ABSTRACT Whole-plant corn silage (WPCS) is a commonly used forage for feeding dairy cattle in Brazil. The aim of this study was to evaluate on-farm ensilaging practices and the nutritional value, microbiology and fermentation profiles of WPCS from dairy farms in the south of the state of Minas Gerais, Brazil. Silages from 54 dairy farms located in nine cities were sampled and a questionnaire was distributed for completion to describe the herd profile and ensilage practices. Herd size ranged from 8 to 1,000 lactating cows, and 52 % of the farms had fewer than 50 cows in lactation. The majority of the farms cultivated hard endosperm texture hybrids (52 %) and used pull-type forage harvesters (87 %). Double-sided plastic was the most used form of silo sealing (56 %) and 28 % used inoculants. Lactic acid bacteria count was greater than 6.01 log CFU g–1 in 60 % of the samples, and the mean populations of enterobacteria and Bacillus spp. were 4.23 and 4.09 log CFU g–1, respectively. Silo size ranged from 100 to 250 m3 in 44 % of the farms, and the silage removal rate was below 15 cm of the face/d in 41 % of cases. Silage dry matter (DM) concentration was 33 ± 3 % of fresh matter, NDF concentration was 57 ± 7 % of the DM, and in vitro NDF digestibility was 35 ± 11 % of the NDF. Silages with high DM concentrations had large particle size, affecting the nutritional value and the fermentative pattern. Improvements in ensiling practices can potentially inhibit the growth of spoilage microorganisms and raise the nutritional value of silages.

RESUMO. Este estudo avaliou o potencial antagônico de 32 isolados de leveduras selvagens de fermentação de café e cacau. Estas leveduras foram inoculadas em co-cultivo com Aspergillus carbonarius (CCDCA 10608 e CCDCA 10408) e Aspergillus ochraceus (CCDCA 10612) isolado de uvas e grãos de café. O crescimento micelial e a produção de ocratoxina A (OTA) foram avaliados e os esporos foram contados após o cultivo a 28 ° C por sete dias. As leveduras apresentaram maiores efeitos inibitórios (53% em relação ao controle) sobre o crescimento micelial do isolado A. ochraceus (CCDCA10612). Pichia anomala CCMA0148 e Saccharomyces cerevisiae CCMA0159 proporcionaram a maior inibição do crescimento de todas as estirpes fúngicas. Todas as espécies de Pichia apresentaram os maiores efeitos inibitórios na produção de esporos e S. Cerevisiae CCMA 0159 em concentrações de 104 e 107 células mL-1 inibiram a produção de esporos em 100%. Rhodotorula mucilaginosa foi eficaz na inibição da produção de OTA pelos três isolados de Aspergillus. S. cerevisiae CCMA0159 e Pichia anomala CCMA0148 apresentaram alto potencial como agentes de biocontrole nas condições testadas.

ABSTRACT. This study evaluated the antagonistic potential of 32 wild yeast isolates from coffee and cocoa bean fermentation. These yeasts were inoculated in co-cultivation with Aspergillus carbonarius (CCDCA 10608 and CCDCA 10408) and Aspergillus ochraceus (CCDCA 10612) isolated from grapes and coffee beans. The mycelial growth and ochratoxin A (OTA) production were evaluated, and the spores were counted after cultivation at 28°C for seven days. The yeasts presented higher inhibitory effects (53% in relation to the control) over the mycelial growth of the isolated A. ochraceus (CCDCA10612). Pichia anomala CCMA0148 and Saccharomyces cerevisiae CCMA0159 provided the greatest inhibition of the growth of all fungal strains. All Pichia species presented the highest inhibitory effects on the production of spores, and S. cerevisiae CCMA 0159 at concentrations of both 104 and 107 mL-1 cells inhibited the production of spores by 100%. Rhodotorula mucilaginosa was effective at inhibiting OTA production by the three isolates of Aspergillus. S. cerevisiae CCMA0159 and Pichia anomala CCMA0148 showed high potential as biocontrol agents in the conditions tested.

