Exploring the Addition of Herbal Residues on Fermentation Quality, Bacterial Communities, and Ruminal Greenhouse Gas Emissions of Paper Mulberry Silage

Effect of storage time on the silage quality and microbial community of mixed maize and faba bean in the Qinghai-Tibet Plateau

Tibetan Plateau is facing serious shortage of forage in winter and spring season due to its special geographical location. Utilization of forages is useful to alleviate the forage shortage in winter and spring season. Consequently, the current study was aimed to evaluate the influence of storage time on the silage quality and microbial community of the maize (Zea mays L.) and faba bean (Vicia faba L.) mixed silage at Qinghai-Tibet Plateau. Maize and faba bean were ensiled with a fresh weight ratio of 7:3, followed by 30, 60, 90, and 120 days of ensiling. The results showed the pH value of mixed silage was below 4.2 at all fermentation days. The LA (lactic acid) content slightly fluctuated with the extension of fermentation time, with 33.76 g/kg DM at 90 days of ensiling. The AA (acetic acid) and NH₃-N/TN (ammonium nitrogen/total nitrogen) contents increased with the extension of fermentation time and no significantly different between 90 and 120 days. The CP (crude protein) and WSC (water soluble carbohydrate) contents of mixed silage decreased significantly (P < 0.05) with ensiling time, but the WSC content remained stable at 90 days. The Proteobacteria was the predominant phyla in fresh maize and faba bean, and Pseudomonas and Sphingomonas were the predominant genera. After ensiling, Lactobacillus was the prevalent genus at all ensiling days. The relative abundance of Lactococcus increased rapidly at 90 days of ensiling until 120 days of fermentation. Overall, the storage time significant influenced the silage fermentation quality, nutrient content, and microbial environment, and it remained stable for 90 days of ensiling at Qinghai-Tibet Plateau. Therefore, the recommended storage time of forage is 90 days in Qinghai-Tibet Plateau and other cool areas.

Effects of growth stage on the fermentation quality, microbial community, and metabolomic properties of Italian ryegrass (Lolium multiflorum Lam.) silage

Introduction

This study aimed to investigate the effects of different growth stages (booting period-SYK; initial flowering-SCK; full flowering-SSK) on the fermentation quality, microbial community, metabolic pathways and metabolomic characteristics of Italian ryegrass silage.

Methods

Single molecule real-time (SMRT) sequencing and ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS/MS) were used to analyze bacterial communities and metabolites, respectively.

Results

After 60 d of fermentation, SYK had the lowest pH and the highest lactic acid content, which were significantly different from the other groups. The bacteria with the highest abundance in SYK, SCK and SSK groups were Lactiplantibacillus plantarum (63.98%), Weissella minor (28.82%) and Levilactobacillus brevis (64.81%), respectively. In addition, among the main differential metabolites in different growth stages, the number of amino acids was the most, and the corresponding metabolic pathways were mainly amino acid metabolic pathways. The biosynthesis of phenylalanine, tyrosine and tryptophan was significantly enriched (p<0.01) at booting stage and full flowering stage. Purine metabolism and ABC transporter pathway were significantly enriched at the initial flowering (p<0.001). Lactiplantibacillus plantarum had a negative correlation with xanthine and ganoderic acid F. Weissella minor had a positive correlation with D-Mannose and ganoderic acid F. Levilactobacillus brevis had a positive correlation with xanthine, and Latilactobacillus sakei had a positive correlation with cinnamic acid, D-Mannose, 2-Hydroxycinnamic acid and uridine.

Discussion

In conclusion, this study reveals the interaction mechanisms between ryegrass raw materials at different growth stages and epiphytic microorganisms during ensiling fermentation, providing new ideas for screening functional lactic acid bacteria, and laying a theoretical foundation for the production of safe and high-quality silage.

Perilla frutescens as potential antimicrobial modifier to against forage oat silage spoilage

The aim of this study was to investigate the influence of Perilla frutescens, alone or in combination with Lactobacillus plantarum a214 or citric acid, on forage oat silage quality, bacterial and fungal microbiological profile during ensiling and aerobic exposure. With the exception of Perilla frutescens, all additives could improve silage quality of forage oat based on lower ammonia-nitrogen content and higher residual of water soluble carbohydrates during anaerobic fermentation compared to control silage, especially in Perilla frutescens combined with citric acid (CAPF). Lactobacillus was the dominant bacteria in all silages, while CAPF group increased the relative abundance of Lactobacillus lindneri and Lactobacillus brevis compared to control silage. The application of Perilla frutescens suppressed the relative abundance of yeasts such as Pichia fermentans and Wickerhamomyces anomalus in response to aerobic exposure, especially in CAPF treatment, leading to high acetic acids and lower dry matter loss, as well as good aerobic stability. Therefore, Perilla frutescens, alone or in combination with citric acid, has potential to improve aerobic stability of forage oat silage by shifting bacterial and fungal community composition, and can be used as new additive to prepare high-quality silage for animal production.

Effects of Lactobacillus plantarum on Fermentation Quality and Anti-Nutritional Factors of Paper Mulberry Silage

There are few studies on the application of lactic acid bacteria in the reduction of anti-nutrient factors in paper mulberry silage. This study aimed to investigate the effects of different lactic acid bacteria on the fermentation quality and the amount of anti-nutritional factors in paper mulberry silage. Two strains of Lactobacillus plantarum (GX, isolated from paper mulberry silage; GZ, provided by Sichuan Gaofuji Biotechnology Co. Ltd.) were added as silage additives. On days 7, 15, 30 and 60 of the ensiling process, the fermentation quality, and the amount of anti-nutritional factors were measured. Compared with the control group, inoculation with Lactobacillus plantarum could rapidly reduce pH values, leading to lower NH3-N/TN. Besides, it also significantly increased the lactic acid content (p < 0.05). The two strains of L. plantarum significantly reduced the content of hydrolysed tannin, condensed tannin, total tannin, oxalic acid, phytic acid and saponin (p < 0.05). Overall, this study found that the addition of lactic acid bacteria could significantly improve the fermentation quality of paper mulberry and reduce the amount of anti-nutrient factors (p < 0.05).