It appears that animals and humans can ferment collagenous tissues from animal meat into short-chain fatty acids. Collagen is the protein that composes most of the connective tissue in our body, including bones, ligaments, tendons, and cartilage. A study done on cheetahs, examining the ability of their microbiota to ferment these connective tissues into short-chain fatty acids, found the following conclusion:

“Collagen induced an acetate production comparable with [plant fiber] and a markedly high acetate-to-propionate ratio (8.41:1) compared with all other substrates…This study provides the first insight into the potential of animal tissues to influence large intestinal fermentation in a strict carnivore, and indicates that animal tissues have potentially similar functions as soluble or insoluble plant fibers.”

A nose-to-tail carnivore diet provides ample amounts of collagen for the production of short-chain fatty acids.