I have heard of Vegan cat diets. I am sure that there are many sources for specifically a vegan feline diet. I would caution that
Recently, I have read about the need for a cat to be on a vegan diet. Amazing isn’t it? Apparently the cat couldn’t digest some protien found in meat. (!)
I am sure that there are instances of previously carnivore species needing to become herbivores or become extinct.
<from soapbox> How does forcing the cat to eat a non-meat diet entail “cruel” treatment? I mean, really? How is this cruel? If the cat is hungry and you feed it good food that satisfies all of the nutritional needs, he/she wouldn’t know any different. It is cruel to have a cat as a pet and not treat it like a part of your family – otherwise it is just a captive prisoner of yours and THAT would be cruel.