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.

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.

Objetivou-se avaliar o efeito de aditivos microbianos contendo bactérias heterofermentativas ou homofermentativas sobre as características químicas e microbiológicas de silagens de cana-de-açúcar (Saccharum spp.). A cana-de-açúcar foi inoculada com Lactobacillus plantarum, L. paracasei, L. brevis ou L. buchneri, previamente isolados de silagens de cana-de-açúcar, ou inoculantes comerciais contendo L. buchneri ou L. plantarum. As silagens foram produzidas em silos laboratoriais (tubos de PVC - 10 × 60 cm) e avaliadas 90 dias após a ensilagem. O delineamento utilizado foi o inteiramente casualizado com oito tratamentos (sete inoculantes e um controle, sem inoculante) e três repetições. A inoculação influenciou as populações de bactérias ácido-láticas e leveduras e também as concentrações de ácidos graxos voláteis, ácido lático e etanol nas silagens. A inoculação com cepas diferentes da mesma espécie de bactéria resulta em silagens com características químicas e microbiológicas diferentes. Duas cepas de L. buchneri promovem melhores resultados de qualidade das silagens.

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.

Objetivou-se avaliar o efeito de aditivos microbianos com bactérias heterofermentativas ou homofermentativas sobre as características de silagens de cana-de-açúcar (Saccharum spp.). A cana-de-açúcar foi inoculada com as bactérias Lactobacillus plantarum (LP), L. paracasei (LPARA), L. brevis (LBREVIS), L.buchneri (LB), isoladas da silagem de canade-açúcar, e três inoculantes comerciais, dois contendo L. buchneri (Pioneer 11A44TM-LBP e Lalsil Cana-LBLC) e um, L. plantarum (Biomax®-LPB), e avaliada em comparação a uma silagem controle (sem inoculante). Todos os inoculantes foram aplicados com população de 10(5) ufc da bactéria por g de forragem. O delineamento utilizado foi o inteiramente casualizado com oito tratamentos e três repetições. O efeito da inoculação sobre as características bromatológicas foi variável. A silagem contendo a bactéria L. plantarum apresentou maior teor de MS (32,6%), enquanto, para os outros inoculantes, não houve diferença, com média de 28,4%. Os teores de proteína 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 solúveis foi superior a 85% durante a fermentação, para todas as silagens, o que resultou em pH em torno de 3,5. Os valores de pH e nitrogênio amoniacal para todas as silagens estiveram no padrão aceitável para silagens de boa qualidade. Os inoculantes retardaram o aumento da temperatura, em aerobiose, conferindo maior estabilidade aeróbia. Os melhores resultados foram obtidos com os inoculantes LBLC, LB e LPB.

This study was aimed to evaluate the effect of microbial additives containing hetero fermentative or homo fermentative bacteria on the characteristics of sugarcane silages. Sugarcane was inoculated with the following bacteria: Lactobacillus plantarum (LP), L. paracasei (LPARA), L. brevis (LBREVIS), L.buchneri (LB), isolated from sugarcane silage, and three commercial inoculants, two of them containing L. buchneri (Pioneer 11A44TM-LBP and Lalsil Cana-LBLC) and one L. plantarum (Biomax®-LPB) and control (without inoculation). All the inoculants were applied in population of 10(5) log cfu.g-1 of fresh forage. A completely randomized design was used with eight treatments and three replicates. The effect of inoculation on the bromatological characteristics was variable. The silage containing L. plantarum (LPB) showed significantly higher dry matter content (32.6%), while all the others strains studied showed similar effect, with average of 28.4%. The crude protein content ranged from 3.6-4.9% and NDF content ranged from 60-66.7% DM. The ADF, hemicellulose and ash contents were similar for all silages. All treatments used more than 85% of the soluble carbohydrate, which resulted in pH around 3.5. The pH and ammoniacal nitrogen values were acceptable. The inoculants were more effective for the aerobic evaluation of silages, because they slow down temperature and improve the aerobic stability with best results observed in treatments LBLC, LB and LPB.

