Effect of supplementing herbal feed additives on the fermentation pattern and In vitro methane production by total mixed rations with different roughage to concentrate ratios

This study was taken up to assess the effect of supplementing dry extracts of six herbss containing saponins [HFAs; kulthi (Dohichos biflorus), patha (Cissampelos pareria), aritha (Sapindus trifoliatus), methi (Trigonella foenum graecum), shikakai (Acacia concina) and shatavari (Asparagus racemosus)] in total mixed rations (TMR) on the in vitro methane emission and nutrient utilization. TMR with different roughage to concentrate (R:C) ratio of 80:20, 75:25, 70:30 and 65:35 on DM basis were formulated and HFAs were supplemented @ 1-3% on dry matter basis. Aritha had the highest (P<0.01) concentration of both water and methanol soluble saponins and condensed tannins (leucocyanidins). Patha followed by kulthi had the highest (P<0.01) concentration of vitamin C, flavonoids, total phenols and true tannins. The data were analyzed by 2 (incubation periods) × 6 (Type of HFAs) × 4 (Levels of HFAs) × 4 (R:C ratios) factorial design. The digestion kinetic parameters revealed that with the increase in level of concentrate in the diet, irrespective of type and level of HFAs supplemented, the lag period for fermentation of diet decreased (P<0.01) linearly. In-vitro gas production studies concluded that the herbal feed additives like patha, kulthi and shatavari rich in bioactive compounds supplemented at the rate of 2% to the TMR containing roughage to concentrate ratio of of 65:35 on DM basis improved the net gas production, nutrient digestibility, volatile fatty acid production, feed conversion efficiency ME availability and mitigated methane emmision.