Methane Mitigation Potential of Tannins and their Impact on Digestibility of Nutrients In-vitro

Potential of Citrullus colocynthis as herbal feed additive for ruminants

To assess the potential of Citrullus colocynthis as herbal feed additive for ruminants, colocynth fruit as a whole, its seeds and peel-pulp were evaluated at various levels (0, 0.5, 1.0, 1.5, 2.0, 2.5, 4.0%) with total mixed ration (roughage to concentrate ratio: 65:35) as substrate in 3×7 factorial design by in vitro gas production technique. Phytochemical analysis revealed significant variation (P<0.01) in total phenols, non-tannin phenols, true tannins, saponins, flavonoids and vitamin C content among different parts of colocynth fruit. Irrespective of the part used, varying level of Citrullus colocynthis had significant effect on net gas production (NGP; ml/24/g), metabolizable energy (ME) availability, methanogenesis, digestibility of neutral detergent fiber (NDF) and true organic matter (TOM) in comparison to control; however the effect was pronounced at 1% level of supplementation. No significant difference in total volatile fatty acids (TVFA) production and acetate production was observed at varying levels of Citrullus colocynthis except at 4% level when total mixed ration (TMR) was used as substrate. Irrespective of its level, supplementation of Citrullus colocynthis fruit as a whole, seeds and peel-pulp significantly improved NGP (P<0.001) and ME (P<0.01) availability in comparison to control group whereas partitioning factor (PF; P>0.578), digestibility of NDF (P>0.905) and true OM (P>0.228) remained unaffected between different test groups. However, TVFA production, acetate, propionate and butyrate concentration was observed lower (P<0.001) in peel-pulp and seed supplemented group. From above results it can be concluded that supplementation of Citrullus colocynthis fruit at 1% level of substrate had potential to improve rumen fermentation characteristics and reduce methanogenesis, however in vivo assessment on ruminants need to be conducted to evaluate the persistency of effects along with health concerns.

Effect of herbal feed additives containing saponins on rumen fermentation pattern

Macrotyloma uniflorum (kulthi) seeds, Asparagus racemosus (shatavari) roots or Acacia concina (shikakai) pods were supplemented to total mixed rations (TMR) @ 0-3% (on DM basis) to assess the impact of herbal feed additives (HFAs) on the in vitro rumen fermentation pattern. The saponin content and 2, 2-diphenyl-1-picrylhydrazyl- hydrate (DPHH) antioxidant activity was highest in A. racemosus than other HFAs. But total phenols, non tannin phenols, true tannins, condensed tannins, vitamin C and flavanoid contents were highest inM. uniflorum and lowest in A. concina. The dose/level of supplementation of HFAs, irrespective of their nature did not affect net gas production (NGP) and availability of metabolizable energy (ME) from TMR, but digestibility of nutrients and partitioning factor (PF) decreased in comparison to the unsupplemented group. The total and individual volatile fatty acids (VFAs) production; and acetate to propionate ratio was improved when the TMR was supplemented with HFAs at 1% level. The methane and ammonia-N production was depressed at 2% level as compared to control group. Irrespective of the dose, the total VFAs, acetate, and propionate production was higher while ammonia-N decreased in M. uniflorum supplemented TMR than other HFAs supplemented groups. Methane production from the TMR was comparable in the diet supplemented with different HFAs, however, diet supplemented with M. uniflorum resulted in lower methane production. Amongst the tested HFAs, M. uniflorum was a richer source of most of the bio-active compounds. Based on in vitro fermentation parameters, M. uniflorum supplemented to TMR @ 2% gave the best results.

