Effects of feeding rates and feeding frequency on the growth performances of juvenile hybrid sturgeon, Acipenser schrenckii Brandt♀ x A. baeri Brandt♂

The objective of our study was to establish an optimal feeding frequency and feeding rate for rearing hybrid sturgeon (Acipenser schrenckii Brandt female x A. baeri Brandt male) in production during the juvenile growth phase. The growth and survival of juvenile hybrid sturgeon were determined at four different feeding rates and three different frequencies. The feeding rates were 2%, 3%, 4%, and 5% body weight per day, and these daily rations were offered in 2, 4, and 6 fractions over the day. Thus, a 4 x 3 experimental design was used with triplicates per treatment involving a total of 36 tanks. Initial stocking density was 400 fish per tank with initial body weight of 7.79 +/- 0.37 g. Fish were kept at 18 +/- 1.0 degrees C in circular tanks and fed one commercial diet (41% protein, 12% lipid, 9-10% moisture and 10% ash). Fish were weighed every 2weeks to regulate the feeding rates, and the number of fish per tank was reduced by 50% every 4 weeks to maintain the same stocking density. After 12 weeks of feeding, all fish were sampled for weight measurements. Survival, weight gain ratio (WGR), specific growth rate (SGR), feed efficiency (FE), and feeding costs were calculated. Feeding frequency markedly affected WGR and SGR (P < 0.01), but had no significant effect on FE and feed cost (P > 0.05). All parameters were significantly affected by feeding rate (P < 0.01). The interaction between feeding rates and feeding frequencies had significant effects on final body weight (FBW) and WGR (P < 0.05). Fish fed 5% BW/day administered in 6 portions resulted in the highest WGR (P < 0.01). Broken line analysis on SGR indicated the optimum feeding rates of juvenile hybrid sturgeon to be 3.7% BW/day. The body composition did not result in a significant difference in all treatments (P > 0.05). Statement of relevance The research of AQUA-D-14-00653 determines more effective feeding frequency and rate for juvenile hybrid sturgeon under commercial production conditions. (C) 2015 Elsevier B.V. All rights reserved.