IV. Chemical and Biochemical Composition of Sturgeon Products

The aim of this study was to develop and establish a molecular method for species identification of sturgeon products, esp. black caviar, used in the international trade. Sequences of the entire cytochrome b (cytb) gene from 858 fish specimens were used for discriminating between 22 sturgeon species, and potential species-specific restriction sites were determined. No single restriction endonuclease can be used for the differentiation of all species. Depending on the species, from one to four different enzymes are necessary for species identification. Overall, using seven different restriction endonucleases, 17 acipenseriform species can be separated on the mtDNA level on the basis of characteristic species-specific restriction patterns. Three species of the genus Scaphirhynchus (S. albus, S. platorhynchus and S. suttkusi), as well as Acipenser gueldenstaedti and A. persicus, were not differentiated. Our approach provides an opportunity to identify and control the trade in sturgeon products outside of the three main caviar producing species, A. gueldenstaedti, A. stellatus, and Huso huso. Besides the trade, the method is important for the management and conservation programs. The necessity to combine nuclear and mtDNA markers for more precise identification is also discussed. The following hybrids were observed using mitochondrial and nuclear markers: one A. gueldenstaedti/A. stellatus hybrid, one A. gueldenstaedti/Acipenser ruthenus hybrid, five hybrids between A. gueldenstaedti or A. persicus and A. nudiventris.