Figure 3.

Mean (±s.e.) changes relative to time 0 in concentration and δ¹³C_VDPB of acetate (a, b) and propionate (c, d) in in vitro gut content fermentations spiked with H¹³CO₃⁻. Fermentations performed with kangaroo forestomach content resulted in significantly more incorporation of ¹³C label than fermentations performed with bovine rumen fluid, indicating that reductive acetogenesis contributes to a larger proportion of the acetate pool in kangaroos than it does in cattle. Additional data for butyrate and valerate are presented in Supplementary Figure S4. ▴ Bovine rumen fluid (grain-fed) (n=4). • Bovine rumen fluid (grass-fed) (n=3). ▪ Kangaroo forestomach content (n=3).