Daniele Rebouças Santana Loures

Fermentation and epiphytic microflora dynamics in sugar cane silage

Silagens de cana-de-acucar caracterizam-se pela extensa atividade de leveduras, alto teor de alcool e grandes perdas de materia seca - MS. Conhecer melhor o processo fermentativo e fundamental para o desenvolvimento de tecnicas eficientes de ensilagem da cana. Este trabalho avalia a mudanca temporal na composicao quimica, nas perdas de MS e na microflora epifita nestas silagens. Cana-de-acucar (RB835486) foi colhida manualmente (12 meses de crescimento), picada em picadora estacionaria e ensilada em baldes de plastico de 20 L com valvulas para gases e aparato para colheita de efluentes. Os silos laboratoriais foram mantidos sob temperatura ambiente e amostrados apos ½, 1, 2, 3, 7, 15, 45, 90, 120 e 180 dias. Etanol atingiu 6,4% na MS no 15o dia apos ensilagem, seguido pelo desaparecimento de 71% dos carboidratos soluveis - CHOs. As perdas gasosas e a perda total de MS estabilizaram-se apos 45 dias (16% e 29% da MS). A contagem de leveduras foi maxima no segundo dia (5,05 log ufc g-1). O pH atingiu nivel abaixo de 4,0 no terceiro dia. A producao de efluentes foi insignificante (20,1 kg t-1). O teor de MS da forragem decresceu (35% para 26%) do dia 0 ao 45o dia. O padrao de variacao na concentracao de etanol foi inverso a concentracao de CHOs e a reducao da digestibilidade da silagem. O desenvolvimento de metodos de controle das leveduras, provavelmente com o uso de aditivos, melhorara a eficiencia no uso de silagens de cana-de-acucar pelos pecuaristas.

Efeito do tratamento com aditivos químicos e inoculantes bacterianos nas perdas e na qualidade de silagens de cana-de-açúcar

Objetivou-se avaliar a eficacia de aditivos quimicos e inoculantes bacterianos na inibicao da producao de etanol, na diminuicao das perdas de MS e na melhoria da digestibilidade in vitro de silagens de cana-de-acucar. Foram testados os seguintes tratamentos (doses com base na materia natural): sem aditivos - controle; UR - ureia (0,5; 1,0; 1,5%); NaOH - hidroxido de sodio (1,0; 2,0; 3,0%); PROP - propionato de calcio (0,05; 0,1; 0,2%); BENZ - benzoato de sodio (0,05; 0,1; 0,2%); SORB - sorbato de potassio (0,015; 0,03; 0,045%); PLA - Lactobacillus plantarum (1 x 106 ufc/g); BUCH - Lactobacillus buchneri (3,64 x 105 ufc/g); PLA/UR 0,5% - L. plantarum combinado com 0,5% de ureia; PLA/UR 1,0% - L. plantarum combinado com 1,0% de ureia. A ensilagem foi realizada em baldes plasticos de 20 L adaptados com valvulas para eliminacao de gases e dispositivo para coleta de efluentes. Os dados foram coletados aos 90 e aos 180 dias apos a ensilagem. Nenhum dos aditivos foi capaz de reduzir a concentracao de etanol nas silagens. Os tratamentos PROP 0,1% e PLA causaram aumento no teor de alcool em relacao a silagem controle (4,8 e 12,5% vs 3,8% da MS, respectivamente). Os tratamentos UR, NaOH, SORB-0,03%, BUCH, PLA/UR 0,5% e PLA/UR 1,0% reduziram a perda total de MS. As silagens tratadas com ureia, hidroxido de sodio, benzoato de sodio e sorbato de potassio 0,045% apresentaram maior digestibilidade in vitro da MS em comparacao a silagem controle.

