Aerobic Stability Of Silage Research Articles

Lactic acid bacteria strains for enhancing the fermentation quality and aerobic stability of Leymus chinensis silage

AbstractLeymus chinensis is an important grass in China and Russia. Six lactic acid bacteria (LAB) strains (LB, LPL1, LPL2, LPL3, LCL and WH) from L. chinensis silage were screened and identified and their effects on fermentation quality were investigated. All six strains were grown at 6·5% NaCl and pH 4·00. Strains LPL1, LPL2 and LPL3 were identified as Lactobacillus plantarum, and LB, WH and LCL were classified as Lactobacillus brevis, Weissella hellenica and Lactobacillus casei respectively. The six isolated strains and a commercial inoculant (Lactobacillus buchneri) were added to L. chinensis for ensiling at densities of 500 and 600 kg m−3. The control was sprayed with the same volume of distilled water. The effects of the strains on fermentation quality after 45 d ensiling and aerobic stability during 8 d of exposure to air were evaluated. The 600 kg m−3 silage had lower pH, butyric acid, ammonia nitrogen content and coliform bacteria counts than the 500 kg m−3 density silage (P < 0·05). The six isolated strains decreased pH, butyric acid content and increased lactic acid content, and all inoculants increased L. chinensis silage aerobic stability except LCL (P < 0·05). The fermentation quality of L. chinensis silage increased with higher ensiling density. The LAB strains improved the fermentation quality, and high‐quality silage could be obtained at low ensiling density with the addition of the LAB strains. The strains improved the aerobic stability; Lb. buchneri and Lb. brevis showed the best performance.

Replacement of aruana grass by gliricidia (Gliricidia sepium) on silage quality

Our objective was to investigate the effect of the replacement of aruana grass by gliricidia on the fermentative losses, chemical composition, and aerobic stability of silages. For ensiling, whole-crop aruana grass (75 d of growth) was chopped (275 g kg-1 dry matter - DM) and ensiled alone or associated with gliricidia (270 g kg-1 DM; 150 d of growth). For gliricidia, we used only the leaves and stalks to ensile. The evaluated treatments were different ratios of aruana grass to gliricidia (100:0, 75:25, 50:50, 25:75, and 0:100), with four replicates (mini-silos). The silage composed only of gliricidia exhibited a lower pH than the other silages. Dry matter recovery was not affected by the treatments, although effluent losses were affected. The replacement of aruana grass by gliricidia 50% at ensiling resulted in a higher lactic acid bacteria count. The aruana grass silages displayed lower protein contents and a higher neutral detergent fiber content than the gliricidia silages after 40 d of fermentation. Consequently, the silage consisting of 100% gliricidia showed higher in vitro DM digestibility, presenting an increase of 8.13% after 40 d of fermentation compared with 100% of aruana grass silage. After silo opening, the gliricidia silage was very stable (>72 h). The low quality of aruana grass silage is improved by replacing this grass with significant amounts of gliricidia (approximately 75%).

Short communication: Use of a mixture of sodium nitrite, sodium benzoate, and potassium sorbate in aerobically challenged silages

Aerobic instability is still a common problem with many types of silages, particularly well-fermented silages. This study evaluated the effect of adding an additive mixture based on sodium nitrite, sodium benzoate, and potassium sorbate to a variety of crop materials on fermentation quality and aerobic stability of silages. Ensiling conditions were challenged by using a low packing density (104±4.3kg of dry matter/m3) of forage and allowing air ingression into silos (at 14 and 7 d before the end of the storage, for 8 h per event). Additive-treated silages were found to have significantly lower pH and reduced formation of ammonia-N, 2.3-butanediol, and ethanol compared with untreated control silages. Yeast growth was significantly reduced by additive treatment in comparison with untreated control silage. Consequently, additive-treated silages were considerably more aerobically stable (6.7 d) than untreated control silages (0.5 d). Overall, adding 5mL/kg of fresh crop of the additive based on sodium nitrite, sodium benzoate, and potassium sorbate reduced undesirable microorganisms in silages and thereby provided suitable ensiling conditions and prolonged aerobic stability, even under air-challenged laboratory ensiling conditions.

