Microbial community and fermentation characteristic of Italian ryegrass silage prepared with corn stover and lactic acid bacteria

Impacts of Low Temperature and Ensiling Period on the Bacterial Community of Oat Silage by SMRT

The objective of this study was to investigate how storage temperatures influence the bacterial community of oat silage during the ensiling process via PacBio single molecule, real-time sequencing technology (SMRT). Forage oat was ensiled at four different temperatures (5 °C, 10 °C, 15 °C, and 25 °C) and ensiling days (7, 14, 30, and 60 days). With the rise in storage temperature, the lactic acid content showed an increased trend. Acetic acid production was observed highest in silage fermented at 5 °C compared with other treatments, and Enterococcus mundtii was also the dominant bacterial species. Lactiplantibacillus pentosus and Loigolactobacillus rennini were exclusively detected in silages at 10 °C, 15 °C, and 25 °C, and dominated the fermentation after 60 days of ensiling at 10 °C and 25 °C, respectively. In addition, L. pentosus, L. rennini, and E. mundtii may be related to changes in the fermentation products due to the differences in ensiling temperature. In conclusion, results of this study improve our understanding of the complicated microbial composition underlying silage fermentation at low temperatures, which might contribute to target-based regulation methods for enhancing silage quality and developing new inoculants.

Abundance and diversity of epiphytic microbiota on forage crops and their fermentation characteristic during the ensiling of sterile sudan grass

This study aimed to evaluate the effects of exogenous epiphytic microbiota inoculation on the fermentation quality and microbial community of sudan grass silage. Gamma irradiated sudan grass was ensiled with distilled water (STR), epiphytic microbiota of sudan grass (SUDm), forage sorghum (FSm), napier grass (NAPm) and whole crop corn (WCCm). The FSm inoculated silage have significantly lower lactic acid (LA) concentration and higher pH during early ensiling, while LA concentration gradually and significantly increased with the progression of ensiling and have lower pH in relation to other treatments for terminal silage. Inoculation of NAPm resulted in lower LA and higher acetic acid (AA) concentrations, higher pH, ammonia-N and dry matter losses for terminal silage, followed by SUDm silage. Inoculations of WCCm significantly increased LA production and pH decline during early ensiling and have higher LA and pH then NAPm and SUDm silages during final ensiling. The early fermentation of SUDm silage was dominated by genus of Pediococcus. The genera of Lactobacillus were predominant in WCCm and NAPm silages during 3 days of ensiling, while Weissella dominated initial microbial community of FS silage. The terminal silage of NAPm was dominated by Enterobacter and Rosenbergiella, while Enterobacter and Lactobacillus dominated terminal SUDm silage. The final silage of FSm was dominated by Lactobacillus, Weissella and Pediococcus, while Lactobacillus and Acetobacter dominated terminal WCCm silages. The results demonstrated that among the four forages the epiphytic microbiota from forage sorghum positively influenced the microbial community and fermentability of sudan grass silage.

Beneficial Effects of Tannic Acid on the Quality of Bacterial Communities Present in High-Moisture Mulberry Leaf and Stylo Silage

Tannic acid (TA), a type of polyphenol, is widely distributed in plants, especially in legumes. Not only does it possess antimicrobial properties, but it also has the ability to bind with proteins. The fermentation parameters, nitrogen fractions, antioxidant capacity, and bacterial communities present in mulberry leaves and stylo (Stylosanthes guianensis) ensiled with or without 1 and 2% TA per kilogram of fresh matter (FM) were investigated after 75 days’ fermentation. The results showed that 1 and 2% TA both significantly decreased the butyric acid content (4.39 and 7.83 g/kg dry matter (DM), respectively) to an undetectable level in both mulberry leaf and stylo silage. In addition, 2% TA significantly increased the contents of lactate (24.0–39.0 and 8.50–32.3 g/kg DM), acetate (18.0–74.5 and 9.07–53.3 g/kg DM), and the antioxidant capacity of both mulberry leaf and stylo silage, respectively. With the addition of 1 and 2% TA, the pH values (5.55–5.04 and 4.87, respectively) and ammonia-N (NH₃-N) content (85.5–27.5 and 16.9 g/kg total nitrogen (TN), respectively) were all significantly decreased in stylo silage. In addition, TA increased the relative abundance of Weissella, Acinetobacter, and Kosakonia spp. and decreased that of undesirable Clostridium spp. TA can thus be used to improve the silage quality of both mulberry leaf and stylo silage, with 2% TA being the better concentration of additive to use.

