Aditivos químicos e microbianos no controle de perdas e na qualidade de silagem de cana-de-açúcar (Saccharum officinarum L.). / Chemical additives and bacterial inoculants on control of losses and quality of sugar cane (Saccharum officinarum L.) silage.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

The objective of this project was to evaluate chemical and microbial additives on ethanol control in sugar cane silages, aiming to decrease dry matter (DM) and nutritional losses during storage. Three laboratory silos trials were conducted to study fermentation process and associated losses, and one additional experiment was carried out to evaluate animal performance. For the laboratory trials sugar cane (12 months vegetative growth) was ensiled in 20 L plastic buckets provided with valves for gas release and a device for effluent collection: Experiment I: Aimed to characterize fermentation, DM losses and epiphytic microflora dynamics during ensilage. Silage sampling at ½ , 1, 2, 3, 7, 15, 45, 90, 120 and 180 days after sealing indicated: intensive growth of yeast population until day two of fermentation (5.1 log cfu g -1 ); ethanol reached its highest content after 15 days from sealing (6.4% in DM) when 68% of the water soluble carbohydrates (CHOs) disappeared; total DM (29%) and gases (16% of the DM) losses reached a plateau after 45 days of ensilage; effluent yield was negligible (20 kg t -1 ); silage pH was lowest after 180 days of storage (3.47); ethanol production led to increased CHOs loss and higher fiber content in the silage, which in turn were associated with reduction in silage s IVDDM (63 to 47%). Experiment II: The main objective was to evaluate the addition of wet basis): urea (0.5, 1.0,1.5%), NaOH (1, 2, 3%), calcium propionate-PROP (0.05, 0.1, 0.2%), sodium benzoate-BENZ (0.05, 0.1, 0.2%), potassium sorbate-SORB (0.015, 0.03, 0.045%), L. plantarum-LAB (1 x 10 6 cfu g -1 ), L. buchneri-BUCH (3.64 x 10 5 cfu g -1 ), urea (0.5 e 1.0% fresh basis) plus L. plantarum-Lact/Ur 0.5% and Lact/Ur 1.0% on silage quality, DM losses and aerobic stability. Comparison of treated silages with control after 90 and 180 days from sealing indicated: none of the additives were effective to decrease ethanol concentration in silages and PROP-0.1% and LAB even increased (P<0.05) alcohol levels (4.8 and 12.5% vs 3.8% in control DM); urea, NaOH, SORB-0.03%, BUCH, Lact/Ur 0.5% and Lact/Ur 1.0% treated silages showed lower total DM losses (P<0.05); higher IVDDM was achieved by adding urea, NaOH, BENZ and SORB-0.045% (P<0.05); aerobic stability was improved with BUCH, Lact/Ur 1.0%, urea-1.5%, NaOH (1 and 2%) and BENZ-0.2% treatments (P<0.05). Experiment III: The objective was to compare the effects of additives screened in experiment II based on silage fermentation traits, DM losses and aerobic stability. Treatments were (wet basis): urea (0.5%), sodium benzoate-BENZ (0.1%), potassium sorbate-SORB (0.03%), L. plantarum-LAB (1 x 10 6 cfu g -1 ) e L. buchneri-BUCH (3.64 x 10 5 cfu g -1 ). Comparing treated silages with control after 94 days from sealing indicated: urea, BENZ, SORB and BUCH resulted in silages with less etanol, however LAB resulted in higher ethanol concentration (P<0.05); urea and SORB treatments decreased total DM losses (P<0.05); IVDDM was higher for urea and lower for LAB treated silages (P<0.05); CHOs content was higher in BENZ treated silage (P<0.05). Regression slopes performed through 144 days after sealing indicated: ethanol yield was maximum between 60 and 90 days; gases losses were extended up to 90 days and was lower in urea treated silages; BUCH inoculated silages showed a trend to loose more CHOs; treatment with urea and SORB resulted in silages with increased total DM and effluent losses; IVDDM reduced linearly with time in chemically treated silages, probably due to the increased effluent yield. BUCH and BENZ improved silages aerobic stability over control (78 and 72 h vs 48 h). Experiment IV: Thirty two Holstein heifers (388 kg) were allocated to 4 treatments, 4 replications each, in a block design. The animals were fed total mixed rations containing 46% sugar cane silage, within the following treatments (wet basis): control (without additive), urea (0.5%), sodium benzoate-BENZ (0.1%) e Lactobacillus buchneri-BUCH (3.64 x 10 5 cfu g -1 ). Average daily gain (ADG) showed 21% increase (P<0.05) for BENZ and 32% for BUCH over control (0.9 kg d -1 ); better feed conversions (DMI/ADG) were observed for BENZ and BUCH (7.6 and 7.7 vs 9.4); DM intake (2.2% BW) did not differ (P>0.10) across treatments. Urea treated silage was similar to control in all traits (P>0.05).

ASSUNTO(S)

animal performance feed additives for animals silagem sugar cane fermentation fermentação nutritive value cana-de-açúcar valor nutritivo crescimento animal aditivo alimentar para animai silage

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