I have to say Michelle, I never did with Max, and I haven't with Poot either.
As long as they are eating a good balanced diet, then that's the best thing.
Actually, saying that I do put Plaque Off in wet food as its supposed to help teeth and gums, which FIV cats are renowened to have issues with, but other than that, I can't think of anything specific!
Can I ask what's driving the questions hun? Hope all is well with you and the furries xx