Effects of antibacterial peptide-producing Bacillus subtilis and Lactobacillus buchneri on fermentation, aerobic stability, and microbial community of alfalfa silage

This study assessed the effects of antibacterial peptide-producing Bacillus subtilis (BS), Lactobacillus buchneri (LB), or their combination on fermentation, proteolysis, aerobic stability, and microbial communities during ensiling and aerobic exposure phases of alfalfa silage. The results showed that the BS-treated silage displayed a higher lactic acid concentration, less proteolysis, and higher aerobic stability than those in the control silage. Both LB and BS treatments increased Lactobacillus and Ascochyta abundance, and decreased Enterococcus and Sporormiacea abundance after 60 d of fermentation. LB and BS also inhibited the growth of Enterococcus after 3 d of aerobic exposure but similar to the control silage, the fungal community of BS silage was dominated by Candida and Pichia after 9 d of aerobic exposure. Therefore, inoculation of BS improved silage fermentation quality, aerobic stability and bacterial community during ensiling and after 3 d of aerobic exposure.

Characterization of the microbial community, metabolome and biotransformation of phenolic compounds of sainfoin (Onobrychis viciifolia) silage ensiled with or without inoculation of Lactobacillus plantarum

The present study investigated the bacterial community, metabolome and biotransformation of phenolic compounds in sainfoin silage inoculated either with or without Lactobacillus plantarum. Our results revealed that the epiphytic microbiota of wilted sainfoin mainly comprised Acinetobacter, Spingomonas, Pseudomonas, Lactobacillus, Delftia and Aquabacterium. After ensiling, L. acetotolerans, L. buchneri, L. plantarum, L. pentosus and Clostridium tyrobutricum were the dominant species. Compared to the control, the inoculant L. plantarum increased the relative abundance of L. buchneri while decreased that of the other dominant species. The ensiling process increased the concentrations of 21 flavones, 16 flavonols, 16 flavonoids, 14 flavanones and 9 isoflavones while decreased other 32 flavones and 11 anthocyanins, which mainly modulated by the "isoflavonoid biosynthesis" and "flavonoid biosynthesis" pathways. The inoculant L. plantarum mainly reduced the concentrations of 10 flavones. Compared with the control, the inoculant L. plantarum mainly affected the metabolism pathways related to carbohydrates and nitrogen.

Effects of various epiphytic microbiota inoculation on the fermentation quality and microbial community dynamics during the ensiling of sterile Napier grass

AIM

To investigate epiphytic microbiota transformation of forages, their adaptation and contributions to fermentation quality of silage.

METHODS AND RESULTS

Gamma-irradiated chopped Napier grass were ensiled with distilled water (STR), extracted epiphytic microbiota of Napier grass (NAP), sudan grass (SUD), whole crop corn (WCC) and forage sorghum (FS). Inoculating Napier grass with WCC significantly increased lactic acid (LA) concentrations during the initial ensiling period followed by a decline after 30 days. Relative to other silages (except STR) inoculation with NAP resulted in lower LA and greater pH, ammonia-N and dry matter (DM) losses. Silage inoculated with FS and SUD maintained lower pH as well as higher (P < 0·05) LA concentrations after 60 days of storage. During day 3 of ensilage, WCC, NAP and SUD inoculated silage were dominated by bacterial genera of Lactobacillus, while Lactococcus dominated the FS silage. Final silages were dominated by Lactobacillus in all treatment silages, however Enterobacter (16·3%) in NAP and Acetobacter (25·7%) in WCC silage were also prominent during the final ensiling.

CONCLUSION

The inoculation of epiphytic microbiota of forage sorghum and sudan grass positively influenced the microbial community and fermentability of sterile Napier grass silage.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first time to investigate the effects of various epiphytic microbiota as silage inoculants which can be used as alternative source of environmental friendly and economically feasible silage additives.

