You should never, microwave, wet food. I forget now why, but, its a really bad idea. I warm my wet food, by mixing it with hot water, so its real real soupy. The coldness, of the wet food, counter acts, the hot water, and it makes it like room temp. I know, I felt it, before I gave it to him. You should be mixing wet food with water anyhow, even if it is right from the cubbard. You need to keep them flushed out and hydrated. Especially with little boy kitties, you need to keep them flushed out, to keep the crystals from forming, per say. It also prevents the urine from being too concentrated. Too concentrated urine can cause bladder inflammation and kidney issues. One should have the urine concentration checked, at least twice a year. They insert a needle into the bladder, and test the urine, its called urine specific gravity, normal is ballpark 1.035, Bump just had his checked, and his is 1.036, they also checked his creatanine, and that is normal. The creatanine is done by a blood test, and that gets sent to Antech, turnaround is 24-48 hrs. If ya got an issue, best to catch it early.
Bump gets tested because of his health issues, for him, anything not normal, it is critical to catch his early.