Methane production, fermentation characteristics, and microbial profiles in the rumen of tropical cattle fed tea seed saponin supplementation

Abstract Belmont Red Composite rumen-cannulated steers ( n  = 8, 364 ± 8.4 kg liveweight, LW; least squares means ± s.e.m.) were used to assess effects of feeding tea seed ( Camellia sinensis L.) saponin (TSS) supplementation on performance, methanogenesis, fermentation pattern and rumen microbial communities. The expectation was to use TSS to potentially modulate the rumen microbial population and decrease enteric methane (CH 4 ) production. The steers were fed twice a day with a basal diet (BD) that contained a mixture of 0.15 Rhodes grass ( Chloris gayana ) hay plus 0.85 of a commercial concentrate before CH 4 emissions were measured in open-circuit respiratory chambers for 48 h. Steers were then adapted progressively to doses of 20 and 30 g/day of TSS for 10 and 6 days, respectively before new CH 4 measurements were recorded. Final placement in chambers was conducted after 13 days of TSS removal (BDP). Rumen fluid samples from each steer were collected for the treatments BD, BD + 20 g TSS, BD + 30 g TSS and BDP. Growth performance and CH 4 emissions were not affected by the addition of TSS, but compared to the BD and TSS diets, daily CH 4 emissions (g) and yield (g CH 4 /kg DMI) were lower (P  Fibrobacter succinogenes increased by 2 fold (P  R. albus increased by 100 fold (P  R. flavefaciens was 100 fold lower in TSS supplemented and BDP groups than in BD control group (P  in vitro results and small ruminant trials where TSS caused a dose-dependent reduction in CH 4 emissions.