Microbial community dynamics during alfalfa silage with or without clostridial fermentation

This study was conducted to examine the effects of Lactobacillus plantarum (LP) and sucrose (S) on clostridial community dynamics and correlation between clostridia and other bacteria in alfalfa silage during ensiling. Fresh alfalfa was directly ensiled without (CK) or with additives (LP, S, LP + S) for 7, 14, 28 and 56 days. Clostridial and bacterial communities were evaluated by next-generation sequencing. Severe clostridial fermentation occurred in CK, as evidenced by the high contents of butyric acid, ammonia nitrogen, and clostridia counts, whereas all additives, particularly LP + S, decreased silage pH and restrained clostridial fermentation. Clostridium perfringens and Clostridium butyricum might act as the main initiators of clostridial fermentation, with Clostridium tyrobutyricum functioning as the promoters of fermentation until the end of ensiling. Clostridium tyrobutyricum (33.5 to 98.0%) dominated the clostridial community in CK from 14 to 56 days, whereas it was below 17.7% in LP + S. Clostridium was negatively correlated with the genus Lactobacillus, but positively correlated with the genera Enterococcus, Lactococcus and Leuconostoc. Insufficient acidification promoted the vigorous growth of C. tyrobutyricum of silage in later stages, which was mainly responsible for the clostridial fermentation of alfalfa silage.

Effect of wet sea buckthorn pomace utilized as an additive on silage fermentation profile and bacterial community composition of alfalfa

To effectively preserve nutrients, alfalfa silage was treated without (control) or with Lactobacillus plantarum (LP) and their mixture (LP + SBP). Results showed that SBP decreased (P < 0.05) final pH value and ammonia-N of total N, increased (P < 0.05) lactic, acetic and propionic acid contents, resulting in more residual water soluble carbohydrate and crude protein contents and less fiber content in relative to control. Moreover, SBP decreased (P < 0.05) the number of observed species, richness index of ACE and diversity index of Shannon at early stage of ensiling, while Lactobacillus plantarum, Lactococcus lactis, and/or Lactobacillus brevis dominated in silages. In particular, LP + SBP enhanced the growth of Lactococcus lactic at early stage and Lactobacillus plantarum at late stage of ensiling, resulting in higher lactic and acetic acid contents and lower propionic acid content as compared with LP. These confirmed that SBP could be used as an additive for improving silage quality of alfalfa.

Dynamic microbial diversity and fermentation quality of the mixed silage of corn and soybean grown in strip intercropping system

This study assessed the fermentation quality and microbial community of corn (Zea mays L.) and soybean (Glycine max Merr.) (CS) mixed silage in strip intercropping system. CS mixed silage increased lactic acid content and decreased ammonia-N content compared to 100% soybean (S) silage, while it decreased ammonia-N content compared to 100% corn (C) silage. The largest number of epiphytic lactic acid bacteria was detected in CS fresh materials. During ensiling, Weissella and Lactobacillus dominated silage, the relative abundance of Lactobacillus in mixed silage was higher than that in S silage with the same S variety. After aerobic exposure (AE), synergistic effect existed in low relative abundance bacteria correlating with ammonia-N content and pH at ensiling 60 days and AE 7 days. In conclusion, CS mixed silage modified microbial community and improved fermentation quality.

Effect on the ensilage performance and microbial community of adding Neolamarckia cadamba leaves to corn stalks

To comprehensively evaluate the fermentation performance and microbial community of corn stalks (CS) silage mixed with Neolamarckia cadamba leaves (NCL), CS were ensiled with four levels (0%, 10%, 30% and 50% of fresh weight) of NCL for 1, 7, 14, 30, 60 days in two trials. The results showed that all silages were well preserved with low pH (3.60-3.88) and ammonia nitrogen content (0.08-0.19% DM). The silage samples with NCL displayed lower (P < 0.05) acetic acid, propionic acid and ammonia nitrogen contents and lactic acid bacteria population during ensiling than control silages (100% CS). The addition of NCL also influenced the distribution of bacterial and fungal communities. Fungal diversity (Shannon's indices were 5.15-5.48 and 2.85-4.27 in trial 1 and trial 2 respectively) increased while the relative abundances of Lactobacillus, Leuconostocs, Acetobacter and two moulds (Aspergillus and Fusarium) decreased after added NCL. In summary, mixing NCL is a promising effective approach to preserve protein of CS silage and inhibit the growth of undesirable bacteria and mould, thus to improve the forage quality to some extent.

