DefinePK

Abstract

An experiment was conducted to study the effects of purified saponin at the level of 0, 1.55, 3.10, 4.65 and 6.20 mg/30 ml rumen inoculum in triplicate on rumen methanogenesis and rumen fermentation characteristics by in vitro gas production technique. The total gas production was significantly (P<0.01) reduced in all saponin treated groups when compared to the control. The highest level of reduction in total gas was observed with 4.65 mg saponin treatment than other treatment groups. The methane production was significantly (P<0.01) decreased in all saponin treated groups when compared to the control. The highest level of methane reduction was observed with 6.2 mg saponin treatment than other treatment groups. The decreases in methane reduction were 14.04 %, 21.90 %, 34.30 % and 37.60 % in 1.55, 3.10, 4.65 and 6.20 mg saponin levels respectively than 0 mg saponin level. The percentage of methane on total gas production was also significantly (P<0.01) reduced in all saponin treated groups than the control. The highly significant (P<0.01) reduction was observed with 4.65 mg of saponin treatment and this treatment decreased the methane percentage on total gas production by 15.04 % when compared to the other treatment groups. The methane emission per 100 mg of digested substrate was also significantly (P<0.01) reduced with 4.65 mg saponin treatment than other treatment groups. No significant difference was observed on pH and ammonia nitrogen levels in all the treatment groups. The in vitro true dry matter digestibility (IVTDMD) was not affected by saponin and no significant difference was observed. The protozoal count was significantly (P<0.05) reduced in all saponin treated groups when compared to the control. The reduction in protozoal counts were 14.40%, 15.56%, 19.31% and 23.05% respectively with 1.55, 3.10, 4.65 and 6.20 mg saponin treatments when compared to the control. The bacterial count in all saponin treated groups was not significantly affected, however the bacterial counts showed a decreasing trend with increased levels of saponin when compared to the control. No significant difference was observed on total volatile fatty acids (TVFA), acetic acid, propionic acid, butyric acid and acetate to propionate ratio in all saponin treated groups when compared to the control. Based on our findings we concluded that treatment with purified saponin reduces the total gas and methane emission significantly without affecting the rumen fermentation characteristics such as pH, ammonia nitrogen, IVTDMD, microbial load and TVFA.