PSVIII-6 - Effect of adding plant extracted saponin (PES) on accumulative gas production kinetics and methane emission of the prairie blend pelleted feed products in ruminant system

Abstract: The objectives of this study were to study the effect of adding plant extracted saponin (PES) as phytochemical feed additive on in vitro accumulative gas production kinetics and methane (CH₄) emission of blend pelleted feed products in ruminant system. Four levels of PES (0, 1, 2, 3%) were added to canola meal and pea mixtures with two different ratios (CMP1: 50:50; CMP2: 70:30) which were used to make Prairie blend pellet feed products. The accumulative gas production kinetics and CH₄ were determined using in vitro systems. Ruminal fluid for in vitro studies was obtained from rumen fistulated lactation dairy cows. The experimental design was a RCBD with the PES level as a fixed effect and in vitro run with fistulated animals as a random effect. The data was analyzed using Mixed Model Procedure of SAS. Polynomial contract was used to determine linear and quadratic relationship. The results showed that adding PES did not significantly affect the asymptotic production (a) with an average of 104.06 ±12.38 (SD) mL/g DM, the gas production fractional rate (c) with an average of 1.00 ± 0.90 %/h, the average production at half of asymptotic production (AP) with an average 11.26 ± 0.87 mL and lag time with an average of 2.08 ± 0.81 h. As to CH₄ emission at different incubation time, the result showed that at short incubation times (2h, 4h, 12h), adding PES showed numerically reduced CH₄ from 277 to 1.08 ml/g (at 2h) and 4.39 to 1.59 ml/g (at 4h). With increasing PES level, CH₄ was significantly linearly reduced (P=0.019) from 8.31 to 6.30 ml/g at 12h incubation time. At long incubation (24 h), adding PES did not have significant impact on CH₄. In conclusion, adding PES at the studied levels to Prairie blend pellet feed products did not significantly affect accumulative gas production kinetics but it had a high potential to decrease CH₄ emission at short incubation times.