Lactic acid bacteria (LAB) have been proposed for the control of undesirable fermentation and, subsequently, aerobic deterioration due to their ability to produce antimicrobial metabolites in silage mass. To investigate the effect of specific LAB on the silage fermentation characteristics and bacterial community composition of oat in cold regions, silages were treated without (control) or with three LAB strains (LB, Lentilactobacillus buchneri; nLP, low temperature tolerant Lactiplantibacillus plantarum; pLP, phenyllactic acid-producing Lactiplantibacillus plantarum), and then stored at ambient temperature (−2.63 ± 5.47–14.29 ± 5.48 °C) for 30, 60, and 90 days. Compared with control, inoculation of LAB decreased the final pH value, butyric acid content, ammonia-N of total N and dry matter loss of silage. Treatments with nLP and pLP increased (p < 0.05) lactic acid content, whereas LB increased (p < 0.05) acetic acid content of silage. Lactiplantibacillus and Leuconostoc dominated in the silages with relative abundance of 68.29–96.63%. A prolonged storage period enhanced the growth of Leuconostoc in pLP-treated silage. In addition, pLP increased (p < 0.05) the aerobic stability of silage as compared with nLP. In conclusion, inoculation of LAB improved silage fermentation and/or delayed aerobic deterioration by shifting bacterial community composition during ensiling. Phenyllactic acid-producing Lactiplantibacillusplantarum as an inoculant exhibited potential for high quality silage production.

A total of 30 Simmental crossbred cattle (6.50 months old, 265.0 ± 22.48 kg) were randomly divided into three groups, with 10 heads per group, and fed for 45 days. The diet treatments consisted of the Control group without PFDG supplementation, the PFDG-15% group with 15% PFDG substituting for 15% concentrate, and PFDG-30% group with 30% PFDG substituting for 30% concentrate. The results showed that compared with the Control group, the average daily gain (ADG) of the cattle in the PFDG-30% group decreased significantly (0.890 vs. 0.768 kg/d, p = 0.005). The serum malondialdehyde content of cattle in the PFDG-15% and PFDG-30% groups decreased significantly (p = 0.047) compared to that of the Control group. However, the serum superoxide dismutase activity of cattle in the PFDG-30% group was significantly higher than that of the Control group (p = 0.047). Meanwhile, both the PFDG-15% and PFDG-30% groups (1758.47 vs. 2061.30 μg/mL) showed higher serum levels of immunoglobulin G, while the interleukin-10 concentration was lower in the PFDG-30% group (p = 0.027). In addition, the PFDG-15% and PFDG-30% groups shifted the rumen microbiota by improving the abundances of F082 (related to propionic acid production) and fiber-degrading bacteria (Lachnospiraceae_UGG-009 and Prevotellaceae_UCG-001) and reducing the abundance of the disease-associated bacteria Selenomonas. A Kyoto encyclopedia of genes and genomes (KEGG) analysis illustrated that three key metabolic pathways, including phenylalanine metabolism, pyrimidine metabolism, and tryptophan metabolism, were enriched in the PFDG-15% group, but eight key metabolic pathways, including arachidonic acid metabolism, were enriched in the PFDG-30% group. Importantly, both the PFDG-15% and PFDG-30% groups increased (p < 0.01) the activities of cellulase, lipase, and protease in the rumen. Finally, the different bacterial abundance in the rumen was associated with changes in the ADG, serum antioxidant capacity, immune status, rumen enzyme activity, and metabolites. These results suggest that PFDG alters rumen microbiome abundance, metabolome, and enzyme activity for enhancing serum antioxidant capacity and the immune status, but when the supplemental level reaches 30%, it has a negative effect on ADG and the anti-inflammatory factors in finishing cattle.

Broussonetia papyrifera L. (paper mulberry) is an alternative woody plant, which can used to replace part of the protein feed for ruminants. Ensiling is an effective way to preserve fresh pasture and to solve the problem of stable storage and feed conversion of paper mulberry in the rapid growth period. However, low dry matter (DM), water-soluble carbohydrate, and lactic acid bacteria (LAB) reduce the quality of paper mulberry silage. This study assesses the influence of wilting time (0 h and 3.5 h; lighting: 3.43 × 10⁴ Lux) and three additives (Enterococcus durans, CL; cellulase, CE; and formic acid, FA) on the fermentation quality, aerobic stability, and bacterial community of whole plant B. papyrifera silage. The whole plant B. papyrifera sample was mowed and wilted for 0 h and 3.5 h, and then had CL, CE, or FA added, followed by 60 days of ensiling. The results show all silage samples had high fermentation quality with pH below 4.2, ammonia-nitrogen below 100 g/kg DM, and no detectable butyric acid. The additives protected the DM and the crude protein from protease activity (p < 0.05), and CL was the most effective among them. Furthermore, wilting time influenced the silage’s bacterial communities, but overall, CL treatment had the greatest impact on bacterial communities. Wilting time and formic acid treatment significantly improved aerobic stability (p < 0.05). Enterococcus was positively correlated with lactic acid (LA), while negatively correlated with LA and Weissella (p < 0.001). Enterococcus was identified as the main driver of the whole plant paper mulberry ensiling process in the present study. In conclusion, compared to other additives, LAB is the most effective and economical to improve the fermentation quality and reduce the protein degradation of whole plant paper mulberry silage. Our findings provide a theoretical basis to improve the quality and production of paper mulberry silage.

