In vitro and in vivo evaluations of wine lees as feeds for ruminants: Effects on ruminal fermentation characteristics, nutrient digestibility, blood metabolites and antioxidant status

Abstract Wine lees are by-products of wine-manufacturing, but the usefulness as animal by-product feed has not yet been revealed. The present study was aimed to investigate the usability of wine lees as feed for ruminants in fattening conditions by in vitro and in vivo trials. In in vitro experiments (in vitro I and II), the following four treatments were prepared: 100% dry matter (DM) rolled barley as a control (WL0), and replaced 7.5% DM, 15.0% DM, and 22.5% DM of wine lees as three treatments (WL7.5, WL15, WL22.5, respectively). A linear decrease in gas production was observed at 48 h after incubation with an increase in the percentage of wine lees in the substrate (P 0.05). As wine lees increased, the proportion of ruminal propionate at 4 h after feeding and plasma malondialdehyde, which is one of the oxidative stress markers, were decreased (P