Carla Luiza da Silva Ávila

Chemical and microbiological characteristics of sugar cane silages treated with microbial inoculants.

The aim of this research was to evaluate the effect of microbial additives containing heterofermentative or homofermentative bacteria on the chemical and microbiological characteristics of sugar cane (Saccharum spp) silages. Sugar cane was inoculated with Lactobacillus plantarum, L. paracasei, L. brevis or L. buchneri previously isolated from sugar cane silages or commercial inoculants containing L. buchneri or L. plantarum. Silages were produced in laboratory silos (10 × 60 cm PVC tubes) and evaluated 90 days after ensiling. A randomized complete design was used with eight treatments (seven inoculants and control - without inoculant) and three replications. The inoculation with bacteria affected lactic acid bacteria, yeast populations, volatile fatty acids and ethanol contents in the silages. Inoculation with different strains of the same species of bacteria result in silages with different chemical and microbiological characteristics. Two of the L. buchneri strains show the best results in relation to silage quality.

Effects of different compaction degrees, inclusion of absorbent additive and wilting on the chemical composition of tanzania grass silages

The objective of this work was to evaluate the effects of different compaction degrees, inclusion of absorbent additive and wilting on the chemical composition of tanzania grass silages. The experiment was conducted using tanzania grass (Panicum maximum Jacq. cv. Tanzânia I) harvested at 60-65 days of growth. The forage was ensiled in experimental PVC silos fitted with Bunsen type valves, with capacity for about 4 and 8 kg each. The treatments consisted of three types of silages (control, 5% of citric pulp and pre-wilted) with five compaction degrees (400, 500, 600, 700 and 900 kg/m3). The experimental design was random blocks, with four replicates. Citric pulp and pre-wilting increased the dry matter content of tanzania grass silages. The increased density resulted into decreases in the pH values and amoniacal-N contents; the greatest densities resulted in pH values within the ideal range. The presence of citric pulp and the pre-wilting practice reduce the losses by effluent and gas relative to the control. As the density increased, the amount of effluent increased in the control silage and decreased in silages with citric pulp.

Effect of the addition of Lactobacillus sp. in sugarcane silages

Objetivou-se avaliar o efeito de aditivos microbianos com bacterias heterofermentativas ou homofermentativas sobre as caracteristicas de silagens de cana-de-acucar (Saccharum spp.). A cana-de-acucar foi inoculada com as bacterias Lactobacillus plantarum (LP), L. paracasei (LPARA), L. brevis (LBREVIS), L.buchneri (LB), isoladas da silagem de canade-acucar, e tres inoculantes comerciais, dois contendo L. buchneri (Pioneer 11A44TM-LBP e Lalsil Cana-LBLC) e um, L. plantarum (Biomax®-LPB), e avaliada em comparacao a uma silagem controle (sem inoculante). Todos os inoculantes foram aplicados com populacao de 105 ufc da bacteria por g de forragem. O delineamento utilizado foi o inteiramente casualizado com oito tratamentos e tres repeticoes. O efeito da inoculacao sobre as caracteristicas bromatologicas foi variavel. A silagem contendo a bacteria L. plantarum apresentou maior teor de MS (32,6%), enquanto, para os outros inoculantes, nao houve diferenca, com media de 28,4%. Os teores de proteina bruta variaram de 3,6 a 4,9% e os de FDN, de 60,0 a 66,7%. As porcentagens de FDA, hemicelulose e cinzas foram semelhantes em todas as silagens. O consumo de carboidratos soluveis foi superior a 85% durante a fermentacao, para todas as silagens, o que resultou em pH em torno de 3,5. Os valores de pH e nitrogenio amoniacal para todas as silagens estiveram no padrao aceitavel para silagens de boa qualidade. Os inoculantes retardaram o aumento da temperatura, em aerobiose, conferindo maior estabilidade aerobia. Os melhores resultados foram obtidos com os inoculantes LBLC, LB e LPB.

Aerobic stability of sugar cane silages with a novel strain of Lactobacillus sp. isolated from sugar cane

The objective of this research was to evaluate the effect of the addition of two Lactobacillus strains on the aerobic stability of the sugar cane (Saccharum spp.) silages. The experiment was carried out in a completely randomized design with three replicates in split-plot in time scheme, so that the treatments (silages without inoculant and with novel strain or commercial inoculants) were randomized on plot and in times of aerobic evaluation of the silages (zero, two, four, and six days after the opening of the silos) as subplots. The loss of stability of silages was continuous during the time of aerobic exposure. Inoculants influenced the changes in populations of lactic acid bacteria and yeasts and in the ammoniacal nitrogen, acetic acid and ethanol concentrations. The dry matter, crude protein, soluble carbohydrates contents and pH values showed similar changes in all three silages studied. A linear increase in crude protein content and pH values and decrease in the soluble carbohydrates content were observed. The dry matter contents increased to a maximum of 335 g/kg on fresh matter at four days, followed by reduction after six days. The results showed that the use of inoculants is recommended because it promoted higher production of acetic and propionic acids, reducing the population of yeast and, therefore, improving the aerobic stability of silages.

