Silagem do bagaço de laranja aditivada com polpa cítrica peletizada

Abstract

This study evaluated the fermentation profile of orange bagasse ensiled with three levels of dry matter (DM) using citrus pulp pellets as a moisture-absorbing additive. Thirty experimental silos (3 treatments, 5 storage times, 2 replicates) were prepared using 25-liter plastic buckets containing orange bagasse and three levels of pelleted citrus pulp (0, 6% and 20%) as additive. A completely randomized design with repeated measures over time was used. The periods of anaerobic storage were 3, 7, 14, 28 and 56 days. Natural orange bagasse contained 13.9% DM, which increased to 19.1% and 25.5% with the inclusion of 6% and 20% citrus pulp pellets, respectively. The apparent density was inversely correlated with DM content and a higher level of compaction (982 kg/m 3 ) was observed in the mass ensiled with the lowest DM level (13.9%). Additionally, lower compaction (910 kg/m 3 ) was found in the mass ensiled with the additive. The chemical composition of the mass ensiled with or without citrus pulp pellets did not differ significantly in terms of protein, ether extract, neutral detergent fiber, lignin or in vitro DM digestibility (P≥0.05), as expected. Thus, it was possible to analyze only the effect of the inclusion of citrus pulp pellets on the increase in DM content. The inclusion of 20% of the additive reduced (P<0.01) losses due to effluent (98% less) and gas production (81% less) compared to the control treatment at the end of the anaerobic storage period. In this treatment, a higher (P≤0.05) log number of lactic acid bacteria (4.61 log CFU/g) was also observed compared to the other treatments, indicating that the increase in DM favored the growth of these bacteria. In addition, the low yeast count (about 1 log CFU/g sample) and the pH below 4.0, which were probably due to the production of lactic and acetic acids, show that the orange bagasse is rich in fermentable soluble carbohydrates and is indicated for ensiling. In conclusion, orange bagasse can be efficiently conserved as silage if the initial DM content is at least 25%. The inclusion of 20% (in relation to orange bagasse weight) citrus pulp pellets as moisture-absorbing additive is recommended to guarantee adequate fermentation and to reduce losses inherent to the ensiling process.