Supplementation of Selected Tanniniferous Phyto-sources at Graded Level Decreases Methane Production in vitro

Aim: This study was carried out to determine the effect of graded level supplementation of selected tanniniferous phyto-sources, viz. Syzygium cumini, Machilus bombycina and Acharas zapota on in vitro methane, fermentation characteristics and rumen protozoa population in order to determine the optimum dose of supplementation for the inclusion in the ruminant diet to achieve methane reduction.

Study Design: This study was design based on previous screening studies carried out in our laboratory. A graded level study was carried out here to determine the optimum dose of inclusion of these phyto-sources in the ruminant diet.

Methodology: In vitro gas production test was carried out by adding these sources at different levels viz. 0%, 5%, 10%, 15% and 20% to the basal diet consisting finger millet straw (Elusine coracana) as roughage source and concentrate in 70:30. The gas samples obtained after 24 h of incubation were analysed using gas chromatograph. The effect of phyto-sources on rumen fermentation characteristics and protozoa population was determined using standard methodologies.

Results: The addition of these phyto-sources significantly (P=.05) reduced the total gas production at 10% in case of Machilus bombycina and above 10% in Syzygium cumini, while Acharas zapota had reduce gas production at the highest inclusion level. However, all the phyto-sources reduced methane production as the percentage of inclusion increased. Effect on fibre digestion was also observed. A significant effect (P=.05) on rumen ammonia-N and protozoa were observed. An overall reduction in TVFA was also recorded in this study.

Conclusion: This study confirms that the selected phyto-sources were potent methane inhibitor. Considering 200 mg of basal diet, S. cumini and A. zapota can be included within 10% of the basal diet and M. bombycina, at a maximum of 5% to reduce methane without affecting rumen fermentation unfavourably. However, long-term in vivo trials should be conducted to determine the efficacy of these phyto-sources on enteric methane emission.