Cats are "Obligate Carnivores" meaning they are "meat eaters" and if you want your kitten to survive you 'must' feed him/her a high meat protein diet. Do not impose on your cat your beliefs, you have a choice, he does not! "Orijen" is one of the best cat food available and what I feed my cats and kittens in my cattery.
"Why are Cats Obligate Carnivores?
Cats "guts" are much shorter than ours. They do not have the ability to fully digest and utilize the nutrients in plant material. Although theoretically, they might get enough protein from plant material to exist, they need taurine in order to thrive. Taurine is found primarily in the muscle meat of animals, and is most highly concentrated in the heart and liver.
In the wild, cats may get a small amount of grain and other plant material from the stomachs of their prey, but our domestic cats really do not need large amounts of grain. Corn is a good example. Corn is a cheap source of protein, and many of the "supermarket brands" of dry cat food are packed with corn in various forms, e.g., corn bran, corn germ meal, ground corn, corn gluten, corn gluten meal. If I could give you one rule of thumb only, it would be to shy away from any cat food containing corn, especially listed at or toward the the top of the ingredients. (Pet food ingredients are generally listed in descending order by dry weight.)
It should also be noted that some manufacturers practice "splitting" to keep corn from the very top of the list. Splitting is carefully calculating the percentage of each kind of corn so that the aggregate total weighs more than any other ingredient, however none of the corn ingredients is listed at the very top. There is nothing illegal about this practice, but it puts the consumer at a disadvantage. It would be much more transparent if manufacturers were required to list the percentage by weight of each ingredient. Corn is not only a poor source of protein, it is a known allergen to some cats.
While some cat food manufacturers add small amounts of vegetables and fruits to their formulas, the premium foods always have named meat protein high on the list of ingredients. The fruits and vegetables are generally added for their vitamin and mineral content, and sometimes for their probiotic value.
Vegetarian Cat Food
Some vegetarian humans prefer not to handle meat in any form, and purchase commercial vegetarian foods for their cats. Although these foods meet the AAFCO nutritional standards for a "complete and balanced diet," they have come by it artificially. In my opinion, it's much like using bleached flour for white bread, then adding back the nutrients one would get naturally from a good, whole-grain bread. How can you be sure you've added back all the nutrients? Learn more about vegetarianism and veganism for cats from this article: Should I try a Vegan Diet for my Cats?
In short, "Cats need meat to survive"
Question: Should I try a vegan diet for my cats?
Answer: Cats are obligate carnivores - that is, their digestive system is totally unsuited to break down the cell walls to release the nutrients in vegetable foods.
Food will only remain in their system for a couple of hours, as compared with about 24 hours for omnivores like ourselves or days as in most herbivores. They are adapted to eat relatively small amounts of highly digestible, energy-dense food, with an optimal level of vitamins, minerals and micronutrients. Proteins derived from vegetables are much less easily digested, lack many of the vitamins, minerals and micronutrients that are necessary for complete absorbtion and must be consumed in much greater quantities to obtain sufficient energy for healthy functioning.
Humans, whose need for high-quality protein is far less than those of cats, have a difficult time remaining optimally nourished on a solely vegetable-derived diet, and must pay particular care with food types, quantities and combinations, as well as take a variety of supplements, to avoid becoming malnourished or suffering from various deficiencies. I find it highly unlikely that any vegan diet could supply all the nutrients a cat needs to thrive.
While I can appreciate the philosophical stance that can lead to a human's eschewing all animal-derived products, and recognise that they have a perfect right to opt for this for themselves, it can only be regarded as cruelty, and ultimately abusive, to force a cat to follow such practices. They need meat not just for the protein, but for all the other factors that are found in it, for its concentrated energy and for its speed of digestion. For a cat, plant-derived foods are simply not good enough.