Fermentation, losses, and aerobic stability of sugarcane silages treated with chemical or bacterial additives

Utilization of sugarcane Saccharum officinarum L. silage is increasing in Brazil but intensive ethanol production during fermentation reduces forage quality. This experiment aimed to evaluate the effects of additives on fermentation and aerobic stability of sugarcane silages produced in minisilos. Treatments were (fresh basis): untreated silage (control), urea (5.0 g kg-1), sodium benzoate (1.0 g kg-1), potassium sorbate (0.3 g kg-1), Lactobacillus plantarum (1 x 106 cfu g-1), and Lactobacillus buchneri (3.64 x 105 cfu g-1). At the 94th day after ensilage, ethanol concentration was lower in urea, benzoate, sorbate and L. buchneri supplemented silages and higher in L. plantarum inoculated silage, as compared to control. Urea and benzoate treated silages showed the highest and L. plantarum treated silage the lowest in vitro dry matter digestibility. Effluent production was higher in the urea treated silage. Inoculation with L. buchneri reduced 50% ethanol production as compared to control. Urea and L. buchneri reduced yeast count. Aerobic stability was enhanced by L. buchneri and benzoate. Sodium benzoate and L. buchneri were the most promising additives, improving both silage fermentation and aerobic stability; inoculants containing L. plantarum can be deleterious to fermentation and conservation of sugarcane silages.

Características do efluente e composição químico-bromatológica da silagem de capim-elefante sob diferentes níveis de compactação

An experiment was conducted using elephant grass (Pennisetum purpureum Schum.) cv. Cameroon, with the purpose of determining the quantitative and qualitative characteristics of effluent released, correlating this with levels of pressure and the quality of silage. The material with 13% of dry matter was ensiled in experimental plastic silos. The levels of pressure were: 356.67; 446.67; 531.33; 684.00 and 791.00 kg/m3. The effluent of silages with high moisture content was collected and measured during seven days. In silages with high moisture content, for level of 356.67 kg/m3, were found proportional losses to those found in high pressure (791.00 kg/m3). In relation of minimum of total losses, the pressure more desirable was 550.00 kg/m3, in this experimental conditions. The values of DOB5 (14.596,69 mg/L), DQO (31.138,2 mg/L), DQO/DBO (2.38), pH (4.30), Mg (0.3997% DM) and Na (0.0008% DM) did not varied with pressure and number of days of collect. Content of P, K, level of ammoniacal nitrogen, total nitrogen, organic nitrogen, crude protein and total solids were influenced by pressure and number of days.

Efeito de enzimas fibrolíticas e do teor de matéria seca em silagens de capim-tanzânia sobre os parâmetros ruminais, o comportamento ingestivo e a digestão de nutrientes, em bovinos

The present trial aimed to study the effects of forage wilting or the addition fibrolytic enzymes to the Tanzaniagrass (Panicum maximum Jacq. cv. Tanzania) during the ensiling process or after the silage unloading and before animal feeding. The fermentation and ruminal kinetics parameters, animal ingestive behavior, dry matter intake and in vivo nutrient digestibilities in bovine were measured. Treatments consisted of forage ensiling as described: A - wilted forage without enzymes; B - fresh forage without enzymes; C - wilted forage with enzymes at ensiling (2 L/t wet forage); D - fresh forage with enzymes at ensiling; E - enzymes applied into silage (10 L/t wet silage) 30 minutes before feeding (direct-fed). Silage samples were submitted to chemical analysis and screened for particle size measurements. Five ruminally cannulated Nellore steers were randomly assigned to a 5 x 5 Latin square design and fed with 50% silage total mixed rations diets. The ruminal passage rate of solid (2.23%/hour) and liquid (4.83%/hour) phases were similar for all treatments. The molar concentration (109.62 mM) of total VFAs and ammonia-N (5.6 mg/dL) observed in ruminal fluid were similar across silages diets. The forage wilting determined lower C2:C3 ration in the rumen. The animal ingestive behavior measured as total time (minutes/day) and rate (minutes/DM kg) was not changed with enzymes application, averaging DM eating (247; 24), DM ruminating (426; 43) and DM chewing (673; 67), respectively. Rations containing wilted silages showed less rumination and chewing. The mean DM (47.5 vs. 53.6%), NDF (45.8 vs. 55%) and ADF (45.5 vs. 54.8%) digestibilities were decreased on total mixed rations containing wilted silages. The wilting of Tanzaniagrass or the addition of fibrolytic enzymes resulted in marginal improvement, both in the ruminal parameters or animal ingestive behavior.