The influence of ensiling potato hash waste with enzyme/bacterial inoculant mixtures on the fermentation characteristics, aerobic stability and nutrient digestion of the resultant silages by rams

The present study aimed to evaluate effects of ensiling potato hash (PHW) with enzyme either alone or in combination with bacterial inoculants on the fermentation characteristics, aerobic stability and nutrient digestion using rams. The PHW was mixed with wheat–bran (B) at 80:20 (% fresh matter) and ensiled in 210L drums for 90 days. The PHWB mixture was treated as: control (untreated), viscozyme, an enzyme containing hemicellulase and pectinase from Aspergillus spp (denoted as Visco), Viscozyme+Lalsil fresh LB (Lactobacillus buchneri NCIMB 40788) (denoted as E+LAB1), and viscozyme+silosolve (containing strains of Lactobacillus plantarum (DSM 16568), Enterococcus faecium (DSM 22502) and Lactobacillus buchneri (DSM 22501) (denoted as E+LAB2). After 90 days of ensiling, PHWB silage samples were collected per treatment and analysed for fermentation characteristics and nutritive values. The PHWB silage was then mixed with ground alfalfa hay at 68:32 (% DM basis) and fed ad libitum to 24 (6 rams/treatment) matured South African Dorper rams (39.7±2.21kg live weight) in a digestibility study. The fibre fractions (aNDF and ADF) and ADL content of PHWB silage were significantly reduced (P<0.05) in the treated silages compared to the control (306g aNDF/kg DM and 124g ADF/kg DM) respectively. Lactic acid content was lowest (58g LA/kg DM; P<0.05) in the control compared to the treated silages. The E+Lab1 treated PHWB silage had lowest (P<0.05) content of CP (<142g CP/kg DM) and significantly greater (P<0.05) content of ammonia-N (>5.3 NH3-N g/kg TN) compared to other treatments. Acetic acid content was lowest (3.4g AA/kg DM; P<0.05) in the Visco treated silage compared to other treatments. This resulted in greater (P<0.05) CO2 production (41g CO2/kg DM) in the Visco treated silage compared to other treatments when exposed to air. However, the addition lactic acid bacteria (LAB) to viscozyme (E+LAB1 and E+LAB2) increased (P<0.05) the contents of LA and AA and improved silage aerobic stability compared to other treatments. Greater (P<0.05) intake of DM (1887g/d) and lower (P<0.05) digestibility of DM were obtained in rams fed on the control silage diet compared to those fed the treated PHWB silage diets. The E+LAB1 and E+LAB2 treatments improved (P<0.05) nutrient digestion, nitrogen (N) retention and energy balance in rams compared to control treatment.

Nutritive value, total losses of dry matter and aerobic stability of the silage from three varieties of sugarcane treated with commercial microbial additives

The practice of ensiling sugarcane without additives results in marked reduction in silage nutritional value due to the rapid fermentation of water-soluble carbohydrates by yeasts. Using commercial inoculants containing homo and heterolactic bacteria during the ensiling process is an important alternative. However, the effectiveness of these inoculants has not been determined. Thus, we aimed to evaluate the effect of using two commercial inoculants during the fermentation of three varieties of sugarcane on the nutritive value, total losses of dry matter and aerobic stability of the silages. We used a completely randomized design in a 3×3 factorial scheme (three varieties and three treatments) with five repetitions. The silages were produced in experimental PVC silos (50cm height and 10cm diameter), remaining closed for a period of 30 days. Treatments consisted of no inoculant, inoculant A (Lalsil® sugarcane, Lactobacillus buchneri, strain NCIMB 40788, 2.5×1010CFU/g) and inoculant B (Silobac® 5, Lactobacillus plantarum, strains CH 6072 and L286, 1×105CFU/g). In all treatments, silages showed increased concentrations of NDF and ADF, and reduction in DM relative to material prior to ensiling. Treatment with inoculant B resulted in greater total losses of DM and fractions of ammonia nitrogen, as well as lower levels of IVDMD and smaller ME, especially for variety RB92579. Treatment with inoculant A improved aerobic stability of silages. The high concentration of sugars (Brix) presented by RB92579 seemed to favor the activity of the yeast and consequently the losses.

