Influence of graded replacement of paddy straw with brewer’s spent grain on rumen protozoa, enzyme profile and feed fermentation under in vitro

Abstract

The present study was conducted to assess effect of sun dried brewer’s spent grain with soluble (DBSG) supplementation on rumen fermentation, enzyme profile, ciliate protozoal population and dry matter degradability in paddy straw based diet in vitro. Substrate (500 mg), for example paddy straw was gradually replaced by DBSG (00 mg DBSG + 500 mg of paddy straw, 125 mg DBSG + 375 mg paddy straw, 250 mg DBSG + 250 mg paddy straw, 375 mg DBSG + 125 mg paddy straw and 500 mg DBSG + 00 mg paddy straw) for this study. DBSG contained 96.8% OM, 19.7% CP, 72.8% NDF, 28.4% ADF, 22.9% cellulose and 5.2% lignin on DM basis. TVFA concentration and propionic acid production increased due to inclusion of DBSG in the incubation medium. The activities of polysaccharide degrading enzymes e.g., carboxy-methyl cellulase, xylanase and β-glucosidase decreased with supplementation of DBSG. However, activities of amylase showed the reverse trend. The number of total ciliate protozoa as well as holotrich and spirotrich protozoa increased with increasing level of DBSG. In vitro dry matter and organic matter digestibility of paddy straw/incubating substrate also improved with supplementation of DBSG. It is concluded from the study that supplementation of DBSG in paddy straw based diet improved rumen fermentation e.g., TVFA and propionic acid production under in vitro condition.