This study investigated the effect of partially replacing fish meal (FM) in diets with plant protein ingredients on the growth, feed intake, feed efficiency, and nutrient retention of Siberian sturgeon, Acipenser baerii Brandt, juveniles. FM was replaced with soy protein concentrate (SP) and rape meal (RM). Three experimental feeds (40% crude protein, 10% fat) were prepared by extrusion. The protein sources in diet FM were fish meal, blood meal, and fish hydrolysate. In diet SP, the fish meal and fish hydrolysate were substituted with soy protein concentrate, and in diet SP-RM, with soy protein concentrate and rape meal. Each diet was fed to triplicate groups of sturgeon with a mean initial mass of 14 ± 1.3 g. The growth test lasted for 50 days, and were carried out in flow-through tanks of 600 dm3 capacity. The sturgeon from group FM reached an individual body weight that was about 10% higher than that of the fish from the other dietary variants; the significance of the differences was confirmed statistically (P < 0.05). The specific growth rates (SGR) were similar during the growth test (about 4% d-1) and did not differ significantly. The feed conversion (FCR) and protein efficiency (PER) ratios were not significantly affected by the different dietary treatments, and were about 1.2 and 2.1, respectively. The proximate composition of the sturgeon bodies was similar, except with regard to lipid content. Protein retention, which ranged from 29.5 to 33.2%, was higher in groups SP and SP-RM. Lipid retention was the lowest in the SP-RM group. The results indicated that soy protein concentrate and rape meal are sufficient partial fish meal substitutes in feed for sturgeon juveniles.
