Alterações químicas e microbiológicas nas silagens de capim-Tifton 85 após a abertura dos silos

Abstract

RESUMO -O trabalho foi conduzido para avaliação da presença de Listeria sp. e de fungos nas silagens de capim-Tifton 85 sem emurchecimento, com emurchecimento por uma e duas horas e sem emurchecimento com adição ou não de polpa cítrica (5,0% do peso verde). As amostragens foram efetuadas no momento da abertura do silo (80 dias da ensilagem), aos 15 e 30 dias após exposição ao ar, para avaliar os teores de matéria seca (MS), as alterações químicas (pH, N amoniacal, ácidos orgânicos) e a ocorrência de Listeria sp. e de fungos. Os dados foram analisados segundo o delineamento em blocos casualizados, em esquema de parcelas subdivididas (nas parcelas foram avaliadas as silagens submetidas aos tratamentos e nas subparcelas, os períodos de exposição ao ar), com quatro repetições. Observaram-se baixos teores de ácidos orgânicos e de N amoniacal decorrentes dos altos valores de MS, o que acarretou baixa formação de produtos fermentados e elevação do pH. A presença de Listeria sp. foi observada em 65,6% das amostras no momento da abertura dos silos e, destas, 10% foram positivas para Listeria monocytogenes. As silagens apresentaram baixa estabilidade aeróbia, tendo sido registrado aumento na ocorrência dos fungos Penicillium, Fusarium e Pithomyces com o prolongamento do período de exposição ao ar.Palavras-chave: bactéria, microbiologia, sanidade animal, silagem de capim Chemical and Microbiological Changes of Tifton 85 Grass Silage after Silos OpeningABSTRACT -The experiment was carried out to evaluate the fermentation characteristics, Listeria sp. and molds occurrence on Tifton 85 silage no wilted, wilted for one and two hours and no wilted with or without citrus pulp (5.0 % of fresh forage). The samplings were taken at the opening of the silos (80 days after ensiling), 15, and 30 days after air exposition to evaluated dry matter (DM) content, chemical changes (pH, ammonia N, organic acids) and Listeria sp., and molds occurrence. Data were analyzed according to a randomized block design in split plot scheme, considering the silage on the plots, and periods of air exposure on the split plot, with four replications. Low contents of organic acids and ammonia N due to the high silage DM content that promotes low formation of fermentable products and high pH values was observed. The occurrence of Listeria sp. was observed in 65.6% of the silage samples at the opening of the silos and, from them 10% of these were Listeria monocytogenes. The silages showed poor aerobic stability, having been registered higher amount of Penicillium, Fusarium and Pithomyces occurrence, along the air exposition periods.

Microbial and fermentation profiles, losses and chemical composition of silages of buffel grass harvested at different cutting heights

“…However, for grasses, these values are acceptable and consistent with the values reported in the literature (Schocken-Iturrino et al, 2005;Pereira et al, 2007;Santos et al, 2011). In order to match the values found for corn silage, it would be necessary to use additives for absorbing moisture and/or sources of soluble carbohydrates, which would require further evaluation, especially in the aspects of costs and nutritional value.…”

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

“…Castro et al (2006) evaluated the microbiological profile of silages of Tifton 85 bermudagrass with different dry matter concentrations and application of additives and observed sporadic colonies of Aspergillus sp, Penicillium sp in the initial sampling and absence in the other storage periods (32 and 180 days). Schocken-Iturrino et al (2005) evaluated the presence of fungi in Tifton 85 bermudagrass silages with wilting and citrus pulp and observed low aerobic stability and an increase in occurrence of Penicillium, Fusarium and Phitomyces as they were more exposed to air.…”

Microbiota indigenous milk, mesophilic lipolytic and proteolytic colonial cheese matured, produced at different times of the year

“…Regarding Listeria, the presence of this microorganism indicates an environmental contamination (SCHOCKEN-ITURRINO et al, 2005;RIBEIRO et al, 2006), which is very frequent in silages. Of the 10 samples evaluated at 30 days of maturation, three were positive for Listeria.…”