Effect of dietary flaxseed meal on growth, blood biochemistry, reproductive hormones and oocyte development in previtellogenic Siberian sturgeon (Acipenser baerii Brandt, 1869)

Abstract

To evaluate the effects of dietary flaxseed meal (FSM) on growth and physiological changes of Siberian sturgeon Acipenser baerii, 32 previtellogenic female fish (955.06 ± 53.38 g) with the same maturity stage were selected and randomly distributed in eight tanks (500 L). Fish were fed with different levels of dietary FSM including 0 (Control), 50 (F50), 100 (F100), and 150 (F150) g kg−1 diet for 6 months. All experimental diets were formulated to be isonitrogenous and isoenergetic based on 42% crude protein and 21.0 MJ kg−1 diet. The fish were fed according to their satiation, three times a day and uneaten pellets were counted to measure feed intake. At the end of the experiment, the results showed no significant differences in growth parameters. In biochemical parameters, plasma glucose and cholesterol increased significantly (P < 0.05) compared to control group, whereas triglyceride, total protein, albumin, globulin and calcium remain unchanged (P > 0.05). There were significant decreases in 17β-estradiol and testosterone in the control compared to F150 (P < 0.05). There was no significant difference in luteinizing hormone level (P > 0.05), but the highest level of follicle stimulating hormone was found in groups fed with FSM (P < 0.05). Plasma triiodothyronine and thyroxine levels were not significantly affected by dietary treatments (P > 0.05). Oocyte size increased in groups which were fed with FSM compared to the control (P < 0.05). The results of this study indicated that feeding with FSM in Siberian sturgeon had positive effects on 17β-estradiol, testosterone, follicle stimulating hormone, plasma glucose and cholesterol, and enhanced ovarian development but had no effect on growth. Altogether, dietary inclusion of FSM at the level of 150 g kg−1 could improve accelerating oogenesis and increase some key sex steroids in female Siberian sturgeon.