Use of spent brewer's yeasts as an additive of pasture silages and its effects on nutritional quality and pH

Jose Daza1*, Verónica González1, Rodrigo Moldenhauer2, Camila Reyes1, Jorge Rivas1, Carolina Solís1, Francisca Muñoz1, Adriana Carvajal1, Viola Saldivia1, and José L. Urrejola2
Livestock systems at Region Aysén del General Carlos Ibáñez del Campo depend on forage conservation during the spring-summer season, generally with low nutritional quality to animal requirements. To reduce nutrient loss, additives are commonly used, being spent brewery yeast a potential additive. Therefore, a study was carried out with the inclusion of two spent brewer’s yeast (Lager and Ale) as an additive in pasture mini silos compared to two commercial additives (SiloSolve MC™ and Josilac grass™) and mini silo without additive. It was observed that spent brewer’s yeast has a negative effect on crude protein and metabolizable energy, contents that decreased to 9.8% and 2.5%, respectively, compared to control. However, Ale yeast declined faster and maintained lower pH levels below 4.1. Spent brewer’s yeast do not improve nutritional quality, however decreased pH levels of pasture silage. Therefore, it should be noted that the effect of spent brewer’s yeasts has been insufficiently evaluated. Thus, is still a lack of trials within large scale of silage conservation and its effects on animal feed performance.
Keywords: Additive, Brewer?s yeasts, fermentation, Saccharomyces carlsbergensis, Saccharomyces cerevisiae, silages.
1Instituto de Investigaciones Agropecuarias, INIA Tamel Aike, PO Box 296, Coyhaique, Chile.
2Cervecería Belga de la Patagonia (D’OLBEK), Coyhaique, Chile.
*Corresponding author (jose.daza@inia.cl).