The effects of diets containing rapeseed meal on Siberian sturgeon (Acipenser baerii) growth, muscle composition, and physiological performance

Sturgeon farming is a rapidly developing aquaculture sector which requires high-quality feeds. As an ingredient of animal feeds, fishmeal is often replaced with cheaper plant-based protein sources, such as rapeseed cake meal, a by-product of canola oil pressing. The aim of the present study is to evaluate the effects of diets containing various levels of rapeseed cake meal on the juvenile Siberian sturgeon (Acipenser baerii) growth, hematological and biochemical parameters, as well as muscle composition. An 8-week feeding trial was conducted on fish with average body weight of 216.2 ± 45.7 g. Fish were fed diets were 0%, 10%, 20%, and 30% of fish meal and soybean meal were replaced with rapeseed meal (groups A, B, C, and D, respectively). Additionally in E diet (30% rapeseed meal) effects of phytase addition RENOZYME® HiPhos 20000 in concentration 2000 IU was tested. During the experiment, no mortalities were observed in each of the studied groups. Similar values of morphometric and breeding parameters were observed in groups A, B, C, D and E. No hematological effects of rapeseed diets occurred, except for significantly lower erythroblast levels in groups B, C, D, and E compared to A. Group B showed a higher plasma glucose concentration compared to the other groups. ALT activity in groups D and E were lower than in groups A, B, and C. The muscles of individuals from group B showed the highest dry matter and fat content, while the highest protein content occurred in group C. Despite significant differences in the values of some parameters, the obtained results indicate that the replacement of 10–30% of fishmeal with rapeseed meal in the feed for the juvenile Siberian sturgeon did not compromise fish survivability, growth performance, health, or body composition, although phytase addition did not improve the effects of administering rapeseed-containing feed.