[Early stages of the incubated chicken egg as a model in experimental biology and medicine]

Early stages of the incubated chicken egg (appr. first third of the incubation period) are demonstrated as a model of experimental research in biology and medicine. Following a short introduction on anatomy and embryology, some advises on experimental methodology are given (application of test substances, evaluation). The application of this model is shown in several examples: as an alternative of animal experiments in ocular and mucosal toxicity, to study angiogenesis, aspects of tumour biology, or the effects of heavy metals. Furthermore, incubated eggs at day 4 of incubation can be used to investigate functional parameters of the cardiovascular system and effects of drugs on this system. Finally, the possibilities and the limitations of the test-system are discussed. It has to be pointed out that this system works in a period of incubation without any sensitivity of the embryo. Therefore, the test system using early stages of the incubated egg -- in contrast to other chicken egg models - is a real alternative to animal experiments.