Objetivou-se avaliar o efeito da adição de duas cepas de Lactobacillus buchneri sobre a estabilidade aeróbia de silagens de capim-mombaça. O experimento foi conduzido em delineamento inteiramente casualizado com três repetições, 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 avaliação aeróbia das silagens (0, 2, 8 ou 10 dias após a abertura dos silos) nas subparcelas. Após 90 dias de armazenamento, os silos foram abertos e amostras de aproximadamente 2,5 kg foram retiradas para avaliação da estabilidade aeróbia com base na temperatura de cada amostra. As mudanças químicas e microbiológicas foram avaliadas. Após abertura dos silos, verificou-se aumento nas populações de bactérias do ácido lático, leveduras e fungos filamentosos. Houve aumento nos valores de pH resultante da redução da concentração dos ácidos orgnicos e de aumentos dos teores de matéria seca e proteína bruta. A adição de L. buchneri às silagens melhorou sua estabilidade, enquanto a silagem sem inoculante apresentou estabilidade de 55 horas. As silagens inoculadas não ultrapassaram essa temperatura limite em um período de 10 dias. A melhoria da estabilidade foi ocasionada pela associação de altas concentrações de cido acético ao ácido propiônico e pela menor concentração de ácido lático no momento de abertura, o que inibiu a proliferação de fungos filamentosos e leveduras após abertura dos silos.

This study aimed to evaluate the effect of the addition of two L. buchneri strains on the aerobic stability of the Mombaça grass 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 experimental or commercial inoculants) were randomized on plot and in times of aerobic evaluation of the silages (0, 2, 8, and 10 days after the opening of the silos) as subplots. After an storage period of 90 days, the silos were opened and samples of about 2,5 kg were collected for the evaluation of the aerobic stability based on the temperature for each sample. The chemical and microbiological changes in the silages were evaluated. As soon as the silos were opened, changes in the silages were observed, with increases in the lactic acid bacteria, yeast and filamentous fungus populations. Also, the pH values increased due to the reduction in the organic acids concentration and to the increase in the DM and CP contents. The addition of L.buchneri to the silages increased their stability. The silages without inoculant was stable for 55 hours. The inoculated silages remained stable for 10 days. The improved stability was a consequence of an association of high acetic acid concentration with propionic acid and lower lactic acid concentration at the moment of silo opening, which resulted in inhibition of yeasts and molds.

Objetivou-se neste trabalho avaliar o efeito do grau de compactação, da inclusão de aditivo absorvente e do emurchecimento da forragem na composição bromatológica de silagens de capim-tanzânia. O capim-tanzânia (Panicum maximum Jacq. cv. Tanzânia I) foi colhido aos 60-65 dias de crescimento e ensilado em silos experimentais de PVC adaptados com válvula tipo Bunsen, com capacidade individual de 8,5 kg. O delineamento experimental utilizado foi de blocos ao acaso, com quatro repetições, em esquema fatorial 3 × 5, composto de três tipos de silagens (testemunha, com 5% de polpa cítrica e com capim pré-emurchecido) e cinco graus de compactação (400, 500, 600, 700 ou 900 kg/m³). O aumento da densidade reduziu o pH e o N-amoniacal, de modo que, em maiores densidades, o pH se manteve na faixa ideal. A inclusão de polpa cítrica e o pré-emurchecimento do capim reduziram as perdas por efluente e gás das silagens. Com o aumento da densidade, a quantidade de efluente aumentou na silagem testemunha e diminuiu nas silagens com polpa cítrica.

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.

