Abstract
A general description is given of the embryonic and early larval development of teleost fishes, especially the cyprinids Barbus conchonius L. and Cyprinus carpio L. Moreover experimental studies on the migration of neural crest cells and the development and differentation of digestive tract and gonads have been reported.
Neural crest cells migrate in a similar way as in higher vertebrates. A number of these cells reach the gut shortly before the first endocrine cells are distinguished. However, a relation between both cell types is hitherto not demonstrated.
At the time of the first food intake by larvae, different cell types of the intestine, i.e. absorptive cells, mucus cells, and endocrine cells are distinguished. Leucocytes are present between the intestinal epithelial cells from early development onwards, suggesting the presence of a gut-associated immune system, which might offer prospectives for oral vaccination.
Primordial germ cells are clearly visible from the early somite stage onwards. The differentiation of the gonads starts much later, i.e. at the end of larval development, with a fast proliferation of the germ cells. Monoclonal antibodies raised against germ cells, might effect in vivo destruction of germ cells. This may be of importance in the culture of fish for food consumption.
