No abstract

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 foenumgreacum, 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.

The in vitro rumen fermentation parameters and the antimethanogenic potential of three Asteraceae species: Chamaemelum nobile, Centaurea pulata and Chrysanthemum segetum were determined. Serum bottles containing 200 mg of each plant and 30 ml of the culture medium (artificial saliva plus rumen juice) were incubated for 24 h. After incubation, pH, volatile fatty acid (VFA), ammonia (NH3) and methane (CH4) productions were recorded. Methanogens and protozoa were quantified using  a Real Time PCR technique (qPCR). Cumulative gas productions, in vitro organic matter digestibility and VFA were not significantly affected by the added species when compared to the control (P > 0.05). The effects of Chamaemelum nobile and Chrysanthemum segetum on methane production, NH3 and acetate to propionate ratio (C2:C3) were similar. The two species were able to modulate rumen fermentation to produce significantly lower CH4 concentrations (-24.3% and -27.1%, respectively) compared to the control. C.pulata produced the highest cumulative gas and stimulated the microbial metabolism with an increase in C2:C3 ratio, NH3 and methane production (P < 0.05). No significant effect of the three species on methanogenic Archaea and protozoa was registered (P > 0.05). The three species studied herein show a good potential for mitigating ruminal methane production without any undesirable effects on the main fermentation parameters.