Effect of ensiling whole crop oat with lucerne in different ratios on fermentation quality, aerobic stability and in vitro digestibility on the Tibetan plateau

Community Synergy of Lactic Acid Bacteria and Cleaner Fermentation of Oat Silage Prepared with a Multispecies Microbial Inoculant

To investigate community synergy of lactic acid bacteria (LAB) and cleaner fermentation of oat silage, oat silages were prepared with or without (control) commercial LAB inoculants LI1 (containing Lactiplantibacillus plantarum, Lentilactobacillus buchneri, Lacticaseibacillus paracasei, and Pediococcus acidilactici) and LI2 (containing Lactiplantibacillus plantarum and Lentilactobacillus buchneri). The microbial community, LAB synergy, and cleaner fermentation were analyzed at 1, 3, 6, 15, 35, and 90 days of ensiling. The LAB inoculant improved fermentation quality, with significantly (P < 0.05) lower pH, ammonia nitrogen content, and gas production and higher lactic acid and acetic acid contents than those of the control. Enterobacteriaceae was the main bacterial community in early stage of fermentation, which utilizes sugar to produce CO2 gas, causing dry matter (DM) and energy loss. As fermentation progressed, the microbial diversity decreased, and the microbial community shifted from Gram-negative to Gram-positive bacteria. The inoculation of multispecies LAB displayed community synergy; Pediococcus acidilactici formed a dominant community in the early stage of fermentation, which produced an acid and anaerobic environment for the subsequent growth of Lentilactobacillus and Lacticaseibacillus species, thus forming a LAB-dominated microbial community. The predicted functional profile indicated that the silage inoculated with LI1 enhanced the carbohydrate metabolism pathway but inhibited the amino acid metabolism pathway, which played a role in promoting faster lactic acid production, reducing the decomposition of protein to ammonia nitrogen, and improving the fermentation quality of silage. Therefore, oat silage can be processed to high-quality and cleaner fermented feed by using an LAB inoculant, and LI1 showed better efficiency than LI2. IMPORTANCE Oat natural silage is rich in Enterobacteriaceae, increasing gas production and fermentation loss. Lactic acid bacteria interact synergistically to form a dominant community during ensiling. Pediococci grow vigorously in the early stage of fermentation and create an anaerobic environment. Lactobacilli inhibit the harmful microorganisms and result in cleaner fermentation of oat silage.

The effects of native lactic acid bacteria on the microbiome, fermentation profile, and nutritive value of Napier grass silage prepared with different legume ratios

Mixing grass with legumes before ensiling is beneficial for improving dry matter and crude protein yield, but additional information is needed to balance nutrient content and fermentation quality. In this study, the microbial community, fermentation characteristics, and nutrient content of Napier grass mixed with alfalfa at different proportions were assessed. Tested proportions included: 100:0 (M0), 70:30 (M3), 50:50 (M5), 30:70 (M7), and 0:100 (MF). Treatments included: (CK) sterilized deionized water; (IN) selected lactic acid bacteria: Lactobacillus plantarum CGMCC 23166 and Lacticaseibacillus rhamnosus CGMCC 18233 (1.5 × 10⁵ cfu/g of fresh weight for each inoculant); and (CO) commercial lactic acid bacteria: L. plantarum (1 × 10⁵ cfu/g of fresh weight). All mixtures were ensiled for 60 days. Data analysis was used as a completely randomized design with a 5-by-3 factorial arrangement of treatments. The results showed that with increasing alfalfa mixing ratio, dry matter, and crude protein increased, while neutral detergent fiber and acid detergent fiber decreased both before and after ensiling (p < 0.05), which was not influenced by fermentation. Inoculation with IN and CO decreased pH and increased the lactic acid content compared to CK (p < 0.05), especially in silages M7 and MF. The highest Shannon index (6.24) and Simpson index (0.93) were observed in the MF silage CK treatment (p < 0.05). The relative abundance of Lactiplantibacillus decreased with increasing alfalfa mixing ratio, while the abundance of Lactiplantibacillus was significantly higher in the IN-treated group than in other treatment groups (p < 0.05). A higher alfalfa mixing ratio improved the nutrient value, but also made fermentation more difficult. Inoculants improved the fermentation quality by increasing the abundance of Lactiplantibacillus. In conclusion, the groups M3 and M5 achieved the optimal balance of nutrients and fermentation. If a higher proportion of alfalfa needs to be used, it is recommended to use inoculants to ensure sufficient fermentation.

