In fact, traditional cultures preferred organ protein over that found in animal muscle, believing that it was healthier. (wellnessnova.com)
This means you should be using animal muscle meat protein and not animal by - product protein or vegetable protein. (felinefriendlycare.com)
Forget about all artificial or plant proteins that are not made of animal muscles, such as meat by - products and protein comes from grains. (yorkiemag.com)