Proponents of the Biologically Appropriate Raw Food or B.A.R.F diet insist that our cats, dogs and ferrets require 15-25% plant material in their diet to simulate scavenger behavior or digested plant material in prey animals like rabbits. While cats and ferrets are obligate carnivores and should ONLY eat meat, organs and bones, dogs are facilitative carnivores. This means that in hard times they will dig up a tuber or search out alternative food sources IF THEY ARE IN DIRE NEED. In the wild wolves are known to go for days even a week and a half without eating while in search of food. When they find it, often they gorge in case of another lull in feeding. Some smaller prey like rabbits consumed in only a few gulps will have plant material in the digestive tract, while large prey is torn into. With these larger prey, wolves are known to be observed by such researchers as David Mech who has studied wolves for over 30 years actually shaking out the stomach contents of their prey meaning they are NOT eating digested plant material (L. David Mech & Luigi Boitani (Eds.) Wolves: Behavior, Ecology, and Conservation,Chicago: U. of Chicago Press, 2003.) Whether a wolf eats plant material out of desperation or ate their prey’s digestive contents on a regular basis it still probably wouldn’t make up 15-25% of their daily diet especially because they most likely wouldn’t be eating daily.
Raw diet, raw fruits and veggies right?! WRONG! Aside the fact that cats, dogs and ferrets are carnivores, raw fruits and vegetables are made with a hard to break down insoluble fiber called cellulose. Only some animals have digestive processes like rabbits and cows to break down this component, not even humans can properly break it down. Since cats, dogs and ferrets are carnivores, lacking the proper enzymes like cellulase and amylase to break down plant material, their digestive tract is so short it is not able to take the time to break down this food stuff. While the human digestive tract is 30 feet long, cat and dog digestive tracts are only about 2.5 times their body length. Animals like the rabbit and the cow who are experts at breaking down plant material and cellulose have specialized stomachs and enlarged cecums not found in humans, cats, dogs or ferrets. At the end of the day plant material is only absorbed maximally at 20% which is evident as it is often excreted and visible in the feces.
In order to accommodate this problem some companion pet owners will try and emulate prey digestive matter for their cats, dogs and ferrets by boiling and then blending plant material. However, this is absolutely the wrong approach.
First of all, a rabbit nor any other prey animal will be eating cooked food nor will they be eating some of the vegetables and fruits that humans like to put in that boiling pot of water. Boiling water actually causes fruits and vegetables to lose nutrients. By even soaking them in water, nutrients including vitamins are dissolved. As the water boils it disrupts the fruits and veggies, evaporating nutrients further. The longer the food is boiled the more the plant matter breaks down which on the one hand is more ideal than raw vegetables and fruit whose strong cellulose wall can’t be broken down by our cat, dog and ferret's digestive system, but this also means even more nutrients are being depleted and destroyed. Some water that fruits and vegetables are boiled in are nutrient rich but heat, light and exposure to air subject nutrients to quick destruction. The question then is if you are avoiding kibbles or canned food because it is devoid of nutrients from the high temperatures of processing why provide nutrient devoid veggies and fruits?
After boiling a variety of fruits and veggies, many companion pet owners will then throw everything into a blender. This is an attempt to emulate digestion and breaking down of food stuff. This however further damages and denatures fruits and veggies. High speed blending creates a vacuum of oxygen into the machine, the same oxygen that when certain vitamins and minerals come in contact with are destroyed. Furthermore, like many machines that are ran either for long times or at high speeds, begin to get hot and as we learned from boiling hot water above, heat quickly destroys vitamins and minerals in fruits and vegetables.
Finally, there are no commercially available species appropriate live enzymes that can be added to this boiled and blended mixture to create the same digestive material that a rabbit would contain in their digestive tract.
So it’s certainly a tradeoff cook your veggies to break down the cell walls and deplete nutrients or feed raw veggies and only gain 20% nutrient absorption. The only real viable option is to simply leave them out of the diet and if they are fed, only feed them when they are within whole raw prey that your companion is consuming.