Silagens de sorgo (Sorghum bicolor L. Moench) aditivadas com subprodutos de cervejaria

Abstract

Ensilage is the conservation of forage through fermentation in an anaerobic environment, carried out by the action of microorganisms that produce organic acids favorable to this fermentation. The use of additives that can enhance this process proves to be relevant to its use. The wet brewery residue (RUC) and autolyzed yeast (LA) are agro-industrial by-products from the manufacture of beer, due to being discarded, they are categorized as low-cost foods that can be used as additives in silage, an alternative source of feed for ruminant animals. Two experiments were carried out, using RUC and LA incorporated in sorghum ensilage, with the objective of evaluating the quality through proximate and microbiological evaluations. Sorghum was cut 90 days after planting, ensiled and stored in experimental PVC silos, with an average capacity of 4 kg of material, with dimensions of 10 cm in diameter x 50 cm in height. For both experiments, a completely randomized design (DIC) with four treatments and three replications was adopted. For experiment I, addition of RUC: T0) sorghum forage (control); T1) sorghum forage + 25% RUC; T2) sorghum forage + 35% RUC; T3) sorghum forage + 45% RUC and T4) sorghum forage + 55% RUC. Experiment II, addition of LA: T0) sorghum forage (control); T1) sorghum forage + 2.5% LA; T2) sorghum forage + 5% LA; T3) sorghum forage + 7.5% LA and T4) sorghum forage + 10% LA. The mini silos were opened 30 days after ensiling and samples were taken for the determination of proximate and microbiological analyses. The addition of RUC to sorghum silage promoted an increase in the following contents: mineral matter, crude protein, neutral detergent fiber, hemicellulose and ether extract. It maintained the average loss contents, pH, acid detergent fiber and total digestible nutrients. It verified a reduction in the levels of dry matter, total carbohydrates and non-fibrous carbohydrates. Treatments T0 and T1 expressed favorable results. Silage with LA provided an increase in the content of crude protein, there was a reduction in the levels of pH and dry matter, the other fractions did not show significant gains. The T0 treatment showed better results according to the levels obtained. Of the additives used in this experiment, the RUC promoted improvements in the parameters considered crucial for quality silage.