Addition of Lactic Acid Bacteria Can Promote the Quality and Feeding Value of Broussonetia papyrifera (Paper Mulberry) Silage

Current approaches on the roles of lactic acid bacteria in crop silage

Lactic acid bacteria (LAB) play pivotal roles in the preservation and fermentation of forage crops in spontaneous or inoculated silages. Highlights of silage LAB over the past decades include the discovery of the roles of LAB in silage bacterial communities and metabolism and the exploration of functional properties. The present article reviews published literature on the effects of LAB on the succession, structure, and functions of silage microbial communities involved in fermentation. Furthermore, the utility of functional LAB in silage preparation including feruloyl esterase-producing LAB, antimicrobial LAB, lactic acid bacteria with high antioxidant potential, pesticide-degrading LAB, lactic acid bacteria producing 1,2-propanediol, and low-temperature-tolerant LAB have been described. Compared with conventional LAB, functional LAB produce different effects; specifically, they positively affect animal performance, health, and product quality, among others. In addition, the metabolic profiles of ensiled forages show that plentiful probiotic metabolites with but not limited to antimicrobial, antioxidant, aromatic, and anti-inflammatory properties are observed in silage. Collectively, the current knowledge on the roles of LAB in crop silage indicates there are great opportunities to develop silage not only as a fermented feed but also as a vehicle of delivery of probiotic substances for animal health and welfare in the future.

Effect of different organic acid additives on the fermentation quality and bacterial community of paper mulberry (Broussonetia papyrifera) silage

To investigate the effects of different organic acid additives and their concentrations on the fermentation quality and bacterial community of paper mulberry silage, paper mulberry was left untreated (control) or was treated with ethylenediaminetetraacetic acid (EDTA), propionic acid (PA) or citric acid (CA), the amount of each additive was 2 g.kg^-1 FM, 5 g.kg^-1 FM and g.kg^-1 FM. All groups were ensiled for 3, 7, 15, 30 and 60 days. Compared to the control, adding EDTA reduced protein breakdown, preserved more water-soluble carbohydrates of the silages (WSCs, 24.74 g.kg^-1 DM), and high concentrations of EDTA inhibited the activity of undesirable microorganisms. Adding PA increased the abundance of Lactiplantibacillus and decreased the abundance of Enterococcus, and it caused a rapid decrease in the pH of the silage at an early stage (from 6.50 to 5.31) while altering the microbiota, and low concentrations of PA resulted in high LA (66.22 g.kg^-1 DM) concentration and low PA (9.92 g.kg^-1 DM) concentration at 60 days of ensiling. Different concentrations of additives altered the microbial community of paper mulberry to different degrees. High concentrations of PA and CA can increase the abundance of Lactiplantibacillus. High concentrations of CA resulted in a rapid decrease in silage pH at an early stage and higher WSC concentration. These results suggest that EDTA, PA and CA can be used as additives to improve the quality of paper mulberry silage.

A newly developed strain of Enterococcus faecium isolated from fresh dairy products to be used as a probiotic in lactating Holstein cows

The objective of this study was to determine the ability of an isolated strain (EGY_NRC1) or commercial (NCIMB 11181) Enterococcus faecium as a probiotic for lactating cows. Two experiments were conducted: In Experiment 1, the effects of three levels (1, 2, and 3 g/kg diet, DM basis) of isolated and commercial E. faecium on in vitro ruminal fermentation kinetics, gas, methane (CH₄) and nutrient degradability were determined. In Experiment 2, thirty multiparous Holstein cows (633 ± 25.4 kg body weight) with 7 days in milk, were randomly assigned to 3 treatments in a completely randomized design in a 60-day experiment. Cows were fed without any additives (control treatment) or supplemented with 2 g/kg feed daily of E. faecium EGY_NRC1 (contain 1.1 × 10⁹ CFU/g) or commercial E. faecium NCIMB 11181 (contain 2 × 10¹² CFU/g). Diets were prepared to meet cow's nutrient requirements according to NRC recommendations. Probiotic doses were based on the in vitro Experiment 1. Feed intake, digestibility, blood parameters and lactation performance were evaluated. In Experiment 1, the isolated E. faecium linearly and quadratically increased (P < 0.001) in vitro total gas production (TGP), the degradability of dry matter (dDM) and organic matter (dOM) while decreased (P < 0.05) methane (CH₄) percent of TGP, NH₃CH₄ production, and pH. The commercial E. faecium increased TGP and decreased (P < 0.01) CH₄ production, pH and increased the dDM and dOM, short chain fatty acids and ruminal NH₃-N concentration. In Experiment 2, the isolated E. faecium increased (P < 0.01) total tract digestibility of DM, neutral and acid detergent fiber, daily milk production and feed efficiency compared to the control treatment without affecting feed intake and milk composition. Moreover, the isolated E. faecium increased (P < 0.05) the proportion of C18:1 trans-9, C18:2 cis-9-12 and C18:2 trans-10 cis-12. Both isolated and commercial E. faecium improved (P < 0.01) organic matter, crude protein and nonstructural carbohydrates digestibility, increased serum glucose (P = 0.002) and decreased serum cholesterol (P = 0.002). Additionally, both E. faecium strains decreased C23:0 (P = 0.005) in milk. In conclusion, the use of E. faecium (isolated and commercial) at 2 g/kg DM of feed improved feed efficiency and production performance, with superior effects on animal performance from isolated E. faecium compared to the commercial one.

