Dietary effect of nucleotide supplement (Ascogen®) on growth performance and intestinal microbial flora in Siberian sturgeon (Acipenser baerii)

The present study was conducted to evaluate the dietary effect of nucleotide on growth performance and intestinal microbial flora in Siberian sturgeon ( Acipenser baerii). ). Four hundred fifty fish of A. baerii (39.77 +/- 10.24 g initial weight) were distributed into 15 tanks (300 L) and they were fed with different levels of nucleotide (Ascogen (R)) including 0.0 (control), 0.2 (diet 1), 0.4 (diet 2), 0.6 (diet 3), and 0.8 (diet 4) g kg(-1 )in triplicates for nine weeks. The fish were fed daily until apparent satiety. The results showed no significant differences in the final length and survival rate among the experimental groups (p>0.05). p >0.05). However, the final weight, weight gain, daily growth rate, specific growth rate, and condition factor were significantly enhanced in the groups fed with diet 3 and diet 4 (p<0.05). p <0.05). The count of intestinal lactic acid bacteria (LAB) was the same among the experimental groups (p>0.05), p >0.05), while the total count of the intestinal bacteria was significantly decreased compared to the control group (free from nucleotide) (p<0.05). p <0.05). In conclusion, most of the growth indices were improved in the fish fed with nucleotide at 0.6 and 0.8 g kg(-1). However, the treated diets could not affect the intestinal LAB population in Siberian sturgeon.