Effect of plants containing secondary metabolites on ruminal fermentation and methanogenesis in vitro

Abstract

The effect of kalmegh (Andrographis paniculata), neem (Azadirachta indica), bamboo (Bambusa balcooa), kesuti (Eclipta alba), kanchan (Alternantherd sessilis) leaves and akanda (Calotrips gigantea) bark were tested at 3 different levels of replacement (0, 30 and 60 mg per 200 mg of substrate, consisting of paddy straw and concentrate mixture in 1:1 ratio) for in vitro methane production, ciliate protozoal population, enzyme profile and rumen fermentation characteristics. The gas as well as methane production (ml/g DM) was significantly lower due to inclusion of Andrographis paniculata, Azadirachta indica and Calotrips gigantean in the incubation medium. Holotrich and spirotrich protozoal number also reduced due to inclusion of Andrographis paniculata, Azadirachta indica and Calotrips gigantean. Azadirachta indica, Alternantherd sessilis and Eclipta alba had no influence on the enzyme activity of carboxymethyl cellulase, xylanase and β-glucosidase. However, specific activity of carboxymethyl cellulase and xylanase reduced significantly due to addition of Andrographis paniculata and Calotrips gigantea in the incubation medium. The results indicated that plant tested in the present experiment (leaves of Andrographis paniculata and Azadirachta indica and bark of Calotrips gigantea) reduces ruminal methanogenesis without much adverse effect in rumen fermentation.