This study determined how the fermentation and aerobic stability of corn silage are affected by treatment with molasses or 2 dual-purpose inoculants applied at or above the recommended rate. Corn ...forage (DeKalb 69–70) was harvested at 39% dry matter (DM) and ensiled after treatment with no additives (control, CON), molasses (MOL), Buchneri 500 inoculant, or Pioneer 11C33 inoculant. Molasses was applied at 3% of forage DM. Buchneri 500 was applied at the recommended rate of 8mg/kg fresh forage to supply 1×105 cfu/g of Pediococcus pentosaceus 12455 and 4×105 cfu/g of Lactobacillus buchneri 40788 (BB) or at twice the recommended rate (DBB). Pioneer 11C33 inoculant was applied at the recommended rate of 1.1mg/kg fresh forage to supply 1×105 cfu/g of a mixture of Lactobacillus plantarum, L. buchneri, and Enteroccocus faecium (PN) or at twice the recommended rate (DPN). Each treatment was applied in quadruplicate and the treated forages were ensiled within 20-L mini silos for 135 d at 18 to 35°C. Molasses-treated silages had greater ash and starch concentrations than CON silages and greater lactate and ethanol concentrations than other silages. Like CON silages, MOL silages had high yeast counts (>105 cfu/g); consequently, they deteriorated within 30h as shown by temperature increase. Inoculant-treated silages had lower lactate to acetate ratios than CON or MOL silages largely because they had greater acetate concentrations. Consequently, all inoculant-treated silages had fewer yeasts (<105 cfu/g) and were more stable (>30h) than CON and MOL silages. When applied at recommended rates, PN and BB had similar effects on silage chemical composition, fermentation, fungal counts, and aerobic stability, except for a lower lactate concentration in PN silages. Concentrations of VFA, and NH3-N, pH, and extent of aerobic stability were similar for PN, DPN, BB, and DBB silages. However, lactate concentration was greater in DPN than in PN. In conclusion, MOL application increased ethanol and lactate concentration and did not improve aerobic stability. Both dual-purpose inoculants made the fermentation more heterolactic and thereby improved the aerobic stability of corn silage. Doubling the rate of application of either inoculant did not further improve fermentation or aerobic stability.
The fates of hydrophobic zein proteins, which encapsulate corn starch to create vitreous endosperm, have not been investigated in high-moisture corn (HMC). To assess influences of ensiling time and ...inoculation on zein proteins in HMC, quadruplicate samples of 2 random corn hybrids (A and B), containing 25.7 and 29.3% moisture, were ground, inoculated with (I) or without 600,000 cfu/g of Lactobacillus buchneri 40788 (Lallemand Animal Nutrition, Milwaukee, WI), and ensiled for 0, 15, 30, 60, 120, and 240 d. Nutrient composition crude protein (CP), starch, acid detergent fiber, and neutral detergent fiber, fermentation (pH, lactate, and acetate), and protein degradation markers (buffer-soluble CP, isopropanol-soluble CP, and NH3-N) were evaluated. At 0 and 240 d, α, γ, δ, and β zein subunits were profiled using HPLC. Data were evaluated as a split-split plot using the PROC MIXED procedures of SAS. Ensiling time and inoculation decreased pH, and altered lactate and acetate contents of HMC. Lactate and acetate contents of A, AI, B, and BI at 240 d were 0.40, 0.32, 1.11, 0.73, and 0, 0.35, 0.30, and 0.87% of DM, respectively. Buffer-soluble CP in HMC increased from 1.5 to 2.0% of DM at 0 d to >4.0% of DM at 240 d. Inoculation had no effect on buffer-soluble CP but increased NH3-N content of HMC. Corn A contained more isopropanol-soluble CP than did corn B and peak areas for 6 α, and all γ and δ zein regions were greater for corn A. Ensiling (0 vs. 240 d) decreased all zein subunits with the exception of 2 α and 1 δ subunit. Ensiling decreased (42.2–73.2%) γ zeins, which are primarily responsible for cross-linking in the starch-protein matrix. Despite altering lactate and acetate contents, inoculation had no effect on degrading hydrophobic zein proteins in HMC. Data suggest that hydrophobic zein proteins in the starch-protein matrix of HMC are degraded by proteolytic activity over an extended ensiling time.
