Chemical and microbiological changes and aerobic stability of marandu grass silages after silo opening

Abstract

-This trial had the objective of characterizing the microbial population and evaluating the aerobic stability of Marandu grass silages with pelleted citrus pulp (PCP). The collected forage was submitted to the following treatments: Silage of Marandu grass; silage of Marandu grass + 50 g/kg PCP and silage of Marandu grass + 100 g/kg PCP on natural matter basis.Metal cylindrical containers with 80 cm of height and 50 cm of diameter were used as silos during assays of microbiological dynamics and chemical changes of silages in anaerobiosis. Evaluations were performed on days 0, 2, 4 and 6 after silos were opened. The aerobic stability was evaluated by change in temperature, using approximately three kilograms of silage inside styrofoam boxes that were placed inside a climatic chamber. A completely randomized experimental design and split plot arrangement were used in the two assays, with five replications. Treatments were the plots and time was the subplots.Bacillus and enterobacteria were present on the Marandu grass silages with 0 g/kg PCP, which also showed pH increase throughout the feedout phase. Yeast was detected on the silages that were added with PCP. A trend of increasing temperature with extension of the aeration time was observed mainly in the silages containing 100 g/kg PCP. Isolated yeast strains showed lactate assimilation. Silages were found to be unstable due to the silo opening, both by bacterial or yeast development, which reduced the nutritional value.Key Words: additive, Brachiaria brizantha, losses, spoilage microorganismsAlterações químicas e microbiológicas de silagens de capim-marandu após a abertura dos silos RESUMO -Esta pesquisa foi realizada com os objetivos de caracterizar a microbiologia e avaliar a estabilidade aeróbia de silagens de capim-marandu contendo polpa cítrica peletizada (PCP). A forragem colhida foi submetida aos seguintes tratamentos: silagem de capim-marandu; silagem de capim-marandu + 5% PCP e silagem do capim-marandu + 10% de PCP com base na matéria natural. As alterações químicas e microbiológicas foram feitas aos 0, 2, 4 e 6 dias após a abertura dos silos (tambores de metal com 80 cm de altura e 50 cm de diâmetro). Na avaliação da estabilidade aeróbia por meio da alteração da temperatura, 3 kg de silagem foram colocados em caixas de isopor, que foram armazenadas em câmara climática. Nos dois ensaios realizados, utilizou-se delineamento inteiramente ao acaso com cinco repetições, em esquema de parcelas subdivididas, de modo que os níveis de PCP na silagem corresponderam às parcelas e o tempo, às subparcelas.As silagens sem polpa apresentaram desenvolvimento de bacilos e enterobactérias e aumento do pH no decorrer do desabastecimento dos silos. A presença de leveduras foi detectada nas silagens contendo o aditivo e aumentou do primeiro ao sexto dia de aeração. A digestibilidade in vitro da matéria seca (DIVMS) reduziu com o aumento dos tempos de aeração.A temperatura nas silagens com 10% de PCP aumentou durante a aerobiose. Com a abertura dos silos, as silagen...

Production and quality of silages pearl millet and paiaguas palisadegrass in monocropping and intercropping in different forage systems

“…Tropical grass silages become stable at higher pH values, normally above 4.20 (JOBIM et al, 2007;BERNARDES et al, 2009;RIGUEIRA et al, 2013). The data from this study correspond with the above-mentioned results.…”

Bromatological and microbiological characteristics of sugarcane silages treated with calcium oxide

“…The yeasts cause considerable reductions in dry matter contents of silages for producing CO 2 , ethanol and water during fermentation of carbohydrates, however, the calcium oxide with its buffer characteristics (Bernardes et al, 2009), could have made improper conditions to development of yeast blocking its favorite fermentative route, favoring preferentially the lactic acid bacteria homofermentative in silages (Table 5) confirmed by reduction of gasses losses and increases of dry matter recovery with additions of calcium oxide.…”

Aerobic stability of tifton 85 silage with and without pre-drying in the sun

“…Oscillations relative to the room temperature in the temperatures of Tifton 85 silages with or without wilting in the sun, in three opening times of the silos (28, 56, and 112 days) after the aerobic exposure up to 144 hours. The evaluation of the breakdown of aerobic stability in silages is relevant because the anaerobic environment of a silo is responsible for its conservation after the opening aerobic (Bernardes et al 2009). After the opening of the silos, the breakdown of the aerobic stability due to the air penetration in the silo causes a decrease of the nutritive value with the aerobic deterioration of the ensiled material (Rezende et al 2011).…”

“…After the opening of the silos, the breakdown of the aerobic stability due to the air penetration in the silo causes a decrease of the nutritive value with the aerobic deterioration of the ensiled material (Rezende et al 2011). This process is due to the multiplication of the aerobic deteriorating microorganisms that were latent during the anaerobic phase of silage (Bernardes et al 2009). In this study, about the silage temperature, it can be inferred that the dehydration period adopted was adequate, because it allowed to obtain silages that were stable after exposure to air (Table 1).…”