Mixed Fermentation of Lactiplantibacillus plantarum and Bacillus licheniformis Changed the Chemical Composition, Bacterial Community, and Rumen Degradation Rate of Tea Residue

Tea residue, as a byproduct in tea processing, is highly nutritious and can be used as a good raw material for ruminant feed. This study aimed to investigate the effects of Lactiplantibacillus plantarum (L. plantarum) and Bacillus licheniformis (B. licheniformis) mixed fermentation of tea residue mixture (tea residue:wheat bran, 7:3) on chemical composition, bacterial community, and rumen degradation rate. Changes in chemical composition and bacterial community were evaluated after 0 (F0), 1 (F1), 3 (F3), and 5 (F5) days of fermentation. The rumen degradation rate was studied by the in situ nylon bag method. Compared with group F0, acid soluble protein in other groups increased while pH and neutral detergent fiber decreased (p < 0.05). The group F5 was the best. The diversity of bacterial communities in group F0 was significantly lower than those in the other groups (p < 0.05). The relative abundance of phylum Firmicutes and the genus Lactobacillus increased with increasing fermentation time. The rumen degradation rates of dry matter, crude protein, neutral detergent fiber, and acid detergent fiber were increased after fermentation. In conclusion, mixed fermentation of tea residue by L. plantarum and B. licheniformis can ameliorate chemical composition, reduce bacterial community diversity, and improve the rumen degradation rate.

Effect of Amomum villosum essential oil as an additive on the chemical composition, fermentation quality, and bacterial community of paper mulberry silage

Paper mulberry (Broussonetia papyrifera L., PM) is being used as a new type of animal protein feed to address the feed crisis. To investigate the effect of additives on the chemical composition, fermentation quality, and bacterial community of PM silage (at room temperature, 25°), paper mulberry was fermented with formic acid (FA), Amomum villosum essential oil (AVEO) and lactic acid bacteria (LAB) inoculant treatments. The results showed that fresh PM had a low water-soluble carbohydrate (WSC) content and large amounts of unclassified bacteria. Compared with the CK and LAB treatments, the FA and AVEO treatments significantly (P &lt; 0.05) decreased the pH and increased the lactic acid content of PM silage after 60 days of ensiling. In the AVEO-treated silages the abundance of Lactococcus in the early stage of ensiling increased by 14.09%, the abundances of Levilactobacillus and Lentilactobacillus in the late stage of ensiling increased by 58.34 and 91.12%, respectively, and the abundance of Stenotrophomonas decreased by 94.71%, resulting in improved PM silage quality. These results confirmed that AVEO could potentially be developed as a new additive for improving the fermentation quality of silage.

Effects of Microbial Inoculants on Fermentation Quality and Aerobic Stability of Paper Mulberry Silages Prepared with Molasses or Cellulase

Paper mulberry (Broussonetia papyrifera L.) is an unconventional forage with high crude protein content and is widely used in China. In order to evaluate the pattern of fermentation quality and the aerobic stability when inoculated with lactic acid bacteria, laboratory-scale silage was prepared. The experimental groups included a control group (CK), a Lactobacillus plantarum ‘LC365283’ (selected from paper mulberry silage) treatment (L1), a commercial inoculant Lactobacillus plantarum treatment (GF), a commercial inoculant Lactobacillus buchneri treatment (FR), a 3% molasses treatment (MO), a 150 U/g cellulase treatment (CE), and their combinations (MO + L1, MO + GF, MO + FR, CE + L1, CE + GF, and CE + FR). The changes in bacterial community and composition of the fermentation products were evaluated after being ensiled for 30 days and unsealed for 1, 3, 5, and 7 days. Compared with the CK, MO and CE, the silages treated with L1, MO + L1, and CE + L1 showed higher lactic acid concentrations, lower pH values, and lower ammonia nitrogen concentrations (p < 0.05). During the first 3 days of aerobic exposure, the pH values and organic acid content changed slightly in all treatments. The present study suggests that addition of L1 was better than commercial inoculum, and the paper mulberry silages could be well preserved after being unsealed for 3 days.