Higher Aerobic Stability Research Articles

Effects of light wilting and heterolactic inoculant on the formation of volatile organic compounds, fermentative losses and aerobic stability of oat silage

This study examined the effects of light wilting and applying a heterolactic inoculant on the formation of volatile organic compounds, fermentative losses and aerobic stability of oat silage. White oat (Avena sativa cv. URS Charrua) at heading stage was cut during the morning and allowed to wilt for 5 h or directly harvested in the afternoon. After mechanical chopping, forages were treated or not with Lactobacillus buchneri 40788 at 4 × 105 cfu/g. Treated forages were packed into 1.96 L gas-tight silos and stored for 112 d. Wilting was effective in increasing the dry matter (DM) content from approx. 200 to 300 g/kg and decreasing gas production during fermentation. Direct-cut favored the fermentation, resulting in higher lactic acid and lower pH in uninoculated silages. Silages treated with L. buchneri had lower content of lactic acid, greater concentrations of acetic acid, ethanol and ethyl acetate, and substantially higher fermentative losses. Unwilted silage inoculated with L. buchneri had more 1-propanol, propionic acid and propyl acetate, perhaps due to the metabolism of epiphytic strains of Lactobacillus diolivorans. The heterolactic inoculant also led to higher content of NH3-N, 2,3-butanediol and 2-butanol in unwilted oat silage. Treating oat silage with L. buchneri delayed the increase in silage temperature upon air exposure; nonetheless, all silages presented high aerobic stability. Hence, inoculation with L. buchneri is not recommended for oat silages with DM concentrations up to 300 g/kg because it increases fermentative losses.

<b>Corn grain processing improves chemical composition and fermentative profile of rehydrated silage

This study evaluated the effects of the rehydration and ensiling of corn grain with two geometric mean diameters (GMD) of 0.55 and 1.83 mm obtained by the diameter of the sieved used on the fermentation characteristics and chemical composition of the silage. The experimental design was completely randomized with two treatments and six replications, as follows: rehydrated fine-corn grain silage (RFS) and rehydrated coarse-corn grain silage (RCS). Ground corn was rehydrated with water to achieve moisture levels close to 350 g kg-1. There was no effect on the dry matter recovery, though the recovery rate was high, with values greater than 97% in both silages. The particle size influenced the fiber content, with lower values in the RFS. The acetic and lactic acid concentrations were higher in the RFS, but the pH of the silages did not change. Oxygen exposure changed the pH of silages to 4.25 and 4.38 for RFS and RCS, respectively. After opening the silos, the silages showed high aerobic stability after 90 hours, which resulted in lower deterioration and lesser loss of quality. The geometric mean diameter of corn grain affects the silage fermentative profile and nutritional value.

<b>Nutritional composition and aerobic stability of winter cereal silage at different storage times

The objective of the experiment was to evaluate the nutritional composition, dry matter (DM) recovery and aerobic stability of winter cereal silages under different storage periods. The materials used were wheat (Triticum aestivum cv. BRS Gralha Azul), barley (Hordeum vulgare cv. BRS Brau), white oat (Avena sativa cv. URS Guará), black oat (Avena strigosa cv. Embrapa 139) and triticale (X Triticosecale IPR 11), in three storage periods: 60, 120 and 180 days. The experiment was conducted in a 5x3 factorial, completely randomized design, consisting of five forage species and three storage periods, with five replicates. In nutritional assessment, barley silage presented low values of acid detergent fiber (ADF; 331.2, 355.2 and 378.5 g kg DM-1 for 60, 120, 180 days, respectively), high total digestible nutrients (TDN; 558.2, 544.7 and 531.6 g kg DM-1 for 60, 120, 180 days, respectively), high DM recovery and aerobic stability. Wheat and triticale showed a decrease in DM recovery with the increase in storage length, although showed high aerobic stability. The storage period had a different effect on forages; however, storage period above 60 days provided no benefits for the variables evaluated.

Re‐ensiling and inoculant application with Lactobacillus plantarum and Propionibacterium acidipropionici on sorghum silages

AbstractRe‐ensiling of previously ensiled forage has been a common practice in Brazil, and the use of inoculants may provide a means of reducing dry‐matter (DM) loss. This study aimed to determine the effect of re‐ensiling and the use of microbial inoculants on the quality of sorghum silage. Treatments were presence/absence of an inoculant (Lactobacillus plantarum and Propionibacterium acidipropionici) in the silage, and the re‐ensiling, or not, of the material after 24 h of exposure to air, and these were tested in a factorial 2 × 2 design. Losses due to gas, effluent and total DM were assessed, as were the fermentation characteristics, chemical composition, aerobic stability, and aerobic counts of microorganisms. Effluent loss was higher in re‐ensiled silage, and these silages had lower lactic acid content and higher levels of acetic and propionic acids. The in vitro DM digestibility was lower in the re‐ensiled sorghum silages. The re‐ensiled silage had higher aerobic stability. The inoculant only increased the acetic acid content of the silage. The re‐ensiling of sorghum silage increased effluent loss by 71·2%, and reduced DM digestibility by 5·35%. The use of inoculant did not influence the quality of sorghum silage.

