Nile tilapia (Oreochromis niloticus) skin is a well-known biomaterial used as an occlusive dressing for burn treatment. It is also an inexpensive and important source of collagen. This study aims to describe the ultrastructural aspects of Nile tilapia skin, assess its collagen amount and organization, and compare quantitative methods of histochemical and immunohistochemical analysis (in all sterilization steps ...