My Magnum, bless his memory, had terrible food and environmental allergies. They were so bad he had chronic inflammatory bowel disease and would have seizures. Anyway he was placed on Science Diet Z/D
Ultra (which is totally devoid of protein antigens) and did not have another seizure for the remainder of his life once he was on that diet [4+ years]. The Z/D formula is just their reduced antigen formula and I don't think it's that great for those with serious food allergies so its best to go with the
Z/D Ultra formula (antigen free).
I will say that you will need to supplement the Science Diet with Omega fatty acids. Their formulas do not have enough given the stress of dietary sensitivities. I gave Magnum fish oil, vitamin E, and flaxseed oil as supplements to this food. Otherwise you will be dealing with dry itchy skin problems using Science Diet.
For Mariah and Drago I am using an all natural brand food (which wasn't available when Magnum was around) called Pinnacle.
Breeder's Choice Pet Foods - Premium, Natural Pet Foods and Treats for Dogs and Cats They are on the Trout and Sweet Potato formula. My cat, Jasper, gets the kitty formula and all of them really love it. It's so nice to have more natural choices these days.
Good luck, Tracy