In vitro rumen fermentation kinetics, metabolite production, methane and substrate degradability of polyphenol rich plant leaves and their component complete feed blocks.

BACKGROUND

This experiment aimed at assessing polyphenol-rich plant biomass to use in complete feed making for the feeding of ruminants.

METHODS

An in vitro ruminal evaluation of complete blocks (CFB) with (, leaves) and without ( hay) polyphenol rich plant leaves was conducted by applying Menke's in vitro gas production (IVGP) technique. A total of six substrates, viz. three forages and three CFBs were subjected to in vitro ruminal fermentation in glass syringes to assess gas and methane production, substrate degradability, and rumen fermentation metabolites.

RESULTS

Total polyphenol content (g/Kg) was 163 in compared to 52.5 in with a contrasting difference in tannin fractions, higher hydrolysable tannins (HT) in the former (140.1 vs 2.8) and higher condensed (CT) tannins in the later (28.3 vs 7.9). The potential gas production was lower with a higher lag phase (L) in CT containing and the component feed block. alone and as a constituent of CFB produced higher total gas but with lower methane while the partitioning factor (PF) was higher in and its CFB. Substrate digestibility (both DM and OM) was lower ( < 0.001) in compared to other forages and CFBs. The fermentation metabolites showed a different pattern for forages and their CFBs. The forages showed higher TCA precipitable N and lower acetate: propionate ratio in while the related trend was found in CFB with . Total volatile fatty acid concentration was higher ( < 0.001) in leaves than hay and leaves. It has implication on widening the forage resources and providing opportunity to use forage biomass rich in polyphenolic constituents in judicious proportion for reducing methane and enhancing green livestock production.

CONCLUSION

Above all, higher substrate degradability, propionate production, lower methanogenesis in CFB with leaves may be considered useful. Nevertheless, CFB with also proved its usefulness with higher TCA precipitable N and PF. It has implication on widening the forage resources and providing opportunity to use polyphenol-rich forage biomass for reducing methane and enhancing green livestock production.