Rehydration of corn grain with acid whey improves the silage quality

Our objective was to investigate the effects of rehydration with acid whey or water at three moisture levels, as well as the effects of bacterial inoculation, on the fermentation, chemical composition and aerobic stability of corn grain silages. The trial was conducted in a completely randomized design with four replicates in a factorial arrangement as follows: 3 (rehydration with three different moisture levels: 300, 350 and 400mL/kg of corn grain)×2 (silage inoculated with bacteria or not inoculated (control))×2 (liquid used in the rehydration: acid whey or water). Overall, corn grain silages rehydrated with acid whey produced more lactic acid than the silages rehydrated with water (13.8 vs. 12.6g/kg of dry matter (DM), respectively). In addition, increases in the rehydration of corn grain silages promoted decreases (linear) in lactic acid concentration as well as in production of total acids. Although inoculated silages had higher pH as consequence of the rehydration using water at the three levels, these treatments presented high DM recovery. In general, neutral detergent fiber (aNDFom) decreased if inoculant was applied in corn grain silages rehydrated with acid whey. After silos opening, silages rehydrated with 350 or 400mL/kg (independent of the liquid) had lower aerobic stability than silages rehydrated with 300mL/kg. Overall, we found that the inoculant did not promote significant changes in the composition of the corn grain silage. In contrast, the potential of the use of acid whey in ensiling corn grain is high, as its addition leads to improvements in the fermentation process and aerobic stability of the silages.

Evaluation of the effects of two Lactobacillus buchneri strains and sodium benzoate on the characteristics of corn silage in a hot‐climate environment

AbstractThis study determined the effectiveness of two Lactobacillus buchneri strains (commercial and indigenous) and sodium benzoate (SB) in improving the aerobic stability of corn silage under laboratory and field conditions. Two experiments were carried out to test the following treatments: untreated forage, commercial L. buchneri (CLB), indigenous L. buchneri (ILB) and SB at a 2 g kg−1 concentration. Both inoculants were applied at a rate of 1 × 106 colony forming units of bacteria per gram of forage. In experiment 1, five replicates of each treatment were ensiled in 15‐L laboratory silos. The nutritional, fermentation and microbiological characteristics and aerobic stability of the silage were determined. In experiment 2, the top of a bunker silo was divided into four parts (blocks) along its length before it was sealed, and the treatments were randomly applied. Three bags were buried in each experimental unit (two at the top and one at the core) to determine the loss of dry matter (DM) and the silage characteristics. In experiment 1, ILB exhibited a lower lactic acid concentration and higher 1,2‐propanediol and acetic acid levels, which provided intermediate aerobic stability (67 h). In both experiments, treatment SB exhibited higher residual water‐soluble carbohydrate levels and longer aerobic stability relative to the other treatments. In experiment 2, there were lower DM losses and higher digestibility coefficients when SB was applied, similar to that found at the core. Overall, SB was the most effective additive for improving fermentation, preserving nutrients and reducing the aerobic deterioration of corn silage at the top of a bunker silo in a hot‐climate environment.

The Effect of Commercial Additive (Toxic-Chec) and Propionic Acid on the Fermentation and Aerobic Stability of Silage with Pig Excreta

ABSTRACT The experiment was carried out to evaluate the effect of Toxic-chec commercial additive and propionic acid on the fermentation and aerobic Stability of silage made with pig excreta, corn stover, molasses and urea; during fermentation. The growth of microorganisms in the silage and aerobic stability of the silage were tested. Microsilos were conducted in the laboratory with the following treatments made in triplicate (T): T1 = silage without additive; T2 = silage + 0.05% commercial additive; T3 = silage + 0.05% propionic acid. Three microsilos were realized by treatment in a complete randomized design. The study was carried out in the laboratories of Rumen Microbiology and Animal Nutrition, Graduate College, Montecillo State Campus, Mexico, between June and November 2012. The results showed that the additives tested affected the pH in treatments, but did not affect the concentration of volatile fatty acids, acetic, propionic and Original Research Article

