Effect of additives in the chemical composition of broad bean silages (Vicia faba)

Abstract

Legumes have low ensilability due to their high buffering capacity and low content of soluble carbohydrates. However, the broad bean (Vicia faba) can be an alternative forage for ruminant feeding, having the advantage of its low buffer capacity, high protein content and high digestibility. The inclusion of additives to silage is intended to improve the quality of fermentation, provide aerobic stability, and increase the nutritional value of silage. The objective was to evaluate the effect of different additives on the quality of broad bean forage silage. Broad bean forage was harvested 116 days after sowing, and the following treatments were evaluated in laboratory silos: 1) Inoculum of homofermentative lactic bacteria Enterococcus faecium, Pediococcus pentosaceus and Lactobacillus plantarum (INOC), 2) Formic acid at 85 % concentration (FORM), 3) Cane molasses applied at 4% fresh weight (MEL), as well as 4) Control treatment without additives (CON). A completely randomized experimental design with five laboratory silos per treatment was used. Chemical analyzes were performed for dry matter, organic matter, crude protein, neutral detergent fiber, acid detergent fiber, ethereal extract, pH, starch content, in vitro digestibility of dry matter, estimated metabolizable energy content, and proportion of effluents produced. The inclusion of additives did not modify the chemical composition of the broad bean silage (P>0.05). Given the low initial dry matter content in the broad bean forage, the effluent represented more than 18% of the ensiled forage. Broad bean silage has a good crude protein content and an average value of metabolizable energy. However, the large proportion of effluents can be an environmental problem. The evaluated additives did not improve the chemical composition of broad bean silages, nor the loss of dry matter, or the production of effluents.