Whole plant soybean (WPS) is a kind of legume resource with characteristics of high nutrition, large biomass, and wide distribution. In the present study, we have investigated the feasibility and effects of gallic acid (GA) on WPS silage quality, nitrogen distribution, tannin content, and bacterial community. The 0.5 and 1% (fresh matter basis) GA were added into WPS for dynamic ensiling (days 3, 7, 14, and 30, respectively). The results showed that the WPS silage with GA addition significantly decreased pH value (6.16–5.38 at ensiling day 30), coliform bacteria count and butyric acid (65.3–62.0 g/kg dry matter at ensiling day 30), and amino nitrogen contents (259–88.2 g/kg total nitrogen at ensiling day 30) and promoted lactic acid (9.62–31.5 g/kg dry matter at ensiling day 30), acetic acid (24.1–85.6 g/kg dry matter at ensiling day 30), and tannin (total phenol and hydrolyzable tannin) contents. Additionally, the GA addition also contributed to the change of bacterial community, where Firmicutes and Lactobacillus were most abundant on phylum and genus levels, respectively. The above results suggested that GA additive applied in WPS silage was an effective strategy to protect nutrition and improve fermentation quality, and the 1% GA addition showed a better effect.

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Some excellent legume forages are difficult to ensile naturally due to their high buffering capacity and low water-soluble carbohydrate content. This may cause serious problems like proteolysis. In the present study, strains of lactic acid bacteria with high acid productivity and high tannin tolerance were screened from different silages and combined with tannic acid (TA) as an addition to ensiling. The screened strains were identified as Lactobacillus plantarum (LP), with four of these strains then selected for their high tannin tolerance. Stylosanthes guianensis and whole-plant soybean (WPS) were ensiled with 1 and 2% (fresh matter basis) TA, four LP strains alone (6 log10 colony forming units per gram of fresh matter), or TA combined with LP strains. Fermentation parameters and in vitro rumen fermentation characteristics were analyzed after 30 days of fermentation. The results showed that TA + LP can be used to reduce pH values (P < 0.01), non-protein nitrogen (P < 0.01), and ammonia-nitrogen (P < 0.01). The in vitro crude protein digestibility of WPS silage was also decreased with the addition of TA + LP (P < 0.01). These results indicate that the addition of TA combined with tannin tolerance LP strains may improve the fermentation quality of legume silage, especially for reducing proteolysis.

N. cadamba leaves, a byproduct of wood production, are always discarded in the field. N. cadamba leaves have strong antibacterial property, which might be recycled to inhibit undesirable bacteria and enhance the fermentation quality of silage. Ensiling, a traditional conservation method for animal feed, is commonly used all over the world. It is known that high-moisture forages, especially legumes, are difficult to ensile directly as much ammonia-N and butyric acid produced by undesirable bacteria will reduce the feeding value. To investigate the effects of N. cadamba leaf meal on the fermentation quality of stylo silage, 5% and 10% N. cadamba leaf meal were mixed with stylo for 30 days of ensiling in two independent experiments. Results showed that the silage pH and butyric acid content of stylo silage were decreased (p < 0.01) by 10% N. cadamba leaf meal. In experiment 2, contents of nonprotein-N and ammonia-N were significantly decreased (p < 0.05), while the true protein content was significantly increased (p < 0.05). The same results on the changing tendency were also obtained in experiment 1. In addition, N. cadamba leaf meal addition also decreased the bacterial diversity. The relative abundance of Clostridium and Lelliottia decreased, whereas that of Lactobacillus increased when N. cadamba leaf meal was added. It is worth noting that the addition of N. cadamba leaf meal also improved the antioxidant activity of stylo silage. The aforementioned results suggested that mixing N. cadamba leaf meal to high moisture forages could be an effective strategy to enhance silage fermentation quality, and it is also a feasible way to recycle N. cadamba leaves.

Antibiotic resistance genes (ARGs) are considered environmental pollutants posing a potential human health risk. Silage is an important and traditional feed, mainly for ruminants.

Broussonetia papyrifera has increasingly been used as a high-quality feedstuff for ruminants due to its advantageous characteristics. The storage temperature can influence the fermentation quality of silage; however, the effect of temperature on B. papyrifera leaves (BPL) silage has not been reported. In the present study, the fermentation quality and bacterial community of BPL, stored at 15 °C and 30 °C, were investigated during ensiling (day 3, 7, 14, 30) with or without Lactobacillus plantarum strain (LP) added. The pH and the coliform bacteria counts were significantly lower in silage stored at 30 than 15 °C (p < 0.01), while the lactic acid content increased significantly (p < 0.05). Adding LP decreased the dry matter loss, pH, coliform bacteria count, and ammonia-N and butyric acid contents at 30 °C. The relative abundance of Lactobacillus increased, while the bacterial diversity decreased in the silage stored at 30 °C when LP was added. During silage, the high abundance of Lactobacillus decreased gas and carbon dioxide (CO2) production, and the lowest gas and CO2 production were detected in silage stored at 30 °C when LP was added. In conclusion, adding LP and storing it at 30 °C could effectively improve the quality of BPL silage.

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This article intends to improve the recycling of waste sugarcane (Saccharum officinarum) tops and the value-added utilization of pyroligneous acid. Fresh sugarcane tops can be used by ruminants, but they are prone to dehydration and mildew during storage, reducing their feeding value. Pyroligneous acid, a by-product in the process of making biochar, has good antibacterial effects. Adding pyroligneous acid to sugarcane tops for silage fermentation may be an effective way to promote the recycling of sugarcane tops. Thus, the fermentation quality and bacterial community of sugarcane tops ensiled with or without 1–2% pyroligneous acid for 5, 10, 20, or 100 days were investigated. Results showed that pyroligneous acid increased the acetic acid content and reduced ammonia-N concentration, and numbers of coliform bacteria and molds in sugarcane tops silages. On the other hand, the addition of pyroligneous acid decreased the diversity of bacteria in sugarcane-top silage. Pyroligneous acid decreased Firmicutes and Leuconostoc relative abundances while increasing Lactobacillus relative abundances. Fermentation was also limited by the addition of pyroligneous acid, which reduced metabolic activities during ensiling. Graphical abstract