The present study aimed to investigate the effects of 2 corn silage inoculation strategies (homofermentative vs. heterofermentative inoculation) under field conditions and to monitor responses in ...silage variables over the feeding season from January to August. Thirty-nine commercial dairy farms participated in the study. Farms were randomly assigned to 1 of 3 treatments: control (nonactive carrier; Chr. Hansen A/S, Hørsholm, Denmark), Lactisil (inoculation with 1 × 105 Lactobacillus pentosus and 2.5 × 104 Pediococcus pentosaceus per gram of fresh matter; Chr. Hansen A/S), and Lalsil Fresh (inoculation with 3 × 105 Lactobacillus buchneri NCIMB 40788 per gram of fresh matter; Lallemand Animal Nutrition, Blagnac, France). Inoculation with Lactisil had no effects on fermentation variables and aerobic stability. On the contrary, inoculation with Lalsil Fresh doubled the aerobic stability: 37, 38, and 80±8h for control, Lactisil, and Lalsil Fresh, respectively. The effect of Lalsil Fresh on aerobic stability tended to differ between sampling times, indicating a reduced difference between treatments in samples collected in April. Lalsil Fresh inoculation increased silage pH and contents of acetic acid, propionic acid, propanol, propyl acetate, 2-butanol, propylene glycol, ammonia, and free AA. The contents and ratios of dl-lactic acid, l-lactic acid relative to dl-lactic acid, free glucose, and dl-lactic acid relative to acetic acid decreased with Lalsil Fresh inoculation. Lalsil Fresh inoculation increased the silage counts of total lactic acid bacteria and reduced yeast counts. The Fusarium toxins deoxynivalenol, nivalenol, and zearalenone were detected in all silages at all collections, but the contents were not affected by ensiling time or by inoculation treatment. The effect of inoculation treatments on milk production was assessed by collecting test-day results from the involved farms and comparing the actual milk production with predicted milk production within farm based on test-day results from 2007 and 2008. The average milk production of lactating cows at test days during the study (January to September 2009) was 30.7±0.5kg of energy-corrected milk/d. Milk production was 104.6±0.7% of the predicted yield and did not differ among treatments. In conclusion, the present study showed that homofermentative inoculants might not compete efficiently or might not deviate sufficiently from the epiphytic flora on whole-crop corn to affect fermentation in standard qualities of corn silage. Heterofermentative inoculation increased aerobic stability and numerous fermentation variables. None of the treatments affected milk production, and more-stable corn silage seemed to have a similar production value as compared with less-stable homofermented silage. Heterofermented silage can be evaluated for its properties to limit aerobic silage deterioration in the feed chain.
The microbial hosts of antibiotic resistance genes (ARGs) found epiphytically on plant materials could grow and flourish during silage fermentation. This study employed metagenomic analysis and ...elucidated the occurrence and transmission mechanisms of ARGs and their microbial hosts in whole-crop corn silage inoculated with homofermentative strain Lactiplantibacillus plantarum or heterofermentative strain Lentilactobacillus buchneri ensiled under different temperature (20 and 30 °C). The results revealed that the corn silage was dominated by Lactobacillus, Leuconostoc, Lentilactobacillus, and Latilactobacillus. Both the ensiling temperature and inoculation had greatly modified the silage microbiota. However, regardless of the ensiling temperature, L. buchneri had significantly higher ARGs, while it only exhibited significantly higher mobile genetic elements (MGEs) in low temperature treatments. The microbial community of the corn silage hosted highly diverse form of ARGs, which were primarily MacB, RanA, bcrA, msbA, TetA (58), and TetT and mainly corresponded to macrolides and tetracyclines drug classes. Plasmids were identified as the most abundant MGEs with significant correlation with some high-risk ARGs (tetM, TolC, mdtH, and NorA), and their abundances have been reduced by ensiling process. Furthermore, higher temperature and L. buchneri reduced abundances of high-risk ARGs by modifying their hosts and reduced their transmission in the silage. Therefore, ensiling, L. buchneri inoculation and higher storage temperature could improve the biosafety of corn silage.
