I need some advice on starting raw(for a cat). please.

[RolandsMom]

I have decided im going to try Roland on raw (with kibble as well).
i am trying him on the Solid gold tuna canned at the moment to see how he react to the fish but am not sure where i should start with the raw. our pet supply store is great and has a bunch of different kinds for cats. considering his allergy to something,which is the least likely to be an allergenic to cats? turkey, bison, fish, beef or chicken? if he is okay on the canned tuna, he should be okay on the fish right? how do i start introducing the raw? do i just give it to him or start small?
any advice is appreciated!