In this study, the influence of two lactic acid bacteria (LAB) strains [Lactobacillus rhamnosus BDy (LR-BDy) and Lactobacillus buchneri TSy (LB-TSy)] selected from Southwest China on the fermentation characteristics and in vitro gas production of Broussonetia papyrifera (paper mulberry) silage were experimentally explored. The experimental groups were a control group (C), an LB-TSy treatment (LB), an LR-BDy treatment (LR), and an LR-BDy + LB-TSy hybrid group (LR × LB). After the LAB were added, the pH value of paper mulberry silage significantly declined (p < 0.05), and the crude protein content was effectively preserved (p < 0.05). However, no significant changes were found in the levels of neutral detergent fiber, acid detergent fiber, and crude ash (p > 0.05). The lactic acid content in paper mulberry silage was evidently increased (p < 0.05). The in vitro gas production in the LR at 36, 48, and 72 h were markedly higher than that in the other treatments (p < 0.05). Owing to the addition of LAB, the microbial diversity in paper mulberry silage was reduced, while the relative bacterial abundance of Lactobacillus was enhanced. Hence, the addition of LAB selected from the warm and humid region in Southwest China can improve the quality of paper mulberry silage and elevate its feeding value in this region.

Distiller’s grains (DG), a major by-product of the Chinese Baijiu industry, represent an inexpensive yet high-quality protein raw material. Previous studies have shown that probiotics-fermented distiller's grains (FDG) hold the potential to serve as an effective livestock feed resource. However, the impacts of feeding FDG-based diets on rumen enzyme activities, rumen microbial communities and metabolism in finishing cattle, along with their underlying regulatory mechanisms, remain poorly understood. After 45 days of feeding FDG diets, rumen enzyme activities increased significantly. Feeding 10% FDG diets increased the relative abundance of the bacterial genus Prevotella_1 and the fungal genera Candida, Mucor, and Scedosporium in the rumen. Conversely, the relative abundances of bacterial genera Veillonellaceae UCG-001 and Candidatus Saccharimonas, as well as fungal genus Talaromyces, were reduced notably in the rumen following FDG diet supplementation. Compared to the FDG-10% group, the FDG-20% group exhibited a higher relative abundance of the beneficial bacterial genus Bifidobacterium and the fungal genus Plectosphaerella. Non-targeted metabolomic analysis indicated that the differential metabolites were primarily categorized as benzenoids, lipids and lipid-like molecules, and organic acids and derivatives, which were significantly enriched in the neuroactive ligand-receptor interaction and taste transduction metabolic pathways. Untargeted lipidomic analysis further demonstrated that feeding 20% FDG diets elevated the levels of glycerophospholipids in the rumen. Spearman analysis identified the correlations between specific bacterial and fungal genera and rumen enzyme activities, differential metabolites, and lipids. These results suggest that feeding FDG diets potentially improves rumen enzyme activities and up-regulates the levels of glycerophospholipids in the rumen, which may be associated with the alterations in specific rumen microbiota involved in degrading cellulose. Of these, 20% FDG replacement emerges as a better dose within the range of FDG additions in this study.

Fermented distillers’ grains (FDG) are commonly used to enhance the health and metabolic processes of livestock and poultry by regulating the composition and activity of the intestinal microbiota. Nevertheless, there is a scarcity of research on the effects of the FDG diet on the gastrointestinal microbiota and its metabolites in cattle. This study examines the impact of FDG dietary supplements on the gastrointestinal flora and metabolic profile of Guanling cattle. Eighteen cattle were randomly assigned to three treatment groups with six replicates per group. The treatments included a basal diet (BD), a 15% concentrate replaced by FDG (15% FDG) in the basal diet, and a 30% concentrate replaced by FDG (30% FDG) in the basal diet. Each group was fed for a duration of 60 days. At the conclusion of the experimental period, three cattle were randomly chosen from each group for slaughter and the microbial community structure and metabolic mapping of their abomasal and cecal contents were analyzed, utilizing 16S rDNA sequencing and LC-MS technology, respectively. At the phylum level, there was a significant increase in Bacteroidetes in both the abomasum and cecum for the 30%FDG group (p < 0.05). Additionally, there was a significant reduction in potential pathogenic bacteria such as Spirochetes and Proteobacteria for both the 15%FDG and 30%FDG groups (p < 0.05). At the genus level, there was a significant increase (p < 0.05) in Ruminococcaceae_UCG-010, Prevotellaceae_UCG-001, and Ruminococcaceae_UCG-005 fiber degradation bacteria. Non-target metabolomics analysis indicated that the FDG diet significantly impacted primary bile acid biosynthesis, bile secretion, choline metabolism in cancer, and other metabolic pathways (p < 0.05). There is a noteworthy correlation between the diverse bacterial genera and metabolites found in the abomasal and cecal contents of Guanling cattle, as demonstrated by correlation analysis. In conclusion, our findings suggest that partially substituting FDG for conventional feed leads to beneficial effects on both the structure of the gastrointestinal microbial community and the metabolism of its contents in Guanling cattle. These findings offer a scientific point of reference for the further use of FDG as a cattle feed resource.