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•Effect of temperature and LAB on ARGs' occurrence and transmission in corn silage were illustrated.•ARGs in corn silage are mainly associated to macrolide and tetracycline resistance.•Temperature influenced the silage microbiota, ARGs and MGEs than LAB inoculants.•High-risk ARGs (tetM, TolC, mdtH, and NorA) mostly related to plasmids were reduced.•Higher temperature and L. buchneri inoculant enhanced the biosafety of corn silage.
Aims
The objective of this study was to evaluate the potential of hexanoic acid (Hex) as a silage additive.
Methods and Results
The effect of Hex, Lactobacillus plantarum (Lp) and their combination ...(Hex + Lp) on the aerobic stability of napier grass silage was investigated. Napier grass was ensiled without additives (C) or with Lp, Hex or Hex + Lp for 60 days followed by 7 days of aerobic exposure. After 60 days of ensiling, the Lp silage had the lowest pH and the highest lactic acid (LA) concentration among all silage, whereas the highest water‐soluble carbohydrates (WSC) content was observed in Hex + Lp silage, followed by Hex silage. After 60 days of ensiling, the population of yeasts in C and Lp silages was > 3·0 log10 CFU per g FW, while that of Hex and Hex + Lp was <2·0 log10 CFU per g FW. During aerobic exposure, the pH in the Lp and C silages increased (P < 0·05) above 7·0 on day 5. The pH of Hex silage was the lowest among all silages on day 3 and 5, followed by a significant (P < 0·05) increase until 7 days of aerobic exposure. There were no significant changes in pH and AA of Hex + Lp silage over the duration of aerobic exposure. The concentrations of LA in C, Lp and Hex silages decreased while that of Hex + Lp silage remained stable after 3 days of aerobic exposure. The Hex delayed the decline of WSC contents and the increase in yeasts over the aerobic exposure period.
Conclusion
Addition of Hex (97 h) and Hex + Lp (>168 h) improved aerobic stability (P < 0·05) as compared to the control (83 h).
Significance and Impact of the Study
Hex or in combination with L. plantarum inhibited the proliferation of yeasts during aerobic exposure of napier grass. Thus, Hex is an alternative antifungal additive to improve aerobic stability.
AIMS: This study aimed to evaluate the effects of inoculation of strains of lactic acid bacteria (LAB) isolated from sugarcane grown in a Brazil on the quality of corn silage. METHODS AND RESULTS: ...Three strains of Lactobacillus buchneri (UFLA SLM11, UFLA SLM103 and UFLA SLM108), five strains of Lactobacillus plantarum (UFLA SLM08, UFLA SLM41, UFLA SLM45, UFLA SLM46 and UFLA SLM105), and one strain of Leuconostoc mesenteroides (UFLA SLM06) were evaluated at 0, 10, 30, 60 and 90 day after inoculating corn forage. The inoculation of the LAB strains did not influence the chemical composition of the silage, but pH, acetic acid and 1,2‐propanediol were affected by treatment. The silages inoculated with UFLA SLM11 and SLM108 contained the lowest yeast and filamentous fungi counts during fermentation. Bacteria belonging to the Enterobacteriaceae family, Clostridium genus were detected in the silages inoculated with Lact. buchneri UFLA SLM 11, 103 and 108, as shown by DGGE analysis. Silages inoculated with Lact. buchneri UFLA SLM 11 showed higher aerobic stability. CONCLUSIONS: The Lact. buchneri UFLA SLM11 strain was considered promising as a starter culture or inoculant for corn silages. SIGNIFICANCE AND IMPACT OF THE STUDY: The selection of microbial inoculants for each crop promotes improvement of silage quality. Studies on the chemical and microbiological characteristics of silage provide useful information for improving ensiling techniques.
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.