Objetivou-se conhecer as variações nos teores de carboidratos solúveis das silagens de capim-tanzânia com aditivos, durante a fermentação, bem como os valores de poder tampão e a relação carboidratos solúveis x poder tampão desta forrageira. O capim-tanzânia (Panicum maximum Jacq. cv. Tanzânia I) foi 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 válvula tipo Bunsen, com capacidade para aproximadamente 3 kg. Os tratamentos consistiram de três aditivos (polpa cítrica, farelo de trigo e fubá de milho), em quatro doses (3, 6, 9 e 12%) mais uma testemunha sem aditivos e oito tempos de abertura dos silos (0, 1, 2, 3, 7, 14, 28 e 56 dias). O delineamento experimental adotado foi o de blocos ao acaso, em esquema fatorial com tratamento adicional [(3 x 4) + 1] x 8 com três repetições. O capim-tanzânia colhido aos 60-65 dias de idade apresentou baixa concentração de carboidratos solúveis e todo o carboidrato da forragem, sem e com aditivos, foi consumido durante o processo de fermentação. Os três aditivos influenciaram os teores de carboidratos solúveis e o poder tampão da forragem, porém, a polpa cítrica foi o aditivo que mais contribuiu para aumentar a concentração de carboidratos solúveis da forragem e reduzir o poder tampão. Aumento da relação carboidratos solúveis:poder tampão propicia melhores condições para que o processo de fermentação resulte em silagem de melhor qualidade.

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.

Em geral, gramíneas forrageiras colhidas em estádio de desenvolvimento mais jovem apresentam baixos teores de MS, o que, associado aos baixos teores de carboidratos solúveis, pode prejudicar o processo de fermentação, comprometendo a qualidade final da silagem. Dessa forma, deve-se adotar procedimentos que modifiquem esse quadro, como a utilização de aditivos. Com este trabalho, objetivou-se avaliar a fermentação das silagens do capim-tanzânia com aditivos em relação aos teores de nitrogênio amoniacal e pH, e entre esses aditivos, determinar qual deles e em que dose conferem as melhores qualidades à silagem produzida. O experimento foi conduzido nas dependências 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 válvula tipo Bunsen, com capacidade para aproximadamente 3 kg cada um. Os tratamentos constituíram-se de três aditivos (polpa cítrica, farelo de trigo e fubá 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 repetições. As adições de polpa cítrica, farelo de trigo ou fubá de milho melhoram as características fermentativas das silagens de capim-tanzânia. As silagens sem aditivos também apresentaram valores de pH e nitrogênio amoniacal característicos de uma silagem de qualidade satisfatória; no entanto, os aditivos devem ser utilizados com o intuito de prevenir perdas.

In general, forage grasses harvested at younger development stage present low contents of DM that associated to the low content of soluble carbohydrates, can harm the fermentation harming the final quality of the silage. Thus, it is indispensable to adopt procedures which modify this picture such as the use of additives. This work aimed to evaluate the fermentation of Tanzania grass silages with additives in relation to the ammonia-N content and pH, and among these additives, to determine which of them and what dose confers the best qualities to the produced silage. The experiment was carried out in the Animal Science Department of UFLA by utilizing tanzaniagrass (Panicum maxium Jacq. cv. Tanzania I) established in a Clayey Dusky red Latosol and harvested at 60-65 days of growth. The forage was ensiled in experimental PVC silos, adapted with valves type Bunsen with capacity of about 3 kg each. The treatments consisted of three additives (citrus pulp, wheat meal and corn meal) in four doses (3, 6, 9 and 12%) plus one without additives and 8 times of silo opening (0, 1, 2, 3, 7, 14, 28 and 56 days). The experimental design utilized was randomized blocks, constituing a factorial scheme with additional treatment [(3x4) + 1] x 8 with 3 replicates. The addition of citrus pulp, wheat meal and corn meal improves the fermentative characteristics of the tanzaniagrass silage. The silages without additives present values of pH and ammonia-N characteristics of a satisfactory quality silage but the use of additives is recommended to prevent losses.