Composition and Content of Fatty Acids in Muscle Tissue of the Potanin Altai Osman Oreoleuciscus potanini (Cypriniformes, Actinopterigii) from Mongolian Reservoirs

The composition of fatty acids in the muscle tissue of the unique Central Asian carp-like fish, Potanin Altai osman Oreoleuciscus potanini, was studied for the first time. The populations of these fish in the reservoirs of the semiarid zone (Durgun and Taishir) during the period of their formation are considered. It was shown that the content of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids in O. potanini corresponds to the median of this value in the order Cypriniformes. It was established that the basis of the food web of the herbivorous form of this species consists of microalgae (diatoms, Euglena and, possibly, chrysophytes), as well as bacteria. At the same time, the levels of bacterial biomarkers, 15-17BCFA and 17:0 were significantly higher in fish in the Durgun reservoir, whereas the level of EPA (diatom biomarker) in O. potanini was higher in the Taishir reservoir. The established higher values of the heavy nitrogen isotope content in the muscles of O. potanini from the Taishir reservoir are most likely associated with the yet unformed benthic communities and with the incomplete diversification of the riverine form of the Potanin Altai osman into lacustrine forms.