Feeding Bristlenose catfish high protein foods is a really bad idea, which if done really regularly will probably result in death as BNs are veggies.
You can use bloodworm if you are trying to condition them for breeding but only in small doses.
I feed beef heart twice a week to my Angels.
Some finds its way to the bottom of the tank and my Plecs eat it. They seem fine. But then I do have some of the more carnivous species (L029, L114)