Dynamic profiles of fermentation characteristics and bacterial community composition of Broussonetia papyrifera ensiled with perennial ryegrass

Broussonetia papyrifera (B. papyrifera) has been proposed to improve silage fermentation due to its high content of protein and abundant active plant extracts. Thus, dynamic profiles of fermentation quality and bacterial community of B. papyrifera mixing with perennial ryegrass in different ratios: 100:0, 90:10, 80:20, 70:30, 60:40, and 50:50 were examined during 60-d fermentation. Results showed that adding perennial ryegrass increased soluble carbohydrate content and lactic acid production in silage and decreased pH and population of epiphytic microorganisms. Adding ryegrass exerted a remarkable effect on the silage bacterial community with a dramatic decrease in the abundance of Enterobacter. Spearman's rank correlation showed that silage lactic acid concentration was positively correlated with Lactobacillus and Stenotrophomonas abundance, while ammonia nitrogen concentration was positively correlated with the abundance of Enterobacter. In conclusion, B. papyrifera ensiled with perennial ryegrass could improve B. papyrifera silage quality and provide high-quality forage resources for sustainable ruminant livestock production.

Effects of citric acid on fermentation characteristics and bacterial diversity of Amomum villosum silage

To study the effects of citric acid on fermentation process of Amomum villosum silage, A. villosum was ensiled without or with 1%, 2% citric acid and fermentation parameters and bacterial diversity were analyzed after 3, 7, 14, 30 days ensiling, respectively. Citric acid treated silages had lower dry matter loss (1.83% vs 2.23%), pH (3.84 vs 6.02), ammonia-N (0.33 vs 1.79 g/kg DM) and coliform bacteria number (<2.00 vs 7.27 log₁₀ CFU/g FM) than the control after 30 days ensiling. The relative abundance of lactic acid bacteria, Pediococcus and Lactobacillus increased, whereas undesirable microorganisms like Enterobacter, Escherichia-Shigella and Pantoea decreased in citric acid treated A. villosum silage. These results indicated that quality A. villosum silage could be obtained by citric acid addition.

Effects of Lactobacillus plantarum additive and temperature on the ensiling quality and microbial community dynamics of cauliflower leaf silages

In order to enable rapid disposal and proper preservation of discarded vegetable for waste valorization, ensiling was employed to preserve cauliflower leaves for 30 days at different temperatures (20 ~ 45 °C) with and without the addition of Lactobacillus plantarum L8. The L. plantarum inoculant reduced dry matter (DM) loss and enhanced the preservation of protein and soluble carbohydrate while decreasing pH and ammonia nitrogen content. The silages at 35 °C exhibited the best fermentation profile characterized by the highest lactic acid content (185 g·kg^-1 DM) and the lowest pH (4.08) and ammonia nitrogen content (37.6 g·kg^-1 total nitrogen) with L. plantarum inoculation. The presence of exogenous L. plantarum improved the silage fermentation, enriched Lactobacillus and Weissella, and reduced the microbial richness/diversity, resulting in efficient lactic acid fermentation, especially at 30 and 35 °C. Moreover, the microbial community dynamics was correlated with the chemical compositions and fermentation metabolites in silages.

