Fracionamento de proteína e carboidratos em silagens de capim-elefante contendo subprodutos agrícolas

Abstract

The experiment was conducted to determine fractioning of carbohydrate and protein of elephantgrass silage containing cassava meal, coffee hulls and cocoa meal. A completely randomized experimental design was used in a 3 × 4 factorial scheme, composed of three byproducts added to elephantgrass at four levels (0, 10, 20 and 30% of natural matter), each one with five repetitions. The material was ensiled in PVC silos, which remained closed for 60 days. Cassava meal contributed to reduce the content of acid detergent insoluble nitrogen, presenting the greatest values for protein A fraction and for the B1+B2 fraction contents. However, cocoa meal provided increment of C fraction, significantly increasing the content of unavailable protein for ruminal microorganisms. The addition of cassava meal, followed by coffee hulls provided the greatest total carbohydrate content in all the levels used. The A+B1 carbohydrate fractions increased according to the levels of added by-products, and coffee hulls was responsible for the lowest content of this fraction in the silages. Cocoa meal favors increase of nitrogenous fractions, but increase of acid detergent insoluble nitrogen, C fraction, of silages produced with this additive is a limiting factor. Cassava meal increase content of non-fibrous carbohydrates in the silage, while coffee hull and cocoa meal increase non-digestible fraction of carbohydrates. © 2010 Sociedade Brasileira de Zootecnia.