Estabilidade aeróbia de silagens de capim-mombaça tratadas com Lactobacillus buchneri

Objetivou-se avaliar o efeito da adicao de duas cepas de Lactobacillus buchneri sobre a estabilidade aerobia de silagens de capim-mombaca. O experimento foi conduzido em delineamento inteiramente casualizado com tres repeticoes, em esquema de parcelas subdivididas no tempo, de modo que os tratamentos (silagens sem inoculantes e com inoculante experimental e comercial) foram aleatorizados nas parcelas e os tempos de avaliacao aerobia das silagens (0, 2, 8 ou 10 dias apos a abertura dos silos) nas subparcelas. Apos 90 dias de armazenamento, os silos foram abertos e amostras de aproximadamente 2,5 kg foram retiradas para avaliacao da estabilidade aerobia com base na temperatura de cada amostra. As mudancas quimicas e microbiologicas foram avaliadas. Apos abertura dos silos, verificou-se aumento nas populacoes de bacterias do acido latico, leveduras e fungos filamentosos. Houve aumento nos valores de pH resultante da reducao da concentracao dos acidos orgnicos e de aumentos dos teores de materia seca e proteina bruta. A adicao de L. buchneri as silagens melhorou sua estabilidade, enquanto a silagem sem inoculante apresentou estabilidade de 55 horas. As silagens inoculadas nao ultrapassaram essa temperatura limite em um periodo de 10 dias. A melhoria da estabilidade foi ocasionada pela associacao de altas concentracoes de cido acetico ao acido propionico e pela menor concentracao de acido latico no momento de abertura, o que inibiu a proliferacao de fungos filamentosos e leveduras apos abertura dos silos.

Perfil de fermentação das silagens de capim-tanzânia com aditivos teores de nitrogênio amoniacal e ph

Em geral, gramineas forrageiras colhidas em estadio de desenvolvimento mais jovem apresentam baixos teores de MS, o que, associado aos baixos teores de carboidratos soluveis, pode prejudicar o processo de fermentacao, comprometendo a qualidade final da silagem. Dessa forma, deve-se adotar procedimentos que modifiquem esse quadro, como a utilizacao de aditivos. Com este trabalho, objetivou-se avaliar a fermentacao das silagens do capim-tanzânia com aditivos em relacao aos teores de nitrogenio amoniacal e pH, e entre esses aditivos, determinar qual deles e em que dose conferem as melhores qualidades a silagem produzida. O experimento foi conduzido nas dependencias do Departamento de Zootecnia da UFLA, utilizando o capim-tanzânia (Panicum maximum Jacq. cv. Tanzânia I) estabelecido em um Latossolo Roxo Argiloso e colhido com 60-65 dias de crescimento. A forragem foi ensilada em silos experimentais de PVC, adaptados com valvula tipo Bunsen, com capacidade para aproximadamente 3 kg cada um. Os tratamentos constituiram-se de tres aditivos (polpa citrica, farelo de trigo e fuba de milho), em quatro doses (3, 6, 9 e 12%) mais uma testemunha, sem aditivos, e 8 tempos de abertura dos silos (0, 1, 2, 3, 7, 14, 28 e 56 dias). O delineamento experimental utilizado foi o de blocos ao acaso, constituindo um esquema fatorial com tratamento adicional [(3 x 4) + 1] x 8 com 3 repeticoes. As adicoes de polpa citrica, farelo de trigo ou fuba de milho melhoram as caracteristicas fermentativas das silagens de capim-tanzânia. As silagens sem aditivos tambem apresentaram valores de pH e nitrogenio amoniacal caracteristicos de uma silagem de qualidade satisfatoria; no entanto, os aditivos devem ser utilizados com o intuito de prevenir perdas.

