Physiological changes and reproductive performance of Sterlet sturgeon Acipenser ruthenus injected with thiamine.

To evaluate the effects of thiamine on physiological changes and spawning performance of Sterlet sturgeon Acipenser ruthenus, 45 farmed female fish (698.6±8.9g) were randomly distributed in 9 tanks (1000L) and fed a diet with 1g/kg of an anti-thiamine drug. This was provided for 5 months prior to spawning. Thiamine hydrochloride was intraperitoneally injected to fish at three different doses: 0 (T0 , as control), 5 (T5 ) and 50 (T50 ) mg/kg body weight at days 30, 90 and 150 after the experiment started. After five months, the results showed no significant differences in weight gain and hemoglobin level, but hematocrit significantly increased in T5 group. There was no significant difference in glucose-6-phosphate dehydrogenase and estradiol-17β, but testosterone was significantly increased in the T50 group. Total thiamine concentration in the eggs was significantly higher in T50 than that detected in the control group. Fecundity and larval mortality at 6day post hatch (dph) showed no significant differences among treatments, while the number of eggs per gram was significantly lower in T0 than that observed in T50 . Larval weights at 1 (11.6mg) and 6 (23.1mg) dph and larval lengths at 6 (15.6mm) dph were significantly affected by the treatment with the highest level of thiamine injection (T50 ). Diseases symptoms such as yolk sac deformation, erratic pattern of swimming, and loss of equilibrium were observed at 4 dph in T0 and T5 groups. The overall results revealed that thiamine injection has positive effects on reproductive performance in the sturgeon and the negative impacts of anti-thiamine in the offspring can be reduced by the injection of this vitamin to the broodstock.