Hmm, well, I know my two really love the smell or taste of Salmon oil. There are also some great tips on how to switch your cat over on catnutrition.org. It's been my mainstay since the kitten came to live here and I started workign with the raw diet (she was raised on it). Khan, however, has been a horribly finicky eater since he got here, and we've had nothing but trouble getting him to eat *anything* ...until he found raw.
That being said.. we've been trying some mixtures, and the only thing he consistently doesn't have trouble with (unless he just eats it way too fast, and I think I've only seen this once) is the chicken. I haven't tried him on venison, but if I remember correctly, the lamb is difficult for them to digest. He is about 50/50 with the beef, but often we mix that in with the chicken.. usually when we're getting low. He's really had no issues with the chicken at all, though.
I don't know if having a fish allergy will keep your kitty from being able to use the Salmon oil or not, but it really does have a strong smell, and it makes it easier with my crew to sneak in the extra vitamins and fiber that they're usually finicky about. From what catnutrition says, though.. you should only use a few drops a week. I do occasionally soft boil an egg (although this is really just my preference..supposedly they don't get samonella (sp?) poisoning so the eggs don't need to be cooked). I just like the texture better.. it doesn't make the mixture quite so soupy. He loves the yolk, and again, it has a strong enough flavor/smell to mask any extras..
Those two might work for you. I got the salmon oil capsules, and just poke a hole in it and squirt a drop or five on it. They do have a *really* strong smell, so you may not need more than a drop.
I'm having an issue with my kitten, and sneaking some other stuff into her food (she doesn't notice it with the Salmon oil), so I've got to call my vet today and see what he says about too much salmon oil, since they're only supposed to be getting a few drops a week.
I'll let you know what I find out.