The feasibility and effects of exogenous epiphytic microbiota on the fermentation quality and microbial community dynamics of whole crop corn

This study analyzed the feasibility and effects of exogenous epiphytic microbiota on the fermentation quality and microbial community of whole crop corn. Gamma irradiated whole crop corn was ensiled with distilled water (STR), extracted microbiota of whole crop corn (WCC), Napier grass (NAP), forage sorghum (FS) or Sudan grass (SUD). WCC significantly increased LA concentration and decreased the pH during early ensiling. FS had significantly higher LA and lower pH during terminal ensiling. NAP caused higher pH and AA followed by the SUD silage. During 3 d of ensiling WCC and FS silage was dominated by Lactobacillus and Lactococcus while Weissella dominated NAP and SUD silage. Terminal silage was dominated by Lactobacillus in FS and Acinetobacter in NAP while Lactobacillus, Acetobacter, Acinetobacter and Sphingobium dominated WCC and SUD silage. The study demonstrated that FS microbiota transplantation positively influenced the microbial community and fermentation quality of whole crop corn silage as compared to other microbiota.

Microbial Community Dynamics and Natural Fermentation Profiles of Ensiled Alpine Grass Elymus nutans Prepared From Different Regions of the Qinghai-Tibetan Plateau

Feed deficiency during the long cold period of a year is one of the major problems that the traditional year-round animal grazing system has faced on the Qinghai-Tibetan plateau (QTP) since ancient time. Therefore, ensiling the grasses from grassland could be a desirable feeding regime to preserve high quality forage and to alleviate the seasonal unbalanced feed supply problem on this plateau. The present study was designed to investigate dynamics of bacterial community and natural fermentation quality of ensiled Elymus nutans collected from grasslands in four different areas with different elevations [Tianzhu County (TZ), 2965 m; Golog Prefecture (GL), 3763 m; Damxung County (DX), 4228 m, and Nagqu Prefecture (NQ), 4752 m] on the QTP. The bacterial community was characterized by using the PacBio single molecule with real-time sequencing technology (SMRT). The harvested fresh E. nutans grasses were ensiled in vacuum-sealed polyethylene bags for 14, 30, 60, and 90 days. Obvious differences in the epiphytic bacterial community of the fresh E. nutans samples from the four areas were observed, which resulted in various bacterial community dynamics and fermentation qualities of ensiled E. nutans. Higher fermentation quality was observed in silage samples from Nagqu than in those from the other areas (P < 0.05). Lactic acid bacteria (LAB) involved in fermentation of E. nutans from low altitude areas consisted of Pediococcus pentosaceus, Lactobacillus sp., Leuconostoc mesenteroides, and Lactobacillus coryniformis, whereas major LAB species involved in the fermentation of E. nutans silage from high altitudes included L. mesenteroides, Lactobacillus brevis, and Lactobacillus sp. Correlation analysis between bacterial composition and fermentation quality of E. nutans silages made from the four different areas in the QTP indicated that the LAB species responsible for silage fermentation in different areas were totally different, which was mainly due to the different epiphytic bacterial compositions in fresh E. nutans before ensiling. The present results provide important information on revealing the bacterial communities and fermentation quality of ensiled E. nutans, and on future screening of LAB isolates for making high quality silage in order to alleviate feed shortage of the traditional year-round grazing system on the QTP.

Microbial Community and FermentationDynamics of Corn Silage Prepared withHeat-Resistant Lactic Acid Bacteria in a HotEnvironment

To develop a silage fermentation technique to adapt to global climate changes, the microbiome and fermentation dynamics of corn silage inoculated with heat-resistant lactic acid bacteria (LAB) under high-temperature conditions were studied. Corn was ensiled in laboratory silo, with and without two selected strains, Lactobacillus salivarius LS358 and L. rhamnosus LR753, two type strains L. salivarius ATCC 11741Tand L. rhamnosus ATCC 7469T. The ensiling temperatures were designed at 30 °C and 45 °C, and the sampling took place after 0, 3, 7, 14, and 60 days of fermentation. The higher pH and dry matter losses were observed in the silages stored at 45 °C compared to those stored at 30 °C. Silages inoculated with strains LS358 and LR753 at 30 °C had a lower ratio of lactic acid/acetic acid. The dominant bacterial genera gradually changed from Pediococcus and Lactobacillus to Lactobacillus in silages during ensiling at 30 °C, while the bacterial community became more complex and fragmented after 7 d of ensiling at 45 °C. The high temperatures significantly led to a transformation of the LAB population from homo-fermentation to hetero-fermentation. This study is the first to describe microbial population dynamics response to high temperature during corn ensiling, and the results indicate that L. rhamnosus 753 shows potential ability to improve silage fermentation in tropics and subtropics. bacteria community; fermentation dynamics; high temperature; lactic acidbacteria; corn silage.

