I'm very sorry to hear about your cat.
All I can relate is my own experience-I have a 10 year old spayed female cat who has been on the Ultra for about 6 months now with no problems. In fact, her coat is beautiful, her muscle tone is better than it has been in years and she is experiencing a second kittenhood of playfulness.
My concerns with this food are the 2 that Prin mentioned, so I keep a close eye on her, but so far, so good. My dogs are eating the Ultra dog food and are also doing quite well.
The goal of life is to make your heartbeat match the beat of the universe,
to match your nature with Nature.~Joseph Campbell~
"You can't have a good day in bad underwear"- Fruit of the Loom ad