Microbiological profile and aerobic stability of Tifton 85 bermudagrass silage with different additives

The objective of this study was to evaluate the microbiological profile and aerobic stability of silage with Tifton 85 bermudagrass and different additives and wilting. The studied treatments were: pre-drying in the sun for two hours before ensiling; use of bacterial-enzymatic inoculant; addition of soybean peel; addition of corn grits and use of salt in the surface layer of the silo. The experimental design was completely randomized with six treatments and four replications. Plants of Tifton 85 bermudagrass with 38 days were ensiled in experimental silos with Bunsen valves, with compacting density of 236 kg silage per m³ for Tifton 85 bermudagrass, which was pre-dried in the sun; the average silage was 294 kg m-3 for the other treatments. The ratios between soybean hulls and corn grits, added to the silage, were calculated based on the initial DM content from Tifton 85 bermudagrass in order to obtain 320 g/kg DM of the material to be ensiled. There was an increase of lactic bacteria and Clostridium as well as an absence of enterobacteria after the silo opening. Fungi developed only in Tifton 85 bermudagrass and its treatments before the ensilage and yeasts developed in silages of Tifton 85 bermudagrass when they received soybean hulls or corn grits after silo opening. There was no breach regarding aerobic stability of silages during the studied period. The pH reached the highest values within 48 hours after opening the silos, but there were variations during this period.

Barley forages for modern global ruminant agriculture: A review

Ruminants have evolved on forages that comprise major portions of most modern dairy and beef cattle diets. Cattle require minimum amount of effective fiber to maintain healthy rumen conditions. However, high fibre levels limits feed intake. Dietary fiber levels and physical properties contribute to such hypophagia. Forage bulkiness, particle size, lignification and rumen passage rate determine fiber quality. Barley forage (BF, Hordeum vulgare, L.) serves dairy diets where and when alfalfa or corn silages are less accessible. Being lower in protein, intermediate in soluble protein, and higher in starch and cellulose, barley silage (BS) is a suitable replacement for alfalfa silage. Barley forages have usually lower fiber levels among winter cereal crops. Barley forages may not reduce feed intake as much as other cereal crops, notably triticale and oats. Beef studies suggest superior or similar weight gain and feed efficiency by feeding BS versus wheat, triticale and oat silages. Growth response to BS appears comparable to corn silage. Reduced BS particle size reduces chewing activity in lactating cows, and even with adequate fiber intake has little effect on milk fat. Inoculants containing Lactobacillus buchneri, Lactobacillus plantarum, Pediococcus pentosaceus, and Propionibacterium freudenreichii along with carbohydrases can lower silage pH and improve organic acids production and silage aerobic stability. Altered barley silage chop length alters chewing activity but not necessarily rumen pH. Maturity stage affects nutritional value of BF due to altered protein and fiber contents and rumen fermentation patterns. Genetic variance among BF cultivars can affect nutrient profiles and rumen digestibility. Barley forages are cost-effective entities along with alfalfa hay and silage and corn silage for environmentalist ruminants to host optimal rumen and peripheral nutrient metabolism. Adequate effective fiber with sufficient but not very high fermentable starch, and modest degradable proteins make BF a unique ingredient for the sustainable modern ruminant production.

The effects of three silage inoculants on aerobic stability in grass, clover-grass, lucerne and maize silages

The objective of the study was to investigate the effects of homofermentative and heterofermentative lactic acid bacteria (LAB) inoculants on fermentation and aerobic stability in a variety of crops and dry matter concentrations. The experiments were conducted with lucerne, ryegrass, ryegrass-timothy, red clover-ryegrass and whole crop maize using three additives in laboratory scale conditions. Each treatment and crop was replicated 5 five times when determining the chemical composition and aerobic stability in the silage. The data were statistically analyzed as a randomized complete block by using the GLM procedure of SAS. Additive application reduced pH and formation of butyric acid, alcohols and ammonia-N in all crops compared with the untreated silage (p &lt; 0.05). The use of additives increased the content of lactic acid except heterofermentative LAB in maize with 276 g kg-1 DM and increased the content of acetic acid except homofermentative LAB in ryegrass-timothy and maize with 276 g kg-1 DM compared with the untreated silage (p &lt; 0.05). It was observed that the aerobic stability of silages was improved significantly (p &lt; 0.05) by using homofermentative and heterofermentative LAB inoculants.

