And I forgot to read the very first post, but just to clarify...cats may eat the stomach of their prey but it doesn't mean they eat the plants.
A mouse for example is manly herbivorous, so its stomach content is just fermented vegetable matter. It is a mix of bacteria (symbiotic) and fatty acids (volatile). This can help aid in the management of the cat's own intestinal flora, and might contribute a little to the cats energy source. But it will lose ninety percent of its energy because it has moved up a trophic level, so it doesn't add very much energy. Just thought that might be interesting to know as well since I am a biology nerd...
~Kruša-HMPK fancy slough dragon female~
~Nerim-VT fancy baby female~
~Micah-half mainecoon/half persian male~
~Milo-half mainecoon/half persian male~