The nutrients in Moringa oleifera leaf contribute to the improvement of stylo and alfalfa silage: Fermentation, nutrition and bacterial community

Moringa oleifera leaf (MOL) has been proved to improve silage fermentation but the exact reason is unclear yet. Fermentation quality, protein preservation, antioxidant activity and bacterial community of stylo and alfalfa ensiled with 5%, 10% dry MOL, stylo or alfalfa were investigated. The present results showed that mixing MOL led to the decrease of pH (5.15 vs 4.76, 5.71 vs 4.57 for stylo and alfalfa, respectively), butyric acid (15.1, 28.3 g/kg DM vs not detected), ammonia-N (111 vs 50.7, 351 vs 100 g/kg total N) contents, and the increase of lactic acid content (8.70 vs 13.0, 0.23 vs 14.0 g/kg DM) and antioxidant activity relative to the control. The relative abundance of Clostridium was lowered (55.4% to 1.69%, 8.34% to 0.57%), whereas Lactobacillus was increased (14.9% to 63.2%, 11.7% to 23.5%). In conclusion, nutrients in MOL help to improve protein preservation and nutritional value of high-moisture stylo and alfalfa silage.

Metagenome analyses reveal the role of Clostridium perfringens in alfalfa silage anaerobic deterioration

The clostridial fermentation caused by the outgrowth of Clostridia was mainly responsible for the silage anaerobic deterioration. Our previous results showed that Clostridium perfringens dominated the clostridial community in poor-fermented alfalfa silage. This study was conducted to further examine the role of C. perfringens in silage anaerobic deterioration through fermentation products and the microbial community analyses. Direct-cut alfalfa was ensiled with C. perfringens contamination (CKC) or with the addition of Lactobacillus plantarum, sucrose and C. perfringens (LSC). Contamination with C. perfringens enhanced the clostridial fermentation in CKC silage, as indicated by high contents of butyric acid, ammonia nitrogen and Clostridia, while LSC silage was well preserved. The genera Bifidobacterium, Garciella and Clostridium dominated the bacterial community in CKC silage, while predominate genus was replaced by Lactobacillus in LSC silage. The clostridial community in CKC silage was dominated by Garciella sp. (26.9 to 58.1%) and C. tyrobutyricum (24.4 to 48.6%), while the relative abundance of C. perfringens was below 5.0%. Therefore, the effect of Clostridia contamination on ensiling fermentation was dependent on the ensilability of the silage material. Garciella sp. and C. tyrobutyricum, rather than C. perfringens, played dominant role in the clostridial fermentation in CKC silage.

Improving the quality of rice straw silage with Moringa oleifera leaves and propionic acid: Fermentation, nutrition, aerobic stability and microbial communities

Mixed ensiling is believed an effective way to improve nutrient preservation and utilization. The effect of mixing Moringa oleifera leaves (MOL) on silage quality, aerobic stability and microbial communities of rice straw ensiled with/without propionic acid were investigated after 140 days fermentation. The results showed that mixing MOL decreased the pH (4.69 vs 3.85), butyric acid (17.4 g/kg DM vs not detected), ammonia-N (3.36 vs 2.17 g/kg DM) and fiber contents (626 vs 462 g/kg DM) but increased protein content (88.4 vs 125 g/kg DM) of rice straw silages. It also increased the relative abundance of Lactobacillus (12.96% vs 50.82%) at unsealing and Issatchenkia (2.02% vs 36.03%) after exposure to air, and might improve aerobic stability of silages. The addition of propionic acid could inhibit deaminization activity during ensiling and exposure to air. It is suggested mixing MOL could improve the fermentation quality and nutrition of rice straw silage.

