Manti
Your leopards "should" be able to eat just about anything that is size appropriate, and, that it is actually interested in eating. Remember, just because we are captive breeding these animals, doesn't mean that the NBI are not intact. Now, if you want to talk nutritionally you have to think what are you feeding your manti that is going to help the positive progressive health and growth of your leopards. Whether you are feeding your geckos pinky mice or the occaisional earthworm, and yes they do eat them (possible alternative diet?), it really comes down to the health of whatever your feeding your lizards. As long as they are healthy and you have leos that will eat them, then you should have a cheap alternative on your hands.