Nutritional and Possible Medicinal Value of Siberian Sturgeon (Acipenser baerii) and Sterlet (Acipenser ruthenus) Ovarian Fluid

Chemical analysis of samples of ovarian fluid (OF), a secondary product of breeding of the two common species of Acipenseridae family in Russian aquaculture, was carried out in order to assess its nutritional and possible medicinal value. It has been established that the dominant organic component of OF of both species is a water-soluble or water-dispersible protein easily absorbed by the digestive tract. Proteomic analysis of the samples has shown that the main component of the protein fraction of OF is a highly nutritious protein vitellogenin. Amino acid analysis has shown that 350 g of dried sturgeon OF or 245 g of dried sterlet OF satisfy the needs of an adult human in all essential amino acids per one day. Eighty-five grams of dried sturgeon OF or 55 g of dried sterlet OF covers the daily requirement of an adult for vitamins C, B-1, B-2, B-3 (PP) and B-6, a number of macroelements (Na, K, Ca, Mg) and microelements (Fe, Cu, Mn, Zn, Cr). Furthermore, Cu content is significantly higher in sturgeon OF, and Fe content is significantly higher in sterlet OF, which is partly confirmed by the relative content of Cu and Fe carrier proteins, ceruloplasmin and transferrin, respectively. In addition, a number of proteins of physiological significance for fish were identified. The possible medicinal value of OF consists, among other things, in significant content of various antioxidant proteins in OF of both species. The use of OF as a food supplement could improve the profitability of sturgeon breeding by producing an additional valuable product, and would also expand the range of natural dietary supplements on the market.