Fermentation quality, bacterial community, and predicted functional profiles in silage prepared with alfalfa, perennial ryegrass and their mixture in the karst region

There is little information regarding the dynamics of fermentation products and the bacterial community in silage prepared with alfalfa (MS), perennial ryegrass (LP), and their mixture in the karst region. In this study, we explored the effects of combining MS with LP in different ratios (100% MS, 70% MS + 30% LP, 50% MS + 50% LP, 30% MS + 70% LP and 100% LP; fresh matter basis) on silage chemical composition, fermentation quality, bacterial communities and predicted functions during the ensiling process. Each treatment was prepared in triplicate and stored at room temperature (22–25°C) for 7, 15, and 45 days. The dry matter (DM) and water-soluble carbohydrate content of the silages increased as the LP proportion in the mixed silage increased; at 45 days, the 70% MS + 30% LP, 50% MS + 50% LP and 30% MS + 70% LP silages contained higher (p &lt; 0.05) CP content than the 100% MS and 100% LP silages. The 30% MS + 70% LP and 100% LP silages exhibited lower (p &lt; 0.05) pH and higher (p &lt; 0.05) LA content than the other silages; at 45 days, none of the silages contained PA or BA. As fermentation proceeded, the abundance of harmful (Enterobacteriaceae and Sphingomonas) and beneficial (Lentilactobacillus, Lactiplantibacillus, Secundilactobacillus, and Levilactobacillus) microorganisms decreased and increased, respectively, as the LP proportion in the mixed silage increased. The predicted functional distribution of microbial communities and metabolic pathways revealed that the 30% MS + 70% LP and 100% LP silages had a stronger capacity for fermentation and a weaker capacity for nitrate reduction than the other silages. Moreover, as the fermentation proceeded, the 30% MS + 70% LP and 100% LP treatments enhanced the functions of “Metabolism,” “Genetic information processing” and “Organismal systems” at level 1, the functions of “Amino acid metabolism” and “Nucleotide metabolism” at level 2, and the functions of “Metabolic pathways,” “Biosynthesis of secondary metabolites,” “Biosynthesis of antibiotics” and “Purine metabolism” at level 3. Thus, adding LP could improve the fermentation quality of MS silage by changing the composition and metabolic function of microbes; furthermore, ensiling 30% alfalfa with 70% ryegrass can produce high-quality silage in the karst region.

Modulation of Fermentation Quality and Metabolome in Co-ensiling of Sesbania cannabina and Sweet Sorghum by Lactic Acid Bacterial Inoculants

