus was the predominant genus in IR silages since the onset of the ensiling. These results suggest that alfalfa microbiota affected bacterial community succession in Napier grass silages, which in turn affected the fermentation products. Adding alfalfa microbiota to sterile Napier grass could decrease acetic acid concentration compared with NG silages; however, it increased ammonia-N concentration compared with IR silages after 3 d of ensiling.

This study aims to evaluate the fermentation characteristics of Lactobacillus plantarum and Pediococcus spp isolated from sweet sorghum silage to enhance the fermentation quality of Napier grass and sweet sorghum silage. Based on molecular 16S ribosomal ribonucleic identification the isolated strains were phylogenetically related to Lactobacillus plantarum (HY1), Pediococcus acidilactici (HY2) and Pediococcus claussenii (HY3). Strains HY1, HY2 and HY3 and commercial bacteria Lactobacillus plantarum, Ecosyl; (MTD\1( were ensiled with sweet sorghum and Napier grass and the non-inoculated grasses, have been arranged in a completely randomized experimental design in a 5 (inoculants) × 3 (ensiling periods). In both grasses, the fermentation characteristics chemical composition and microbial population were assessed at 5–30 and 90 days of ensiling. The results showed that the effect of addition inoculants significantly reduced (p < 0.05) the pH, ammonia-N, acetic acid and undesirable microbial population and increased (p < 0.05) lactic acid and lactic acid bacteria counting when compared to the control. The effect of ensiling days on silage quality through the increasing lactic acid, acetic acid, ammonia-N, propionic acid and butyric acid whereas decreasing pH and water-soluble carbohydrates and microbial counts. In both sweet sorghum and Napier silage treated with isolated strains showed the best results in silage quality. The HY3 belongs to Pediococcus claussenii was not extensively studied in silage but it has shown good fermentation quality which strongly recommended to apply as probiotic.

This study was conducted to evaluate the effect of lactic acid bacteria (LAB) on fermentation quality, mycotoxin concentrations, and microbial communities of whole-crop corn silages infested with mycotoxigenic fungi. Cultured spores (10⁶ cfu/mL) of mycotoxigenic Aspergillus flavus and Fusarium graminearum were sprayed (5 mL) on corn forage on 27 July and 10 August 2018. On 21 August 2018, sprayed (FI; 3 plots) and unsprayed (NFI; 3 plots) corn forage were harvested at the 1/2 kernel milk line stage, followed by chopping and ensiling without inoculants (CON), or with Lactobacillus buchneri (LB, 1 × 10⁶ cfu/g FW), Lactobacillus plantarum (LT, 1 × 10⁶ cfu/g FW), or L. buchneri + L. plantarum (BT: both L. buchneri and L. plantarum applied at 0.5 × 10⁶ cfu/g FW). After 90 d of ensiling, FI silages had a higher (p < 0.05) pH value and higher acetic acid (ACA), ethanol, and ammonia nitrogen (ammonia N) concentrations, but lower (p < 0.05) lactic acid (LA) concentrations than NFI silage. The inoculants decreased pH and increased LA concentration and LA/ACA compared with CON. The aflatoxin B₁ (AFB₁) was only detected in FI fresh corn and silages; ensiling decreased (p < 0.05) AFB₁ concentration compared with fresh corn, and LB and BT decreased AFB₁ concentration compared with CON. The zearalenone (ZEN), deoxynivalenol (DON), and fumonisin B₁ (FB₁) concentrations were similar (p < 0.05) for NFI silages, while ZEN concentration in BT was the lowest (p < 0.05) among all FI silages; DON and FB₁ concentrations in LB, LT, and BT silages were significantly lower (p < 0.05) than those of CON in FI silages. The fungal infestation increased the bacterial and fungal diversity of silages compared with NFI silages. The FI silages had a higher relative abundance (RA) of Lactobacillus, Weissella, Wickerhamomyces, Pichia, and Epicoccum than the corresponding NFI silages. The RA of Aspergillus and Fusarium markedly decreased after 90 d of ensiling, and the inoculation expanded this trend irrespective of fungal infestation. The Penicillium in FI silages survived after 90 d of ensiling, while the inoculants decreased the RA of Penicillium. Inoculants mitigate the adverse effects of fungal infestation on corn silage quality by changing the bacterial and fungal communities.