Study found that life of crustacean disease resistance greatly exceeded the vertebrate animals, containing chitin insects, squid, bacteria, turtle shell, shrimps and crabs and other animals, can in extremely harsh conditions for survival and reproduction, and full of vitality. But human and fish and other vertebrate animals adapt ability is poor, as long as the water slightly polluted, climate change, life will be threatened. Crustaceans and vertebrates survive enormous resistance difference has aroused great interest of scientists. After the study confirmed that the resistance difference is that these animals containing chitosan material.