I am thinking to give orijen food but i read contains high protein and magnesium and persian cats have kidneys problems.what is your opinion?
Minor but important correction: ALL cats have kidney problems. Excluding PKD as a kidney problem, persians are no more likely to develop CRF than a moggie.
The question is why does CRF develop in the first place. The standard answer is the protein in the diet of cats causes the kidneys to fail. Thus, by lowering the protein, the kidneys are spared. This is a theory and not a fact. The studies which seem to support it are also flawed.
Some holistic vets don't agree with the high protein/kidney problem relationship. Cats evolved to eat high protein. They would not have evolved to eat something that would shorten their lives. I personally feel, and my vet agrees, it is not the level of protein, but the nature of the protein.
So, Orijen has a reputation for better quality protein sources. The amount of protein would not matter to me -- but the over all ingredients would.