Glycerin as an additive for sugarcane silage

The ensiling of sugarcane induces loss of energy by alcoholic fermentation, and the addition of crude glycerin may improve the nutritional value of this forage. The objective of this work was to evaluate sugarcane silage with different concentrations of glycerin and the response of different starter cultures to the changes in microbial diversity, products of fermentation, and aerobic stability. The glycerin treatments increased dry matter (DM) and water-soluble carbohydrates (WSC) and reduced the neutral detergent fiber (NDF) concentration. The presence of glycerin resulted in a linear effect (p < 0.01) for DM, WSC, NDF, and DM loss. The silage inoculated with Lactobacillus hilgardii UFLA SIL52 showed a decrease in DM loss (p < 0.01). The glycerin treatments reduced the production of lactic acid (p = 0.05) and tended to decrease ethanol (p = 0.06) concentration. The dosage of glycerin did not affect aerobic stability (p = 0.28). Addition of glycerin to sugarcane silage improved chemical characteristics, decreased the ethanol content, and changed the microbial diversity.

In situ Inhibition of Escherichia coli Isolated from Fresh Pork Sausage by Organic Acids

The main aim of this study was to evaluate the inhibitory effect of different concentrations of organics acids citric, lactic, acetic, and propionic on E. coli isolated from pork sausage. Two experiments were performed in vitro, respectively: agar disc diffusion and minimum inhibitory concentration (MIC) determination. In agar disc diffusion, the minimum concentration of 1.29 M of citric acid inhibits bacterial growth. There was no statistically significant difference in the MIC of citric and lactic acids; citric and lactic acids were more effective than acetic and propionic acids. Based on in vitro results, lactic and citric acids were added to pork sausages with E. coli. The addition of citric acid caused a significant reduction (P < 0.01) in the pH of the sausages. Citric acid was most effective 15 d after inoculation; E. coli counts were reduced by 4.53 log units compared with time 0. Due to late inhibitory action of citric acid in the study, its effect may be more effective over E. coli in sausage that requiring longer storage, such as fermented sausages.

Avaliação dos conteúdos de carboidratos solúveis do capim-tanzânia ensilado com aditivos

The aim of this study was to check on the effect of additive addition on the variations in the water soluble carbohydrate contents of the tanzaniagrass silage during the fermentation period, and to know the buffering capacity values and water soluble carbohydrate: buffering capacity ratio of this forage. Tanzaniagrass (Panicum maximum Jacq. cv. Tanzânia I) was established in a Clavey Red Dusk Latosol and harvested at 60-65 day of age. The forage was ensiled in experimental PVC silos, fitted with Type Bunsen valves, with a capacity of about 3 kg each. The treatments consisted of four doses (3, 6, 9 and 12%) of three additives (citrus pulp, wheat meal and corn meal), plus one check without additives and 8 times of silo opening (0, 1, 2, 3, 7, 14, 28 and 56 days) building up a factorial scheme with an additional treatment [(3 x 4) + 1] x 8 with 3 replicates. The experiment was run in a completely randomized block design. Water soluble carbohydrate content of tanzaniagrass at 60-65 days of age was low and all of it was consumed during the fermentation process, regardless of additive treatments. All three additives, mainly the citrus pulp, favored the water-soluble carbohydrate contents and buffering capacity of the silages. An increase of the water soluble-carbohydrate: buffering capacity ratio contributes to the yield of better quality silage by assisting in the fermentation process.

New inoculants on maize silage fermentation

The objective of this study was to evaluate the effect of bacterial inoculants at two inoculation rates on chemical and biological characteristics of maize silage. The treatments consisted of two inoculating rates (5 and 6 log cfu g-1of forage) for each strain of lactic acid bacteria (LAB) identified as Lactobacillus buchneri, L. hilgardii, or L. plantarum. The maize was ensiled in experimental PVC silos. Samples were taken for the determination of the contents of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), water-soluble carbohydrates (WSC), organic acids and alcohols, for the evaluation of the populations of lactic acid bacteria, yeasts, filamentous fungi, and for the determination of pH values during ensilage and after 30 or 90 days of fermentation. The doses of inoculants did not promote significant differences on the evaluated characteristics. There was effect of inoculants on acetic acid, 1.2-propanediol, LAB population, filamentous fungi, and pH value. No significant influence of the treatments with inoculants was observed in the variables DM, WSC, CP, lactic acid concentrations, or ethanol. The maximum temperature, i.e., the time to achieve the maximum temperature (TMT) and aerobic stability (AS), was not influencied by treatments. However, a decrease in maximum temperature, an increase in TMT, and improvement in the AS were observed after 90 days of fermentation. These results proved the advantage of microbial inoculation. The treatments influenced LAB populations and filamentous fungi, but no effect was observed on the yeast population. The best inoculation dose is 6 cfu g-1 of forage because it provides higher reduction of filamentous fungi in maize silage, thereby decreasing the aerobic deterioration by these microorganisms.