The effect of carbohydrate additive and inoculation on quality of red clover silage

In this experiment, wilted masses of red clover of cultivar K-17 from the first cut was ensiled in three treatments: a) no additives, b) with the addition of corn (6% of biomass) and c) with the addition of inoculant BioStabil Plus. The experiment design was according to the method of a completely random plan (single factorial trial) in triplicates. Based on the results it can be concluded that the wilted biomass of red clover can be successfully ensiled without additives. However, the inoculation of red clover biomass achieves the most favourable pH value (4.20), the lowest level of degradation of the protein expressed in the amount of NH3-N (107.7 gkg-1 N), the largest production of lactic acid (91.3 gkg-1 DM) and acetic acid (42.6 gkg-1 DM), in the absence of butyric acid. Adding maize meal in the amount of 6% contributed to somewhat more favourable fermentation and increase of the energy value of silage. When using the DLG and Weissbach methods for assessing the quality of silage, all silages were classified into the first class. Contrary to this, according to the Zelter method, control and inoculated silages were evaluated as class III, because of the large amounts of acetic acid. In practices inoculants based on homo-and hetero-fermentative bacteria of lactic acid fermentation are recommended for use, because the increased production of acetic acid contributes positively to te aerobic stability of silage.

Scientific Opinion on the safety and efficacy ofBacillus amyloliquefaciens(NCIMB 30229) as a silage feed additive for all species

A strain of Bacillus amyloliquefaciens is intended to be added to forages to promote the ensiling process (technological additive, functional group: silage additive). The identity of the strain and its susceptibility to relevant antibiotics has been established. However, the strain produces cyclic lipopeptides which possess potent surfactant activity, known to be involved in food intoxication. Although the strain is intended for use only in the production of silage, as a spore former it will survive the ensiling process and be ingested by target animals. The spores will also survive passage through the gastrointestinal tract of animals and be a potential source of contamination of food of animal origin and of the environment. The greatest risk would be to those handling the product on farm following oral, dermal and respiratory exposure. Consequently, the FEEDAP Panel concludes that use of the strain in the production of silage presents a hazard to consumers, users and the environment, and potentially also to the target animals. A total of three laboratory experiments with laboratory-scale silos, each lasting at least 90 days, were carried out using samples of forage of differing dry matter and water-soluble carbohydrate content. In each case, replicate silos containing treated forage were compared with identical silos containing the same but untreated forage. The potential of the additive to improve aerobic stability of silages at the proposed dose of 5.0 107 CFU/kg fresh materials was not convincingly demonstrated.

Laboratory evaluation of absorbents and additives on the fermentation quality of potato hash

This study was conducted to determine the ensiling potential of potato hash (PH) with poultry litter (PL) and hay as absorbents, and whey and molasses as additives. Mixtures of 800 g/kg PH and 200 g/kg of either PL or hay were produced and treated with no additive, whey and molasses. The experiment was conducted in a 2 absorbents × 3 additives factorial design. Mixtures were ensiled in 1.5 L anaerobic jars, and sampling was done on days 0, 4, 10, 20, 40, 60, and 90 for the determination of fermentation quality and nutritive value. Further, an aerobic stability test was done on day 90 by exposing silage to air for 5 days. Ensiling PH with hay compared to PL resulted in a better quality silage as indicated by (P < 0.05) improved fermentation characteristics and chemical composition. Although, the addition of PL significantly increased (P < 0.05) the crude protein (CP) and ash contents in PH silage, fermentation, and the aerobic stability of silage was poor and could influence animal performance negatively. It seems that whey and molasses were effective in improving the in vitro organic matter digestibility (IVOMD) and fermentation characteristics of PH. Further studies are needed to elucidate these effects on animal performance. Key words: Aerobic stability, by-products, potato hash, energy, molasses, whey.

