Effects of dietary synbiotic on growth, survival, lactobacillus bacterial count, blood indices and immunity of beluga (Huso huso Linnaeus, 1754) juvenile

This study aimed to determine the effect of synbiotic (Biomin IMBO) as feed additive on beluga (Huso huso) juvenile with an average body weight of 26.45 +/- 0.19 g. Experimental diets at which supplemented with 1.0, 2.0 and 4.0 g synbiotic per kg of feed were fed to beluga juvenile, whereas the control group was fed with no synbiotic. After the feeding trial for 8 weeks, growth performance, survival, lactobacillus bacterial count, blood indices and immunity were tested. Even though, some growth performance and feed utilization parameters including WG, SGR and FCR were improved in group fed with 2.0 g kg(-1) synbiotic; however, there were no significant differences (P > 0.05) in growth and feeding parameters between juveniles fed control and synbiotic supplementation diets. In terms of intestinal microbiota, there were no significant differences in total and lactic acid bacteria among treatments (P > 0.05). In addition, there were no significant differences of RBC counts, haematocrit, monocyte, lymphocyte, neutrophil, serum glucose and serum total protein levels between the treatment groups (P > 0.05), but group 2 and 4 g kg(-1) synbiotic showed a significant difference (P < 0.05) in WBC counts and haemoglobin, respectively. Furthermore, alternative complement activity (ACH50) and serum total immunoglobulin (Ig) were significantly increased in 2.0 g kg(-1) synbiotic fed fish (P < 0.05); however, it did not change the lysozyme activity, significantly (P > 0.05). These results indicate that synbiotic improves immunity of beluga sturgeon without detrimentally impacting the growth performance, modulates intestinal microbiota and basic haematological parameters assessed. Thus, we suggest that 2.0 g kg(-1) level of synbiotic may be used as an immunity promoter for beluga sturgeon juvenile.