Effects of ethanol, molasses and Lactobacillus plantarum on the fermentation quality, in vitro digestibility and aerobic stability of total mixed ration silages in the Tibetan plateau of China.

In Tibet, it is common practice to make and relocate total mixed ration (TMR) silages before feeding due to the uneven distribution of forages temporally and spatially. This study was conducted to investigate the effects of Lactobacillus plantarum (L), molasses (M) or ethanol (E) on the fermentation quality and aerobic stability of local adaptive TMR silage. After 45 days of ensiling, pH and ammonia nitrogen in inoculated TMR silages were significantly lower than control. During the first 6 days of the aerobic exposure test, a small fluctuation in lactic acid concentration for all TMR silages was observed, and then silages with ethanol continued this trend, while lactic acid in silage without ethanol sharply decreased until the end of the aerobic exposure period. Meanwhile, pH gradually increased along the aerobic exposure; silages treated with ethanol showed lower pH after 9 days of aerobic exposure. The population of yeast gradually increased during 6 days of aerobic exposure, after that an accelerated rise was observed in TMR silages without ethanol. The combinational beneficial effect of L. plantarum and ethanol was found in combined addition of ethanol and Lactobacillus plantarum silages (EL), indicated by intermediate fermentation quality and higher aerobic stability.

Improving corn silage quality in the top layer of farm bunker silos through the use of a next-generation barrier film with high impermeability to oxygen

This study examined the effect on the fermentation, chemical, and microbiological quality of corn silage covered with a new-generation high oxygen barrier film (HOB) made with a special grade of ethylene-vinyl alcohol (EVOH) compared with a standard polyethylene film (PE). Two bunkers (farms 1 and 2) were divided into 2 parts lengthwise so that half of the silo would be covered with PE film and the other with HOB film. Plastic net bags with fresh chopped corn were buried in the upper layer (close to and far from the wall) and in the central part of the bunkers. During spring-summer consumption, the bags were unloaded, weighed, and subsampled to analyze the dry matter (DM) content, neutral detergent fiber and starch contents, pH, lactic and monocarboxylic acids, yeast and mold counts, aerobic and anaerobic spore-former counts, and aerobic stability. We also determined the economic benefit of applying the novel covering. The top layer of silage conserved under the HOB film had a higher lactic acid content and lower pH; lower counts of yeasts, molds, and aerobic and anaerobic spore-formers; higher aerobic stability; and lower DM losses than the silage conserved under the PE film. The use of the HOB film prevented almost all of the silage in the upper layer from spoiling; only 2 out of 32 samples had a mold count >6log10 cfu/g. This led to a net economic gain when the HOB film was used on both farms due to the increased DM recovery and reduced labor time required to clean the upper layer, even though the HOB film cost about 2.3 times more than the PE film. Furthermore, use of the HOB film, which ensures a longer shelf life of silage during consumption, reduced the detrimental effect of yeasts, molds, and aerobic and anaerobic spore-formers on the nutritional and microbiological quality of the unloaded silage.

Perdas fermentativas e estabilidade aeróbia de silagens de milho inoculadas com bactérias ácido-láticas em diferentes estádios de maturidade

Objetivou-se, nesta pesquisa, avaliar o efeito de inoculantes bacterianos em silagens produzidas com plantas de milho em diferentes estádios de maturidade quanto às perdas fermentativas e estabilidade aeróbia. Utilizou-se o delineamento inteiramente casualizado, em esquema fatorial 3x5, e avaliaram-se dois inoculantes (Silobac® e Maize All®) e uma silagem controle em 5 estádios de maturação fisiológica do milho, com 4 repetições. Verificou-se efeito positivo dos inoculantes quanto às perdas fermentativas, e a adição de Silobac® e Maize All® promoveram perda de matéria seca (PMS) 1,78 e 1,75 pontos percentuais a menos que a silagem controle (7,95%). As silagens produzidas com 2/3 de linha de leite e camada negra (CN) apresentaram menor PMS, o que se deve principalmente a menor produção de efluente. A silagem que levou maior tempo para apresentar quebra da estabilidade aeróbia foi aquela produzida a partir de plantas de milho no estádio camada negra e inoculada com Maize All®, ao passo que se notou menor estabilidade para outras silagens inoculadas com esse mesmo produto em virtude do aumento no teor de umidade das silagens. Os inoculantes utilizados neste trabalho são eficientes em diminuir as perdas de MS durante o processo fermentativo, contudo, contribuem com maior aporte de nutrientes nas silagens, o que resulta em menor estabilidade após a abertura dos silos. Silagens produzidas com maior concentração de MS apresentam menores perdas de MS durante a fermentação, assim como são mais estáveis em contato com o oxigênio.