Aspectos qualitativos da silagem de capim-elefante com fubá de milho e casca de soja

The objective of this study was to evaluate the effects of corn meal and soybean hulls in silage Pennisetum purpureum cv. Roxo Botucatu. The experiment has adopted a completely randomized design in a split-plot, with seven treatments (elephant grass pure soy cone (5 and 10%) and corn meal (5 and 10%) alone or in joint same proportions totaling 5 to 10%), three open times and three replications. We used a randomized design in a split-plot, with seven treatments (elephant grass pure, soybean hulls (5 and 10%) and corn meal (5 and 10%) of isolated form or together in the same proportions totalizing 5 and 10%, three open times and three replications. There were used experimental silos made of bucket of 20 L. Silos were opened at 7, 14 and 28 days after ensiling, and evaluated the effluent losses, dry matter, pH, total titratable acidity (TTA) and aerobic stability of silage. The use of additives in ensiling reduced the effluent losses. Dry matter varied with the use of additives, obtaining higher values for the silage with 10% soybean hulls or corn meal, in relation to elephant grass pure silage. The results of pH present interaction between treatment and time of opening, with the desired values 7 days after ensiling.The breaking of aerobic stability occurred 48 hours after opening the silo for the treatments containing corn meal alone or together with soybean hulls for both levels. The use of corn meal, either individually or in combination with soybean hulls, was effective in improving the standard of silage fermentation elephant grass, however, additional care should be taken about management after opening the silo.

The aerobic stability of silage: key findings and recent developments

AbstractWhen silage is exposed to air on opening the silo, or after its removal from the silo, fermentation acids and other substrates are oxidized by aerobic bacteria, yeasts and moulds. The aerobic stability of silage is a key factor in ensuring that silage provides well‐preserved nutrients to the animal with minimal amounts of mould spores and toxins. In this paper, key findings and recent developments are reviewed, and findings of recent research are integrated in terms of four themes: (i) the most significant biochemical and microbiological factors, (ii) physical and management factors, (iii) type of additive and (iv) silo sealing. The development of yeasts and moulds during plant growth, and during field wilting or storage, and the concentration of undissociated acetic acid in silage are important microbiological and biochemical factors affecting aerobic stability. Silage density and porosity are key physical factors that affect the rate of ingress of oxygen into the silage mass during the feed‐out period. A target for potential silage aerobic stability is 7 d including time in the feed trough. To achieve this target, speed of harvest should be coordinated with packing tractor weight to achieve a minimum silage density by the time of feed‐out of 210 kg DM m−3, maximum proportional porosity of 0·4 and a rate of silage removal, which matches or exceeds the depth of air penetration into the silo. The use of additives to increase aerobic stability is advisable when there is the risk of these objectives not being met. Novel microbial approaches to solving the problem of silage aerobic deterioration are needed.

Effects of cinnamon leaf, oregano and sweet orange essential oils on fermentation and aerobic stability of barley silage

Silage additives are marketed with the primary aim of improving the fermentation and/or aerobic stability of silage. The objective of this study was to evaluate the impact of three different essential oils (EOs; cinnamon leaf (CIN), oregano (ORE) and sweet orange (SO)) on the fermentation characteristics and stability of barley silage. Chopped whole-plant barley (Hordem vulgare L.) forage was ensiled either untreated (0 mg kg⁻¹ dry matter (DM)) or treated with CIN, ORE or SO (37.5, 75 and 120 mg kg⁻¹ DM). Moulds were not detected in any treatments, including the control, after 7 days of air exposure. All EOs at a concentration of 120 mg kg⁻¹ silage DM decreased (P = 0.001) yeast populations in comparison with the control during air exposure. Net gas, methane and ammonia concentrations in vitro did not differ among treatments. Changes in volatile fatty acid concentrations were small, and in situ data showed no changes in DM and neutral detergent fibre digestion rates for CIN, ORE or SO at concentrations up to 120 mg kg⁻¹ DM. The findings from this study show that a concentration of 120 mg EO kg⁻¹ DM decreased yeast counts during aerobic stability tests. However, all EO treatments had minimal effects on data from in vitro and in situ incubations.

