Effect of Camellia sinensis and Trigonella foenum-greacum saponins on in vitro rumen fermentation of vetch-oat hay

The present study was conducted to investigate the effect of two plants rich in saponins on in vitro ruminal fermentation traits of vetch-oat hay using gas syringes as incubators. Two plants, Camellia sinensis and Trigonella foenum-greacum, were added to 200 mg of vetch-oat hay at levels of 0, 2, 4, 6 and 8 mg and 0, 48, 54, 60 and 66 mg, respectively. Gas production was dose-dependent for both plants and decreased for all incubation times with the increasing doses. Methane concentration was decreased at all inclusion levels and for each incubation time. The highest methane reduction was observed at 48h of incubation for both plants. This decrease varied between 48.78-52.84% and 45.52-72.35% for Camellia sinensis and Trigonella foenum- greacum, respectively. Ammonia-N concentrations also decreased significantly (P 0.002) when the plants rich in saponins were included with the vetch-oat hay. In addition, these plants significantly inhibited the protozoa growth in ruminal fluid (P 0.001). At 24h incubation, protozoa counts were reduced by 81.86% and 83.29% for the high levels of Camellia sinensis and Trigonella foenum-greacum, respectively. Finally, in vitro truly dry matter digestibility was significantly affected by the inclusion of plants rich in saponins (P 0.05). It is suggested that addition of these saponin-rich plants to feed could modify the rumen fermentation and inhibit the release of methane and ammonia, which may be beneficial for improving nutrient utilization and animal growth.