EN
Within 17 September 31 October 1997, fry of the Russian × Siberian sturgeon hybrid of 31.1 g mean individual weight and sterlet fry of 25.4 g mean individual weight were fed two trout feeds: the Danaex 4.85 and the Safir differing, i.a., in their gross energy content (5470 and 5173 Kcalˇg1, respectively), each feed being offered in triplicate. The fish were kept in cages, stocked at 80 ind./cage, placed in power station cooling water of temperature changing within 12.223°C. Water temperaturedependent differences in fish growth were revealed: the hybrid grew better at 1923°C, while the sterlet growth was better at 1218°C. In both fish groups, the Danaex 4.85 produced better food conversion rate (FCR) and apparent net protein utilisation (aNPU).