Effect of tannin supplementation from Uncaria gambir extract on rumen fermentation, microbial protein and in vitro gas production

Gambir (Uncaria gambir) is a tropical plant which contains tannin as a main phenolic compounds. This research was aimed to quantify the ability of tannin to bind protein and evaluate the addition of tannin from gambir extract on rumen fermentation, microbial protein and in vitro gas production. The treatments consisted of RC0 (0%), RC2 (2%), RC4 (4%) and RC6 (6%) of gambir extract level in mix rations with 70:30 ratio (concentrate:forage). Parameters measured were protein precipitation, VFA production, NH₃ concentration, microbial protein and kinetics of gas production. The result showed that tannin from gambir extract had a significant ability (P<0.05) to precipitate protein Bovine Serum Albumin. Supplementation of tannin from gambir extract significantly increased (P<0.05) NH₃ concentration and microbial protein. There was no significant effect on VFA total production (P>0.05). Gas production in RC0, RC2, RC4 and RC6 was decreased (P<0.05) after 48 hours incubation by 49.28 ml, 48.41 ml, 47.40 ml and 47.07 ml, respectively. It was concluded that the addition of tannin from gambir extract with level 6% in rations can be used to increased in vitro rumen fermentation.