Physiological changes and reproductive performance in presence or absence of thiamine in the diet of Sterlet sturgeon, Acipenser ruthenus

To evaluate the effects of thiamine (vitamin B₁) on physiological changes and reproductive performance of Sterlet sturgeon (Acipenser ruthenus), 30 females (averaged 698 ± 15 g) were selected in maturity stage IV and were randomly distributed in six fiberglass tanks (1063.3 liters) with two treatments and three replicates. The first treatment was fed with a dry diet containing 10 mg/kg thiamine hydrochloride, while second one was fed with 1 g/kg amprolium hydrochloride as an anti-thiamine compound for five months. After this period, fish were induced for spawning by LHRH-A2. At the end of the experiment, the growth parameters showed no significant differences between treatments (P>0.05). In the first treatment (fed with thiamine), the levels of hematocrit and hemoglobin were significantly increased (P<0.05), but no significant differences were observed in the number of red blood cells, white blood cells, blood indices and differential white blood cells (P>0.05). Germinal vesicle migration was measured in three stages (day 0, 75 and 150) which had a significant decrease in thiamine-fed treatment (P<0.05) at the middle and end of the experiment. Glucose-6-phosphate dehydrogenase and estradiol values showed no significant differences (P>0.05) between the treatments, while a significant increase in testosterone were observed in thiamine-fed treatment (P<0.05). The number of eggs per gram and the latency time increased significantly in anti-thiamine and thiamine–fed treatments, respectively (P<0.05), but fecundity and thiamine content in the eggs showed no significant differences between the treatments (P>0.05). According to the results, the presence of thiamine in the diet led to improvement in some physiological and reproductive indices in Sterlet sturgeon and it seems to be an essential vitamin in reproduction season for Sterlet broodstocks.