FEEDING CONDITIONS FOR STURGEONS (Acipenseridae) IN THE CASPIAN SEA

Abstract

Extended Abstracts: Environmental biology 293 temperatures respectively. These results are consistent with the data for adult fishes, preferring different environmental temperatures (Hochachka, Somero, 1984). For a comparison of catalytic efficiencies of enzymes from embryos of sturgeon and other fishes adapted to <different habitat temperatures, the Arrhenius activation energy (Ed for lactate dehydrogenase was used. For the embryos of Siberian sturgeon and sterlet at the early gastrula stage E, values for this enzyme shows 18.72*1.29 and 20.18~k1.8 1 kcal/mol respectively. Similar E, values were observed for lactate dehydrogenase from embryos of loach and zebrafish. However the enzyme from the embryos of fish preferring cold habitats displays lower E, values than that from other species. These data suggest that lactate dehydrogenase from embryos of fish adapted to cold habitats display higher catalytic efficiency than other species (Hochachka, Somero, 1984).The thermal inactivation (T,, values) of lactate dehydrogenase from embryos of Siberian sturgeon and sterlet at the early gastrula stage was also investigated. The T,, values for the enzyme from these species was 71"C, whereas for zebrafish and loach those were 73.5 and 75°C respectively. This values for the embryos of Atlantic salmon and rainbow trout were 69°C. These data confirm the observations pointing out that thermal stability of proteins from various eciothermic animals correlates with the habitat temperatures (Alexandrov, 1977; Swezey, Somero, 1982; Jaenicke, 1991). References: Alexandrov V.Ya. (1977) Cell:;, Molecules and Temperature. Springer-Verlag. Berlin. Dettlaff T.A., Dettlaff A.A. On relative dimensionless characteristic of the development duration in embryology.