METHANE PRODUCTION UTILIZING TANINIFEROUS PLANTS AS SUBSTRATE IN RUMINAL FERMENTATION IN VITRO AND EFFECT OF PHENOLIC EXTRACTS ON RUMINAL MICROFLORA

Abstract

The use of forages rich in condensed tannins (TC) on ruminant diets is a strategy that has served for mitigating CH4 emissions; however, the mechanism of action of such compounds in the rumen, has not been clarified. The antimicrobial effect of both, quebracho (Schinopsis balansae) condensed tannins (TCQ) and oregano oil (AO) on ruminal microflora was evaluated. Successively, TCQ, AO and tow taniferus plant species (Mimosa diplotricha L. 4.3% TC and Tagetes erecta 1.3% TC) were evaluated in a base diet (DB) at different inclusion levels (low, medium and high). The fermentation kinetic and CH4 production was measured in an in vitro system. Results showed that the microorganisms’ growth was inhibited by TCQ at 3% and AO at 555 ppm, highlighting their antibacterial properties. Diets showed crude protein values higher than 100 g/kg DM. The DB produced 63.9 ml/g DM of CH4 at 48 h of incubation and treatments showed a range of 5.0 to 55.3 ml/ g DM of CH4 (p<0.001). Seventy percent of CH4 was produced at 24 h of incubation in the DB and treatments. Methane emission was reduced by the inclusion of taniniferous species and AO diminished CH4 production convincingly; however, fermentation kinetics was affected by AO at high inclusion levels due to its antibacterial effect.