Sesbania cannabina (SC) is a protein-rich roughage that thrives under moderate-severe saline-alkali (MSSA) soils with the potential to relieve the shortage of high nutritive forage. Sweet sorghum (SS) also tolerates MSSA soils and contains rich fermentable carbohydrates which could improve the fermentation quality in mixed silage. The present study investigated the silage quality, bacterial community, and metabolome in the mixed silage of SC and SS (SC-SS) with or without lactic acid bacterial (LAB) inoculants. Four ratios (10:0, 7:3, 5:5, and 3:7) of SC and SS were treated with sterile water or LAB inoculants (homofermentative Companilactobacillus farciminis and Lactiplantibacillus plantarum, and heterofermentative Lentilactobacillus buchneri and Lentilactobacillus hilgardii), which were analyzed after 60 days of ensiling. Results revealed that LAB inoculation improved the fermentation quality by increasing the lactic acid content and decreasing the ammonia nitrogen and butyric acid contents compared with the untreated group. LAB inoculation also raised the relative feed value by reducing indigestible fibers [e.g., neutral detergent fiber (NDF), acid detergent fiber, and hemicellulose]. Microbial and metabolomic analysis indicated that LAB inoculants could modify the bacterial community and metabolome of SC-SS silage. In co-ensiling samples except for SC alone silage, L. buchneri and L. hilgardii were the dominant species. Metabolites with bioactivities like anti-inflammatory, antioxidant, antimicrobial, and anti-tumor were upregulated with LAB inoculation. Furthermore, correlation analysis demonstrated that active metabolites (e.g., glycitin, glabrene, alnustone, etc.) were positively correlated with L. buchneri, while tripeptides (e.g., SPK, LLK, LPH, etc.) were positively correlated with L. hilgardii. Adequately describing the SC-SS silage by multi-omics approach might deepen our understanding of complicated biological processes underlying feature silages fermentation. Moreover, it may also contribute to screening of targeted functional strains for MSSA-tolerating forage to improve silage quality and promote livestock production.

Effects of different additives on fermentation quality and aerobic stability of a total mixed ration prepared with local feed resources on Tibetan plateau

To improve the utilization efficiency of total mixed ration (TMR) on Tibetan plateau, the effects of different additives on fermentation quality and aerobic stability of the ensiled TMR prepared with local feed resources were studied. A total of 150 experimental silos were prepared in a completely randomized design to evaluate the following treatments: (a) control; (b) Lactobacillus buchneri; (c) acetic acid; (d) propionic acid; (e) 1,2-propanediol; and (f) 1-propanol. After 90 days of ensiling, silos were opened for fermentation quality and in vitro parameters analysis, and then subjected to an aerobic stability test for 14 days. The acetic acid, 1,2-propanediol and 1-propanol treatments increased (p < .05) pH and acetic acid content, and lowered (p < .05) the lactic acid production in comparison to control. There were no statistically significant differences in in vitro digestibility parameters among the treatments. Treatments of acetic acid, 1,2-propanediol and 1-propanol substantially improved the aerobic stability of the ensiled TMR, as indicated by almost unchanged pH and lactic acid contents throughout the aerobic exposure test. These results indicated that acetic acid, 1,2-propanediol and 1-propanol had no adverse effect on in vitro digestibility and could be effective additives for enhancing the aerobic stability of ensiled TMR prepared on Tibetan plateau.

Effects of Ensiling Oxytropis glabra with Whole-Plant Corn at Different Proportions on Fermentation Quality, Alkaloid Swainsonine Content, and Lactic Acid Bacteria Populations

Simple Summary

In Inner Mongolia, developing innovative forages is an indispensable way to ease the shortage of animal feed. Oxytropis glabra (OG) has become a dominant population, with a high nature yield in the degraded grassland of Inner Mongolia. As a typical legume, it is rich in amino acids and trace elements, so using OG to feed livestock is a valuable strategy. However, it contains swainsonine (SW), which hinders the utilization of OG. This study was conducted to evaluate silage fermentation and SW removal from OG ensiled with whole-plant corn at different proportions, and the result showed ensiling a mixture of OG and corn could be a valuable approach for producing livestock feed, as it had a positive effect on fermentation quality and SW detoxification; the optimal ratio was 1:1. In the silages, Lactobacillus plantarum was the most common microorganism present in all mixture silages, and Lactobacillus amylovorus and Lactobacillusbrevis were prevalent at lower ratios of corn to OG. All representative strains were able to remove SW from OG fermentation, and the strains of L. amylovorus and L. plantarum had a higher SW removal rate. These mixtures of silages could make OG useable as a feed source in ruminant production.

