This study was conducted to evaluate the effects of dietary thymol–carvacrol on the growth
performance and blood parameters in great sturgeon. A basal diet was formulated using
common feed ingredients supplemented with thymol–carvacrol powder at 0, 1, 2, and
3 g kg−1, leading to four experimental diets. Each experimental diet was randomly assigned
to triplicate 350 L tanks. Great sturgeon with an initial weight of 43.6
±
1.6 g was randomly
distributed in the experimental tanks. Results showed that inclusion of dietary
thymol–carvacrol significantly increased the final weight, specific growth rate (SGR) and
weight gain (P<0.05) of great sturgeon compared to the control. Feed conversion ratio (FCR)
was also improved (P<0.05) in fish that received thymol–carvacrol, but it had no effect on
survival (P>0.05). The total number of red and white blood cells was not different among
the treatments but fish feeding on thymol–carvacrol diets had more lymphocytes (P<0.05).
In conclusion, administration of thymol–carvacrol can improve growth performance and
immunity of great sturgeon.