Effects of inoculation of Lactobacillus rhamnosus and Lactobacillus buchneri on fermentation, aerobic stability and microbial communities in whole crop corn silage

Whole crop corn silage may be prone to spoilage after exposure to air. To investigate control of fermentation and aerobic spoilage by using silage additives, Lactobacillus rhamnosus and Lactobacillus buchneri were added to whole crop corn silage, and shifts in microbial communities were examined. Bacterial and fungal communities were identified by denaturing gradient gel electrophoresis analysis at the time of opening the silo and after conducting aerobic deterioration tests. Inoculation of L. rhamnosus did not affect fermentation, whereas that of L. buchneri decreased the lactic acid content and increased the acetic acid content. Aerobic stability was enhanced in silage stored for a long period (120 days), with increases in the acetic acid content even without L. buchneri inoculation. A high aerobic stability was achieved with a shorter ensiling period (56 days) in L. buchneri-inoculated silage. Lactic acid bacteria (LAB) inoculation did not alter the indigenous bacterial community, and the inoculated species were detected only as additions. Lactobacillus brevis, Pediococcus parvulus, Weissella confusa and Klebsiella pneumoniae were found in both the pre-ensiled crop and the silage, whereas Weissella paramesenteroides, Lactobacillus plantarum and Lactobacillus lactis were seen exclusively after ensiling. Inoculation also had little effect on the fungal community during the fermentation process. Candida magnolia, Cryptococcus flavus and Candida intermedia were detected, both in the pre-ensiled crop and the silage, whereas Candida glabrata and Candida quercitrusa were identified exclusively in the silage. Marked changes were seen in the fungal community after aerobic spoilage; Saccharomyces exiguus, Saccharomyces martiniae, Pichia fermentans, Pichia deserticola and Pichia kudriavzevii appeared in the spoiled silage. These results indicated that LAB inoculation produces few changes in bacterial and fungal communities in corn silage and that substantial changes occur in the fungal community when the silage is spoiled.

Skład chemiczny i jakość kiszonek z sorgo cukrowego i kukurydzy

Sweet sorghum (Sorghum saccharatum) silage, maize (Zea mays) silage, and sorghum and maize (1:1) silage were investigated. The silages were analysed for chemical composition, quality and aerobic stability. Dry matter was the lowest (20.88%) in sorghum silage and the highest (37.45%) in maize silage. In sorghum silage, the concentration of crude ash and crude fibre was higher, and that of crude protein, crude fat and N-free extractives lower compared to maize silage. Neutral detergent fibre and acid detergent fibre were the highest in sorghum silage and the lowest in maize silage. The silages were dominated by lactic acid, with trace amounts of butyric acid. Maize silage was higher lactic acid and higher total acids than others. All silages were of very good quality according to Flieg-Zimmer scale. Silage pH ranged from 4.20 to 4.31. Sorghum silage was characterized by higher aerobic stability (81h) compared to the other silages from maize (74h) and sorghum and maize 1:1 (69h).

Resistance to aerobic deterioration of total mixed ration silage: effect of ration formulation, air infiltration and storage period on fermentation characteristics and aerobic stability

AbstractBACKGROUND: High aerobic stability can be expected when wet brewers' grains are stored as a total mixed ration (TMR) silage. To understand the factors affecting the stability, the effects of ration formulation, air infiltration and storage period were studied.RESULTS: A TMR containing wet brewers' grains, hay, maize, wheat bran, beet pulp and molasses was ensiled in laboratory silos for 14 and 56 days. The effects of hay species (lucerne or sudangrass) and air infiltration (Exp. 1) and of excluding one, two or three items from the six ingredients (Exp. 2) were examined. Ethanol was the main fermentation product in all TMR silages in this study. Aerobic deterioration occurred in 14 day silages prepared with sudangrass hay along with air infiltration (Exp. 1), and with the simplest recipe where three items (hay, maize and wheat bran) were excluded (Exp. 2). No deterioration occurred in 56 day silages regardless of ration formulation and air infiltration. Yeasts receded in 56 day silages, except with the simplest recipe, to the 102 cfu g−1 level and remained undetectable in the presence of air (Exp. 2).CONCLUSION: TMR silage can resist aerobic deterioration provided that a sufficient ensiling period has elapsed. Silages stored for only a few weeks may be susceptible to deterioration when air is infiltrated or where fewer ingredients are used in the TMR mixture. Copyright © 2007 Society of Chemical Industry

Effect of adding caprylic and capric acid to grass on fermentation characteristics during ensiling and in the artificial rumen system RUSITEC

Silage was prepared from grass that was treated either with caprylic or capric acid, prior to ensiling, to increase aerobic stability. The silage was introduced to the RUSITEC in order to measure the effect of treatment on in vitro microbial metabolism. Although, caprylic acid inhibited lactic acid formation during the ensiling process, aerobic stability was high. Capric acid did not interfere with lactic acid production yielding silage with moderate stability. In RUSITEC neither caprylic nor capric acid had an effect on protozoa counts, but both lowered apparently degraded organic matter (OMAD). Caprylic acid promoted methane and acetate production while propionate production and microbial yield were lower. Capric acid had no effect on the production of methane, acetate and propionate; butyrate production increased and microbial yield remained unaffected. Caprylic and capric acid are highly preservative, yielding silage of good quality and high aerobic stability indicating their efficiency against spoilage micro-organisms. The bactericidal effect however, was modified during the ensiling process since both lost some toxicity against rumen protozoa and methanogenic bacteria. Net production of rumen microbial cell mass per unit OMAD was not impaired.