Effects of Lactic Acid Bacteria Isolated From Rumen Fluid and Feces of Dairy Cows on Fermentation Quality, Microbial Community, and in vitro Digestibility of Alfalfa Silage

The objective of this study was to select lactic acid bacteria (LAB) isolated from the rumen fluid and feces of dairy cows, and evaluate their effects on silage quality of alfalfa after 30 or 60 days of ensiling. One hundred and four LAB strains were isolated from rumen fluid and feces of six dairy cows, of which four strains (Lactobacillus plantarum F1, L. plantarum F50, Lactobacillus salivarius L100, and Lactobacillus fermentum L120) and one commercial inoculant (GFG) isolated from forage were employed for further study. The silages treated with F1 had the lowest (P < 0.05) pH value and the highest (P < 0.05) lactic acid (LA) content in all treatments. Besides, higher (P < 0.05) in vitro digestibility was also observed in F1-treated silage after 60 days of ensiling. The microbial analysis showed that the Lactobacillus abundance in the F1-treated silages increased to 60.32%, higher than other treatments (5.12–47.64%). Our research indicated that strain F1 could be an alternative silage inoculant, and dairy cows could be a source for obtaining excellent LAB for ensiling.

Dynamics of proteolysis, protease activity and bacterial community of Neolamarckia cadamba leaves silage and the effects of formic acid and Lactobacillus farciminis

To investigate the reason for well preservation of protein in Neolamarckia cadamba leaves (NCL) during ensiling, fresh NCL were ensiled with or without addition of 2.0 mL/kg formic acid (FA) or 1.0 × 10⁹CFU/kg Lactobacillus farciminis (LF), and the dynamics of protease activity and microbial community were analyzed. Nonprotein-N, free amino acid, ammonia-N, the activities of carboxypeptidase and aminopeptidase, and bacterial diversity were low during NCL ensiling. Exiguobacterium dominated in NCL silage and its relative abundance increased while Enterobacter abundance decreased during ensiling. FA lowered (P < 0.05) pH and coliform bacteria number, while LF increased (P < 0.05) lactic acid bacteria number, lactic acid content and Lactobacillus abundance at the early stage of fermentation. In summary, protein in NCL can be well preserved during ensiling likely due to its low protease and bacterial activity, and FA and LF improve the quality of NCL silage in different ways.

Bacterial diversity and fermentation quality of Moringa oleifera leaves silage prepared with lactic acid bacteria inoculants and stored at different temperatures

Four lactic acid bacteria strains (LP, LF, LL, W), isolated and selected from Moringa oleifera leaves (MOL) silage, were identified as Lactobacillus plantarum, L. farciminis, Lactococcus lactis, Weissella thailandensis, respectively. Fermentation quality and bacterial community of MOL ensiled without or with the four strains at 15 °C and 30 °C were investigated. Results showed that all the LAB strains decreased (P < 0.05) the pH and ammonia-N content of MOL silage. Silage stored at 30 °C showed higher (P < 0.05) DM loss, acetic acid and ammonia-N content, and lower LAB count than 15 °C. The environmental temperature also made a great influence on bacterial community of MOL silage. Bacterial diversity was lower and the abundance of Lactobacillus was higher in silages stored at 15 °C. In conclusion, LAB inoculants and a relatively low environmental temperature could be effective to improve the quality of MOL silage.

Fermentation quality and microbial community of alfalfa and stylo silage mixed with Moringa oleifera leaves

The silage quality of alfalfa and stylo without or with 25%, 50% Moringa oleifera leaves (MOL) was investigated, and microbial community after ensiling was analysed. Results showed that the silage samples with MOL have lower butyric acid (0.50 vs 1.20, 0.60 vs 14.5 g/kg dry matter (DM) in alfalfa and stylo silage, respectively), ammonia-N (152 vs 262, 109 vs 180 g/kg total N) content and DM loss (7.71% vs 14.6%, 6.49% vs 18.9%). The addition of MOL also influenced the bacterial community distribution. The relative abundance of Enterobacter decreased from 58.6% to 30.5%, 17.4% to 9.1% in alfalfa and stylo silage when 50% MOL was added. Clostridium decreased from 23.5% to 0.2% in stylo silage, whereas Lactobacillus abundance increased from 30.4% to 49.9%, 41.8% to 86.0% in alfalfa and stylo silage, respectively. In conclusion, mixing with MOL could be a feasible way to improve the quality of alfalfa and stylo silage.