•Effect of microbial pretreatment on biogas production of non-sterile, rotted silage maize straw was evaluated.•Microbial community maintained structure and functional stability in non-sterile ...condition.•Biogas production yields significantly increased after microbial pretreatment.
Using microbial community MC1 to pretreat lignocellulosic materials increased the yield of biogas production, and the substrate did not need to be sterilized, lowering the cost. Rotted silage maize straw carries many microbes. To determine whether such contamination affects MC1, rotted silage maize straw was pretreated with MC1 prior to biogas production. The decreases in the weights of unsterilized and sterilized rotted silage maize straw were similar, as were their carboxymethyl cellulase activities. After 5d pretreatment, denaturing gradient gel electrophoresis and quantitative polymerase chain reaction results indicated that the proportions of five key strains in MC1 were the same in the unsterilized and sterilized groups; thus, MC1 was resistant to microbial contamination. However, its resistance to contamination decreased as the degradation time increased. Following pretreatment, volatile fatty acids, especially acetic acid, were detected, and MC1 enhanced biogas yields by 74.7% compared with the untreated group.
Two experiments were conducted on alfalfa to investigate the effects of the addition of commercial chestnut hydrolyzable tannin at ensiling on 1) silage fermentation quality in lab-scale silos and ...protein degradation in the rumen, and 2) silage fermentation quality and proteolysis in bale silages. Wilted alfalfa was prepared with 4 tannin levels (0, 2, 4, and 6% on a dry matter (DM) basis; T0, T1, T2, T3, respectively) and ensiled in lab-scale silos. Silages (33% DM) were analyzed for fermentation quality, protein rumen degradability in situ, and organic matter digestibility in vitro through gas production after 120 d of conservation. Wilted alfalfa containing 0 and 4% tannin (T0 and T2) was harvested at 40% DM (wilting level I) and 53% DM (wilting level II) for bale (600mm diameter) silage. Silages were analyzed for fermentation quality after 78 d of conservation. All the silages were well fermented with no butyric acid. Lab-scale silages showed reductions in ammonia, nonprotein nitrogen (NPN) and DM losses in T2 and T3 treatments, while the fermentation acid profiles were unaffected. In experiment 1, the untreated silage (T0) had the highest protein degradability after being incubated in the rumen. The addition of tannin reduced crude protein ruminal disappearance in a dose-dependent manner. However, the tannin reduced the organic matter digestibility by 5.1% for all of the tannin addition levels. The tannin positively affected the silage quality in the round bale silages, in particular reducing ammonia and NPN in the lowest wilting level. In both experiments, T2 treatment reduced proteolysis without any influence of DM on the binding reaction and reduced the NPN by 15% in comparison to the control.
Aims
Ferulic acid esterase (FAE)‐producing Lactobacillus species isolated from ensiled Elymus nutans growing on the Qinghai‐Tibetan plateau were characterized, and effects of their application to the ...alfalfa ensiling process and the evidence to synergic effect between cellulase and FAE were investigated.
Methods and Results
The results of 16S rRNA gene sequence and species‐specific polymerase chain reaction amplification showed that two screened strains with high FAE activity were Lactobacillus plantarum A1 (LP) and L. brevis A3 (LBr). The optimum temperature and pH for the LP and LBr was 37°C and 6·4 respectively. The FAE exhibited a good stability at temperatures between 25 and 50°C and at pH values of 5·0–7·0. The two strains and a commercial cellulase (CE) were applied as additives to alfalfa silage. After 60 days of ensiling, the lactic acid in the control and CE groups were significantly lower than those of the other treatment groups. The neutral detergent fibre and acid detergent fibre contents in the LP group were significantly lower than those observed in the other groups. At the same time, the combination of CE and FAE‐producing lactic acid bacteria synergistically improved the fermentation quality of the silage.
Conclusions
The addition of the FAE‐producing strain of L. plantarum A1 to alfalfa silage improved its fermentation quality, and reduced the fibre content of the silage.
Significance and Impact of the Study
The screened homo‐fermentative and FAE‐producing strain of L. plantarum A1 could be a candidate strain in improving fermentation quality and fibre digestibility of ensiled forages.
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