Herbal feed additives containing essential oil: 1. Impact on the nutritional worth of complete feed in vitro

This study was taken up to assess the impact of supplementing herbal feed additives [HFAs; fruit of Myristica fragrans (Jayphall), seeds of Anethum sowa (Suva), fruit of Apium graveolens (Ajmo), fruit of Cuminum cyminum (Jeera), bark of Cinnamonum zeylanicum (Dalchini), or whole plant of Eclipta alba (Bhangro)] containing essential oils as active component on the nutrient utilization and methane production using wheat straw-based total mixed ration (TMR) as a substrate by in vitro gas production technique. The essential oil content was the highest (P < 0.01) in M. fragrans followed by E. alba and A. sowa. In addition to essential oils, these HFAs also contained saponins, tannins, and antioxidants. The HFAs were supplemented at 1-3% of substrate dry matter (DM). The data were analyzed by 6 × 4 factorial design. Irrespective of level of HFA, the net gas production (NGP) and metabolizable energy (ME) availability was the highest (P < 0.01) in TMR supplemented with C. zeylanicum comparable with E. alba, but higher than TMR supplemented with other HFAs. Supplementation of TMR with different HFAs did not affect the digestibility of neutral detergent fiber (NDF) and true organic matter (TOM) and partitioning factor (PF). The total volatile fatty acids (VFAs), acetate, propionate (P < 0.01), and butyrate (P < 0.05) production was the highest in TMR supplemented with A. sowa, and the lowest was observed in TMR supplemented with C. cyminum. The isobutyrate and valerate production was also the highest (P < 0.01) in diet supplemented with A. sowa, but isovalerate production was the highest (P < 0.01) in diet supplemented with C. zeylanicum. The A:P ratio was the best in TMR supplemented with A. sowa. The efficiency of rumen fermentation was the highest, and efficiency of conversion of hexose to methane was the lowest in diet supplemented with A. sowa as compared to all other supplements. The in vitro methane production expressed as either percent of NGP, ml/100 mg DM of substrate/24 h, or as ml/100 mg of digestible OM/24 h was the lowest in TMR supplemented with A. sowa. The ammonia nitrogen production from TMR supplemented with M. fragrans and A. sowa was comparable, but significantly (P < 0.01) lower than TMR supplemented with other HFAs. Irrespective of the nature of HFA, the NGP and ME availability were significantly (P < 0.01) higher in TMR supplemented with HFAs at all levels as compared to un-supplemented TMR. As compared to control, the digestibility of NDF and that of TOM was depressed slightly in all the HFA-supplemented TMRs. The supplementation of HFAs at 2% of substrate DM improved (P < 0.01) the production of total VFAs, acetate, and propionate, and that of isovalerate in comparison to the un-supplemented TMR. The acetate to propionate ratio increased (P < 0.01) with the increase in the level of supplementation of HFAs containing essential oils. The methane and ammonia productions were depressed significantly when TMR was supplemented at 2% level of HFAs as compared to control TMR. It was concluded that supplementation of TMR with A. sowa at 2% of substrate was fermented better as indicated by the production of total and individual VFA, methane, and ammonia as compared to TMR supplemented with other HFA or un-supplemented TMR.

Effect of supplementation of saponin containing herbs on in vitro methane production under different feeding systems

This study was taken up to assess the effect of herbal feed additives [HFAs; kulthi (Dohichos biflorus), patha (Cissampelos pareria), aritha (Sapindus trifoliatus)] supplemented at 0–3% on DM basis of total mixed rations (TMR) on the in vitro methane production and nutrient fermentation in a 3 × 4 factorial design. TMR with different roughage to concentrate ratio (R:C) of 80:20, 75:25, 70:30 and 65:35 on DM basis were formulated. The roughage portion was made up of wheat straw and maize green fodder in 70:30 ratio. The chemical analysis of HFAs revealed that aritha had the highest concentration of both water and methanol soluble saponins; and condensed tannins (Leucocyanidin). Patha followed by kulthi had the highest concentration of vitamin C, flavonoids, total phenols and true tannins. The digestion kinetic parameters revealed that with the increase in level of concentrate in the diet, irrespective of type and level of supplementation of HFAs, the lag phase for fermentation of diet decreased linearly. The data conclusively revealed that the best response with respect to net gas production (NGP), digestibility of nutrients, methane production, volatile fatty acid (VFA) production, ME availability and other fermentation parameters from TMRs with different R:C ratios was observed in kulthi and patha supplemented at the rate of 2% of TMR with R:C ratio of 65:35 on DM basis.