Abstract

Oxytropis glabra (OG) is a leguminous forage that is potentially valuable for solving the shortage of feed for livestock production, while, in large quantities, it may be toxic because of its swainsonine (SW) content. In this study, OG was ensiled with whole-plant corn (Zea mays L.) at 10:0, 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, and 0:10 ratios on a fresh matter basis, and, after 60 d of ensiling, the chemical composition, fermentation characteristic, SW removal rate, lactic acid bacteria (LAB) populations, and their capabilities for SW removal were analyzed. As the proportion of corn in the silage increased, the pH, as well as the propionic acid, ammonia-N, dry matter, crude protein, and SW contents, decreased linearly, while the lactic acid, neutral detergent fiber, and residual water-soluble carbohydrate contents increased linearly. Lactobacillus plantarum was the most common microorganism present in all mixture silages. Lactobacillus amylovorus and Lactobacillusbrevis were prevalent at lower ratios of corn to OG. Meanwhile, the LAB strains belong to L. amylovorus and L. plantarum had a higher SW removal rate. Our results suggested that ensiling OG with whole-plant corn improves fermentation and decreases SW content, and that 5:5 is the optimal ratio, so this type of mixed silage could make OG useable for ruminant production.

Comparative analysis of ensiling characteristics and protein degradation of alfalfa silage prepared with corn or sweet sorghum in semiarid region of Inner Mongolia

This study was conducted to evaluate silage fermentation and protein degradation of alfalfa prepared with corn or sweet sorghum (SS) at different mixing ratios. The chemical composition, ensiling characteristics, and protein degradation of alfalfa prepared with and without corn or SS at mixing ratios of 7:3, 1:1, and 3:7 on a fresh matter (FM) basis were studied. The alfalfa had the highest crude protein (CP) content and lactate buffering capacity (LBC), but lower water-soluble carbohydrate (WSC) content than corn and SS. After 60 days of ensiling, the corn and SS silages had good quality, with lower pH and ammonia-N content, and higher dry matter (DM) content than the alfalfa silages. In the alfalfa and corn mixture silages, the DM contents linearly increased with an increase in the proportion of corn, while the pH, non-protein N (NPN), ammonia-N, and peptide-N contents linearly decreased. In the alfalfa and SS mixture silages, the DM and NPN contents linearly increased with an increase in the proportion of SS, while the pH, lactic acid, and ammonia-N contents linearly decreased. This study suggests that alfalfa silage prepared with corn has more positive effect on fermentation quality and inhibiting protein degradation than addition of SS.

Ensiling characteristics, in vitro rumen fermentation, microbial communities and aerobic stability of low-dry matter silages produced with sweet sorghum and alfalfa mixtures

BACKGROUND

Silages produced with grass and legume mixtures may have positive associative effects on silage quality and animal performance when ruminants are fed the silages. The present study aimed to determine the preservation characteristics, in vitro rumen fermentation profile and microbial abundance of silages, produced with mixtures of sweet sorghum (SS) and alfalfa (AF) in different ratios: 100:0 (Control), 75:25 (SA25), 50:50 (SA50), 25:75 (SA75) and 0:100 (SA100) on a fresh weight basis.

RESULTS

As the proportion of AF increased in the silages, pH, acetic acid, ammonia nitrogen and crude protein (CP) concentrations, and aerobic stability increased (P < 0.05), whereas lactic acid and neutral detergent fibre (NDF) and acid detergent fibre (ADF) concentrations decreased (P < 0.05). Increasing the proportion of AF in the silages, increased (P < 0.05) the in vitro degradability of dry matter and CP, as well as the proportions of genus Prevotella, but decreased (P < 0.05) the in vitro degradability of NDF (IVNDFD) and ADF (IVADFD) and proportions of Butyrivibrio fibrisolvens. Compared to the Control silage, SA25 silage had greater (P < 0.05) proportions of Fibrobacter succinogenes and Ruminococcus flavefaciens, IVNDFD, IVADFD, ruminal short chain fatty acids and microbial protein concentrations, as well as lower (P < 0.05) methane production.

CONCLUSION

The silage produced with the SS to AF ratio of 75:25 was the most suitable for ruminants use as a result of the optimal balance of fermentation quality, feed-nutritional value and aerobic stability. © 2018 Society of Chemical Industry.