Supplementation with tea saponins and statins to reduce methane emissions from ruminants

Summary

​This project assessed the effects of tea seed saponin (TSS) and fermented red rice (FRR) containing statin on dry matter intake (DMI), rumen fermentation, microbial ecology, animal health and methane (CH4) emissions.

The first TSS experiment identified the maximum daily dose of TSS supplementation [114 mg/kg liveweight (LW)] that did not compromise productivity in steers. In a second experiment, CH4emissions were not significantly reduced by increasing TSS (maximum of 62.8 ± 1.19 mg TSS/kg LW), but adverse impacts on animal health occurred.

These responses in cattle differ from published results where TSS reduce methane production. The sequential dose-response experiments with FRR showed the lowest level of FRR (40 g/d) reduced CH4yield (g/kg DMI) compared to the unsupplemented control, but were not different from control at the higher doses. Adverse effects on DMI and metabolism occurred once the dose was greater than 100g/day.

The FRR study suggests that transient reductions in methane production occurred, but as the time on supplementation and dose increased, the effect dissipated. These results suggest that rumen microbes adapt to statin and negate the CH4 inhibition response. Feeding TSS or FRR supplements to cattle appears not to be a practical strategy for reducing CH4 emissions.