Efficacy of Aqueous Plant Extracts as Rumen Fermentation Modulators

The present in vitro study was conduct to investigate the effect of water extracts of ten medicinal plants on rumen fermentation characteristics and methanogenesis with sorghum based different diets i.e. D₁ (50R:50C), D₂ (80R: 20C) and D₃ (20R:80C). Ten medicinal plant parts (selected on their active principles) were used for the preparation of water extract. Some of the compounds and Plant secondary metabolites (PSM) present in water extracts were estimated by using suitable methods. Screening was done using all the 10 extracts at single dose (2 ml/30 ml of inoculation medium) and using single substrate i.e. D₁ and screened on the basis of maximum reduction in methane production with minimum effect on in vitro dry matter digestibility (IVDMD). Finally, Neem (Azadiracta indica) leaf extract was selected and evaluated in detail at four doses (0, 1, 2 and 3 ml) and three diets i.e. D₁, D₂ and D₃. The results showed that tannins, phenolics, sugar and protein contents were highest in garlic (A. sativum) extract, while the methane production was decreased significantly (P<0.01) with increasing concentration of neem leaf extract. It was further noticed that there was significant decrease (P<0.01) in acetate propionate ratio due to addition of neem leaf extract. On the basis of overall results it could be concluded that extract of neem leaf has potential to decrease methane production and increase propionate production in wheat straw based diet. However, the effective dose of this extract was found at 2 ml/30 ml of inoculation medium reducing methane production by 40% without affecting the other ruminal fermentation parameters.