Caracterização da composição química e da digestibilidade in vitro de silagens de mucilagem do desfibramento do sisal, aditivadas ou não, em diferentes tempos de armazenamento

Abstract

Cattle raising is one of the main activities in the Brazilian semi-arid region, but due to the climate marked by the great water restriction during most of the year this activity is a great challenge for the producers. The sisal (Agave sisalana Perrine) is a plant native to Mexico, which has adapted and is in good extension of the Brazilian northeast. It is mainly used for the extraction of the fiber in its leaves, but only 3% to 5% of the material is used for this purpose, so the use of the sisal defibration co-products, especially the mucilage, is an alternative feedingstuffs, including in the form of silage. Because it is a material with high humidity, the use of moisture-sequestering additives in silage promotes higher quality of the product. In this context, the objective was to characterize the chemical composition and in vitro digestibility (DIV) of dry matter (DM), organic matter (OM) and neutral detergent fiber (NDF) of pure sisal defibration mucilage silages (SIL- MUDS) and corn bran (SIL-MUDS MI) and wheat bran (SIL-MUDS TRI) in different opening times. The experiment was carried out at the Animal Science Department of the Federal Rural University of Pernambuco. For the preparation of the silages the material was acquired in a sisaleira property located in the state of Paraíba, in the municipality of Barra de Santa Rosa. Wheat and Wheat Bran were obtained from agricultural products stores in the regional trade. The mixture was made in the proportion of 75 MUDS: 25 additive and silage was done manually in 12 polyethylene bottles with volume of 200 liters and 4 storage times (30, 60, 90 and 120 days). Analyzes for determination of the chemical composition were made according to Detmann et al. (2012) and the IVD following the principles proposed by Tilley and Terri (1963). For the chemical composition of the silages it was observed that the inclusion of the additives promoted a 93% increase in the DM content and 6% to 9% in the OM content in relation to SIL-MUDS. The NDF content of SIL-MUDS MI was 53% lower than SIL-MUDS and SIL-MUDS TRI was 16.9% higher than SIL-MUDS. For the storage times, there was a small percentage variation, except for the crude protein content (PB), where SIL-MUD MI and SIL-MUDS TRI presented increases of 41.78% and 18.30%, respectively, of the 30 at 120 days of storage. With regard to MS DIV, SIL-MUDS MI presented a 15% higher value than SIL-MUDS. While the DIV of MO was 12.8% higher in SIL-MUDS MI than in SIL-MUDS, and 22.1% lower in MUDS + TRI silage compared to MUDS silage. Thus, the inclusion of ground corn and wheat bran as additives for mucilage silage of the Sisal defibration promotes the maintenance of DM content and chemical composition of silage, as well as DIV of MS, OM and NDF.