Herbal feed additives containing tannins: impact on in vitro fermentation and methane mitigation from total mixed ration

Authors: MANJU WADHWA, PRABH KAUR SIDHU, MOHINDER PAL SINGH BAKSHI

Abstract: Total mixed ration (TMR) containing roughage and concentrate mixture in a 65: 35 ratio on dry matter (DM) basis was supplemented with herbal feed additives [(HFAs); Acacia catechu (Katha), Areca catechu (Supari), and Acacia nilotica (Babul)] at 0-4% on DM basis to assess their impact on fermentation pattern and methane production by using in vitro gas production technique. Areca catechu had the highest (P < 0.01) concentration of condensed tannins (CTs), saponins, and vitamin C as compared to other HFAs. The net gas production (NGP), digestibility of NDF and true OM, and ME availability, partitioning factor (PF), volatile fatty acids (VFAs), and microbial biomass production were higher (P < 0.01) at 24 h as compared to t-half incubation, irrespective of type and level of HFAs supplemented. Acacia nilotica had an edge over Acacia catechu with respect to digestibility of nutrients and ME availability. VFAs production and efficiency of rumen fermentation was the highest from the Areca catechu-supplemented TMR. Irrespective of type of HFAs and incubation period, the digestibility of NDF and that of true OM were highest (P < 0.01) at the 1% level of supplementation, but depressed thereafter. Amongst HFAs-supplemented groups, VFA production and fermentation efficiency were highest at the 2% level. The results conclusively revealed that supplementing Areca catechu and Acacia nilotica at 2% of TMR (DM basis) inhibited the methane production, without affecting the fermentation pattern.

Keywords: Bio-active compounds, herbal feed additives, hydrogen balance, in vitro, ME availability, methane emission

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