The effect of feeding rate on growth performance and body composition of Russian sturgeon (Acipenser gueldenstaedtii) juveniles

Growth performance and body composition of Russian sturgeon (Acipenser gueldenstaedii) juveniles were determined at four different feeding rates (FR; % body weight [BW] per day). The experiment was carried out in four experimental variants, two replications each. The experimental variants were: V1 - 1.0% BW day-1, V2 - 1.5% BW day-1, V3 - 2% BW day-1 and V4-ad libitum feeding. Fish were distributed into eight tanks; each tank was populated with 18 Russian sturgeon juveniles with an average body mass of 248.19±1.6 g. The fish were fed with extruded pellets with a protein content of 42% and a fat content of 18%. Feeding rate had a significant (p < 0.05) effect on the body weight (BW) and specific growth rate (SGR). At the end of the trial SGR calculated in V1 variant was 0.61% g day-1, in V2 - 0.90% g day-1, V3 - 1.18% g day-1 and V4 - 1.66% g day-1 and the feed conversion ratio (FCR) was for V1 - 1.69, V2 - 1.29, V3 - 1.12 and V4 - 1.01. The best BW was obtained in the group V4, followed by V3 group. The body compositions of muscle were also significantly (p < 0.05) different among treatments. The results of our study suggest for Russian sturgeon an optimal feeding rate between 2% BW day-1 and ad libitum (which was calculated at 2.8% BW day-1), but analyzing the obtained results from an economical point of view and because protein is the most expensive macronutrient in fish diet, we can conclude that the optimum feeding rate for Russian sturgeon juveniles with a mean weight of 248.194 ± 1.59 g can be 2% BW day-1.