Ensiling fermentation products and aerobic stability of corn and sorghum silages

The objective of the present study was to determine the changes that occur in corn (Zea mays) and sorghum (Sorghum vulgare) silages during exposure to air, and to try to elucidate the factors that exert silage aerobic stability. Two corn and two sorghum ensiling experiments were performed in mini-silos. After a storage period of 5 months, the various silages were subjected to an aerobic stability test in bottle systems, which lasted 7 days. In these bottles changes in pH, production of CO2, numbers of yeasts and molds serve as spoilage indicators. Changes in chemical components during aerobic exposure were also followed. The first corn silage was aerobically stable, whereas the second corn silage spoiled; pH values for the unstable silage increased from 3.6 to 4.1 and 5.9, and the CO2 production was 38 and 48 g kg−1 DM, after 4 and 7 days of aerobic exposure, respectively. The first corn silage that was aerobically stable contained high concentrations of acetic acid, whereas the second corn silage that spoiled had low concentrations of VFA. The two sorghum silages were more stable upon aerobic exposure in spite of their low content of acetic acid, and other volatile fatty acids (VFA), which are known inhibitors of fungi.

Bacterial and fungal communities of wilted Italian ryegrass silage inoculated with and without Lactobacillus rhamnosus or Lactobacillus buchneri

To understand the effects of lactic acid bacteria (LAB) inoculation on fermentation products, aerobic stability and microbial communities of silage. Wilted Italian ryegrass was stored in laboratory silos with and without inoculation of Lactobacillus rhamnosus and Lactobacillus buchneri. The silos were opened after 14, 56 and 120 days and then subjected to aerobic deterioration for 7 days. Intensive alcoholic fermentation was found in untreated silage; the sum of ethanol and 2,3-butanediol content at day 14 was about 7 times higher than that of lactic and volatile fatty acids. Alcoholic fermentation was suppressed by L. rhamnosus and L. buchneri inoculation and lactic acid and acetic acid became the dominant fermentation products, respectively. Silages were deteriorated in untreated and L. rhamnosus-inoculated silages, whereas no spoilage was found in L. buchneri-inoculated silage. Enterobacteria such as Erwinia persicina, Pantoea agglomerans and Rahnella aquatilis were detected in untreated silage, whereas some of these bacteria disappeared or became faint with L. rhamnosus treatment. When silage was deteriorated, Lactobacillus brevis and Bacillus pumilus were observed in untreated and L. rhamnosus-inoculated communities, respectively. The inoculated LAB species was detectable in addition to untreated bacterial communities. Saccharomyces cerevisiae and Pichia anomala were the main fungi in untreated and L. rhamnosus-inoculated silages; however, P. anomala was not visibly seen in L. buchneri-inoculated silage either at silo opening or after exposure to air. Inoculation with L. rhamnosus can suppress alcoholic fermentation of wilted grass silage with elimination of enterobacteria at the beginning of fermentation. Addition of L. buchneri may improve aerobic stability, with distinct inhibitory effect observed on P. anomala after silo opening. Bacterial and fungal community analyses help us to understand how inoculated LAB can function to improve the fermentation and aerobic stability of silage.

Trends in legumes ensilaging

Modern trends in legumes ensilaging technology are based on the knowledge of biomass from the aspect of suitability for ensilaging, wilting, addition of carbohydrate feed, use of biological additives, etc. Today, the experiments are conducted, worldwide, with inoculates, which, in addition to homofermentative, also contain heterofermentative lactic acid bacteria. Products of such inoculants contribute to the increase of aerobic stability of silages so their implementation is good for all types of silage. In addition to the usage of those additions, modern technology of silage is based on the maximum mechanization of the ensilaging process, as well as preparing the silage in the form of roto-bales and silo tubes (most inexpensive way of conservation) as well as permanent facilities.